BRITISH HIGH COMMISSION
Status and Prospects of the Offshore Wind Sector in India
Report
Submitted by IT Power Consulting Private Limited and IT Power Limited UK
September 2014
Status and Prospects of the Offshore Wind Sector in India
British High Commission
Report
September 2014
Contractor:
IT Power Consulting Private Limited 410, Ansal Tower 38, Nehru Place New Delhi – 110019, INDIA Tel: +91 (11) 4600-1191/ 92 Fax: +91 (11)4600-1193 Email id: [email protected] / [email protected] Web: http://www.itpower.co.in/
Document control File path & name itp_data/RE Group/Projects/2013/BHC Authors Mark Leybourne, Joe Hussey, Prodyut Mukherjee, Harshvardhan Bhatnagar, Suneel Deambi, Gourav Panwar/ Abhinav Saxena Project Manager Akanksha Chaurey, Ph. D Approved Akanksha Chaurey, Ph. D Date September 2014 Distribution level For Client
Template: ITP REPORT Form 005 Issue: 07; Date: 12/03/2012
September 2014 ii Status and Prospects of the Offshore Wind Sector in India
EXECUTIVE SUMMARY
India has made steady progress in the development of onshore wind power projects over the past few decades and now has the 5th largest industry in the world. Onshore wind capacity now represents over 70% of the overall installed renewable electricity capacity and as of January 2014, this totalled 20,298.83 MW. Despite the success of this industry and a coastline of over 7,600km, India does not yet have any offshore wind capacity. The Government of India’s offshore wind policy was drafted in 2013 and represents a significant step in the progress towards the first offshore wind projects and positive interest in the emerging sector is increasing rapidly. Nevertheless, the creation of an industry faces many barriers and its success will be reliant upon far more than a supportive governmental policy.
The UK has the largest offshore wind industry in the world with over 3.7 GW of capacity currently operational and at least 40GW in planning. This sector has grown at a rate of over 50% per annum since the first project in 2000 and is continuing to install capacity at a faster rate than any other country. During its progress, a multitude of different lessons have been learned from the suitability of various incentives and support mechanisms to the specialised installation methods that now pose far less technical risk to projects than in the initial, early projects. This amassed knowledge can significantly benefit developing industries such as India’s and allow them to progress faster and avoid the mistakes made in other industries than if they were left to progress without support.
This report intends to contribute to the sharing of knowledge between the UK and India as well as providing a resource for interested parties to understand the current conditions in India. It provides an overview of how offshore wind projects are typically developed and presents an overview of the status of offshore wind in the UK and a summary of some the UK’s experiences over the past decade or so. The document is concluded with a review of the current status of wind energy in India and how the local conditions in key states such as Tamil Nadu and Gujarat may influence the development of projects in those regions.
September 2014 iii Status and Prospects of the Offshore Wind Sector in India
TABLE OF CONTENTS
EXECUTIVE SUMMARY ...... III TABLE OF CONTENTS ...... IV 1 INTRODUCTION ...... 1 1.1 World Energy Status ...... 1 1.2 Growth of Renewable Electricity ...... 1 1.3 Wind Energy in the Energy Mix...... 2 1.4 Emergence of Offshore Wind Power Generation ...... 2 1.4.1 Concise History of Offshore Wind Development ...... 3 1.4.2 Global Offshore Wind Status...... 4 1.5 Background to the Project ...... 6 2 DEVELOPMENT OF OFFSHORE WIND PROJECTS ...... 7 2.1 Introduction ...... 7 2.2 Feasibility and Planning ...... 8 2.2.1 Site Selection ...... 8 2.2.2 Metocean ...... 8 2.2.3 Wind Resource Assessment ...... 9 2.2.4 Array Layout and Turbine Siting ...... 11 2.2.5 Geophysical and Geotechnical ...... 13 2.2.6 Environment Impact Assessment ...... 14 2.3 Design and Procurement ...... 16 2.3.1 FEED and Detailed Design ...... 16 2.3.2 Project Procurement and Schedule ...... 18 2.3.3 Project Finance and Risk ...... 18 2.4 Installation and Commissioning ...... 21 2.4.1 Wind Turbines ...... 21 2.4.2 Offshore Wind Foundations ...... 25 2.4.3 Subsea Cables ...... 26 2.4.4 Onshore Substation ...... 28 2.4.5 Offshore Substation ...... 30 2.4.6 Vessels ...... 31 2.5 Operation and Maintenance ...... 32 2.5.1 Scheduled Maintenance ...... 32 2.5.2 Unscheduled Maintenance ...... 33 2.5.3 Vessel to Turbine Transfers ...... 34 2.5.4 Decommissioning ...... 34 2.6 Typical Costs ...... 35 2.6.1 Capital Expenditure (CAPEX) ...... 36 2.6.2 Operational Expenditure (OPEX) ...... 37 2.6.3 Levelised Cost of Energy (LCOE) ...... 37 3 STATUS AND PROSPECTS FOR OFFSHORE WIND PROJECTS IN INDIA ...... 38 3.1 India’s Renewable Energy Scenario and Role of Wind Energy ...... 38 3.1.1 Wind Energy Programme in India ...... 39
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3.1.2 National Wind Energy Mission ...... 39 3.2 Current Status of Onshore Wind ...... 40 3.3 Wind Technology Status ...... 40 3.4 Onshore and Offshore Wind Resource ...... 41 3.5 Key Government Agencies and State Nodal Agencies for Wind Energy ...... 44 3.5.1 Centre for Wind Energy Technology ...... 44 3.5.2 Indian National Centre for Ocean Information Services (INCOIS) ...... 44 3.5.3 The National Institute of Oceanography (NIO) ...... 44 3.5.4 The Indian Naval Hydrographic Department ...... 44 3.5.5 Tamil Nadu Energy Development Agency ...... 45 3.5.6 Gujarat Energy Development Agency ...... 45 3.6 Consenting and Environmental Impact Assessment (EIA) ...... 45 3.7 Incentives for Wind Power Projects ...... 47 3.7.1 Financial Incentives ...... 47 3.7.2 Fiscal Incentives ...... 47 3.7.3 Regional Incentives ...... 48 3.8 Regulations ...... 48 3.8.1 Renewable Purchase Obligation ...... 48 3.8.2 Wheeling & Banking Charges ...... 48 3.8.3 Forecasting Requirements for Wind Projects ...... 49 3.9 Reasons for Offshore Wind in India ...... 49 3.10 Offshore Wind Project Feasibility ...... 51 3.10.1 Introduction ...... 51 3.10.2 Gujarat ...... 51 3.10.3 Tamil Nadu ...... 61 3.11 Indian Supply Chain Potential ...... 74 4 CONCLUSIONS ...... 76
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1 INTRODUCTION
1.1 World Energy Status
Coal, natural gas and oil accounted for around 87% of the global primary energy consumption in 2012. Coal increased its share to 29.9% in comparison to a share of 23.9% for natural gas. Oil’s share fell marginally from 33.4% in 2011 to 33.1% in 20121. These hydrocarbon fuel resources are rapidly depleting and alternative energy sources are gradually replacing them. Renewables energy resources such as solar and wind represent the fastest growing of these alternative energy resources and are expected to contribute up to 25% of the world’s energy mix by 2018.
Figure 1, The growth of the world's annual electricity generation over the past two decades has been contributed to by a growing generation of electricity from renewable energy sources. [Source: International Energy Statistics, US DoE]
1.2 Growth of Renewable Electricity
Renewable energies have rapidly become a pivotal part of the global energy mix. These account for an ever increasing share of electric capacity added worldwide. Total renewable power capacity exceeded 1,470 GW in 2012, up 8.5% from 2011. Figure 1 shows the share of new renewable energy capacity added in 2012 and it can be seen that more new wind energy capacity was added than any of the other renewable energy resources2. Furthermore, nearly 35,572 MW of wind power capacity was commissioned around the globe in 20133.
Around 70% of new global power capacity that the World will add between 2012 to 2030 will be renewable including large hydro. Figure 2A shows how this new renewable capacity was comprised in 2012, with wind energy providing, by far, the greatest contribution of new capacity. Collectively, coal, oil and gas will account for just 25% of total energy supply with the remaining being nuclear.
1 www.worldwatch.org/fossil-fuels 2 UNEP Review,”Renewable Energy: World Invests $244 bn in 2012, Geographic shift to Developing Countries, June 2013 3 www,clickgreen.org.uk/analysis/business
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Figure 2, [A] Breakdown of new renewable energy capacity added globally in 2012. [B] The total wind energy capacity by country in 2013. [Source: REN21, Global Status Report 2013]
1.3 Wind Energy in the Energy Mix
The global aggregated wind power capacity stood at a total of 318 GW at the end of 20134 and this figure had grown by around 12.5% from the previous year. Figure 2B shows that China currently has the most installed wind energy capacity with around 91.4 GW installed.
Figure 3, The growth of annual wind based electricity for the world and India for comparison. [Source: International Energy Statistics, US DoE]
1.4 Emergence of Offshore Wind Power Generation
One of the key attractions of offshore wind is the availability of a vast wind energy resource at sea that provides stronger, more consistent wind speeds and less turbulence than onshore winds. Offshore wind turbines can be much larger than their onshore equivalents as there is less of a visual intrusion impact and the transportation of large infrastructure is easier offshore. Larger rotors result in higher blade tip speeds, however, this is also less of an issue as there are no noise restrictions for offshore sites. Furthermore, as there are often fewer constraints on space, offshore projects can be of much larger total capacity, meaning that economies of scale can be achieved through a far greater procurement scope and other project development efficiencies.
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Onshore locations with favourable wind resources are highly sought after and can often either be in remote locations or picturesque settings where it would not be possible to achieve planning consent. As a result, the number of suitable onshore wind sites in a country may deplete quickly, as is the case with the UK, and so offshore wind is becomes an attractive alternative.
Offshore wind is not without its disadvantages; constructing infrastructure such as wind turbines, foundations and substations in the sea is a risky and costly undertaking; turbines need to be adequately protected from the harsh environmental conditions; foundations have to be installed within the available seabed and potentially in deep water and still need to withstand the applied environmental loads; and even once operational, a wind farm has to be maintained from boats at a distance from the closest port.
Given the right combination of market drivers and sufficient, political support, offshore wind is beginning to make a significant contribution to the world’s renewable electricity generation portfolio. Its expense and technical risk are key barriers to large scale deployment, however, as costs begin to reduce and technology continues to improve, the prospects for the sector are bright.
1.4.1 Concise History of Offshore Wind Development
The world’s first offshore wind project was installed at Vindelby, Denmark in 1991 and comprises eleven 450 kW wind turbines that are essentially, regular onshore wind turbines with minor modifications to make them more suited for installation in the sea. The turbines are mounted on gravity base foundations, constructed from concrete and installed in shallow water, 2.5 km off the Danish coast as can be seen in Figure 4. The total cost of the project was approximately €10.25m, therefore giving a installed CAPEX of €2.1m/MW. This project proved the concept and demonstrated that wind turbines could be installed and operated in the sea.
Figure 4, The world's first offshore wind farm [Source: Vindmølleindustrien]
A number of other Danish and Dutch projects followed after the installation of Vindelby, with the growth of the sector being irregular and consisting of small, near-shore projects featuring wind turbines with electrical ratings of less than 1 MW.
Despite conceptualising its first projects in the early 1990s, the UK did not install its first offshore wind project until nearly a decade after Vindelby. This was a small, two turbine demonstration project at Blyth in the north east of England.
Even though the Danish industry had such a large head start over the UK, its progress was comparatively slow due to the support mechanisms that were available in the country at the time. The UK meanwhile offered attractive financial support and also some capital grants to early projects to ensure the early
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growth of the sector. The UK’s support for offshore wind, government policies, favourable wind resource, shallow waters and extensive history in offshore oil and gas activities have been key factors in the success of the industry in the UK and, as a result of these conditions, the UK now has the world’s leading industry.
At the time of writing, the UK has installed a total of 1,115 turbines within 22 different projects and has a total installed capacity of around 3.7GW. The UK continues to offer the most attractive conditions for project developers and investment in offshore wind power.
1.4.2 Global Offshore Wind Status
Despite its increased costs and risks, offshore wind projects have been developed in a number of countries and the installed capacity is increasing at an accelerating rate.
Europe currently has more than 90% of the world’s offshore wind capacity. By the end of 2013, Europe has 69 offshore wind farms3 in eleven countries including; the UK (56%), Denmark (19%), Belgium (9%), Germany (8%), Netherlands (4%), Sweden (3%) and a combination of capacity from Finland, Ireland, Spain and Norway contributing an additional 0.9%. Together, the projects in these countries represent a cumulative, European installed capacity of 6,562 MW. Furthermore, there were 12 additional projects under construction at the time of writing which would contribute an additional 3GW of capacity in Europe. By the end of 2013, there was a total global offshore wind capacity4 of 7,046MW, with 1,567MW of this being new European capacity that came online during 2013. Figure 5 shows the distribution of this capacity by country and highlights the clear lead the UK has over all of the other countries with offshore wind sectors.
Of the 7GW of offshore wind currently generating globally, only 461MW is based outside of Europe4 and the vast majority, 428.6 MW, of this is in China. Nevertheless, there is great and growing interest in many other countries such as the United States, Japan, Korea, Taiwan and, most recently, India.
Figure 5, The distribution of offshore wind generating capacity around the world during 2012 and 2013. [Source: GWEC4]
3 European Offshore Wind Statistics 2013. European Wind Energy Association. 4 Global Wind Report Annual Market Update, GWEC 2013
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In the first six months of 2014, Europe connected a total of 224 offshore wind turbines to the grid, providing a combined, new capacity of 781 MW. These include 16 commercial wind farms and one demonstration site across three countries Belgium(1), Germany(10) and UK(5). The recent trend demonstrates that the UK farms are now going for larger capacity. The total connected capacity in first half of 2014 for UK is 532 MW in 5 farms.
There are 310 wind turbines awaiting to be connected and, once connected, these will add over 1,200 MW to the existing capacity. The total capacity of all the wind farms under construction is over 4,900 MW when fully commissioned. However, these figures are down by 25% as compared to the same period last year.
Figure 6 Annual installed offshore wind capacity[source EWEA 20145]
Asian countries have also set ambitious target for offshore wind with more than 35 GW of capacity targeted to be installed in Asian offshore waters by 2020. The Taiwanese government has set a target of 600 MW by 2020 and 3GW by 2030 and have number of staged schemes planned for it to fulfil this target. China’s target of 5GW by 2015 was particularly ambitious and, as it requires another 4.5GW of capacity, it is on track to miss this target. The key reasons for this are its lack of coordination between the government agencies and the unavailability of an attractive feed-in-tariff for offshore wind; both of which have stalled the industry. The ministry of environment (MOE) of Japan estimates that the country has a theoretical offshore wind resource of 1,573 GW, of which it aspires to achieve 5-6 GW by 2030, predominantly through floating wind turbines. South Korea’s target of 2.5GW by 2019 is mainly driven by the country’s renewable energy target of 11% of total primary energy supply in 2030. Many big companies from the country have shown interest and entered the offshore market recently6.
5 European Offshore Wind Statistics 2014. European Wind Energy Association. 6 Big-Ambitions-Ahead-for-Asian-Offshore_GWEC_July-2013
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1.5 Background to the Project
India is currently seen as an attractive country for renewable energy related investments and currently ranks 7th in the world for investment prospects7. Within this, India’s onshore wind ranks 8th in the world for investment attractiveness and currently, it offshore wind industry ranks 21st, which is unsurprising given the present state of its industry. There are currently a number of issues that are affecting India’s position, including a backlog of subsidy payments and significantly reduced budget for renewables, however, the recent change in Government, which is perceived to be far more pro-renewables than previous administrations, is expected to change the current situation.
The Government of India plans to roll out a 4,300 million rupees “Green Energy Corridor” project to facilitate the flow of renewable energy into national grid. The Planning Commission of the Government of India estimated in its report of the working group on power during the 12th plan (2012-2017) that the fund required for renewable energy investment is around 13.51 billion rupees to meet the targets of the 12th plan. The 12th five year plan sets a target of 29.8GW of new renewable energy capacity to be installed by 2017, of which 15 GW of new wind energy is anticipated to be installed.
The offshore wind power development in India is in a nascent stage primarily due to state-of-the-art technology requirement and shortage of skilled manpower etc. Additionally the capital cost is very high and necessary supply chain is not established. With due realisation of these key constraints, the Ministry of New and Renewable Energy (MNRE) constituted offshore wind energy steering committee (OWESC) associating stakeholder ministries/departments. The primary objective of OWESC is to formulate a policy framework for offshore wind power development in India. Following which, a sub-committee came into being in March 2012 under the aegis of Chairman, Tamil Nadu Electricity Board to suggest draft policy guidelines for the specified purpose. This committee made available its report in September 2012. The core objectives of the draft policy are to:
Promote deployment of offshore wind farms up to 12 nautical miles from the coast Promote investment in the energy infrastructure Promote spatial planning and management of maritime renewable energy resources in the exclusive economic zone Achieve energy security and to reduce the carbon emissions Encourage indigenisation of the offshore wind energy technology Promote R&D in the offshore wind energy sector Develop skilled manpower and employment in the industry Initiate R&D activities up to 200 nautical miles (Exclusive Economic Zone of the country)
India does not, yet, have any practical demonstration experience of offshore wind power projects, however it has an ambition to exploit its offshore wind resources along its 7,600 km of coastline.
