Report for Installation of Lidar Based Offshore Structure for Wind Measurement

Report for Installation of LiDar based Offshore Structure for wind measurement

Submitted to

Ministry of Environment and Forest Government of India Delhi – 110003

SAMIRAN UDAIPUR WINDFARMS LIMITED Ahmedabad

Technical Consultant National Institute of Ocean Technology Ministry of Earth Sciences, Govt. of India Chennai -600 100 February 2016

Table of Contents Table of Figures ...... 4 List of Tables ...... 4 1. Form 1 ...... 5 2. Executive summary ...... 21 3. Introduction ...... 21 3.1. Need for Renewable Energy & World Scenario ...... 21 3.2. Offshore Wind Potential in India and wind energy Policy ...... 22 3.3. SUWL, SEL and NIOT involvement ...... 24 4. Project Description...... 24 4.1. Site Details ...... 24 4.2. Bathymetry & Physical Processes ...... 25 4.2.1. Bathymetry ...... 25

4.2.2. Tide ...... 25

4.2.3. Currents ...... 26

4.2.4. Wave ...... 26

4.2.5. Rainfall ...... 26

5. Proposed Data collection Mast ...... 26 5.1. Description with layout ...... 26 5.2. Structural Design ...... 27 4.2.1. Basic Load ...... 27 5.2.1.1. Dead load...... 27

5.2.1.2. Live Load ...... 28

5.2.1.3. Wind loads...... 28

5.2.1.4. Hydrodynamic loads ...... 28

5.2.1.5. Seismic loads ...... 30

5.2.2. Load Combinations...... 32 5.2.3. Monopile ...... 32 5.2.4. Cyclones ...... 33 5.2.4.1. Axial Compression: ...... 34

5.2.4.2. Elastic Local Buckling Stress ...... 34

5.2.4.3. Inelastic local buckling Stress...... 34

5.2.4.4. Allowable Bending Stress: ...... 36

5.2.5. Earth Quake ...... 36 5.2.5.1. Member Capacity for Earthquake Load Combination: ...... 37

5.2.6. Boat Impact ...... 37 5.2.6.1. Member Capacity for Boat Impact Combination: ...... 37

5.2.7. Platform...... 38 5.2.7.1. Material Properties ...... 38

5.2.7.2. Loads & Load combinations ...... 39

5.2.7.3. Staad Results ...... 40

5.2.7.4. Sectional Classification ...... 41

5.2.7.5. Shear Capacity ...... 41

5.2.7.6. Moment Capacity ...... 42

5.2.7.7. Check for deflections ...... 42

5.2.7.8. Check for web buckling ...... 42

5.2.7.9. Check for web bearing ...... 43

5.2.7.10. Check for stiffeners ...... 43

5.2.7.11. Check for compression flange buckling ...... 43

5.2.7.12. Secondary beams ...... 44

5.2.7.13. Sectional Classification ...... 44

5.2.7.14. Shear Capacity ...... 44

5.2.7.15. Moment Capacity ...... 45

5.2.7.16. Check for deflections ...... 45

5.2.8.17. Check for web buckling ...... 46

5.2.7.18. Check for web bearing ...... 46

5.2.7.19. Check for stiffeners ...... 46

5.2.7.20. Check for compression flange buckling ...... 47

5.2.7.21. Welded Connection design ...... 47

6. Installation procedure...... 48 6.1. Decommissioning procedure ...... 49 6.2. Construction and operational impact assessment ...... 50 6.2.1. Noise level ...... 50

6.2.2. Air Environment ...... 50

6.2.3. Water Environment ...... 50

6.2.4. Fishery...... 50

7. Project Schedule and cost estimates ...... 51 7.1 Project Schedule...... 51

7.2 Cost estimate ...... 51

Table of Figures s Fig. 1 Installed Cumulative Capacity in European countries (Source: EWEA, (2013)) ...... 22 Fig. 2 Wind Speed Distribution at 80m Elevation ...... 23 Fig. 3 Power Production for 3 MW Offshore Wind Turbine...... 23 Fig. 4 Google earth map –Jakhau ...... 23 Fig. 5 Topography map(20km buffer)-Jakhau ...... 23 Fig. 6 Regional Connectivity map-Jakhau ...... 23 Fig. 7 Topography map-Jakhau ...... 23 Fig. 8 Hydrographic map-Jakhau ...... 23 Fig. 9 Bathymetry profile for the prosed site ...... 25 Fig. 10 Layout of Supporting Platform for LiDar...... 27 Fig. 11 Current profile for operational and critical condition ...... 28 Fig. 12 Regions of Applicability of Various Wave Theories ...... 30 Fig. 13 Seismic zone of India ...... 31 Fig. 14 Acceleration Spectrum ...... 32 Fig. 15 Deflected Profiles for Various Sea States ...... 33 Fig. 16 Installation methodology for wind mast ...... 49

List of Tables Table 1 Instruments for collecting various Parameters...... 26 Table 2 Waves Parameters ...... 29 Table 3 Soil Parameters for Different Layers ...... 33

1. Form 1 (For seeking clearance for project attracting CRZ notification) Name of the project: Installation of Lidar based Offshore structure for wind measurement CRZ classification of the CRZ-IV area: Expected cost of the 4 crore project: (I) Basic Information Sr Item Details No. Installation of Lidar based Offshore 1. Name of the project/s structure for wind measurement in Jakhau 2. S. No. in the schedule 1.2m diameter monopile to support Proposed capacity/area/length/tonnage to 5m diameter platform which is 3. be handled/command area/lease located at 7.5m clearance above area/number of wells to be drilled water level 4. New/Expansion/Modernization New 5. Existing Capacity/Area etc. Not Applicable 6. Category of Project i.e. ‘A’ or ‘B’ B1 Does it attract the general condition? If No 7. yes, please specify. Does it attract the specific condition? If No 8. yes, please specify. 9. N23o 07’ 24.42” E 68o 27’ 48.24” Location:

Plot/Survey/Khasra No. NA Village Jakhau Tehsil Abdasa

Sr Item Details No. District Kutch State Gujarat Naliya (28km from Jakhau). Nearest railway station/airport along with 10. distance in km Bhuj (120km from Jakhau)

Naliya is the district headquarters Nearest Town, city, District Headquarters 11. located 28km away from this along with distance in km. location Village Panchayats, Zilla Parishad, Offshore facility near Jakhau port. 12. Municipal Corporation, Local body (complete postal addresses with telephone nos. to be given) 13. Name of the applicant Samiran Udaipur Windfarms Limited C/o Suzlon Energy Limited Suzlon House, 5,Shrimali Society, 14. Registered Address Near Sri Krishna Complex Navrangpura,Ahmedabad-380009 Gujarat India 15. Address for correspondence : Mr. Ranjit Singh Parmar Name

Designation (Owner/Partner/CEO) Sr. President-India Business C/o Suzlon Energy Limited Suzlon House, Address 5,Shrimali Society, Near Sri Krishna Complex Navrangpura,Ahmedabad-380009

Sr Item Details No. Gujarat India Pin Code 380009 E-mail [email protected] Telephone No. 079-66045201, 66045000 Fax No. 079-26565540, 26442844 Details of Alternative Sites examined, if 16. any. Location of these sites should be NA shown on a topo sheet 17. Interlinked Projects None Whether separate application of NA 18. interlinked project has been submitted? 19. If yes, date of submission - 20. If no, reason - Whether the proposal involves ( c ) 21. approval/clearance under: if yes, details of the same and their status to be given. (a) The Forest (Conservation) Act, 1980? (b) The Wildlife (Protection) Act, 1972? (c) The C.R.Z Notification, 1991? Whether there is any Government Offshore wind energy policy of 22. Order/Policy relevant/relating to the site? Ministry New and Renewable Energy 23. Forest land involved (hectares) None Whether there is any litigation pending None 24. against the project and/or land in which the project is propose to be set up? (a) Name of the Court (b) Case No. (c) Orders/directions of the Court, if any None

Sr Item Details No. and its relevance with the proposed project.

(II) Activity 1. Construction, operation or decommissioning of the project involving actions which will cause physical changes in the locality (topography, land use, changes in water bodies and the like) S.No Information/Check list Yes/ confirmation No 1.1 Permanent or temporary No The proposed site is 18km from the shore change in land use, land cover and hence there is no change in the land or topography including use increase in intensity of land use (with respect to local land use plan) 1.2 Details of CRZ classification as CRZ IV as per CRZ notification 2011 per the approved Coastal Zone Management Plan? 1.3 Whether located in CRZ -1 No Not Applicable. area? 1.4 The distance from the CRZ – I - 16.3km areas? 1.5 Whether located within the No Not Applicable. hazard zone as mapped by Ministry of Environment & Forests/National Disaster Management Authority? 1.6 Whether the area is prone to Yes Extreme conditions such as cyclone and cyclone, tsunami, tidal surge, earthquake are being considered in subduction, earth quake etc.? structural design of the Wind Mast.

S.No Information/Check list Yes/ confirmation No 1.7 Whether the area is prone for No Not Applicable. salt water ingress? 1.8 Clearance of existing land, No Not Applicable. vegetation & buildings? 1.9 Creation of new land uses? No Not Applicable 1.10 Pre-construction investigations No Not Applicable e.g., borehole, soil testing? 1.11 Construction works Yes Pile driving and erection of structure.

1.12 Demolition works? No Not Applicable 1.13 Temporary site used for No Not Applicable construction works or housing of construction workers? 1.14 Above ground buildings, No Not Applicable structures or earth works including linear structures, cut and fill or excavations 1.15 Underground works including No Not Applicable mining or tunneling? 1.16 Reclamation works? No Not Applicable 1.17 Dredging/ reclamation/land No Not Applicable filling/disposal of dredged material etc? 1.18 Off shore structures? Yes Offshore wind mast (1.2m diameter pile to support 5m diameter platform which is located at 10m above MSL. 1.19 Production and manufacturing No Not Applicable processes?

S.No Information/Check list Yes/ confirmation No 1.20 Facilities for storage of goods No Not Applicable or materials? 1.21 Facilities for treatment or No Not Applicable disposal of solid waste or liquid effluent? 1.22 Facilities for long term housing No Not Applicable of operational workers? 1.23 New road, rail or sea traffic No during construction or Not Applicable operation? 1.24 New road, rail, air water borne No The route is away from the navigation and or other transport infrastructure hence no alteration for routes required. including new or altered routes and stations, ports, airports etc? 1.25 Closure or diversion of existing No Not Applicable transport routes or infrastructure leading to changes in traffic movements? 1.26 New or diverted transmission No Not Applicable lines or pipelines? 1.27 Impoundment damming, No Not Applicable culverting, realignment or other changes to the hydrology of water courses or aquifers? 1.28 Stream and river crossings? No Not Applicable 1.29 Abstraction or transfers of No Not Applicable water from ground or surface waters? 1.30 Changes in water bodies or the No Not Applicable

S.No Information/Check list Yes/ confirmation No land surface affecting drainage or run-off? 1.31 Transport of personnel or Yes Transport of personnel or materials for materials for construction, construction, operation or decommissioning operation or decommissioning? through vessel (boat / Jackup / barge). 1.32 Long-term dismantling or No No dismantling or decommissioning is decommissioning or restoration proposed. works? 1.33 Ongoing activity during No Not envisaged decommissioning which could have an impact on the environment? 1.34 Influx of people to an area in Yes Temporary construction workers during either temporarily or construction phase. permanently? Operational / maintenance staff will do monthly visit to the platform.