Given the UK’s close relationship with India and that the UK has the world’s leading offshore wind industry, there is an opportunity for the UK to assist India in its development of offshore wind projects. It is with this growing realisation that British High Commission (BHC) came forward to support the very first activity in offshore wind area in India through IT Power Consulting India.
7 RECAI scores and rankings at June 2014 - EY attractiveness index http://www.ey.com/Publication/vwLUAssets/Renewable_Energy_Country_Attractiveness_Index_41_-_June_2014/$FILE/EY- Renewable-Energy-Country-Attractiveness-Index-41-June-2014.pdf
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2 DEVELOPMENT OF OFFSHORE WIND PROJECTS
2.1 Introduction
The development of offshore wind projects can be a long and complex undertaking. Some of the early projects were planned, designed, installed and commissioned within a few years, however, numerous lessons have been learned along the way and as projects have grown in size and complexity, so has the development work required to deliver an operational project.
Typically, the lifecycle of a project can be arranged into four different phases, each having numerous tasks and activities that are associated with them. These phases are:
Feasibility and Planning Design and Procurement Installation and Commissioning Operations and Maintenance
The following chapter attempts to summarise some of the key activities and undertakings in each of the main phases, however, as each project is different, the order in which these task are carried out and the length of work for each will vary between projects and project developers. The chapter concludes with an assessment of the typical costs for European projects.
Although not mandatory, in addition to the device certification, projects may often obtain certification from a certification body such as DNV GL, IEC or LR. The components in the project certification process are summarised in Figure 7 and this provides a point of reference for the aforementioned project activities. Certification helps to provide confidence for contractors, investors and insurers that a project will behave as expected and that the developer has tried to ensure the project has been delivered to an internationally recognised standard.
Figure 7, The processes to be undertaken for project certification according to DNV OSS 901 or IEC 61400- 22.
Although not explicitly stated as an activity in the development process, Health, Safety, Security and Environmental (HSSE) planning, undertaking and management is a crucial component of all phases of development. An HSSE plan will be developed early on in the project’s development and both hazard identification and risk assessment will be required for each phase of the project. These plans and assessments will undergo continuous review to ensure the safe execution and running of the project.
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2.2 Feasibility and Planning
The feasibility and planning development aspects of an offshore wind farm encompass all of the activities that are required to be undertaken before entering the design and procurement phase which precedes the actual construction of the project.
Project development increases in complexity as the activities progress; for example initial work such as site selection and wind resource assessment will begin at a pre-feasibility stage with information being derived mostly from desktop studies; this however, becomes increasingly more detailed as all aspects of the project’s development advance and activities draw on measured, detailed site data.
Ultimately, the project development phase culminates in the completion of the detailed design work for the offshore wind farm and will allow the developer to issue tenders for the fabrication, supply and construction of the project and its components.
Typical key tasks undertaken in the feasibility and planning stages include:
Site selection High level assessment of conditions Project conceptualisation Analysis of project viability Site leasing from seabed owner Grid connection negotiations and agreement Commencing environmental assessments for consent Detailed wind resource assessment – met mast design & installation Site surveys – metocean, geophysical & geotechnical conditions Production of design basis to inform design phase
2.2.1 Site Selection
The first task of a project developer is to select a suitable site for development and carry out a simple pre-feasibility study. This will assess the viability of the site at a high level and determine whether it is worth progressing to undertake a full feasibility study for a project at the site.
In the initial site selection work the developer will consider the data that is already available in order to conduct a desktop study. This will include information on the predicted wind resource, seabed conditions, locations of ports and possible grid connections, analysis of the financial and political environment, identification of any known environmental issues. Much of this typical information is included in this report in section 3.10.
Once a site is selected and deemed to have potential for a project to be developed there, a more detailed feasibility study will be carried out using better quality data before entering initial design work. This will include assessing some potential locations of turbines as described in section 2.2.4,
2.2.2 Metocean
A key initial activity in an offshore wind project is to determine the metocean conditions of the selected site. These are the predicted environmental characteristics which include long term averages and extreme events for the wave climate, wind conditions, temperature and sea ice amongst others. Examples of extreme loading events are shown in Figure 8 and Figure 9.
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Figure 8, Large storm waves impacting the transition piece of an offshore wind turbine, illustrating some of the typical conditions structures will have to withstand.
As with many of the activities in the development of an offshore wind project, the accuracy of the metocean assessment will increase with the progression of the project. Initially, this will be a desktop review of the existing data; this may then progress on to use numerical models but ultimately, some site data will be required to ensure confidence in the metocean data and long term predictions as the detailed design of the infrastructure components will rely heavily on accurate environmental loading.
Figure 9, Tracks of tropical storms from 1945 - 2006 [Source: Citynoise8]
2.2.3 Wind Resource Assessment
Similarly to the analysis of the metocean conditions a Wind Resource Assessment (WRA) should be carried out in a phased approach, low cost methods first and then progressively moving on to more expensive and extensive methods.
8 Data from the Joint Typhoon Warning Center and the U.S. National Oceanographic and Atmospheric Administration
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In the early stages of the project high level information may be enough to produce preliminary wind yield and loading data, later in the development more detailed information would be required to refine those designs
The phases of WRA work include:
Planning of WRA program Desktop assessment Meso-scale studies In-site wind measurements Offshore wind monitoring tower – met mast Modelling from a representative and reliable data source Energy yield analysis Hurricane/Cyclone/Typhoon risk analysis
Desktop studies are the first step in considering the wind resource of the site. This means relying on existing data sources, which might include:
Wind maps Data from existing onshore wind farms / monitoring stations near the coast Data from buoys, lighthouses, met stations Metocean derived data
Meso-scale modelling is a numerical modelling tool and many organisations and companies have developed their own way of doing it. There is no internationally accepted meso-scale modelling technique and it is generally, best used for comparative and feasibility work rather than detailed WRA.
Installing an offshore met mast is the standard, accepted way of monitoring an offshore site’s wind speed, direction, turbulence intensity and, ultimately, the energy resource available. Once installed, these masts can also collect wave and other meteorological data required to inform the design of the wind farm’s components.
The use of LIDAR (LIght Detection And Ranging) is an increasingly attractive option as hub height wind data are required to predict the power production of next-generation large wind turbines and so very large met-masts add a significant cost onto a project before its resource and viability are understood. A key challenge for LIDAR is whether this new information will be accepted by investors as the basis for energy assessments upon which a project’s viability will be judged and its investment attractiveness will be determined. There is currently much work being done in the UK to verify and calibrate these results in order to demonstrate that LIDAR is a suitable measurement technique to replace or supplement a traditional met mast as shown in Figure 10.
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Figure 10, A floating LIDAR buoy (foreground) and standard met mast (background). [Source: Franuhofer IWES]
A good wind resource assessment is key to developing a successful project. Ultimately, any project has to provide enough commercial return to overcome the initial and subsequent outlay and so the financial viability is a critical factor for a project that will determine whether or not it will be developed.
2.2.4 Array Layout and Turbine Siting
Choosing the type of wind turbine generator (WTG) and its exact positioning are two very important parts of the planning work for a wind project. This process has many technical aspects that have to be taken into consideration such as:
Wind conditions (mean speeds, cut in speed, wind rose directions, extreme wind speeds, shear, turbulence intensity) Possible limitations on rotor size from visual impact restrictions in the consent conditions, local maritime regulations on minimum clearance between blade tip and max high water Seabed conditions – areas of shallow water, hard bed rock, unstable ground, possible pockets of sub-bottom gas. Environmental constraints – sea bird feeding areas, fish spawning grounds, presence of protected species, environmentally sensitive zones. Human constraints – shipping lanes, fishing grounds, aviation radar zones. Wake recovery distance will determine downstream turbine locations – typically 7 – 10 rotor diameters. Array cable length optimisation – larger distances between turbines will lead to more cable being required and higher costs.
These features and the choice of turbine model and its characteristics will all be factored into determining the financial viability of the project. A number of these factors are illustrated in the example in Figure 11 which shows some considerations for the positioning of turbines in the Kentish Flats extension project. Some optimisation of the array layout can be carried out depending on the weighting of importance given to each of the considerations. Figure 12 shows some of the array layouts that have been used in Danish offshore wind projects; predominantly, European projects have had fairly regular arrangements.
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Figure 11, Factors taken into consideration for the turbine positioning in the Kentish Flats extension project [Source: Vattenfall]
Figure 12, Typical turbine array layouts for four projects to show the variety of arrangements that have been used in European projects.
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2.2.5 Geophysical and Geotechnical
Geotechnical and geophysical investigations are required to determine the nature of the seabed and the substrata into which foundations and cables will be placed.
The bathymetry, or seabed topography, describes the depths and shape of the underwater terrain. In the same way that topographic maps represent the three-dimensional features (or relief) of overland terrain, bathymetric maps illustrate the seabed that lies underwater. As with the other data assessment tasks, this process will commence with assessing known data from sources such as nautical charts. Various sonar imagine techniques will eventually be used during the site investigation works and will be able to provide an detailed view of the seabed in order to assess the water depths, seabed roughness and slope angles.
Site assessments from moving ship surveys will also be used to reveal information about the sub-bottom data from seismic investigations. This will show the position of the bedrock, amount of sediment cover and geological strata within the site.
Onsite geotechnical investigations typically require boreholes to be drilled at 20-30% of the foundation locations with Cone Penetration Tests (CPTs) undertaken at the other locations. This information allows a geotechnical model to be developed, thereby reducing the risk that the geology and seabed conditions encountered when designing and installing the foundations is as expected. In extreme cases where the geological conditions are particularly varied and complex, more borehole samples will be taken. An extreme example, Sheringham Shoal, is provided in Figure 13, which shows the processed results of the site boreholes that were drilled at every turbine and offshore substation location. This information is critical to the detailed foundation design and also operations of jack-up vessels and any drilling equipment used.
Figure 13, The results of the 89 boreholes at the Sheringham Shoal offshore wind farm site, showing the geological variation across the site. [Source: Scira Ltd.]
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2.2.6 Environment Impact Assessment
The consenting process undertaken in the feasibility and planning phase of development work comprises a large element of Environmental Impact Assessment (EIA) which is a method for systematically examining and assessing the impacts and effects of a development on the environment. This is carried out prior to commencing a project and typically includes the following stages:
Screening determination of whether a development proposal needs an EIA; Scoping determination of the issues to be addressed by the EIA; Consultation and public participation; Original data collection and surveys where necessary to fill data gaps; Impact identification and evaluation; Identification of mitigation and residual impacts; Identification of monitoring requirements; Submission of the Environmental Statement to the relevant authorities as part of the consents process; Liaison and consultation to resolve matters or representations/objections; and Decision on whether the development proposal should proceed.
The resultant Environmental Statement (ES) reports on the EIA and typically contains:
Description of the development proposal, including any alternatives considered; Description of the existing environment at the site; Prediction of potential impacts on the existing human, physical and natural environment at the site and assessment of subsequent effects for each of the following receptors; o Hydrodynamics and Geomorphology o Marine and Coastal Water Quality o Ornithology o Marine Ecology o Natural Fisheries o Marine Mammals o Commercial Fisheries o Landscape, Seascape and Visual Resources and Character o Shipping and Navigation o Marine Archaeology o Military And Aviation o Other Human Activities o Socio-Economic Assessment o Nature Conservation Designations o Geology, Water Resources And Land Quality o Terrestrial Ecology o Landscape and Visual Character o Archaeology and Cultural Heritage o Tourism and Recreation o Traffic and Access o Noise, Dust and Air Quality
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Description of mitigation measures to avoid or reduce such effects; Description of monitoring requirements; and Non-Technical Summary.
The EIA is the responsibility of the developer and is based upon evidence gathered in the surveys of the environment, engagement with key stakeholders and lessons learnt from other projects. The assessment is reviewed by the consenting organisation, usually a government department, and a number of conditions are given to the developer in order to satisfy the consent given.
These conditions require the developer to undertake mitigating measures to reduce or remove detrimental environmental impacts and also to carry out surveys during construction and the first few years of operation to ensure that impacts are not occurring. Monitoring often comprises a Before and After Control Impact (BACI) study which, as the name suggests, uses surveys to look at the environment before and after the activity as well as a control location outside of the influence of the activity. In the UK, the Marine Management Organisation is responsible for ensuring developers meet their consent conditions and may inspect the site during construction to check the activities are not causing adverse effects.
Key issues during construction include; the disturbance of fish during spawning periods; damage and avoidance of mammals due to piling activities; behavioural change of birds and mammals as a result of increased vessel activities; and the loss or change of habitat along the onshore cable route and substation. During construction and within 3 months of the completion of construction, developers are usually expected to carry out:
Surveys for construction debris Scour surveys Suspended Solids monitoring Ornithological monitoring Benthic ecology monitoring Intertidal ecology survey Oyster surveys Fish surveys Operational underwater noise measurements Monitoring colonisation of the underwater structures Electromagnetic emission effects from subsea cables
Figure 14, An example of scour effects at Scroby Sands (red line showing monopile location) [left] and the colonisation of a monopile by shellfish [right]. Source: CEFAS.
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2.3 Design and Procurement
The information generated in the feasibility and planning work will input directly into the design activities undertaken in this subsequent phase of development. There will inevitably be some overlap between these phases as planning is an inherent component of all activities in the development of an offshore wind project and tasks such as surveys will continue during the period in which the design and procurement are carried out. The initial design and the assessment of the design and concept options is often captured under the term, Front End Engineering Design (FEED) which provides the engineering design basis and estimated costs on which a Final Investment Decision (FID) will be made by the developer and its investors. Once the FID gives a project the confirmation to continue, the detailed design will begin. It should be noted that the FID will come after a project has gained consent and in some cases, particularly for large, complex projects, the period between the two may even be up to a couple of years. The detailed design will result in the start of procurement for the infrastructure and installation services.
The typical key tasks undertaken in the design and procurement stages include:
Generation of design and infrastructure options Layout and siting of turbines Electrical requirements and system design Design of installation strategy Planning of construction activities Assessment of vessel and port requirements Obtain planning and environmental consent and licences Obtain final investment decision Continue all design work into detailed design phase Development of commissioning and O&M strategies Technical and commercial risk assessment Device and project certification Tendering for infrastructure, components and services Contractor selection and contract negotiation
2.3.1 FEED and Detailed Design
Front End Engineering & Design (FEED) studies are used to take a project from feasibility and planning to the point where the project can move to the detailed engineering design, procurement and installation stages. As a result, the end of the FEED study is typically when a developer, and its investors, will make a final investment decision (FID) whether or not to undertake the project.
The FEED work has two basic elements; a technical aspect and a commercial aspect:
The technical element is intended to produce the best technical concept definition, a design basis, project standards, management systems, functional design criteria and equipment specifications. This will include an assessment of a variety of different design concepts and methodologies, early optimisation of the basic design and project structure.
Typical technical studies typically include:
Basis of Design: The basis of the design is a live document that captures the current status of the design so that all parties involved in the initial design and detailed design stages are working from the same information.
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Foundation design: To develop a detailed foundation design based on the loadings and the geotechnical conditions, present the design for certification and define how it will be protected over its life. Installation design: To develop a methodology defining how the wind turbine, cables and transformer station will be installed. Electrical design and Grid connection: To define the main configuration of the electrical design including the key questions of locations of transformers, export cables and grid interfaces and the voltages and capacities required. Energy assessment: To provide a final estimate of the energy that will be produced and its statistical variation. Reliability and availability analysis: To provide an indication on how reliable the equipment will be over its life, what is required to maintain it and as a result what availability is likely to be achieved by the wind farm. Interface analysis: To understand all of the interfaces, both technical and commercial. Risk analysis: To demonstrate that a systematic approach to risk identification, reduction, control and mitigation has taken place and that the residual risks are understood.
Also undertaken during this phase of work are a number of commercial elements including:
Financing and insurance: To obtain the financing and insurances required. Costing will be undertaken for the various components and activities identified in the technical elements and will have a target that the estimate is within 10% of the final project cost. Supply chain engagement: Developers will begin to identify potential suppliers and engage with them at a relatively early stage in order to evaluate the capability of the supply chain but, most importantly, to help identify any other specific issues or risks that had not been previously recognised. Tendering: To begin writing the procurement specifications for the major equipment and negotiate performance, warranties, delivery and prices.
Generally, many components of the FEED work are used to support a consent application to the country’s consenting body. As previously mentioned, it is typical that, once a project obtains consent and an FID is made, the design work carried out in the FEED will move into a detailed design phase. During this process, similar aspects of the design will be worked on but at a much finer detail and will use the detailed, site measured data in conjunction with the design standards that are published by a certification body. One of the key undertakings in this phases is the detailed design of the foundations as each foundation for the turbine locations in the project will be different.