1.35 Introduction of alien species? No Not Applicable 1.36 Loss of native species or No Not Applicable genetic diversity? 1.37 Any other actions? No Not Applicable

2. Use of natural resources for construction or operation of the project (such as land, water, materials or energy, especially any resources which are non-renewable or in short supply): S.No Information/Check list Yes/ Details thereof (with approximate confirmation No quantities/rates, wherever possible) with source of information data 2.1 Land especially undeveloped No Not Applicable

S.No Information/Check list Yes/ Details thereof (with approximate confirmation No quantities/rates, wherever possible) with source of information data or agricultural land (ha) 2.2 Water (expected source & No Not Applicable competing users) unit: KLD 2.3 Minerals (MT) No Not Applicable 2.4 Construction material – stone, No Only prefabricated steel will be used.. aggregates, sand/soil (expected source – MT) 2.5 Forest and timber (source – No Not Applicable MT) 2.6 Energy including electricity No Self-propelled boats are being used. and fuels (source, competing users) Unit: fuel (MT), energy (MW) 2.7 Any other natural resources No Not Applicable (use appropriate standard units)

3. Use, storage, transport, handling or production of substances or materials, which could be harmful to human health or the environment or raise concerns about actual or perceived risks to human health S.N Information/Check list Yes/ Details thereof (with approximate o confirmation No quantities/rates, wherever possible) with source of information data 3.1 Use of substances or materials, No Not Applicable which are hazardous (as per MSIHC rules) to human health or the environment (flora,fauna and water supplies) 3.2 Changes in occurrence of No Not Applicable

S.N Information/Check list Yes/ Details thereof (with approximate o confirmation No quantities/rates, wherever possible) with source of information data disease or affect disease vectors (e.g., insect or water borne diseases) 3.3 Affect the welfare of people e.g., No Not Applicable by changing living conditions? 3.4 Vulnerable groups of people who No Not Applicable could be affected by the project e.g., hospital patients, children, the elderly etc., 3.5 Any other causes, that would None Not Applicable affect local communities, fisherfolk, their livelihood, dwelling units of traditional local communities etc

4. Production of solid wastes during construction or operation or decommissioning (MT/month) S.No Information/Check list Yes / Details thereof (with approximate confirmation No quantities/rates, wherever possible) with source of information data 4.1 Spoil, over burden or mine No Not Applicable wastes 4.2 Municipal waste (domestic No Not Applicable and or commercial wastes) 4.3 Hazardous wastes (as per No Not applicable hazardous waste management rules) 4.4 Other industrial process No Not Applicable wastes

S.No Information/Check list Yes / Details thereof (with approximate confirmation No quantities/rates, wherever possible) with source of information data 4.5 Surplus product No Not Applicable 4.6 Sewage sludge or other No Not Applicable sludge from effluent treatment 4.7 Construction or demolition No Not Applicable wastes 4.8 Redundant machinery or No Not Applicable equipment 4.9 Contaminated soils or other No Not Applicable materials 4.10 Agricultural wastes No Not Applicable 4.11 Other solid wastes No Not Applicable

5. Release of pollutants or any hazardous, toxic or noxious substances to air (Kg/hr)

S.No Information/Check list Yes/ Details thereof (with approximate confirmation No quantities/rates, wherever possible) with source of information data 5.1 Emissions from combustion No of fossil fuels from stationary Not Applicable or mobile sources 5.2 Emissions from production No Not Applicable processes 5.3 Emissions from materials No Not Applicable handling including storage or transport 5.4 Emissions from construction No Not Applicable

S.No Information/Check list Yes/ Details thereof (with approximate confirmation No quantities/rates, wherever possible) with source of information data activities including plant and equipment 5.5 Dust or odours from No Not Applicable handling of materials including construction materials, sewage and waste 5.6 Emissions from incineration No Not Applicable of waste 5.7 Emissions from burning of No Not Applicable waste in open air (e.g., slash materials, construction debris) 5.8 Emissions from any other No Not Applicable sources

6. Generation of noise and vibration and emissions of light and Heat:

S.No Information/Check list Yes/No Details thereof (with approximate confirmation quantities/rates, wherever possible) with source of information data 6.1 From operation of Yes Negligible noise is expected during equipment e.g., engines, operation. The machinery to be used will ventilation plant, crushers be properly maintained to avoid noise pollution. 6.2 From industrial or similar No Not Applicable processes 6.3 From construction or Yes During construction there will be noise

S.No Information/Check list Yes/No Details thereof (with approximate confirmation quantities/rates, wherever possible) with source of information data demolition arising out of loading/unloading, transportation of construction materials, crane operation, piling work, etc which will not be significant. Noise levels will be monitored to ensure compliance to norms.

6.4 From blasting or piling Yes Negligible noise is expected during construction work which is in the sea.

6.5 From construction or No Not applicable operational traffic 6.6 From lighting or cooling No Not Applicable systems 6.7 From any other sources None -

7. Risks of contamination of land or water from releases of pollutants into the ground or into sewers. Surface waters, ground water , coastal waters or the sea

S.No Information/Check list Yes/No Details thereof (with approximate confirmation quantities/rates, wherever possible) with source of information data 7.1 From handling, storage, use No Not applicable or spillage of hazardous materials

S.No Information/Check list Yes/No Details thereof (with approximate confirmation quantities/rates, wherever possible) with source of information data 7.2 From discharge of sewage No Not applicable or other effluents to water or the land (expected mode and place of discharge) 7.3 By deposition of pollutants No Not Applicable emitted to air into the land or into water 7.4 From any other sources No Not Applicable 7.5 Is there a risk of long term None Not Applicable build up of pollutants in the environment from these sources?

8. Risk of accidents during construction or operation of the project, which could affect human health or the environment

S.No Information/Check list Yes/No Details thereof (with approximate confirmation quantities/rates, wherever possible) with source of information data 8.1 From explosions, spillages, No Not Applicable fires etc from storage, handling, use or production of hazardous substances 8.2 From any other causes No Not Applicable 8.3 Could the project be No Not Applicable affected by natural disasters causing environmental damage (e.g., floods, earthquakes, landslides,

cloudburst etc)

9. Factors which should be considered (such as consequential development) which could lead to environmental effects or the potential for cumulative impacts with other existing or planned activities in the locality

S.No Information/Check list Yes/No Details thereof (with approximate confirmation quantities/rates, wherever possible) with source of information data 9.1 Lead to development of NO Not Applicable supporting facilities, ancillary development or development stimulated by the project which could have impact on the environment e.g., Supporting infrastructure (roads, power supply, waste or waste water treatment etc.,) Housing development, extractive industries, supply industries, other

9.2 Lead to after use of the site, No Not Applicable which could have an impact on the environment 9.3 Set a precedent for later No Not Applicable developments 9.4 Have cumulative effects due No Not Applicable to proximity to other existing

S.No Information/Check list Yes/No Details thereof (with approximate confirmation quantities/rates, wherever possible) with source of information data or planned projects with similar effects

III. Environmental Sensitivity:

S.N Areas Name/ Aerial distance (within 15 o Identity km ) proposed project location boundary) 1 Areas protected under None Not Applicable international conventions, national or local legislation for their ecological, landscape, cultural or other related value 2 Areas which are important or None sensitive species for ecological reasons – wetlands, watercourses or other water bodies, coastal zone, biospheres, mountains, forests 3 Areas used by protected, None important or sensitive species of flora or fauna for breeding, nesting, foraging, resting, over wintering, migration 4 Inland, coastal, marine or Coastal Marine underground waters waters 5 State, national boundaries No Not Applicable

6 Routes or facilities used by the No Not Applicable public for access to recreation or other tourist, pilgrim areas 7 Defense installations No Not Applicable 8 Densely populated or built up No Not Applicable area S.N Areas Name/ o Identity 9 Areas occupied by sensitive No Not Applicable man-made land uses (hospitals, schools, places of worship, community facilities) 10 Areas containing important, high No - Not Applicable quality or scarce resources (ground water resources, surface resources, forestry, agriculture, fisheries, tourism , minerals) 11 Areas already subjected to No - Not Applicable pollution or environmental damage (those where existing legal environmental standards are exceeded) 12 Areas susceptible to natural hazard which could cause the Yes Seismic Zone ( V) project to present environmental problems (earthquakes, subsidence, landslides, erosion, flooding or extreme or adverse climatic conditions)

2. Executive summary As the onshore wind energy demands more space, higher wind speed and visual intrusion the focus has been shifted towards Offshore Wind Energy in India. The preliminary studies indicated two wind potential sites in Gujarat and in Tamilnadu. Hence the Government has announced National Offshore Wind Energy Policy as an initial step towards the development of offshore wind in the country. This policy allows various government and interested private agencies to get involved in preliminary data assessments in the potential sites.

Hence Samiran Udaipur Windfarms Limited (SUWL) have entrusted Suzlon Energy Ltd (SEL) to arrange for the Survey and Investigations off the coast of Jakhau. M/s Suzlon Energy Limited approached ESSO-NIOT in order to set up a data collecting platform at off coast Jakhau, Gujarat for a period of two years. M/s SEL along with NIOT has done preliminary wind assessment, Environmental Impact Assessments and various other feasibility studies. This report presents the summary of these studies, seeking for CRZ Clearance from Ministry of Environment, Forest and Climate Change.

3. Introduction

3.1. Need for Renewable Energy & World Scenario Worldwide, wind energy is accepted as one of the most developed, cost-effective and proven renewable energy technologies to meet increasing electricity demands in a sustainable manner. While onshore wind energy technologies have reached a stage of large scale deployment and have become competitive with fossil fuel based electricity generation with supportive policy regimes across the world, exploitation of offshore wind energy is yet to reach a comparable scale. The promising factors for offshore wind development are i) Strong / Consistent winds compared to land, ii) Less sound pollution and visual intrusion, iii) Best benefit to coastal areas due to less transmission cost and iv) Exploitation of available onshore wind sites.

The first offshore wind power test facility was setup in Sweden, in 1990; however the first commercial offshore wind farm was commissioned in1991in Denmark [Nikolaou, (2004)]. As of January, 2013 the installed capacities of wind farms in Europe, China and Japan are 5 GW, 0.51 GW and 0.033 GW respectively [EWEA, (2013)]. Proposals exist to expand the respective capacities to 40 GW (Europe) [EWEA, (2009)], 30 GW (China) [Da et al., 2011]

21 and 1 GW (Japan) [www.ewea.org] by 2020. Actually, more than 90% of the global offshore wind farms were located in European waters and the contribution from various counties is shown in Fig. 1. Recently, World’s largest wind farm ‘London Array’ with a capacity of 630 MW is commissioned in United Kingdom [London Array, (2013)]. A project with 0.468 GW capacity is under construction in USA with proposals for expanding the capacity to 10 GW by 2020 [U.S. Department of Energy, (2011)].