Figure 15, Construction of the Burbo Bank offshore wind farm using a jack-up vessel to install the blades.
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2.3.2 Project Procurement and Schedule
Ultimately, a project’s procurement process needs to deliver products and services of appropriate quality and in a timely manner. Contracting the most suitable companies to deliver these products and services will minimise risk of poor quality and late delivery. Furthermore, the way in which these companies are contracted and the strategy taken will determine the spread of risk between the developer and contractors. Estimates9 have shown that savings of between 5-8% per £1 billion in capital spend, can be achieved through careful selection of procurement strategy, thus highlighting the importance of this process.
The outputs of the FEED work, are used to produce robust tender specifications that will help to minimise costs and reduce risk. As with all infrastructure projects, a competitive tendering process is required to award contracts and should ensure full transparency, non-discrimination and equal treatment of tenderers. It is also very important to ensure that the selected contractors are able to meet their guarantee and warranty liabilities in order to financially de-risk their involvement.
Appropriately scheduling this procurement process is important to prevent delays to the project or equipment being ready too early and having to be stored until it can be used. The country’s supply chain is an important factor to consider; and whilst it may be desired to utilise the local supply chain as much as possible, it may be more appropriate to source certain items from other countries, at least initially. India, for example, has a huge onshore wind industry and a considerable offshore oil and gas sector that will play a significant part in supplying services and equipment to projects. Suppliers and contractors from other countries, however, will also have to be considered in order to import offshore wind specific expertise and experience that the local supply chain lacks.
European offshore wind projects have utilised a mixture of contracting strategies that range from single, large Turnkey/Engineering, Procurement and Construction (EPC) contracts to a purely multi-contractual approach across the spectrum of the supply chain. Each of these approaches, and the variations in between, have their various merits and disadvantages including the distribution of the risk profile.
The types of contract that are used in the procurement for offshore wind projects have typically been internationally recognised contracts that have been used as standard for oil and gas projects, such as FIDIC10 (Fédération Internationale Des Ingénieurs – Conseils) and LOGIC11 (Leading Oil and Gas Competitiveness), but have been slightly adapted for offshore wind. It can be argued that these contracts, whilst well suited to oil and gas, are not appropriate for the far less developed offshore wind industry.
The contracting and procurement strategy also has a direct consequence on the securing of finance for the project as different investors have different risk appetites and will have their preference for how risk is spread and mitigated within the project.
2.3.3 Project Finance and Risk
There have been two main approaches to financing offshore wind projects in Europe:
9 http://www.accenture.com/SiteCollectionDocuments/PDF/Accenture-Changing-Scale-Offshore-Wind.pdf 10 http://www.charlesrussell.co.uk/userfiles/file/pdf/Bahrain/FIDIC.pdf 11 http://www.logic-oil.com/sites/default/files/documents/Services%20Onshore%20and%20Offshore %20Edition%202.pdf
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Balance-sheet funding – The majority of projects delivered so far have relied heavily on capital finance provided by the balance sheets of the large developers with an estimated12 77% of the €16 billion invested in Europe’s 5GW being sourced in this way. As much of the available finance from the developers is currently tied up in current projects, many developers are beginning to recycle their capital through the post-construction sale of project shares to more traditional, risk averse investors. There is, however, only a finite amount of balance sheet equity available for projects and this can only be recycled at a certain rate, meaning that, if Europe wishes to continue building at its current rate, projects will need to source a greater proportion of their funds from external sources.
Project financing – A more traditional form of external funding is beginning to play an important part in the current and future European offshore wind projects. A study13 has estimated that in 2011 and 2012, over 30% of all offshore wind project investment in Europe was project-financed, with the majority of this being with construction risk. Risk has been one of the major barriers to acquiring forms of project and debt financing from traditional sources such as banks, bonds and pension funds. The reduction of this risk is therefore, key to improving the attractiveness of these projects to external funders.
The EWEA3 reported that, in 2013, non-recourse debt finance supplied to European offshore wind projects reached €2.13 billion, which was an increase on the €1.93 bn reached in 2012 and comparative to the €2.33 bn in 2011. As part of this, there were two key offshore wind projects that reached financial close during 2013: the German, Butendiek project, and the refinancing of Masdar’s stake in the UK’s London Array.
Project Risk
Project risk has a major bearing on any procurement strategy. In every project, there is a balance between the risks carried by the client and costs; any risk that can be transferred will come at a cost. To minimise project risk and obtain the most economic overall price, risks should be allocated to and managed by the party best placed to control them.
Generally, in construction contracts, the client ends up meeting costs from unforeseen conditions because, by their very nature, they cannot be described in the contract at drafting stage. How the unforeseen conditions are established, controlled, and paid for depends on the type of contract. Any contract that attempts to place the risk of all unforeseen conditions on a contractor is likely to be unnecessarily expensive, as a larger than necessary risk contingency will be included by the bidders in their prices. If the client accepts a reasonable level of risk, they will pay only if the unforeseen condition is realised.
Key risks experienced in an offshore wind project are shown in Figure 16 and Figure 17.
12 Green Giraffe – Energy Bankers (2013). Market trends defy negative sentiment on PF for offshore wind 13 European Wind Energy Association (2013). Financing Offshore Wind Farms
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Figure 16, The top five most concerning risks to equity, debt and service providers in an offshore wind project. [Source: European Wind Energy Association]
Figure 17, Summary of the risk appetite of financiers. [Source: European Wind Energy Association.]
Allocating and management of construction risks are crucial for offshore projects and there are numerous risks to be managed. Typical construction risks include physical damage, consequential loss, third party liability, terrorism, and force majeure events. Project insurance will play a mitigating role for damage to property, with respect to a multitude of risks; however insurance will not cover any knock-on effects from an incident. For example just recently a charter vessel barge, which was being towed by a tug boat, capsized 50 miles southwest of Sardinia, while en route from the cable plant in Naples to Bremerhaven. This has resulted in the likely loss of €28m of cable destined for the 288MW Butendiek and 210MW Deutsche Bucht wind farms. No one was injured and all crew are safe and insurance is in place to cover the loss, although it is unclear how long it will take to produce replacement cables. In this example there are numerous knock-on implications that will affect the projects in question. Activities will be delayed as a result of the cable not being available and installation contractors will have to be rescheduled to lay the cable once it does arrive at the site. This type of risk is, clearly, beyond the control of the project developer, however, it does provide a good example of why a developer should over plan for all eventualities in order to ensure that the unaffected aspects of a project can continue with minor modifications to compensate for the delayed component.
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2.4 Installation and Commissioning
The successful design and procurement of the components and services for an offshore wind project will enable the installation and commissioning work to commence. Most projects, will begin with the installation of the onshore substation and cabling as this can be undertaken in isolation to the offshore works and is not weather dependent. Typically, the first offshore construction work to occur is the installation of the wind turbine foundations. This is followed by the start of the subsea cable laying work, transition piece installation and turbine erection. Usually, the majority of the inter-array, subsea cables will be laid by the time the first turbine is erected. Once a turbine is erected, divers or ROVs can locate the relevant end of the inter-array, subsea cable and attach a cable to it so that it can be winched up into the turbine’s transition piece, usually through a ‘J-tube’. This is the first key milestone in a turbine’s commissioning process and is followed by a number of other activities to test the condition of the turbine and its ability to interface and communicate with the project’s electrical management and control systems. The offshore substation, or substations, is brought to site and installed relatively early on in the offshore construction process. The completion of the electrical installation works (cables and substations) will allow turbines that have been commissioned to start generating power and making revenue. This usually occurs well before all of the turbines have finished being installed.
Typical key tasks undertaken in the installation and commissioning stages include:
Onshore substation construction and onshore cable laying Foundation installation Export and inter array cable laying Transition piece installation and grouting Installation of offshore substations Installation of towers, turbines and blades Connection of subsea cables to turbines and substation Commissioning of individual turbines and offshore substations Management of vessel operations and logistics Port management of delivery, laydown and assembly works Health and safety planning and management
2.4.1 Wind Turbines
The turbines are the most important part of a wind energy project and represent the largest single cost component of a wind farm. Over the years with the advancement of the technology, the capacity of offshore wind turbines has increased means that more output can be generated from a single unit; thus resulting in higher returns and economic viability. Turbines comprise the following main elements: - Rotor; three-blade cantilevered and mounted upwind of the tower with a total mass of around 100 tonnes. The power output is controlled by pitch regulation and the rotor speed is variable between approximately 5-13 rpm. - Blades; made of fibreglass-reinforced epoxy resin and manufactured in a single operation to eliminate weaker areas at glue joints. Each of the three rotor blades are typically 50 - 60 m long although blades for the newest generation turbines can be +80m. - Gearbox; typically, this is a 3-stage, planetary, helical design, mounted in the nacelle and fitted with a fail-safe mechanical brake on the high-speed shaft.
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- Generator; the gearbox output shaft is connected to the generator which has a permanent magnet rotor and stator windings that are specially designed for high efficiency at partial loads. - Tower; the steel turbine towers typically have a structural height of 90-100m in order to provide a minimum clearance of around 20m between the lowest point of the blade tip and mean high water springs. The tower has an internal lift and direct access to the yaw system and nacelle for wind turbine technicians. - Turbine electronics; a microprocessor-based industrial controller with switchgear and protection. Turbines also contain a transformer to step up the generated voltage from 690V to 33kV.
Wind turbines can operate automatically and are self-starting when the wind speed reaches an average of about 3 to 5 m/s, see Table 1. The output increases approximately linearly with the wind speed until the wind speed reaches 12 to 13 m/s. At this point, the power is regulated at rated power. If the average wind speed exceeds the maximum operational limit of 25 m/s, the wind turbine is shut down by feathering the blades. When the average wind speed drops back below the restart, average wind speed, the systems reset automatically.
Figure 18, The nacelle of a Siemens 3.6 MW turbine (left) and a view of a turbine at the Sheringham Shoal farm, as seen from a service vessel.
At present, there are around 10 main models of offshore wind turbines being produced, although there are many others commercially available. Siemens and Vestas have dominated the turbine market in Europe, having around 60% and 27% shares respectively. Each model of turbine, however, has vastly different track records and operational experience. Initially, the first generation of offshore wind turbines were essentially ‘marinised’ onshore wind turbines, not specifically designed to perform in the harsh environment offshore. As a result, these early turbines suffered from many issues, fortunately whilst under warranty from the turbine supplier. Even now, projects continue to be affected by faulty turbines, for example a 300MW project in the UK had around 15 of its wind turbine gearboxes replaced last year alone. Clearly this has significant implications for the project due to the downtime that results and logistics of the replacement activities. Vestas famously had to withdraw one of its turbine models from commercial availability in 2009 as a result of gearbox issues. Furthermore, both BARD and WinWinD have supplied turbines to European project but no longer offer turbines commercially due to technical and financial issues. The main wind turbine models currently available are summarised in Table 1 and some examples are given in Figure 19.
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Table 1, Currently available offshore wind turbine models
Supplier Model Capacity Rotor Diameter Cut-in / Cut-out / Rated Wind Speed (MW) (m) (m/s) Vestas V90-3.0MW 3 90 4 25 15
SWT-2.3-82 2.3 82 3.5 25 13
Siemens SWT-3.6-107 3.6 107 3 - 5 25 13 – 14
SWT-4.0-130 4 130 5 25 11 - 12
GE 4.0 4 110 3 25 – 28 14
Sinovel SL3000 3 91.3 3.5 25 13
Senvion 5M 5 126 3 30 13
Areva M5000-116 5 116 4 25 12.5
Gamesa G128-5.0 5 128 3 30 10
Nordex N90/2500 2.5 90 3 25 13
Figure 19, [L-R] Siemens 3.6, Vestas V90, Senvion (REpower) 5.0, Areva 5.0.
The next generation of turbines being developed and deployed are far better suited for offshore operation as they have been specifically designed for this environment. This new generation of turbine is predominantly aimed at having larger capacity (+6MW) to help reduce the cost of energy, whilst some technology developers are trialling innovations such as direct drive (Alstom Halide) and hydraulic drive (Mitsubishi Sea Angel) turbines. Typically the hub heights and rotor sizes of the new generation devices are much greater in order to capture more energy. This has implications on the design of foundations and support structures, however, these turbines are a key element of the reduction of the cost of energy for offshore wind projects. Table 2, A selection of offshore wind turbines currently under development
Capacity Supplier Model Rotor Diameter (m) (MW) Alstom Halide 6 150
Areva Areva 8MW 8 180
Enercon E-126/7.5 MW 7.5 127
Gamesa G128 5 128
Goldwind GW 6.0 6 150
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Ming Yang SCD 6.5 140
Mitsubishi Sea Angel 7 165
Samsung S7.0-171 7 171
Senvion 6.2M152 6.2 126
Siemens SWT6-154 6 154
Vestas V164-8 8 164
There is much debate about how many turbine types can be supported by the market, with some commentators saying this might be as few as three. There is considerable consolidation taking place; Gamesa merging with Areva; Mitsubishi with Vestas and before the GE takeover, Alstom were considering merging with Areva.
Many of these turbine suppliers are becoming, or have become, vertically integrated, meaning that they supply all components associated with the turbine including; the Nacelle, rotor blades, drive train (including gearbox), generator, controller, tower and grid connection infrastructure. Typically, turbine suppliers do not design or supply transition pieces or foundations, however, Ming Yang is soon to be the first supplier to do so.
Turbines are typically installed on a transition piece, which acts as an intermediate connection between the foundation and the base of the turbine’s tower. The transition piece is intended to ensure the verticality of the turbine tower, provide boat/personnel access facilities and accept the entry of the subsea, inter- array cable. Transition pieces are attached to the foundation using grout, a material similar to concrete, in order to provide a secure connection and to provide a perfectly horizontal base on which to site the turbine’s tower. Between 20 and 100 tonnes of grouting concrete are typically required for each turbine. Turbines are installed on top of the transition piece in much the same way as onshore turbines are. The typical, step-by-step installation process, including the installation of monopile, is shown in Figure 20.
Figure 20, A typical construction approach (left to right) for a monopile foundation and wind turbine, using jack up vessels.
The turbine commissioning process commences straight after the erection of the first turbine. This process involves the connection of the subsea array cable within the turbine, energising of the cable and turbine, testing of subsystems, SCADA interfaces and turbine functionality and concludes with a trial operation of the turbine to ensure its correct operation.
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2.4.2 Offshore Wind Foundations
There are a few types of commonly used offshore wind turbine foundation options such as those shown in Figure 21,, however, with the exception of sites in the Baltic Sea which are generally in shallow water, a monopile has become the standard foundation type used. By 2013, 75% of the foundations3 for the 2,080 turbines installed in European waters were monopiles, whilst 12% were gravity based structures, 5% were jackets, 5% were tripods and the remaining 2% were tri-piles.
A single, or number of foundation types, can be considered during the feasibility and planning work phases. These options will then be considered in more detail in the FEED work and assessments will be made based on the environmental and site specific conditions. Water depth and soil properties/strata of the seabed are the key driving factors when determine the choice of foundation. Currently, there is no universal foundation type suitable for all the kinds of seabed conditions.
Figure 21: Offshore wind turbine foundation options for various water depths
Monopiles: A monopile foundation consists of a large diameter steel tube which either driven or driven and drilled to an adequate depth into the sea bed. The depth of penetration, pile diameter, wall thickness and cross-section profile are all determined by the water depth, environmental loading, turbine loading and ground conditions at the foundation location. The diameter of monopiles increases beyond economic practicality for water depths greater than about 40m. Monopiles are typically 2.5-6.0m in diameter but with some projects having depths of 40m the maximum diameter could possibly be up to 10m. The largest ‘XXL’ monopiles currently used have had a length of +70m, diameter of 6.5m and weigh in excess of 900 tonnes.
Gravity-based structures (GBS): Unlike the piled foundations, gravity-based structures (GBS) are designed to overcome sliding and overturning forces between the bottom of the support structure and the seabed. This is achieved by providing dead loads to weigh down the structure so that it retains its stability under all kinds of environmental conditions.
Suction caisson: Although not yet used for offshore wind turbines, these foundations have been used recently for the foundations of met masts. This innovative approach uses a upturned, bucket type caisson with a monopile attached to it top. The caisson is lowered to the seabed and the water and any air are suctioned out to cause the caisson to effectively suck itself to the seabed. The major limitation of this
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foundation is that it will only work for certain silty/sandy seabed conditions to enable the suction seal to be made.
For deeper locations, more complex, space frame type structures are likely to be considered. These concepts fall into two main categories: multipods (including tripods and tripiles) and jackets. These support structure foundations typically utilise pin-piles (small diameter piles) to secure them to the seabed.
Tripods: A tripod is a three-legged structure made of cylindrical steel tubes. The central steel shaft of the tripod is attached to the turbine tower.
Tri-piles: Tri-piles consist of three, individual foundation piles connected via a transition piece to the turbine tower with the transition piece located above the water level.
Jackets: Jackets are lattice type structures that are formed by the connection of many smaller, cylindrical elements. They are able to have a much larger seabed footprint than monopiles, thus providing better resistance to overturning moments. Their effective cross sectional area at the water’s surface is also comparatively low which helps to reduce environmental loading from waves and currents.
2.4.3 Subsea Cables
A range of subsea cables will be used in an offshore wind project and these will vary depending on the voltage, electrical capacity, seabed conditions and monitoring requirements of the wind farm. Inter-array, medium voltage (typically 33kV) cables are used to connect the wind turbines to the offshore substation and high voltage (typically 132kV) export cables connect the offshore and onshore substation. As the onshore substation is often located at the high-voltage grid connection point, which may be a long distance from the cable landfall point, onshore cable may be used for the land based section as expensive, subsea cable is not required for those conditions.
The subsea cables are most commonly three-core, armoured subsea cables with solid insulation (ERP or XLPE) and typically comprise three electrical conductors, one for each phase, shielding for each conductor; optical fibres for data transmission; and steel armour to help protect the cables as well as increasing their weight to help provide stability whilst on the seabed. See Figure 22 for a typical cross section. Higher voltage cables that use oil as an insulating medium are not deemed to be environmentally acceptable owing to the potential risks associated with oil leakage in the nearshore environment.
Figure 22, Modus' CT-1 trencher (left) and an example cross section of a 132kV, double armoured submarine cable, showing the three conductors and optical cable.
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The inter-turbine array cables pass power between the turbines in series to one of the two offshore substations. Typically, 7 or 8 turbines are connected to the substation by each inter-array cable which may be connected to the offshore substation most commonly in a radial or ring arrangement as shown in Figure 23. The infield cables contain optical fibres embedded between the cores to allow data to be passed ashore from the turbines for condition monitoring and control purposes. Often, different conductor sizes will be used in the inter-array cabling depending on the load current that the cable is required to carry.
Figure 23, Examples of two electrical connection options for joining turbines to the substation; radial arrangement (left) and a ring arrangement (right). [Source: EWEA 2012 Presentation14]
The inter-array cables enter the turbine through a ‘J-tube’ which, as the name suggests, is a hollow tube in the shape of a J. This has a bell shaped mouth at the lower end of the tube and is intended to act as a guide for the subsea cable. The inter-array cables are pulled from the seabed up into the base of the turbine tower through the J-tube as shown in Figure 24. Protection material, such as rock dumping or concrete mattresses are laid on the cable close to the turbine to provide some protection and prevent the movement of the cable which could lead to its failure. Pulling cables into and up through the J-tubes is the most common source of cable failure during the installation process.
14 Benefits in moving the inter-array voltage from 33 kV to 66 kV AC for large offshore wind farms – Presentation at EWEA 2012
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Figure 24, The typical arrangement of internal J-tubes within a monopile and necessary scour protection.
Once laid, or sometimes during the laying process, the cables will be protected by burying them to a depth of 1–3m if the seabed conditions allow. In soft conditions, a remotely operated jetting ROV, such as that in Figure 22 will be used to blast the sediment away using high pressure water to form a void into which the cable can be placed. Alternatively, a cable plough such as that in Figure 25 could be used to plough a trench for the cable. In situations where the seabed’s sediment cover is not sufficient an ROV with a rock cutter may be used to cut out a trench similar to that in Figure 25 and then the trench would be filled once the cable had been installed.
Figure 25, Installation of cables on a beach from land to sea [left] and the trenching burial of a subsea cable [right].
2.4.4 Onshore Substation
An onshore substation is required to convert the power exported by the wind farm into grid compliant electricity that can be fed into the transmission grid which is typically at a high voltage around +300kV. Typically the transmission network operator will publish a ‘grid code’ specification that will define the behaviour of any connected generation plant. This will include voltage and frequency tolerances, power factor and reactive power limits, expected plant response to a system fault, response to grid frequency fluctuations, and requirement to "ride through" short interruptions of the connection. The onshore substation therefore needs to transform and condition the exported electricity as well as supplying electricity to the wind farm (reactive power).
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Many of the electrical components will be similar in specification to the offshore substation, however, there are not the same constraints with weight and space as for the offshore equipment.
The substation will comprise the following elements, many of which can be seen in Figure 26:
Grid transformers transform electricity from the offshore wind farm’s export voltage (~132kV) to higher voltage for onward transmission (+300kV). Transformers are oil- cooled, requiring the use of fire and blast protection. Reactive compensation equipment is used to condition the wind farm power prior to export to the transmission system and typically comprises a STATCOM (static synchronous compensator) unit and separate sets of reactors and capacitors. Harmonic filters ensure that the power exported to the grid complies with the amount of permitted harmonic content in the grid code and, typically, one set of harmonic filtering is required for each circuit connecting to the transmission system. Electrical busbars connect the various components within the substation and feature gas- insulated switchgear at strategic points in order to electrically isolate the different components. Auxiliary transformers provide low voltage supply to the substation and its control buildings. Control building contains a control room for the controlling, monitoring of the substation equipment, cables and offshore equipment. Metering units will be included within this building in order to monitor the power exported and imported to the wind farm. Other facilities may also be included such as office space as well as a kitchen and other welfare facilities
Figure 26, A typical layout of the components of an onshore substation for a large, 700MW project. Source: E.ON Climate & Renewables
If an HVDC (High Voltage Direct Current) system is being used to export power from the offshore wind farm to shore, as may be the case if projects are a long way offshore, HVDC converters will also be included within the onshore substation in order to convert the DC power to AC so it can be stepped up for onward transmission. It should be noted that HVDC systems generally operate at much higher voltages than AC systems (up to 800kV) and that HVDC substations also have much larger footprints and will be more expensive.
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Figure 27, London Array's 630MW onshore substation. Source: London Array Limited.
2.4.5 Offshore Substation
Offshore substations collect power from groups of wind turbines at a medium voltage (typically 33kV) and step up the power to high voltage (typically 132kV) in order to transmit it ashore via the main export cables. The voltage is increased in order to improve the efficiency of power transmission in the export cables as higher voltages result in fewer electrical losses. Offshore substations typically comprise most of the same components as an onshore substation, such as:
GIS switchgear MV/LV-switchgear SCADA/control systems MV/HV transformers Converters (if HVDC). Reactors Earthing systems and transformers Backup generation - UPS system
For a typical 300MW project, such as the UK’s Thanet offshore wind farm, an offshore substation may contain two main transformers and weigh up to around 1,500 tonnes. This was installed on top of a jacket structure foundation which weighed 820 tonnes and was fixed to the seabed using four 1.8m diameter pin piles.
Figure 28, The Thanet offshore wind farm's 300MW offshore substation
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2.4.6 Vessels
A very wide range of vessels are used for the construction and maintenance of European offshore wind projects. These vary from small personnel transport and survey vessels that are around 20-25m in length up to the large heavy lift vessels, such as the 183m long Stanislav Yudin in Figure 28. As many tasks are carried out simultaneously, during the peak of the construction activities, the offshore site can come very crowded with vessels of all types as can be seen in the example in Figure 30. Careful management and planning of these vessels and their activities is required to ensure that operations are carried out smoothly and delays are prevented. In the UK, the jack-up vessels and crane ships used for the installation of turbines typically cost in excess of £100,000 per day; approximately Rs 1 Crore/day.
The selection, design and availability of installation and support vessels will affect the timeline, cost and installation methodology and are therefore major assets in the construction of offshore wind farms. The huge cost of effective offshore installation vessels in Europe is a key hurdle for the wind industry and is even more so in Asia, particularly as vessels will need to be re-purposed to suit the requirements of offshore wind installation activities. Unless specialist vessels are mobilised from Europe, at extreme expense, vessels that are available in Asia will have to be used following modifications to make them suitable. This is similar to the case with the early offshore wind project in Europe where, for instance, old freight vessels were sometime retro-fitted with jack-up legs to allow them to install offshore wind turbines. This was not ideal and projects were delayed as a result. The more specialist vessels now available are far more capable but do come at a much higher cost.
Figure 29, Examples of the jack-up vessels that were used in the erection of turbines for the UK's Sheringham Shoal offshore wind farm.
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In addition to the vessels, the ports used for installation, commissioning and maintenance will require careful planning to enable the storage and marshalling of a large amount of equipment. Ports and quayside storage will be required for the foundations, transition pieces, towers, wind turbine generators and cables. It may not be possible to store all these at a base near the wind farm so there may need to be a forward marshalling area supported by storage at other ports and logistics operations between them.
Figure 30, Punch-through of a jack-up vessel, highlighting the requirement for in-depth pre construction surveys [left] vessel activity at the London Array at which point over 250 personnel were working offshore at any one time [right]. Source: K. Thomsen [L] & Siemens [R]
2.5 Operation and Maintenance
After the final commissioning of the wind farm’s components is completed, the project enters it operation and maintenance phase. The turbines will generate electricity until the end of their design life, at which point the infrastructure will either be re-powered or decommissioned.
Typical key tasks undertaken in the operation and maintenance stages include:
Environmental monitoring surveys as per consent ROV subsea surveys Onsite infrastructure inspections Performance monitoring Proactive maintenance tasks Routine maintenance interventions Reactive maintenance interventions Condition and health monitoring Planning for post-warranty period Refinancing of infrastructure and grid connection Decommissioning
2.5.1 Scheduled Maintenance
It is anticipated that a minimum of three to four, 2-man crew teams may be required to undertake the service and maintenance requirements of the wind turbines. Typical, minor tasks include regular service and maintenance, resetting of breakers, minor fault repairs and small maintenance issues associated with the operation of wind turbines.
The scheduled maintenance periods associated with wind turbines are likely to include the following requirements:
September 2014 32 Status and Prospects of the Offshore Wind Sector in India
• 3 monthly: Checking of lubricants and oil levels, ladder access integrity, navigation lights, aviation lights, etc.
• 6 monthly: Checking of lubricants and oil levels, hydraulic pump levels, controller cabinets, gear box oil levels, emergency stop sensor testing, fire alarm system test, etc.
• 12 monthly: Checking of lubricants and oil levels, pump levels, gear box oil quality tests, overall visual check, tower mounting bolt torque check, yaw ring torque check, blade integrity.
These actions are indicative of the actions undertaken during the 3, 6 and 12 monthly checks and are not intended as an exhaustive list.
In addition, occasional surveys will be required to check the burial depth of the infield and export cables as well as the individual turbine scour protection. In some instances, the details of this inspection have been defined in the environmental statement and may involve the use of 3 dimensional scans of the foundation base to obtain a clear picture of the protection status.
Figure 31, The O&M personnel for some projects gain access to the turbines for day-to-day O&M via helicopter.
2.5.2 Unscheduled Maintenance
Repairs and unplanned maintenance may be required that are not normally incorporated in the scheduled maintenance check periods, including the replacement of failed or damaged components. Nacelle mounted cranes are usually sufficient to load and offload nacelle items requiring repair or replacement, however, support from specialised vessels could be required to load and offload the replacement parts onto the wind turbines. In extreme cases, such as the replacement of turbine gearboxes, an external crane may be required to load/offload critical parts that are too large for the nacelle/workboat crane.
The turbines and substation are connected to a central control and monitoring station, which is often at the O&M port along with the warehouse for spare components and welfare facilities for the offshore O&M crew. Usually, the performance and health of the turbines in the project are monitored 24 hours per day either at the O&M centre or remotely by the turbine supplier – usually Vestas (Denmark) or Siemens (Germany). The condition and health of each turbine is monitored using a wide variety of sensors within the turbine nacelle and tower. These are used to report back to the O&M centre and flag up any issues that arise. This monitoring can sometimes indicate changes in some measurements which could indicate the deterioration or imminent failure of a component. Proactive maintenance can be undertaken in this situation to prevent the failure and stop the event from causing further damage in the turbine. Proactive maintenance tasks can also be undertaken as a result of visual inspections.
September 2014 33 Status and Prospects of the Offshore Wind Sector in India
2.5.3 Vessel to Turbine Transfers
One of the problems of transferring from a vessel to a turbine foundation is that the structure is fixed to the seabed, resulting in considerable relative movement between the vessel and the foundation15. The majority of transfers take place using what is known as the ‘bump and jump’ method, whereby the vessel is pushed bow first onto tubes which run vertically on the outside of the access ladder. The vessel uses sufficient forward thrust to enable it to remain stationary at the point of contact with the foundation and allow personnel to step over onto the ladder as can be seen in the example in Figure 32.
Large waves, especially if there is a strong current across the side of the vessel, can sometimes cause the vessel to lose position. The turbine access ladder is, therefore, set back from the tubes by 450mm which provides a safety zone to prevent anyone on the ladder from being crushed should the vessel move during the transfer procedure.
Although it is not a set rule, most transfers using the bump and jump method are limited to sea conditions of 1.5 m significant wave height or less. Other factors which will affect accessibility will be the wave period and wavelength, and the water current conditions.
To expand the transfer window, a number of ‘walk to work’ systems have been developed. These generally consist of a heave compensating bridging mechanism which attaches to the j-tubes or ladder so that personnel can walk onto the turbine transition piece platform as the bridge remains stationary relative to the turbine. There are number of these systems on the market such as Amplemann, Maxcess and Houlder TAS and not only do they make it safer for personnel to transfer, the transfer can often take place in larger sea states than if using the simple bump and jump method. Despite these advantages, the equipment takes up valuable deck space, payload capacity and has a power demand. Also there is also either a capital cost or charter cost to be accounted for. Other new systems are in development to be better suited to energetic sea conditions, because as the distance from shore increases so does the average significant wave height.
Figure 32, A typical 'wind cat' crew transfer vessel allows maintenance personnel to board the turbine transition piece from the bow of the boat.
2.5.4 Decommissioning
The offshore wind farm’s site will be decommissioned at the end of the infrastructure’s economic lifetime. Towards the end of the initial project lifetime of 20-25 years, the technical conditions of the turbines and
15 http://www.4coffshore.com/windfarms/wind-farm-service-vessels-an-overview-aid246.html
September 2014 34 Status and Prospects of the Offshore Wind Sector in India
infrastructure will be assessed along with the wind farm’s continuing economic potential. It is possible that the wind farm may continue to operate for longer than 20 years, be partially or fully decommissioned, or potentially re-powered depending on how long the developer seabed lease lasts (in the UK, this is typically 50 years). It is recommended that further surveys of the bathymetry should be carried out prior to decommissioning in order to inform the decommissioning process.
The decommissioning procedure for the turbines will, essentially, be the reverse of the installation process. This will require a jack-up barge with a crane capacity exceeding 200 tonnes. Typically, it is estimated that the decommissioning process for around 100 turbines will take approximately 200 days. A summary of a typical decommissioning plan is provided in Table 3. These are reasonably standard decommissioning plans for the UK’s offshore wind industry and most projects intend to leave the embedded pile section within the seabed after cutting it at or below the sea bed. Both the inter-array and export cables will usually be left in situ as they have been buried and removing them from the seabed will cause significant detrimental impact. Leaving these in situ minimises the adverse effects on the underwater environment. Furthermore, whilst the copper conductors of the subsea cables will have a significant scrappage value, this will not usually be sufficient to offset the costs of their recovery. Table 3, Typical decommissioning procedures for the key components of a project
Component Decommissioning Plan
Wind turbine Complete removal from site
Foundations (Turbines and offshore Cut off at or below seabed and removed substations)
Sour protection material Left in situ
Cables (Inter array and export) Left in situ
Offshore substations Removal of substation topside
2.6 Typical Costs
Offshore wind is, currently, an expensive source of renewable energy. The high costs are a direct result of the large technical challenges that need to be overcome in order to install and operate a wind farm in the sea. Evidently, this is significantly more complex and therefore more costly than the onshore equivalent projects. Nevertheless, the advantages of offshore wind over other onshore renewables, as described previously in section 1.4, makes offshore wind an attractive option, provided there is enough financial and political support to ensure its viability. Without financial subsidies, offshore wind would be a long way off being cost competitive with many other forms of renewable energy.
This section explores the typical financial measures used for European offshore wind projects and provides typical costs for each. These are the Capital Expenditure (CAPEX), Operational Expenditure (OPEX) and the Levelised Cost of Energy (LCOE). Equivalent values in INR are given for reference, where 1 GBP = 102.5 INR as of August 2014.
September 2014 35 Status and Prospects of the Offshore Wind Sector in India
2.6.1 Capital Expenditure (CAPEX)
The CAPEX for an offshore wind farm is significantly more than for an onshore project, primarily due to the larger and more specialised turbines and infrastructure required for the offshore environment. The logistics associated with installation offshore also adds a sizeable amount to an offshore project.
Early European projects had a typical CAPEX of around £1.0 - 1.5 million per MW. At this time, projects were simple and the technology used was onshore equipment but mounted on offshore foundations.
Over the past decade, growing market demand for wind turbines and offshore infrastructure has been coupled with increasingly more complex and ambitious projects which has resulted in costs increasing dramatically in comparison with historic projects. Consequently, CAPEX costs for UK projects are currently are in the range of £3.2 to £3.5 million per MW.