3% 1% 5% 6% UK Denmark 8% Belgium Germany Netherland 18% 59% Sweden

Others

Fig. 1 Installed Cumulative Capacity in European countries (Source: EWEA, (2013)) 3.2. Offshore Wind Potential in India and wind energy Policy India has achieved significant success in the onshore wind power development with about 24 GW of wind energy capacity already installed and generating power.

The share of the renewable energy sources under operation in India is around 12% [CEA, (2013)], of its total production, whereas the developed countries already achieved over 20- 30%. Preliminary studies indicated many potential sites in India for wind farms and still this huge potential remains untapped.

Initial preliminary wind potential studies have been carried out along the Indian coast based on the available satellite and buoy data. It is observed that the offshore wind of magnitude 6m/s or more persist for more than 300 days along the coast of Tamilnadu and Gujarat. A suitability analysis for three potential sites of Rameshwaram, Kanyakumari and Jakhau along the Indian coast was carried out in this study based on the long term wind data (1999 to 2009) obtained from ESSO - INCOIS. The data obtained at 10m elevation for 10 years were scaled to 80 m elevation (i.e hub height of wind turbine) using power law. The percentage

22 distribution of these derived wind speeds for the sites Jakhau, Rameshwaram and Kanyakumari are shown in Fig. 2. The mean wind speeds at Rameshwaram, Kanyakumari and Jakhau for derived winds at 80m elevation are 8.5 m/s, 9.1 m/s and 7.3 m/s respectively.

Jakhau Rameshwaram Kanyakumari

PercentageDaysof

Fig. 2 Wind Speed Distribution at 80m Elevation Offshore winds were used to estimate the power production from the power curves provided by the manufacturer. The Plant Load Factor (Ratio of average power produced to the Capacity of turbine) was estimated for various wind turbines with capacities varying from 1.5 to 5 MW. It was observed that 3.0 MW turbine operates at high Plant Load Factor at all the 3 locations along Indian coast. Fig. 3 shows the power produced along with plant load factors for the 3 MW turbines, which is optimum for Indian wind conditions, however, which needs confirmation from the measured data.

Fig. 3 Power Production for 3 MW Offshore Wind Turbine. Fig. 4 Google earth map –Jakhau Fig. 5 Topography map(20km buffer)-Jakhau Fig. 6 Regional Connectivity map-Jakhau Fig. 7 Topography map-Jahau Fig. 8 Hydrographic map-Jahau Based on these studies Ministry of New and Renewable Energy(MNRE) has formulated National Offshore Wind Energy Policy in September 2015(Refer Annexure II) attempting to

23 replicate the success of onshore wind power development in the offshore wind power development.

Electricity generation from renewable sources of energy is an important element in the Government’s National Action Plan on Climate Change (NAPCC) announced in the year 2008. With introduction of this policy, the Government of India is committed to provide a conducive environment for harnessing offshore wind energy in India.

3.3. SUWL, SEL and NIOT involvement National Wind energy Policy of India provides permission for Carrying out preliminary wind resource assessment, oceanography & bathymetric surveys etc. by any government agencies or by interested private players who have proven expertise in offshore studies. While SUEL is given permission for survey and Investigation offshe coast of Jakhau by the Gujarat Maritime Board (GMB), (Ref Annexure I) M/s Suzlon Energy Limited on behalf of SUWL approached ESSO-NIOT for the activities of offshore structures for the wind farms in India. M/s SEL has requested NIOT to take up the activity of design and installation of LIDAR based offshore wind mast at offshore location near Jakhau in Gujarat for offshore wind assessment. M/s SEL with the support of NIOT is setting up a data collecting platform at Jakhau in order to validate the wind potential sites. This data collection platform will be functioning over a period of 2-3 years.).

4. Project Description

4.1. Site Details The project site location is located off coast in kutch district of Gujarat. The project is 18km from the shore, 30km from Jakhau and 42km from Naliya port. The geographical coordinates of the site is N23o 07’ 24.42” E68o 27’ 48.24”.The project site location is shown in Annexure III and Annexure IV. The project site lies within the Indian Territorial waters which is 12 Nautical miles from baseline. The other major towns near project site are Bhuj, Kandla and Mundra. Regional connectivity map of the project site is shown in the Annexure V. Initially three locations have been considered and this location has been finalized based on suitable soil strata, Hydrodynamic condition and also as it is away from navigation channel. Other details such as Topographic and Hydrographic are found in Annexure VI and Annexure VII.

4.2. Bathymetry & Physical Processes

4.2.1. Bathymetry The bathymetry of the project site is relatively flat with minimum undulations. The bathymetry reveals that from -1 m to -5m contours are almost parallel to the shore. The -5m contour is at 5.4km from the shore, -10m contour varies from 5.4km to 14.8km away from the shore. The bathymetry details are shown in Fig.6.The proposed project site is about 10m from MSL which is shown in Fig.9

Fig. 9 Bathymetry profile for the prosed site

4.2.2. Tide Mean High higher water level (MHHW): 2.9m

Mean Low higher water level (MLHW): 2.65m

Mean High lower water level (MHLW): 1.43m

Mean Low lower water level (MLLW): 0.63m

4.2.3. Currents The currents in the Gulf and associated Creeks are largely tide induced. Maximum speed of current is 2m/s.

4.2.4. Wave Significant wave height, Hs =5.5m

Wave Period, Tp=12s

4.2.5. Rainfall Average annual rainfall is of 250mm.Generally rainfall occurs in the period of July to September and the number of wet days per year is 30.