A project’s CAPEX comprises a number of cost components including those for the: development and design, purchase of onshore and offshore infrastructure, and the installation and commissioning of that infrastructure. The roughly £3.0 m / MW CAPEX can be broken down into its separate categories, as provided in Figure 33, which shows that only 4.9 % of the CAPEX is a result of the development costs, whereas 69.1 % is from the purchase of the infrastructure and the remaining 26% is from the installation and commissioning work. Figure 33 also shows how these cost centres can be further broken down into their constituent parts and that the single largest expenditure is the turbine (32.6%) followed by the turbines’ foundations (16%).
Figure 33, The breakdown of CAPEX expenditure into Development, Turbine, Balance of Plant and Installation costs for a typical UK, 300MW project.
The UK’s project pipeline will see projects deployed on a GW level at a scale that is much larger than anything currently in the water. The introduction of new generation, higher output turbines for these projects will be coupled with the benefits through economies of scale to help reduce the costs of offshore wind projects. As a result, more optimistic predictions suggest that the average offshore wind CAPEX
September 2014 36 Status and Prospects of the Offshore Wind Sector in India
could fall to a range of approximately £1.7million to £2.4million per MW16 by 2020 for projects greater than 100 MW.
2.6.2 Operational Expenditure (OPEX)
OPEX comprises all of the expenditure associated with the operation and maintenance of a project during its design lifetime. In comparison to onshore wind projects, OPEX is significantly more expensive for offshore installations as access to the wind farm is dependent on specialist vessels and the weather. Any large maintenance interventions that become necessary through the failure of components could require systems, such as gearboxes, to be replaced which would necessitate the use of large jack-up vessels at costs similar to the initial installation of the turbines.
Experience to date in the UK shows that offshore wind OPEC is around 2 - 4 times more expensive than onshore. Offshore wind operational costs are currently in the range of £100,000/MW/year to £184,000/MW/year16. The next generation, Round 3 projects are expected to see OPEX increase to a range of £110,000/MW/year to £221,000/MW/year due to their additional logistics challenges but, by 2020, are expected to fall to £81,000/MW/year to £185,000/MW/year.
Figure 34, The breakdown of OPEX cost components for a typical 300MW, UK offshore wind project.
2.6.3 Levelised Cost of Energy (LCOE)
Levelised costs take into account the overall cost of energy across the lifetime of a project. In the calculation of LCOE, capital and operational costs, depreciation, project life and learning are all taken into account, to produce long term figures for the cost of energy in £/MWh or equivalent. LCOE figures are useful to provide a comparable estimate of the cost of electricity from different sources.
The LCOE of current, UK offshore wind projects is estimated16 to be in the range of £149/MWh to £191/MWh, and it is predicted that this will fall to between £127/MW and £170/MWh by 2020. The large range of the 2020 LCOE predictions reflects the increased cost of deep water offshore wind that is far from the shore.
The current rising project costs are for an industry that is already borderline in terms of economic viability, making the economic case for developers seeking to construct and own offshore wind farms increasingly difficult to justify. On this basis, the UK has set up a new industry task force to set out a path and action plan for reducing the levelised costs of offshore wind to £100 per MWh by 2020.
16 Review of the generation costs and deployment potential of renewable electricity technologies in the UK – DECC, June 2011
September 2014 37 Status and Prospects of the Offshore Wind Sector in India
3 STATUS AND PROSPECTS FOR OFFSHORE WIND PROJECTS IN INDIA
3.1 India’s Renewable Energy Scenario and Role of Wind Energy
Electricity generated from renewable energy sources has started to grow over the past decade, as shown in Figure 36, and capacity from new generation sources, other than large scale hydro, make up the majority of this new additional capacity. Recently, India’s grid connected renewable electricity generating capacity has exceeded17 31 GW and India occupied the fourth rank globally4 in terms of new installed, renewable electricity capacity (1,729 MW) between January-December 2013.
Figure 35, The growth of India’s annual electricity generation over the past two decades in comparison to the recently growing generation of electricity from renewable energy sources. [Source: International Energy Statistics, US DoE]
Excluding large scale hydro power, other forms of renewable energy sources contribute 13 % of India’s total, installed electricity generation capacity. Figure 36 shows that wind power generation capacity dominates this contribution and is therefore, an important component within India’s electricity mix. There is now more than 21 GW of onshore wind capacity operating in India which represents 8.4 % of India’s total electricity generation capacity17 of 250 GW.
At a high level, there are big drivers for the introduction of more renewable energy capacity in India as electricity demand is growing18 at a rate of 8 % per year which means that around 120 GW of additional electrical generation capacity will be required over the next decade. As India has carbon reduction targets that have been set in its 12th year plan that aim to reduce carbon intensity by 17 % below 2010 levels by 2015 and that it has a long term plan of reducing carbon intensity by 40 – 45 %, the addition of new capacity must be sustainable. Onshore wind will significantly contribute to the new additional capacity, but India is also starting to look to other energy sources, such as offshore wind, to help the supply meet the demand.
17 Central Electricity Authority (MoP) http://www.cea.nic.in/reports/monthly/inst_capacity/jul14.pdf 18 MNRE, 2013: https://www.irena.org/DocumentDownloads/events/CopenhagenApril2012/3_Dilip_Nigam.pdf
September 2014 38 Status and Prospects of the Offshore Wind Sector in India
Figure 36, India's electricity generation capacity by fuel and its renewable electricity mix in June 2014 [Source: Data from Central Electricity Authority19, 2014]
3.1.1 Wind Energy Programme in India
India’s wind power programme commenced in 1983 and initially focused on a national wind resource assessment programme which began in 1985 and the first met-mast was installed in Tamil Nadu in 1986. Several demonstration projects were set up in selective locations in the country with Danish International Development Agency (DANIDA) support including a wind turbine testing station in Southern India. In addition to these programmes, the MNRE set up the Centre for Wind Energy Technology (C-WET) as an autonomous R&D institution of Government of India. C-WET provides an essential role in India’s wind energy sector; carrying out research and development, testing of technologies, publishing standards, providing certification and undertaking wind resource assessments.
In recent years, much of the domestic wind energy policy that delivered such a successful industry has significantly changed. One of the key changes was the withdrawal of the accelerated depreciation incentive mechanism and new installations of onshore wind capacity fell7 by 50% during 2013. The Government of India has brought in a replacement, generation based, support mechanism and will be commencing the National Wind Energy Mission during 2014; both of which are hoped to revive the sector’s growth.
3.1.2 National Wind Energy Mission
Recognising the importance of wind power in India, the Planning Commission recommended the establishment of a National Wind Energy Mission in the 12th Five Year Plan. A concept note for the mission was prepared by the MNRE after preliminary consultation with various stakeholders. In order to obtain the views and suggestions of various stakeholders, a National Consultation was organised by the Ministry in January 2014. This was intended to consider issues relating to the requirement and rational for a new National Wind Energy Mission.
The scope of the mission is to develop an institutional structure to coordinate with the Ministry of Power and its agencies; the planning, regulatory and development agencies; states’ financing and research
19 http://www.cea.nic.in/reports/monthly/inst_capacity/jun14.pdf
September 2014 39 Status and Prospects of the Offshore Wind Sector in India
institutions; and to review the industry’s progress. The mission will set long term goals and targets for onshore wind, offshore wind, small wind, manufacturing research and development. It is intended that the National Wind Energy Mission will increase India’s wind energy capacity to 100 GW by 2020 and reverse 2012’s policy issues that cause the installation rate of new wind energy capacity drop by 50 %.
The Government of India has shown commitment for clarity on long term policies for onshore, offshore and small wind power development. The Indian renewable energy sector is facing grid evacuation problems and the Government of India is intending to address these by formulating an ambitious plan to develop stronger grid infrastructure in the country.
The Government of India has also made a comprehensive plan on renewable integration within its 12th five year plan (33,000 MW envisaged RE capacity) under “Green Energy Corridors”. An Inter State Transmission System has been proposed under the Green Energy Corridor initiative20 and could see the installation 2,780 km of new grid at 765 kV and 620 km of new grid at 400kV. In addition, 6 new substations with a cumulative capacity of 18,000 MVA are also proposed.
The Government of India is also planning to develop the intra-state transmission system20 with 15,000 km of new transmission line and 32 new substations being proposed under the green energy corridor plans. A further proposal of the Green Energy Corridors project is to establish a renewable energy management centre.
3.2 Current Status of Onshore Wind
By June 2014, India had a total, installed, onshore wind capacity19 of 21.14 GW, with the states of Gujarat21 and Tamil Nadu22 having the most capacity, with 3.39 GW and 7.13 GW respectively. It has been estimated that the country has a practical resource of 102,000 MW at an 80m hub height.
In the 11th five year plan, for 2008 – 2013, a target was set to install 9,000 MW of new wind capacity in that period. Due to the attractive fiscal incentives (accelerated depreciation) that were offered by the Government of India, a total of 10,260 MW of new capacity was installed; 5,364 MW was added between 2008 and 2010, 3,196 MW during 2011-12, however, this dropped off significantly during 2012-13 as only 1,700 MW was added. This was predominantly due to the government’s withdrawal of the accelerated depreciation scheme.
The 12th, and latest, five year plan is more ambitious than the last and has set a target of 15,000 MW of new wind capacity to be installed between 2013 and 2018. The target set for the 2013-14 period is 2,500 MW.
3.3 Wind Technology Status
India’s mature wind energy industry supports18 at least 18 major wind turbine supply companies offering a range of turbine capacities and sizes, with rated powers of 250kW to 2.5MW, hub heights up to 100m and rotor diameters of up 110m. Table 4 provides a list of the Indian turbine manufactures of IEC Class II and III turbines along with information on the devices available.
20 http://mnre.gov.in/file-manager/UserFiles/Presentations-NWM-09012014/IS-Jha.pdf 21 https://www.sldcguj.com/compdoc/Installed%20capccity%20300614.pdf 22 TEDA website: http://www.teda.in
September 2014 40 Status and Prospects of the Offshore Wind Sector in India
Table 4, Indian suppliers of IEC Class II and III turbines [Source: WISE]
Manufacturer Rating (kW) Drive Speed Generator Class
Enercon 800 Gearless Variable Synchronous II-S
GE Wind 1,500 Gear Variable DFIG II A
GE Wind 1,600 Gear Variable DFIG II
Suzlon 1,250/2,100 Gear Fixed Asynchronous II A/III
Suzlon 1,500 Gear Fixed Asynchronous III A
Suzlon 2,250 Gear Variable DFIG II B
Vestas India 1,650/1,800 Gear Variable Asynchronous II B/ III A
RRB Energy 1,800 Gear Variable Asynchronous II/III
Gamesa 850 Gear Variable DFIG II A/III B
Gamesa 2,000 Gear Variable DFIG II A/III A
Global Wind Power Ltd 2,500 Gear Variable Synchronous III A
Inox Wind Limited 2,000 Gear Variable DFIG III B
Kenersys India 2,000 Gear Variable Synchronous II A
Leitner-Shriram 1,350/1,500 Gearless Variable Synchronous II A/III A
ReGenPowertech 1,500 Gearless Variable Synchronous III A/III B
WinWinD 1,000 Gear Variable Synchronous III B
3.4 Onshore and Offshore Wind Resource
Winds in India are particularly seasonal and are influenced by a strong, southwest, summer monsoon season, that typically occurs between April and September, and a weaker northeast, winter monsoon season.
During C-WET’s extensive wind resource assessment programme, 1100 wind monitoring stations have been set up18 in 33 states/union territories and 233 sites have been identified as having an annual average wind power density > 200 W/m2 (> 6.8 m/s) at a 50 m hub height. Of these sites, 40 are in Gujarat and 45 in Tamil Nadu.
There are seven states (Andhra Pradesh, Gujarat, Karnataka, Kerala, Madhya Pradesh, Maharashtra, Rajasthan and Tamil Nadu) that have been identified as having a high wind power potential and this is reflected by the breakdown of installed wind capacity within each state. C-WET predicts that, throughout the whole country, India has a potential of 102GW of onshore wind resource at an 80 m hub height.
September 2014 41 Status and Prospects of the Offshore Wind Sector in India
Figure 37 shows the variation of India’s onshore wind resource which is most prevalent along the western states of the country. The map shows that Gujarat and Tamil Nadu both have some of the most energetic regions in the India.
Figure 37, A wind energy resource map of India at a 50m hub height [Source: C-WET] Unlike India’s extensive onshore wind resource assessment programme, little work has been undertaken to assess the country’s offshore wind resource. Initial desktop assessment was carried out by C-WET in consultation with Riso, Denmark and also the institute under the Ministry of Earth Sciences such as Indian National Centre for Ocean Services (INCOIS), Hyderabad. INCOIS extrapolated the data collected from floating buoys used for offshore, metocean measurement. The study produced some early estimations of the offshore wind characteristics and has since led into more detailed modelling and studies, conducted by C-WET. The image in Figure 38 shows the output of one modelling study by C-WET that provides the annual average, 80m height, offshore wind speeds along India’s coastline. It can be seen that, around the southern coastal regions, average speeds reach up to around 10 m/s and the Gujarat coast, particularly in the Gulf of Khambat, wind speeds are around 8 m/s.
September 2014 42 Status and Prospects of the Offshore Wind Sector in India
Figure 38, A wind energy resource map showing India’s annual average offshore wind speeds at an 80m hub height based on data modelled by C-WET. [Source: C-WET23]
Figure 39 shows an assessment made by the NIOT (National Institute of Ocean Technologies) using winds derived from satellite data over a 10 year period (1999-2009) with one observation each day at a 10 m height. This data was then scaled up to 80 m height and modelled spatially and temporally and validated by some of NIOT’s offshore data buoys. There is clear monthly variation shown in Figure 39 with the summer months of June and July bringing the largest winds to Gujarat and December and January providing locally high winds in southern Tamil Nadu.
Figure 39, Variation of offshore wind power density in India [Source: NIOT24]
23 http://www.itpower.co.in/wp-content/uploads/2013/04/S.-Gomathinayagam_-CWET.pdf 24 http://mnre.gov.in/file-manager/UserFiles/presentations-offshore-wind-14082013/Atmanand_NIOT.pdf
September 2014 43 Status and Prospects of the Offshore Wind Sector in India
3.5 Key Government Agencies and State Nodal Agencies for Wind Energy
3.5.1 National Institute of Wind Energy
The National Institute of Wind Energy (NIWE), formerly known as Centre for Wind Energy Technology (C-WET), Chennai was established in 1998 as an autonomous institution under the administrative control of the Ministry of New and Renewable Energy. NIWE provides services for wind resource assessment, testing and certification as per International standards and also provides training for capability building in the wind energy sector. The institute may assist in resource assessments and technology selection, capacity building for different stakeholders in offshore wind power development in India. NIWE provides all technical support to developers including wind resource assessment and DPR preparations. State nodal agencies (SNAs) facilitate project development from resource assessment to the final commissioning and also verifies the legal statutory clearances sought by the developer from different departments.
3.5.2 Indian National Centre for Ocean Information Services (INCOIS)
INCOIS is an autonomous body under the Ministry of Earth Sciences. INCOIS provides ocean information and advisory services to industry, government and the scientific community through sustained ocean observations and scientific research. INCOIS is working in the field of offshore wind resource assessment and is also developing a bathymetry map of the waters within India’s EEZ.
3.5.3 The National Institute of Oceanography (NIO)
NIO has its headquarters at Dona Paula in Goa, and also, regional centres at Kochi, Mumbai and Visakhapatnam. It is one of the 38 constituent laboratories of the Council of Scientific & Industrial Research (CSIR), New Delhi. NIO was established in January 1966 following the International Indian Ocean Expedition in early 1960s. The institute’s focus of research has been on observing and understanding the special oceanographic features. They have improved bathymetric datasets for the shallow water regions in the Indian Ocean.
3.5.4 The Indian Naval Hydrographic Department
The INHD is committed to respond to national and international regulations / conventions relating to Safety of Life at Sea and Industrial off-shore development. The department offers to undertake following categories of surveys:
Navigational Surveys Pipeline & Submarine Cable laying Surveys EEZ & Continental Shelf Delineation Surveys Pre & Post Dredging Surveys Coastal Zone Management (CZM) Surveys
The survey capabilities and expertise of this department shall play important role in offshore wind power development.
September 2014 44 Status and Prospects of the Offshore Wind Sector in India
3.5.5 Tamil Nadu Energy Development Agency
TEDA was formed by the Government of Tamil Nadu in 1985 in order to25 help promote the use of new and renewable energy sources, implement renewable projects, promote energy conservation and to encourage renewable energy research and development. Since its formation, Tamil Nadu has seen over 8 GW of renewable energy installed in the state from technologies including wind, solar PV, biomass and biogas; this compares to a total installed, electrical generation capacity within Tamil Nadu of around 21 GW.
3.5.6 Gujarat Energy Development Agency
GEDA is a Gujarat based, state nodal agency established26 by the Government of Gujarat in 1979 to tackle the oil crisis of the 1970s. GEDA has a very similar function to TEDA and other nodal state, development agencies.