5. Proposed Data collection Mast

5.1. Description with layout The LIDAR based offshore met mast is to be located at a water depth of 10m with a tidal variation of 5m. The platform housing LiDAR is at about 7.5m from the MSL. The data collection platform consists of instruments for collecting various parameters required for wind potential studies and design of substructure for wind turbine. This data collection platform is of 5m diameter. The setup of platform is shown in Fig.2 and details of the instruments are given are given in Table 1. To supply power for operation of these instruments solar panel and small wind turbines along with battery supply for back are provided.

S.No Parameters Instrument 1 Wind Velocity, Direction and Profiles LiDar 2 Wave Direction, Height and Periods Wave Rider Buoy 3 Current Velocity, Direction and Profiles ADCP, RCM 4 Tide RTG, ATG 5 PH, Salinity & TSS Water Quality buoy 6 Temperature, Pressure, Humidity Automatic weather Station Table 1 Instruments for collecting various Parameters The platform is provided for supporting all the equipment’s required to measure. Platform consists of central rigid circular beam and main beams radiating from the central beam. Main

26 beams are connected with secondary beams. Trapezoidal plates are resting over the main beams, over which all equipment loads such as wind turbine, LiDar, solar panels, wind measurement instruments and batteries are resting.

Fig. 10 Layout of Supporting Platform for LiDar

The Monopole supporting the data collection platform is of 1.2m diameter which is of 25mm thick. The detailed structural design of the wind mast and platform is as below

5.2. Structural Design The platform is located at water depth of 10 m with a tidal range 5m. The soil is predominantly silty sand with an angle of friction as 34o. The maximum current speed at the location is considered as 1.5m/s.

4.2.1. Basic Load The various loads considered in the design of support structure include dead load, live load, wind loads, Hydrodynamic loads and seismic loads.

5.2.1.1. Dead load Self-weight of the structure, nonstructural members like hand rails, ladder and various instruments mounted on the platform are considered.

5.2.1.2. Live Load A live load of 5kN/m2 is considered in accordance with IS 875: part-2 to accommodate for people’s moment during operations and installation of instruments on platform

5.2.1.3. Wind loads The extreme wind loads were considered in accordance to IS 875 part-3. The critical (extreme) and operational basic wind speeds at reference height of 10m above SWL were 50 m/s and 12 m/s respectively.

The design wind speed, V = k1 x k2 x k3 x Vb = 53 m/s

Where Vb is Basic wind Speed, k1 is probability factor (risk coefficient), k2 = terrain, height and structure size factor and k3 = topography factor. The forces on monopole due to this wind profile were calculated in accordance with API RP 2A WSD.

F= Cs (ρ/2) A V2 = 1.03KN

Where F is wind force, ρ is mass density of air (1.225 kg/m3), V is wind speed, Cs is shape coefficient (0.5 for cylinder shape) and A is projected area.

5.2.1.4. Hydrodynamic loads

In this study two sea states as shown in Table 2 were considered, critical condition (extreme environment) and operational condition. In critical condition the maximum wave height was 3m with a period of 12s and for operational condition the maximum wave height was 1.5m with a period was 7s.The current profiles considered for both sea states are shown in Fig. 2. Wave and current were considered to act in the same direction.

Current Profile

-1 -3 -5 -7 Operational -9

Height (m) Height -11 Extreme -13 -15 0 0.5 1 1.5 2

Velocity (m/s)

Fig. 11 Current profile for operational and critical condition

Water Sea Wave Height Wave Period Wave Length H d Depth State (H, m) (T, s) (L, m) g T2 g T2 (d, m) Severe 3 12 15 137 0.0021 0.011 Normal 1.5 7 15 68 0.0031 0.031 Table 2 Waves Parameters Wave kinematics is estimated using suitable wave theory. Fig.6 (API RP 2A WSD, 2007) shows suitability of various wave theories for a region. Selection of wave theory depends on wave height, Period and water depth. The required parameters for selecting suitable wave theory were given in column 6 and 7 of Table 4. Based on these parameters and Fig.6, Stokes 5th order wave theory was considered for calculating wave kinematics.

Wave and Current forces were calculated using Morison’s equation. This was a semi- empirical formula which assumes the total force as a sum of inertia component due to the fluid acceleration and a drag component due to fluid velocity. Applicability of Morison’s equation depends on the ratio of the wavelength to the member diameter. If this ratio was greater than 5 then the structure will not cause incident wave to diffract and Morison’s equation can be used. If ratio was less than 5 then Diffraction theory, which computes the pressure acting on the structure due to both the incident wave and the scattered wave, should be used, instead of the Morison equation, to determine the wave forces. In this study, this ratio is more than 5 for waves considered in all stated. So, Morison equation is used for calculating forces which was of the following form.

2 2 2 F = CD (ρ/2) D V + (π/4) D ρ Cm U

3 Where F is Force per unit length, ρ is mass density of water (1025 kg/m ), CD is Drag Coefficient for Tubular Section (1.05 – Rough surface), Cm is Inertia Coefficient for Tubular Section (1.2 – Rough surface), U =Acceleration of water particle, V =Velocity of water particle.

Fig. 12 Regions of Applicability of Various Wave Theories For each sea state the phase of the wave was varied from 0° to 360° with a step of 10°. It was observed that maximum base shear and base moment for Monopile occurs at a phase shift of 350°. The wave load at this phase angle was considered for analysis.

5.2.1.5. Seismic loads

Response Spectral method was used for calculating Earthquake forces for both the substructure concepts. In this method response of a structure was obtained by combining the responses of different Mode Shapes. Initially, free vibration analysis was carried out to obtain the modal frequencies and mode shapes. For each mode, a response was obtained from the design spectrum based on the modal frequency and they were combined using suitable modal combination rule to provide an estimate of the total response of the structure. Complete Quadratic Combination (CQC) modal combination rule was used here, as it gives more reliable values when compared with square root of the sum of the squares (SRSS) and sum of absolute peaks methods. In this study for earthquake load cases the Pile-Soil iteration was assumed to be linear.