3.6 Consenting and Environmental Impact Assessment (EIA)
The consenting process for offshore wind in India is likely to have many similarities to the processes undertaken in the consenting of onshore wind projects with shared features from the consenting of other offshore infrastructure projects. A key undertaking of this will be the necessity to obtain clearances from many different government ministries and departments as well as other relevant stakeholders. The key government agencies that are likely to be consulted in the consenting process are:
Central Government Agencies
MoEF (Ministry of Environment and Forests) – EIA, CRZ clearance Ministry of Defence – Security clearance Ministry of Shipping – Clearances for projects near Major Ports MoPNG – Clearance to operate outside oil and gas exploration zones Ministry of Civil Aviation – Aviation Safety DoT – Clearance for operating outside subsea Cable zones Geology and Mining Department – Seabed and related environment issues Dept. of Animal Husbandry, Dairying and Fisheries – No impact on fishing grounds MHA – Declaring offshore wind energy exploitation zone. Department of Space – Clearances relating to satellite launching stations Ministry of Civil Aviation
State Government Agencies
State Government – Clearance for working under Coastal Zone Management Plans State Maritime Boards - Clearances for projects near Minor Ports State Electricity Board or a similar Designated Agency. District Commissioner – Land use permission, public hearing for environmental clearance. Any other stakeholder from the State Government.
The MNRE proposed in its draft offshore wind policy that a nodal agency, the National Offshore Wind Agency (NOWA), will be formed under the policy’s implementation. One of NOWA’s functions will be to
25 Tamil Nadu Energy Development Agency: http://www.teda.in 26 Gujarat Energy Development Agency: http://geda.gujarat.gov.in
September 2014 45 Status and Prospects of the Offshore Wind Sector in India
liaise with and consult these government agencies to assist the developer in obtaining the necessary clearances and permissions from each of them.
The Environmental Impact Assessment of offshore wind projects will very likely be a mandatory requirement as per the Ministry of Environment and Forests’ (MoEF), Environmental Protection Act (1986), EIA notification (1994) and Coastal Regulation Zone (CRZ) Notification (1991)
The MoEF is the nodal agency for regulating environmental protection in India and sets the requirements and assess the EIAs of a range of activities including the construction of new ports and harbours. It is possible that NOWA will become the nodal agency to assist with the preparation and submission of EIAs for offshore wind and may assume the responsibility of assessing EIA applications.
Typically, for port infrastructure projects, the summary information for the project and some relevant documentation have to first be submitted to the State Pollution Control Board, which will initially assess the submission and commence the public hearing process. Once this has been passed by the board, the project developer can submit the full EIA to the MoEF.
A full EIA submission will typically contain the following information and chapters:
Brief description of the project o Need for the project o Project activities Description of the existing environment o Natural setting o Resource availability o Sensitive areas o Social setting Consideration of alternatives o Project alternative o Site alternative Identification of impacts o Methodology of impact identification o Impacts during the construction phase o Impacts during the operation phase o Impacts without the project in the future o Characterisation of impacts Baseline study o Baseline parameters o Sampling criteria o Methodology of analysis o Validation Prediction of impacts o Area/receptors subject to potential impacts o Summary of prediction/calculations o Significance of impacts o Without project o With project with/without EMP Risks due to the project o Area/receptors subject to risks o Frequency of risk o Consequence analysis Mitigation, protection and enhancement measures o Environmental management plan
September 2014 46 Status and Prospects of the Offshore Wind Sector in India
o Monitoring o Disaster management plan o Safety measures and emergency procedures Summary and conclusions
3.7 Incentives for Wind Power Projects
3.7.1 Financial Incentives
India’s successful onshore wind industry grew rapidly, mostly as a result of the incentives that were offered to developers. These included the options of a Generation Based Incentives (GBI) which was Rs.0.50/kWh and Accelerated Depreciation (AD) which was introduced in the early 1990s and allowed wind components to be depreciated by 80 % within the first year of a project (equivalent to Rs. 6.5 crore/MW). The AD incentive was a very attractive prospect to investors but was seen to encourage fraudulent schemes where tax benefits could be reaped without actually building the project. Both the AD and GBI were withdrawn at the end of March 2012 and from 1st April 2012, the AD benefit for wind projects was reduced to a rate of 35 % within the first year of the project (15 % normal and 20 % additional depreciation for power sector projects).
In July 2014, the Government of India announced that it would be reinstating the AD scheme at the original rate of 80%, thus providing a massive boost for the wind sector.
The GBI scheme was reintroduced and provides projects with Rs.0.50/kWh for a period not less than 4 years and a maximum period of 10 years. This is capped at Rs. 100 Lakhs/MW and a the total incentive provided in a year will not exceed Rs. 25.00 Lakhs/MW during first four years of operation.
In addition to this, projects receive a feed-in tariff that is set by the State Electricity Regulatory Commission (SERC) and varies from state to state. Gujarat for instance27 provides Rs. 4.23/kWh and Tamil Nadu provides Rs. 3.5/kWh.
3.7.2 Fiscal Incentives
100% Foreign Direct investment (FDI) is allowed in wind power sector and it has helped greatly in bringing investment. After introduction of GBI, FDI has increased in wind sector. Under the central fiscal policy following tax benefits are available for wind energy projects
Direct taxes Exemption on Income Tax on earnings from the Project u/sec 80IA for 10 years
Indirect taxes Exemption of Excise Duty on WEG. Custom duty concessions (5%) for following wind turbine components are available
Special bearings Gear Box Yaw components Wind turbine controllers
27 http://www.gwec.net/wp-content/uploads/2012/11/India-Wind-Energy-Outlook-2012.pdf
September 2014 47 Status and Prospects of the Offshore Wind Sector in India
Parts of the above components Rotor blades of wind turbines Parts and sub-parts of blades Raw materials for blades, parts and sub-parts of blades
Incentive in Research & Development The income tax department provides for a weighted deduction for an in house R&D activity, which entitles wind turbine manufacturers to claim 200% of the expenditure (other than expenses on land and building) incurred for in-house R&D activity
3.7.3 Regional Incentives
Renewable energy projects are exempted from electricity duty by state government and no VAT or reduced VAT is applicable on Renewable energy components in some states. Tamil Nadu has reduced VAT from 14.5% to 5% and Karnataka offers 5.5% VAT for all the renewable energy components. Gujarat, Tamil Nadu and Maharashtra offer 5% VAT for all renewable components.
Maharashtra has the provision for capital subsidy to the extent of 11% for wind energy projects set up by the cooperative sector. Rajasthan provides soft loan equal to 1/3 of capital cost at low interest rate. Green technology (including wind energy) is listed as a focused group scheme. Under this scheme, export of RE product to all countries is entitled for an additional duty credit equivalent to 2% - 5% of freight on board (FOB) value of exports.
MEDA in Maharashtra has created the Green Cess (tax) fund. This is a dedicated fund in Maharashtra for the development of RE and a part of this fund is utilized to create infrastructure for grid connectivity with proposed wind farms. Similar tax (Cess) is being collected in Karnataka.
3.8 Regulations
3.8.1 Renewable Purchase Obligation
26 SERCs specified the mandatory purchase obligation under Section 86, 1(e) of the Electricity Act, 2003, for purchase of fixed percentage of energy generated from RE sources. The RPO percentage varies from 0.5% to 10.25%, depending on the local renewable resources and the electricity distributed in those states. RPO obligation can be fulfilled through direct purchase via bilateral contracts and tradable REC mechanism which can further generate revenue for RE projects.
3.8.2 Wheeling & Banking Charges
For wind, wheeling charge (electrical transmission and distribution charges paid to the grid owner) for the different states are in the range of 2% (Madhya Pradesh and Maharashtra) to 7.5% (West Bengal). The states of Karnataka, Tamil Nadu and Andhra Pradesh charge 5% of the total energy fed to the grid.
Tamil Nadu and Karnataka allow 5% and 2% of the total renewable energy fed to the grid as bankable energy and can be availed anytime during the financial year. Rajasthan and Maharashtra provide 6 months (April-September) and 12 months of banking period respectively.
September 2014 48 Status and Prospects of the Offshore Wind Sector in India
Figure 40, Typical wheeling and banking charges for onshore wind projects in Tamil Nadu [Source: TEDA]
3.8.3 Forecasting Requirements for Wind Projects
India’s relatively fragile electricity grid was designed for traditional electricity generation with a steady rate of supply. As a result, the Indian grid can struggle with the supply of volatile electricity generation from renewables and can lead to blackouts. To help reduce this effect, India introduced measures in 2012 to try to improve the demand and supply balancing.
Wind energy capacity can present an unknown to grid operators as the operator will not accurately know how much electricity will be generated by the wind in the coming period. Scheduling and forecasting regulations were brought into force in January 2012 and state that wind generation with a total capacity of more than 10 MW and supply power at or above 33kV have to forecast their power generation for the next 24 hours or the generator will be fined. Wind energy generators are required to forecast power generation in 15 minute blocks for the following day and will be fined for estimates that are incorrect by more than 30 %.
In March 2014, however, the penalty component of these regulations was put on hold28 pending a review of the mechanism. Generators are still expected to submit forecasts for the day ahead.
3.9 Reasons for Offshore Wind in India
India has already made steady progress in the development of onshore wind power projects over the past few decades and now has the 5th largest industry in the world. Onshore wind capacity now represents over 70 % of the overall installed renewable electricity capacity and as of May 2014, this totalled 21,264 MW. Despite the success of this industry and a coastline of over 7,600 km, India does not yet have any offshore wind capacity. With so much capability and potential, India need to harness this type of renewable resource and form a considerable contributor in its energy mix. This is attained by venturing into the sea with little modification and upgrade of the onshore technology and experience. The additional aspect would be the foundation that is extensive as well as requires great technological advancement.
India’s onshore wind industry can be complemented by the development of offshore wind projects as much of India’s supply chain that services the onshore wind industry can benefit through the supply of equipment and components to offshore wind farms. India should continue to develop onshore wind projects while also starting to develop offshore wind.
28 http://www.bloomberg.com/news/2014-03-07/india-puts-wind-forecasting-on-hold-on-inaccurate-results.html
September 2014 49 Status and Prospects of the Offshore Wind Sector in India
It may seem too early to consider offshore wind for India as the costs for such projects are still very high in comparison to other forms of renewables, however, an offshore wind industry in India will, most likely, take at least a decade to mature after the first pilot projects. It is, therefore, pertinent to take the first steps now in preparation for the larger scale roll out of projects in future years.
There is still a lot of onshore wind potential that has not yet been exploited, however there are a few issues which will limit how much can be developed; the availability of land in areas of good wind resource is reducing and the land that is available often has a high cost of rent or purchase thus increasing the onshore wind farm’s costs. Secondly, if land can be found with good wind resource at an acceptable cost it may often be far from an electricity grid or centre of population and end users. The electrical capacity of a reasonable size onshore wind farm will be more than the local grid can support and so the electrical network will need to be significantly upgraded or a new, dedicated high voltage line installed, leading to high power evacuation costs. A final, but often important, point is that the transport of equipment (turbine towers and blades in particular) to an onshore site is often very challenging along Indian roads. Taking all of these barriers into account, the amount of onshore wind will be limited and its costs may increase.
A key benefit of offshore wind, in comparison to onshore, is that wind speeds are higher and less turbulent which leads to higher capacity factors of the plant and so increased revenues from the sale of electricity.
Considering the aforementioned points from an offshore perspective; there are vast areas of sea and seabed with suitable wind speeds that do not have land use restrictions. In many cases there are coastal communities with plenty of end users and suitable grid infrastructure that are close to these offshore wind sites. This, however, is something that will need to be taken into account when selecting suitable offshore sites. The transport of the equipment to the site is comparatively straightforward as this is brought to site by vessels from the port which is closest to the point where the structures have been fabricated.
The cost of offshore wind is currently greater than that for onshore wind due to the nature of operating environment and the added complexities of the task, but is expected to reduce in the future. It is likely that an Indian project would aspire to utilise indigenous technologies from some of the manufacturers within the country, potentially leading to lower offshore wind costs in India than, for example, in Europe. As yet, no Indian manufacturer has directly developed an offshore wind turbine as there is no market unless they look further afield where there is already strong competition. Suzlon of India acquired the German company Repower (now called Senvion) in 2009 and this branch of the group provides them with an offshore wind capability with many turbines currently operational and ‘field-proven’ elsewhere in the world. This could be the start of a globally competitive Indian offshore wind industry.
As the offshore wind technology is relatively mature, only a portion of the cost reductions for the offshore wind industry come from technological advances and innovation. Some of the biggest contributors are the economies of scale and maturity of the supply chain; both of which cannot be achieved without an industry in India. Therefore, if there is a wait in the development of the industry for better technological maturity within the international markets, only a small cost reduction benefit is likely to be achieved.
Similarly to the cost reductions, the supply chain will not develop without a demand being present from the industry. India already has a strong oil and gas industry with a variety of vessels and capabilities within the country. These could be mobilised to work on the first offshore wind project, but specialist vessels are not going to be developed until they are required. The vessels that cannot be provided by India’s maritime industry will be mobilised from other countries (such as Europe) and brought to India.
Whilst there are a number of concerns to address before the sector can develop, there are good opportunities for offshore wind in India. India has its own country specific obstacles to clear that are not common to other, more developed offshore industries in other countries. These issues cannot therefore
September 2014 50 Status and Prospects of the Offshore Wind Sector in India
be tackled unless an industry begins to develop and actively work towards overcoming these obstacles. Any potential, offshore wind project developer seeking to develop a project in India will not do so unless the conditions are right and they can ultimately make a profit. The industry will therefore be self-controlling in this respect. For this reason, an initial feasibility study may show that a pilot project is not currently commercially viable, however from the interest that has already been generated from the possibility of this industry’s formation, it is widely believed that the time is right.
3.10 Offshore Wind Project Feasibility
3.10.1 Introduction
The first offshore wind projects in India will most likely be developed in the states of Gujarat and Tamil Nadu. Each of these states has a vast coastline with many potential locations for possible projects, however, as was previously discussed in section, there are a number of considerations to take into account before choosing a site for development. When determining the broader areas of search for potential sites and determining the feasibility of specific sites, the following areas should be assessed:
Resource assessment Bathymetry Seabed and geological conditions Environmental considerations Electricity companies and grid Ports and harbours
The initial studies that have been conducted to analyse the offshore wind energy resource in India indicate that there is likely to be a viable, exploitable resource available. A key issue, however, is the availability of grid to many of the relatively remote coastal locations that are being considered for the initial pilot and demonstration projects.
The following sections provide some initial, high level information on each of these topics for the states of Gujarat and Tamil Nadu.
3.10.2 Gujarat
Wind Resource The state of Gujarat in western India is understood to have offshore wind potential and its wind conditions have been the focus of a number of studies. Gujarat currently has around 3.39 GW of onshore wind capacity installed and many onshore sites with annual average wind power densities29 being 200 – 300 W/m2. The diagrams in Figure 41 show the results from previous modelling studies by NIOT that have sought to predict the annual average wind speeds along the Indian coastline. These have estimated that, for much of the year, speeds along Gujarat’s western coast, between Veraval and Dafrabad, are highest and are typically between 6 – 8 m/s. The resource reduces further inland within the Gulf of Khambat reduces in comparison but wind speeds increase again further south towards the state of Maharashtra.
29 http://www.cwet.tn.nic.in/html/departments_ewpp.html
September 2014 51 Status and Prospects of the Offshore Wind Sector in India
Figure 41, Results of offshore wind speed assessment around India’s coast [Source: NIOT24]
Bathymetry The most common foundation solution, a monopile, starts to become economically unviable in depths greater than around 35m and the cost in general for a project using fixed foundations in water deeper than this will rise significantly. For this reason, developers will tend to prefer shallower waters (<20m) and especially those with few, unfavourable seabed features. The cost of projects also rises with distance from shore due to additional cable being required and further transiting for installation and O&M vessels. Projects become far more ambitious and complex further than around 40km from shore and it is likely that developers will prefer to be <20km.
The map in Figure 42 shows the general bathymetry of the waters around Gujarat and that the seabed in this region is relatively shallow and featureless other than the shelving off of the continental plate, far offshore to the west.
Figure 42, The general bathymetric features of the waters around Gujarat and three possible search areas for potential offshore wind sites. [Source: International Seabed Agency30]
Figure 42 also shows the regions along the Gujarat coast that may be suitable for offshore wind projects and could be areas of search for future developments. These regions have been considered in more detail subsequently in Figure 43, Figure 44 and Figure 45. The diagrams in these figures are nautical charts that have been overlaid with guides to show depth (0-20m, 20-35m and +35m) and distance from
30 http://mapserver.isa.org.jm/GIS/
September 2014 52 Status and Prospects of the Offshore Wind Sector in India
shore (20km and 40km). Please note: the stated depth soundings in the following figures are from a 1986 chart and are quoted in fathoms, where 1 fathom = 1.83 m.
Figure 43 shows the region from Dwarka to Veraval and that the depths increase relatively quickly with distance from shore. Generally, most of the sea within the 20 km boundary is less than 35 m deep, however, depths of less than 20 m are only found in areas less than 5 km from the shore. This region may have a good wind resource but it is likely that it will be better suited to later, more ambitious projects, given the unfavourable depths.