Fig. 13 Seismic zone of India Earthquake spectrum was considered as per IS 1893 Part–4.The considered site comes in zone II (Rameswaram).Reduction factor “R” is 2. Importance factor “I” is 1.5 (same as steel chimney). Soil type is taken as Type II (medium soil). ‘Sa/g’ is the spectral acceleration coefficient corresponding to site specific spectra. The seismic coefficient was calculated as.

푍 푆 [ ]×[ 푎] 2 푔 퐴ℎ = 푅 ( ) 퐼

Where Ah is Horizontal acceleration coefficient, Sa/g is the spectral acceleration, Z is Zone factor (0.36), R is Response Reduction factor (2) and I is Importance Factor (1.5).

The acceleration spectrum shown in Fig.7 was obtained by multiplying Ah with acceleration due to gravity ‘g’ and Scale Factor. The Scale Factor for spectrum along both horizontal directions was 1.0 and for vertical direction was 0.5.

Accleration Spectrum 5 4.5

) 4 2 3.5 3 2.5 2 1.5

Accleration(m/s 1 0.5 0 0 1 2 3 4 Period (s)

Fig. 14 Acceleration Spectrum

5.2.2. Load Combinations Load combinations for offshore wind turbine are considered as per API RP 2A WSD. Three critical cases were considered in design of support structure. Extreme sea state during critical like cyclone, LC1. As a design rule occurrence of two critical events should not be considered at same time in design of any structure. So, while considering earthquake loads all other environmental loads should be normal condition (i.e. operational condition), LC2. Impact of boat on structure at controlled condition, LC3 Combinations. As the Monopile was axi-symmetric, application of load along any direction will have same influence. So, wave heading is not varied with in each load combination.

5.2.3. Monopile The support structure is designed for three load combinations. Pile-soil interaction was modelled using 3 nonlinear springs for each soil layer (Two horizontal and one vertical spring). The nonlinear properties for all horizontal springs are governed by p-y curve (i.e. Lateral Load Vs. deflection of the pile), vertical springs for all layers except bottom most layer by t-z curves (i.e. Skin Frictional resistance vs. deflection along pile) and vertical spring for bottom most layer by Q-z curve (i.e. Tip resistance Vs. Pile Tip Deflection). These curves are generated using API RP 2A-WSD. For Earthquake analysis these curves were linearized (i.e. soil was assumed to behave linearly). The estimated skin friction and end bearing are shown in Table 5.

SKIN FRICTION Tip Resistance DEPTH (m) (Pa) (Pa) 1.5 1957.5 - 3 5872.5 - 4.5 9787.5 - 6 13702.5 - 7.5 17617.5 - 9 21532.5 - 10.5 25447.5 - 12 29362.5 - 13.5 33277.5 - 15 37192.5 1620000 Table 3 Soil Parameters for Different Layers 5.2.4. Cyclones The appropriate loads as explained in earlier were considered and the obtained deflection profiles were shown in Fig.15. The deflections at the platform level are within the allowable limit of l/150. The capacity of the members is checked using API RP 2A WSD. The utilization of monopole is 0.41 and monopile is 0.42. The details calculations are explained below.

Max Deflection - 0.015 m Max Deflection - 0.106 m

Max Rotation - 0.042o Max Rotation - 0.29o

Normal Sea State Severe Sea State

Fig. 15 Deflected Profiles for Various Sea States

5.2.4.1. Axial Compression:

Allowable Axial Compression Fa is determined from the AISC formulas for cylindrical members based on the diameter to thickness ratio. When the ratio is less than 60 then local buckling stress are not checked and if the ratio is greater than 60 Fy is substituted with critical local bucking stresses (Fxe or Fxc whichever is less). (Kl/r)2 [1 − ] F 2C 2 y F = c for (Kl/r) < C a 5 3(Kl/r) 1(Kl/r)3 c + + 3 3 8Cc 8Cc 12π2E F = for (Kl/r) ≥ C a 23(Kl/r)2 c Where,

1 12π2E 2 Cc=( ) Fy E = young′smodulus of elasticity, Mpa K = effective length factor l = unbraced length, m r = radius of gyration, m The members having D/t ratio more than 60 local buckling due to axial compression should be investigated.

5.2.4.2. Elastic Local Buckling Stress Elastic buckling stress can be determined from:

Fxe = 2CEt/D Where, C = critical elastic buckiling coefficient, D = outside diameter , m, t = wall thickness, m.

5.2.4.3. Inelastic local buckling Stress. Inelastic local buckling stress can be determined from:

D 1/4 F = F [1.64 − 0.23 ( ) ] 2CEt/D. xc y t

In our case allowable Fa for Beam element is determined as follows:

Diameter, D(m) = 1.2

Wall Thickness, t (m) = 0.025

Young's modulus, E(Mpa) = 2.10E+05

Yield Strength, Fy(Mpa) = 250

Unbraced Length, l (m) = 27.5

Effective length factor K = 2

Radius of gyration, r(m) = 0.346554469

Moment (KNm) = 850

Vertical load (KN) = 250

= 0.061575216 Area of the section A(m2) = 0.007395183 Moment of inertia I(m) = 0.012325306 Sectional Modulus Z(m3) = 0.346554469 Radius of Gyration R(m) = 158.7052106 Slenderness ratio λ D/t ratio = 50

Cc = 315.4133991

Kl/r ratio = 158.7052106

As D/t ratio is greater than 60 we have to check for local buckling and substitute critical local buckling stress stresses (Fxe or Fxc whichever is less) for Fy. In the calculation of local buckling stress the value of critical elastic coefficient “C” has been taken as 0.3 as per API. The allowable compression and calculated axial stress are as below.