Figure 43, The bathymetry along the Gujarat coast from Dwarka to Veraval, showing approximate 20 km and 40 km lines and depth < 20 m in blue and < 35 m in green. [Source: National Imagery and Mapping Agency, US Gov’t, 1986]
Figure 44 provides the overview of conditions between Veraval and Phulsar on the south coast of the main Gujarat peninsular at the entry to the Gulf of Khambat. As with the western stretches of this peninsular, the depth for much of the region to the west of Diu Head, is unfavourable for sites beyond 20 km from shore. The suitability of sites, however, becomes far more favourable east of Jafarabad as shallow water (<20m) extends offshore beyond the 40 km and a number of sand banks are present in the Gulf of Khambat, providing regions of very shallow water even beyond the 40 km boundary.
September 2014 53 Status and Prospects of the Offshore Wind Sector in India
Figure 44, The bathymetry along the Gujarat coast from Veraval to Phulsar, showing approximate 20 km and 40 km lines and depth < 20 m in blue and < 35 m in green. [Source: National Imagery and Mapping Agency, US Gov’t, 1986]
Figure 45 shows the eastern region of the Gulf of Khambat from Hazira to Nala Sopara in the state of Maharashtra. Similarly to the coast of the other side of the gulf, regions of shallow water extend offshore and provide suitable site conditions for early rounds of offshore wind projects. The water in the region < 20 km from shore typically has depths of less than 20m and for much of the area less than 10 km from shore, the depths are less than 10 m.
Figure 45, The bathymetry along the Gujarat coast along the eastern shores of the Gulf of Khambat from Hazira to Nala Sopara (Maharashtra), showing approximate 20 km and 40 km lines and depth < 10 m in
September 2014 54 Status and Prospects of the Offshore Wind Sector in India
turquoise, < 20 m in light blue and < 35 m in green. [Source: National Imagery and Mapping Agency, US Gov’t, 1986]
Ground Conditions Figure 46 shows the geological make-up of Gujarat. The majority of the coastal geology in the regions previously discussed, comprises undifferentiated alluvial and fluvial sedimentary rock of the Quaternary period, identified by the light brown colour. Along the Dwarka to Phulsar coastline, this is interspersed with older Quaternary and Tertiary rock such as the Chaya, Miliolite, Gaj, Babaguru and Dwarka formations31. Tholeiitic basalts are more prominent inland and in the south eastern parts of Gujarat and are identified in Figure 46 by the regions coloured green.
The ground conditions and geology of the offshore areas are not well known, although the geology in deeper areas has been studied for the prospecting of oil. It is likely that the seabed in the regions of interest for offshore wind projects will mostly comprise alluvium, silt, gravels, sands and clays.
Figure 46, Geological map of Gujarat [Source: Geological Survey of India, Government of India, 2012]
Environmental Considerations The Gujarat coastline can broadly be defined by 5 key regions, based on the distinct natural characteristics of each: The Rann of Kachchh, the Saurashtra coast, Gulf of Kutch, Gulf of Khambhat and the South Gujarat coast. These distinct differences between the regions are predominantly due to variations in climate, substrate constituents and topography. A key environmental consideration is that Mangrove forests are present in many of the creeks and estuaries throughout the state. Table 5 shows the main environmentally sensitive, coastal areas in Gujarat.
31 http://guj-nwrws.gujarat.gov.in/downloads/geology_of_gujarat_eng.pdf
September 2014 55 Status and Prospects of the Offshore Wind Sector in India
Table 5, Summary of Gujarat’s Ecologically important, coastal areas: [Source: http://www.annauniv.edu/iom/iomour/EIA%27s%20gujarat.htm]
Ecological Geographic Site Area [km2] Coastal Length [km] Importance Location
131.4 (Mangrove) Gulf Mangrove 20°15' to 23°35'N 1,307.8 (Mangrove) 94.9 (Coral Main) Kachchh Coral Reef 60°05' to 70°22'E 406.5 (Coral) 75.4 (Coral Island)
Gulf of 22°15' to 22°30'N Estuary 6.4 (Mangrove) 2.6 (Mangrove) Khambat 72°15' to 72°30'E
Gujarat has two of the five designated Marine Protection Areas (MPAs) in the country; the Gulf of Kutch (Kachchh) Marine National Park and the Gulf of Kutch Marine Sanctuary. The Gulf of Kachchh, located on in the north west of Gujarat, is designated as both a wildlife sanctuary and a national park, in order to protect the coral reefs and mangroves. The protected area comprises 42 islands, 20 of which have mangroves, while 33 support coral reefs32. Fortunately, the offshore wind resource in the Gulf of Kutch is not as attractive as it is in the southern regions of the state and so it is unlikely that developers will consider this sensitive region. Table 5 shows, however, that the Gulf of Khambat contains some regions of mangrove that may need to be considered when investigating the suitability of sites for offshore wind development.
Electricity Companies and Grid As a part of the reform process, the Government of Gujarat has devolved various functions of Gujarat Electricity Board. As a result, the Gujarat State Electricity Corporation Limited (GSECL) has been given the responsibility for electricity generation within the state. Electricity transmission has been entrusted to the already existing company; Gujarat Energy Transmission Corp. (GETCO). The distribution network in the state has been split between four separate distribution companies, which serve the northern, central, southern, and western regions of the state. These six companies have been structured as subsidiaries of a parent holding company, Gujarat Urja Vikas Nigam Limited (GUVNL). GUVNL is also the single bulk buyer in the state as well as the bulk supplier to distribution companies and also carries out the trading function in the state. Figure 47 shows the new structure of the various companies within Gujarat’s electricity sector and shows the split from the single state electricity board to the various organisations after the reform process.
32 http://aquaticcommons.org/1562/1/Samudra_mon5.pdf
September 2014 56 Status and Prospects of the Offshore Wind Sector in India
Figure 47, The new structure of the electricity generation, transmission and supply companies in Gujarat.
[Source: http://www.guvnl.com/guvnl/Content.aspx?ContentId=6]
For offshore wind projects, one of the relevant power distribution companies is PGVCL33 which supplies electricity in 8 districts of Gujarat namely Rajkot, Jamnagar, Junagadh, Porbandar, Bhuj, Bhavnagar, Surendranagar and Amreli covering total 83 Talukas. For better administration and consumers' conveniences, the company’s administrative area is divided into 11 circles of which 6 are under direct control of Corporate Office, 4 circles are under the control of Bhavnagar Zonal Office and 1 circle under the control of Bhuj Zonal Office. The arrangement of these regions and PGVCL’s limits are shown in Figure 48.
Figure 48, The extent of PGVCL's remit [Source: PGVCL]
33 http://www.pgvcl.com/
September 2014 57 Status and Prospects of the Offshore Wind Sector in India
The other power distribution company of interest for offshore wind projects is DGVCL. This company is responsible for the southern region of Gujarat up to the border with Maharashtra and covers 7 districts of Gujarat, with a total area of 23,703 km2 and has a total connected load of around 6 GW.
Figure 49, The remit of supply for DGVCL within southern Gujarat [Source: DGVCL34]
Figure 50 shows the general arrangement of the transmission and distribution grid within Gujarat. A key feature to note is that, currently, there are few potential grid connection locations along the northern shores or the Gulf of Khambhat as much of the grid that appears in Figure 50 is actually proposed rather than existing. Nevertheless, there are a number of generating plants that are proposed along this coastline and so there is scope for future offshore wind projects to utilise their grid connections or be developed alongside their projects. The eastern shores of the Gulf of Khambhat, however, has a much stronger grid with a number of generating stations and 220kV substations close to shore. Connection to any of these points, therefore, may be relatively straightforward, depending on the spare capacity of the existing grid.
34 http://www.dgvcl.com/dgvclweb/images/DGVCLMAP.jpg
September 2014 58 Status and Prospects of the Offshore Wind Sector in India
Figure 50, The distribution of electricity generation and grid in Gujarat in 2012. [Source: GETCO]
Ports and Harbours Having a coastline of 1,600 km, Gujarat is the nearest maritime outlet to Middle East, Africa and Europe. The state has the highest number of operational and commercial cargo ports in India. There are 41 ports, of which Kandla is a major port and, of the remaining 40 ports, 11 are intermediate and 29 are minor ports which are under the control of Gujarat Maritime Board, although only 19 of these 41 ports are, however, operational35. These ports can be broadly classified into three categories.
Three all-weather ports, Porbandar, Okha and Sikka ,with all-weather direct berthing facilities. Seven ports are all weather light ports. The remaining thirty ports are fair weather light ports for sailing vessels and fishing boats.
35 http://www.deloitte.com/assets/Dcom-India/Local%20Assets/Documents/aport%20connectivity.pdf
September 2014 59 Status and Prospects of the Offshore Wind Sector in India
Figure 51 shows the locations of the key ports in Gujarat, which may be suitable for use in the construction of offshore wind projects.
Figure 51, The locations of the key ports along Gujarat's coastline.
Pipavav Port
Pipavav port, located on the south of the main Gujarat peninsular, commenced operations in 1996 as was India’s first private sector port. It has two main quays providing over 1,800m of dockside length with a draft of up to 14.5 m. The port has large areas of laydown space that could be made suitable for offshore wind component assembly and load-out for construction
Mundra Port
The port of Mundra is located in northern Gujarat in the Gulf of Kutch. It has numerous berths over various docksides and typically provides for drafts in excess of 15 m. Mundra (Adani) is currently the largest private port in India, having a total area of around 10,000 acres. The port has 225,000 m2 of closed go- downs and 3,150,000 m2 of open storage yards for storage of import or export cargo. Whilst the port is extremely large and capable for offshore wind construction activities, its distance from the likely locations of many projects will mean it is not suitable for installation activities.
Kandla Port
The Port of Kandla offers 12 dry cargo berths with a total quay length of 2532 metres and a maximum draft of around 11.2 m. It also operates six oil jetties, one deep-draught mooring, and four cargo moorings in the inner harbour. The Port of Kandla contains 253 hectares with over 1million m2 of lay down area. Similarly to Mundra, however, its location may make it unsuitable for offshore wind construction activities.
September 2014 60 Status and Prospects of the Offshore Wind Sector in India
Porbandar Port
Portbandar is an artificially protected port, offering all weather operations. It is located on the western coast of the main Gujarat peninsular. It provides a quay with a total available length of 385 m (235 m GMB wharf and 150 m private jetty) with permissible draught up to 9.8 m. The port’s total area covers over 930 Ha and comprises 241,173 m2 of laydown down facilities.
Okha Port
The port at Okha, at the mouth of the Gulf of Kutch, provides a naturally protected harbour that can be used in all weathers. It has an anchorage area 1.3 nm offshore, suitable for vessels of up to 9 m draft. It has two main berth areas; the Sayaji pier provides 180m long dockside with water depths of 8 m; and a dry cargo berth provides 145 m long, dock also with depths of 8 m.
Hazira Port
This port is a deep-water, all-weather port with 2 breakwaters and an additional waterfront for the development of non-LNG cargo handling facilities. Its primary role is the landing of LNG and has an LNG jetty with an LNG storage and re-gasification terminal. The port has been operational since April 2005 with an investment of over Rs. 3,000 crore. In addition to the LNG facilities, the port has two container jetties and three multi-purpose jetties in the non LNG Port area. The approach and port are dredged36 to a depth of -13 m CD which allows vessels with a draft of up to 12.3 m.
Figure 52, Laydown area for turbines destined for the London Array, demonstrating the space required. [Source: Siemens]
3.10.3 Tamil Nadu
Tamil Nadu is situated at the south eastern region of the Indian peninsula and is bordered to the north by the states of Andhra Pradesh and Karnataka and on the west by the state of Kerala. The state has a tropical climate with only slight seasonal variations and the temperature and humidity remain relatively high throughout the year (Typically 20° C to 38° C). The South West Monsoon season is from June to September and the North East Monsoon is from October to December. Both seasons bring rains and seasonal winds.
In addition to Gujarat, Tamil Nadu has also been identified as a location for possible, future offshore wind projects as it is well known that the state has a good wind resource which is coupled with relatively shallow waters. Tamil Nadu is also the home of C-WET which is based in Chennai and has numerous activities within the state including a large met mast that it has erected on a spit of land in Palk Bay.
36 http://www.haziralngandport.com/harbour_details.htm
September 2014 61 Status and Prospects of the Offshore Wind Sector in India
Wind Resource From the initial, desktop wind resource assessment modelling, in Figure 38, it can be seen that Tamil Nadu features a couple of interesting regions that appear to exhibit higher wind speeds than along the rest of the state’s coast. These regions are within the Palk Straits, between India and Sri Lanka, and off the southernmost tip of India.
C-WET recently erected a 100 m tall, met mast at Rameshwaram on the spit of land that protrudes between Palk Bay and the Gulf of Mannar. This mast is located onshore but will provide a good indication of the near, offshore wind conditions in the region. This will be useful in helping to validate numerical models of the wind resource.
Typically, the lightest winds blow in March and April (5.0 - 5.5 m/s) and also fairly slow winds in October and November (~ 7 m/s). Higher wind speeds occur between May to September and during December where typical speeds of 8.0 - 9.5 m/s are common. An NICOIS report37 concluded that annual average wind speed of between 6-8 m/s are present along most of the Tamil Nadu coast at an 80 m height. Furthermore, it is also estimated that much of the Tamil Nadu region has offshore winds > 8 m/s for 200 days of a given year. Figure 53 shows the outputs of some desktop modelling conducted by Riso to provide an assessment of the average annual wind speeds within the Gulf of Mannar and southern Palk Bay. The study used wind speeds derived from satellite data but does not indicate a particularly energetic resource available within the region. Some of the highest wind speeds are located far offshore within the Gulf, where the extremely deep water would prohibit offshore wind deployment with current technology. Further modelling and site data for validation will be required to better determine the offshore energy resource and whether the shallow water sites are energetic enough to make projects viable.
Figure 53, Typical annual average wind speeds for the Bay of Mannar and Palk Bay [Source: Riso38]
37 The assessment of wind energy potential along the Indian coast for offshore wind farm advisories 38 Offshore Wind Potential in South India from Synthetic Aperture Radar, Riso-R, 2011.
September 2014 62 Status and Prospects of the Offshore Wind Sector in India
Bathymetry From an initial review of the bathymetry along the Tamil Nadu coast, see Figure 54, the continental shelf appears to extend a reasonable distance offshore and provides relatively shallow waters in the areas of interest identified from the typical wind speeds. Figure 54 suggests four key regions of search for possible offshore wind projects in Tamil Nadu’s waters; these encompass the southern tip of India, the Gulf of Mannar, Palk Bay, Palk Straits and the section of eastern coast up to Pondicherry. More detailed assessments of the bathymetry in these regions is given in this section.
Figure 54, General bathymetric features of Tamil Nadu's waters, showing four highlighted regions which are possible search areas for offshore wind farm sites. [Source: International Seabed Authority39]
Figure 55 shows the bathymetry around the southern tip of India. This can be seen to shelve of relatively close to shore on the western coast of the region, whereas shallow water extends much further offshore along the eastern coast. The eastern waters of this region also contain a number of sandbanks which help to maintain a shallow depth, however, their benefit to offshore wind projects will depend on their dynamics and how they would behave if a wind farm were to be installed on them. Marine currents, coupled with these sandy deposits may also bring about issues of scour which would have to be addressed.
39 http://mapserver.isa.org.jm/GIS/
September 2014 63 Status and Prospects of the Offshore Wind Sector in India
Figure 55, The bathymetry around the southern tip of India. [Source: National Imagery and Mapping Agency40, US Gov’t, 2001]
The Gulf of Mannar has large amount of shallow water that would be well suited for offshore wind projects. Figure 56 shows that there are large regions of water with depths of less than 10m (light blue) although, this shelves of fairly steeply a little further offshore. Unfortunately, however, this region has a number of significant environmental considerations that are likely to prevent offshore wind projects from being developed here. These environmental issues are further considered in the section that follows.
Figure 56, The coast along the Gulf of Mannar [Source: National Imagery and Mapping Agency41, US Gov’t, 2001]
40 http://www.nauticalchartsonline.com/chart/zoom?chart=63220 41 http://www.nauticalchartsonline.com/chart/detail/63250-Palk-Strait-and-Gulf-of-Mannar
September 2014 64 Status and Prospects of the Offshore Wind Sector in India
Further along the coast from the Gulf of Mannar is the Palk Bay which is located between the coasts of India and Sri Lanka. This whole bay has shallow water depths that are well suited to offshore wind projects and the deepest region in whole bay is about 15m. Figure 57 shows the bathymetry in the bay with water shaded light blue <10m and dark blue <20m. Almost all of the seabed within the first 20km offshore (first red line) has water depths of less than 10m. Even up to the 40km line (second red line) much of the water is <10m and does not exceed 12m.
Figure 57, The bathymetry of Palk Bay. [Source: National Imagery and Mapping Agency, US Gov’t, 2001]
Error! Reference source not found. shows that wind appears to be funnelled through the Palk Strait etween the two headlands. This could make it an ideal region for offshore wind projects as the area is very shallow as is shown in Figure 58. The strait is characterised by three channels (North, Middle and East) and by two groups of sandbanks (Middle Banks and South Banks) located within the strait and separate the channels. A consequence of these features is that tidal flows that are funnelled through the straits are also accelerated through the three channels and so local tidal flows may be strong at times, although the charts state that typically tidal velocities are around 1 knot. Scour may be an issue in this region depending on the placement of projects and turbines. Furthermore, the navigation of vessels through the straits could be restricted by the presence of an offshore wind farm and would increase the risk of collision unless very well lit and marked.
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Figure 58, Palk Strait between Tamil Nadu and Sri Lanka all of the region in blue is less than 20m depth and majority of the straight is <10m – 1984 charts (Green is <35m) [Source: National Imagery and Mapping Agency, US Gov’t, 2001]
Further up the coast, just north of Palk Straits is a large stretch of coastline with relatively few coastal features. Within Tamil Nadu, this continues, in much the same way, up to Chennai however, only the region up to just north of Pondicherry is shown in Figure 59. These two, 200km coastal stretches have relatively shallow water depths although this is more the case in the southerly waters. The region just north of the Palk Straits has similar depths to Palk Bay, with most of the first 20km offshore being <10m deep. For the rest of the coastline, the first 20km offshore is typically <20m deep, however, some regions (green) are 20-30m deep and may be better suited to 2nd and 3rd generation projects that could developed after India has gained project experience.
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Figure 59, Two 200km stretches of the Tamil Nadu coast (left centred on Pondicherry, right has Strait at its lowest point), [Source: National Imagery and Mapping Agency, US Gov’t, 2001]
Ground Conditions Typically, the geology of the Tamil Nadu coastline is characterised by coastal sediments with underlying sedimentary rock and some outcrops of Charnockite. In the northern and southern regions of the state the geology is mostly quartz rich, igneous rock. Figure 60 provides an overview map of the geology in Tamil Nadu and suggests that the offshore ground conditions are most likely to be soft, with clays and sedimentary rock covered with sand. This is useful for assessing high level, offshore wind feasibility as it shows that no hard rock formations are likely to be present in the offshore regions.
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Figure 60, Geological map of the state of Tamil Nadu [Source: Geological Survey of India, 2006]
Environmental Considerations The coastline of Tamil Nadu has a length of about 1,076 km, constitutes about a 15% of the total coastal length of India and stretches along Bay of Bengal, Arabian Sea and Indian Ocean. Realizing the importance of the coastal ecosystems, Coastal Regulation Zone notification was issued in 1991 and the coastal areas have been classified into four categories (CRZ I, II, III and IV). The ecologically sensitive areas are included under CRZ-I, where no human activity is allowed. Tamil Nadu’s ecologically sensitive CRZ-1 areas include; the Pulicat bird sanctuary, Kaliveli backwaters, Pichavaram mangroves, Vedaranyam Wildlife sanctuary, Muthupet mangroves, Ramanathapuram mangroves and Gulf of Mannar biosphere reserve.
Gulf of Mannar Marine Biosphere Reserve (GOMMBRE) is the first Marine Biosphere Reserve not only in India, but in South and Southeast Asia. The Gulf of Mannar Marine National Park covers an area of around 560 km2 from Rameswaram to Tuticorin and resides within the GOMMBRE which, itself, covers an area of 10,500 km2. Figure 61 shows the islands within the GOMMBRE and the extent of the biosphere. This region may be attractive to offshore wind development due to reasonable wind conditions and shallow water, however, it is likely to be challenging to obtain consent.
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Figure 61, The 21 islands within the Marine Biosphere in the Gulf of Mannar [Source: Department of Ocean Development, Government of India]
In addition to the Mannar biosphere and national park, there are a number of other environmentally sensitive areas along the Tamil Nadu coast that should be avoided by offshore wind developers. These are summarised in Table 6 and their locations are provided in the map in Figure 62. Table 6, Environmentally sensitive regions along the Tamil Nadu coast [Source: http://tnenvis.nic.in/tnenvis_old/coastal%20data.pdf]
Ecological Location Site Area [km2] Importance
Thiruvallur Pulicat Lake Lagoon 252.0
Cuddalore Pichavaram Mangroves 10.6
Nagapattinam Vedaranyam & Muthupettai Mangroves 24.5
Ramnad Gulf of Mannar (21 islands) Coral reefs 63.2
Figure 62, Key environmentally sensitive, coastal areas in the state of Tamil Nadu [Source: Institute for Ocean Management, Anna University]
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An important consideration to potential offshore wind developers is that the Tamil Nadu coast is particularly vulnerable to cyclones and storm surges, which will have implications on offshore foundation design, installation planning and the location of onshore infrastructure. Tamil Nadu’s coast also suffers large issues with coastal erosion and so any project infrastructure or activities should ensure that they do not exacerbate these issues.
There are a number of oil exploration and production activities being carried out in the waters around Tamil Nadu, including in the regions of Koilkalapai, Narimanam, Bhuvanagiri and Palk bay. This may help to set a precedent for offshore wind development and help to provide information on the local environmental and physical conditions.
Electricity Companies and Grid Electricity generation and distribution in the state of Tamil Nadu is the responsibility of the Tamil Nadu Electricity Board (TNEB) which was formed in 2010 and is a holding company with two subsidiary companies; the Tamil Nadu Transmission Corporation Ltd. (TANTRANSCO) and the Tamil Nadu Generation and Distribution Corporation Ltd., (TANGEDCO).
TANTRANSCO has a total length of transmission lines of around 25,000 km and 842 substations42, including 72 220kV substations and 14 400kV substations. Much of the existing transmission infrastructure has been upgraded to 400kV from 220kV in the past couple of decades and TANTRANSCO is currently considering a further upgrade to 765kV.
TANGEDCO has around 10,237 MW of grid connected, electrical generation capacity which includes Central share and Independent Power Producers. Key components of this are coal, thermal power stations at Ennore (450 MW), Mettur (1440 MW), North Chennai (1830 MW) and Tuticorin (1050 MW) and the nuclear power plants, MAPS (331 MW) and Kaiga (Karnataka) (227 MW).
In addition to this non-renewable generation, the state has a range of renewable electricity sources such as wind, hydro, biomass and cogeneration which provides an additional capacity of around 7303 MW. Currently43, the total installed capacity in Tamil Nadu is 17,540 MW.
Figure 63 shows the arrangement of the electrical grid (>220kV) and generating stations in southern India. This is useful for providing a rough overview of the grid connections that may be available for offshore wind projects along the Tamil Nadu coastline. At the tip of Tamil Nadu, to the west of the Gulf of Mannar there is a thermal power station at Tuticorin and further south and west is the nuclear station at Kudankulam. These could provide some scope for local grid connections to the 220kV transmission network in those areas. The area around Rameshwaram is served by the thermal gas power station (187 MW) at Valuthur which provides the only transmission grid in the area. Generally, there is poor transmission grid availability around the Palk Bay and Palk Strait coastal regions which could have significant implications on future projects, particularly as this appears to be a fairly attractive region for offshore wind development. There is some coastal connectivity some distance north up the coast from the Palk Strait towards Cuddalore, but there is a fairly large gap between the two. Generally, the grid density improves north of Pondicherry up towards Chennai with a number of substations in coastal regions.
42 TANTRANSCO: http://www.tantransco.gov.in/template_4.php?tempno=4&cid=0&subcid=209 43 TANGEDCO: http://www.tangedco.gov.in/template1.php?tempno=1&cid=0&subcid=184
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The lack of transmission grid infrastructure along many coastal stretches of Tamil Nadu could limit the available locations for offshore wind projects. If new onshore transmission lines are required to join the two, the financial viability of a project would likely be very significantly reduced.
Figure 63, The power map of Tamil Nadu and Southern India, showing power stations, substations and the 220kV and 400kV grids. [Source: Central Board of Irrigation and Power44, 2008]
Ports and Harbours Tamil Nadu has the second longest coastline (1,076 km) with 3 major ports and 17 non-major ports. The non-major ports in Tamil Nadu were administered and controlled by the Tamil Nadu Port Department. The major ports come under the control of Government of India whereas the minor ports come under the
44 http://cbip.org/power_map.html#
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control of the State Government. The Tamil Nadu Maritime Board is responsible for administering, controlling, regulating and managing the minor ports in Tamil Nadu.
Tamil Nadu has45 three major ports at Ennore, Chennai and Thoothukudi which are under the administrative control of the Government of India. In addition, Tamil Nadu has fifteen minor ports, which are under the control of Government of Tamil Nadu, at Cuddalore, Nagapattinam, Pamban, Rameswaram, Valinokkam, Kanyakumari, Colachel, Kattupalli, Ennore, Thiruchopuram, PY-03 Oil Field, Thirukkadaiyur, Punnakkayal, Koodankulam and Manappad.
Figure 64, The main ports of Tamil Nadu that are most likely suited for offshore wind construction
Chennai
Chennai Port, formerly known as Madras Port, is the second largest port of India after the port at Mumbai. Chennai port has three main docks, with a total of 24 berths and draft ranging from 12m to 16.5m. It mostly handles container cargo, cars and general cargo, and has become an important hub port for containers. It has a total open, laydown area of 384,611 m2 and so it is likely that part of the port could be made suitable for offshore wind.
Ennore
The port of Ennore is north of Chennai and was created to deliver coal to the North Chennai, thermal power station. The port has 5 main berths, with each providing a draft of up to 13.5 m and catering for vessel lengths of up to 260 m. The port encompasses an area of around 8 km2 and, with necessary modifications, could become suitable as an offshore construction port.
45 Minor Ports Development Policy of Tamil Nadu : http://www.investingintamilnadu.com/tamilnadu/doc/policy/Tamil_Nadu_Minor_Port_Policy_2007.pdf
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Kattupalli
Kattupalli is the third port in the vicinity of Chennai and is located to the north of Ennore port. The port is currently undergoing significant development with the aim of turning it into one of the largest ports in Asia. It has a maximum permissible draft of 14 m, total quay length of 3.35 km and provides a total, open laydown area of 200,000 m2.
Cuddalore
This port is located at the confluence of the Rivers Uppanar & Paravanar and is a small port in comparison to the others mentioned here, however, with a reasonable amount of development, it may be suitable for some vessels and to act as a supporting port for any projects in the vicinity. Currently, the port only has a 4 m depth available at the quayside and the port entrance is around 2.5 – 3.0 m deep at low tide time. Nevertheless, there is some laydown space and quayside length available.
Karaikal
The port at Karaikal currently handles mostly coal, iron ore and gypsum and provides an open storage area of 600,000 m2. The owners, MARG Group, have ambitious plans to develop the port into a very capable cargo port that will provide 9 berths with two being able to accept Panamax size vessels for general cargo. The berths have a permissible draft of around 14.5 m and can accept vessels in excess of 300 m in length. As this port develops, it is likely that it could be an important piece of infrastructure for installing offshore wind projects in and around Palk Bay, although it is likely to be at least 100 km away from any sites.
Tuticorin
The port at Tuticorin is one of the only large ports on the southern tip of India and is located in the Gulf of Mannar, making it convenient for future offshore wind projects. It currently accepts a large amount of coal, that is delivered to the adjacent power station but also provides facilities for large container ships and can handle a significant amount of cargo. Five of its berths provide a draft of 12.8 m and all of them provide at least 8 m. The port has over 500,000 m2 of open storage space available and, as Figure 66 shows, it is already utilised by Tamil Nadu’s onshore wind industry.
Figure 65, The layout of the port at Tuticorin [Source: V.O.Chidambaranar Port Trust]
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Figure 66, The port at Tuticorin is already in use for the delivery of onshore wind turbine components for use in projects in Tamil Nadu.
3.11 Indian Supply Chain Potential
India’s supply chain for onshore wind has been growing since the first turbines were installed in the early 1990s. Currently, India has the capacity to manufacturer around 3,000 MW of domestic wind turbines per year. A range of technology types are currently deployed in India; ranging from the smaller, sub 500kW devices that are typically developed and manufactured within the country; to the larger MW scale devices that are usually supplied by larger OEMs, in many cases using a predominantly international supply chain. The trend for vertical integration in the bigger OEM turbine suppliers including Vestas, Siemens, GE, Gamesa, and Suzlon has meant that the supply of key components such as blades, gearboxes, generators and controllers have been from in-house arms of the companies, although they also still source some components from other suppliers. In the case of India OEM suppliers such as Suzlon, these have maintained some indigenous supply chain from local manufacturing companies but also utilise a range of international suppliers. In recent years, Indian policies have encouraged local wind turbine manufacturing through the application of customs and excise duties in order to favour importing individual wind turbine components rather than importing complete devices. Up to around 70 % of sub-500kW wind turbines is typically sourced from within the country, however, the import content of higher capacity, multi- MW machines is higher.
The use of India’s supply chain for the supply of components for offshore wind is likely to be limited until domestic turbine manufacturers, such as Suzlon, develop offshore capable turbines. The reliability of offshore devices is critical for a successful project as those that are plagued with unreliable turbines, requiring regular interventions will incur large operational costs which are far more significant than for the onshore equivalent. Initially, therefore, developers are likely to favour well proven offshore wind technology to remove the risk of unreliable technology. Nevertheless, there are a number of other manufacturing and supply opportunities that are likely to be present for Indian suppliers. These may include the fabrication and supply of foundations, construction of onshore substations and grid connections and the development of dedicated O&M ports.
The role of overseas companies in the initial offshore wind projects will be vital in providing the European experience in offshore wind to the inexperienced companies/interested parties in India, which want to venture into the new sector. It is likely, therefore, that India will rely on international companies for the following roles:
Offshore wind measurement campaign: It could be undertaken by the overseas companies in the initial stages of project development and post-measurement scenario too. The companies could provide optimised offshore wind farm layouts etc.
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Design and development: The design would include support foundations for the met-mast, turbines and sub-stations. Offshore wind turbines: In the absence of any Indian company manufacturing offshore wind turbines, the overseas companies may find an opportunity to assemble the turbines in India for the use in domestic projects. Offshore construction logistics: India has some experience in working offshore but does not possess the experience of European companies in the construction of offshore wind farms. It is likely that these companies could supply services to the initial projects and train local firms. Supply of specialist vessels: Suitable vessels which could rapidly undertake offshore wind construction work are unavailable in the region. Despite the long distance and large mobilisation times, these could be supplied by overseas companies. O&M: The operation of offshore wind farms and their maintenance would need the experience of overseas companies post commissioning and during the grid connectivity stage. Such companies could form a joint venture or could mutually undertake the entire responsibility and progressively train the domestic skills available for the offshore wind farms.
Offshore wind power development in India needs a broad based and a multi-disciplinary knowledge and practical competence skill base. The capacity building initiatives as such would involve the participation of the foreign companies with sound exposure to such practices in tandem with the expertise available with the Indian companies. A large number of training modules are thus expected to be developed in an all-inclusive manner for meaningful dissemination amongst the interested group of stakeholders at multiple levels.
In addition, India’s offshore oil and gas industry and its supply chain, may also be able to fill in some of the supply gaps with goods and services that the onshore wind industry cannot provide. Its lessons and experiences gained in working offshore can rapidly be transferred into the developing offshore wind sector.
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4 CONCLUSIONS
Offshore wind is now meaningfully contributing to the electricity mix in a number of different countries and the rate that projects are being rolled out is increasing. In conjunction with this, and as a direct result of the increasing capacity, the costs of offshore wind are reducing. Due to the numerous challenges and risk, however, offshore wind is still a comparatively expensive renewable electricity source and requires favourable political and financial support for it to be economically viable. Nevertheless, for countries that have an exploitable resource and suitable conditions, offshore wind is proving to be a popular option to supplement other renewable energy sources like hydro, solar and onshore wind.
The UK has led the world in the large scale development of offshore wind and has more operational offshore wind capacity than the rest of the world combined. Over the past 15 years the UK has delivered around 3,700 MW of new capacity from over 1,100 turbines and now supplies around 15 TWh of energy per year. Along the way, the UK has learnt many lessons from policy and financing to technical and engineering related issues. Developing industries such as India’s, can learn from these lessons to help avoid the mistakes made by the UK’s sector in its development and to apply the successful elements of the UK’s experience to help advance at a quicker, more successful rate than if just learning on its own. India can also benefit from the knowledge and expertise that can be provided by UK companies that will help to fill the gaps in the supply chain in India for the initial projects and until sufficient capacity can be built in the country to allow local contractors to take on more roles within the development of projects.
Offshore wind could be a viable option for India, providing that the right political will is established and the local supply chain responds to the development of initial projects. Minimising costs will be a key objective in future Indian projects in order for offshore wind to be even remotely competitive amongst the other renewable electricity generation sources. Whilst the cost of energy of offshore wind in India is likely to be comparatively cheaper than for many of the other countries currently developing offshore wind projects, it will be higher than onshore wind and will therefore require a sufficient subsidy or incentive to allow it to be cost competitive with other forms of renewable energy, until the costs can reduce. It is important, however, that quality and safety are not sacrificed in the goal to reduce costs. Successful pilot projects need to be developed in order to demonstrate the technology and attract project developers to finance future projects. Failures and incidents in these early projects will significantly hamper the growth of the industry and should be avoided.
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