Local Elastic Buckling Fxe (Mpa) = 2520

Local Inelastic Buckling Fxc (Mpa) = 257.7872

Allowable Axial Fa(Mpa) = 118.5 Compression

Calculated Axial Stress fa cal(Mpa) = 4.06

5.2.4.4. Allowable Bending Stress: The allowable bending stress can be determined as following:

D 10340 Fb = 0.75 Fy for ≤ t Fy

FyD 10340 D 20680 Fb = [0.84 − 1.74 ] Fy for < ≤ Et Fy t Fy

FyD 20680 D Fb = [0.72 − 0.58 ] Fy for < ≤ 300 Et Fy t

Here in our case the D/t ratio satisfies the second condition and as per API the stresses are as follow

Allowable Bending Stress Fb(Mpa) = 184.107

Calculated Bending Stress Fb cal(Mpa) = 68.96

Interaction Ratio fa cal/Fa + fb cal/Fb = 0.408

Similarly in case of Static analysis for Pile element the interaction ratio is 0.41.

5.2.5. Earth Quake The occurrence earthquake during normal sea state is considered in this case. The deflections at the top of substructure are 0.142 m and less than allowable limit of l/150. From the deflections it can be observed that the design of structure is mainly governed by earthquake. The capacity of the members is checked using API RP 2A WSD. The utilization of monopole is 0.35 and monopile is 0.37. The detailed calculations are given below

5.2.5.1. Member Capacity for Earthquake Load Combination: For Beam Element

Allowable Axial Fa(Mpa) = 118.5 Compression

Calculated Axial Stress fa cal(Mpa) = 4.060075079

Allowable Bending Stress Fb(Mpa) = 184.107

Calculated Bending Stress Fb cal(Mpa) = 57.92

Interaction Ratio fa cal/Fa + fb cal/Fb = 0.348

For Pile Element

Allowable Axial Fa(Mpa) = 143.885 Compression

Calculated Axial Stress fa cal(Mpa) = 3.962

Allowable Bending Stress Fb(Mpa) = 184.107

Calculated Bending Stress Fb cal(Mpa) = 63.8524

Interaction Ratio fa cal/Fa + fb cal/Fb = 0.37436

5.2.6. Boat Impact Boat landing is considered for small boats with a weight less than 25 tons which will be used to transporting people for inspection and maintenance of equipment. Controlled boat velocity of 0.5 m/s is considered for analysis. The kinetic energy due to boat impact is equated to the work done by the structure to find an equivalent point load at water level. This load is applied on the structure along with operational sea state condition. The deflection during boat impact is 0.12 m and less than allowable limit of l/150. The capacity of the members is checked using API RP 2A WSD. The utilization of monopole is 0.42 and monopile is 0.44.

5.2.6.1. Member Capacity for Boat Impact Combination: For Beam Element

Allowable Axial Compression Fa(Mpa) = 143.885

Calculated Axial Stress fa cal(Mpa) = 4.06

Allowable Bending Stress Fb(Mpa) = 184.107

Calculated Bending Stress Fb cal(Mpa) = 71.39

Interaction Ratio fa cal/Fa + fb cal/Fb = 0.41602

For Pile Element

Allowable Axial Compression Fa(Mpa) = 143.885

Calculated Axial Stress fa cal(Mpa) = 4.628

Allowable Bending Stress Fb(Mpa) = 184.107

Calculated Bending Stress Fb cal(Mpa) = 74.64

Interaction Ratio fa cal/Fa + fb cal/Fb = 0.4376

5.2.7. Platform The platform is provided for supporting all the equipment’s required to measure. Platform consists of central rigid circular beam and main beams radiating from the central beam. Main beams are connected with secondary beams. Trapezoidal plates are resting over the main beams, over which all equipment loads such as wind turbine, LiDar , solar panels, wind measurement instruments and batteries are resting. The platform is analyzed for the ultimate and service conditions as per of IS 800:2007. The detail design of structural members is given below.

5.2.7.1. Material Properties

Central rigid beams = ISMC 150

Length of rigid beam = 620 mm

Main beams = ISMC 150

Length of main beams = 1300 mm

Secondary beams = ISMC 75

Length of secondary beams = 1290 mm

Plate thickness = 16 mm

(Increased 4mm for marine consideration)

Steel for plates /Beams = E250 (As per IS 2062:2011)

Field welds = E410

Unit weight of steel = 78.5kN/m3

5.2.7.2. Loads & Load combinations

Loadcase 1 Self weight of the beam

Loadcase 2 Self weight of the plates

Loadcase 3

LiDar weight = 0.765 kN radius of central rigid = 0.6 m

circumference of

central rigid portion = 3.768 m

U.d.l. of LiDar = 0.20 kN/m

Loadcase 4

Windturbine

2nos = 0.981 kN one turbine weight = 0.4905 kN

Loadcase 5

Solar panels + mounting accessories = 0.491+ 0.343

= 0.834 kN u.d.l for solar panels = 0.2836735 kN/m

Loadcase 6

Batteries & enclosures = 2.4525+0.981

= 3.433 kN radius of central rigid = 0.6 m

circumference of

central rigid portion = 3.768 m

U.d.l. of battery = 0.91 kN/m

Loadcase 7

Wind measurement instruments = 0.491 kN

Loadcase 8

Central plate area of central plate = 1.1304 m2 volume of central plate = 0.0180864 m3 weight of central plate = 1.4197824 KN u.d.l of central plate = 0.3768 kN/m

Loadcase 9

People movement = 5kN/m2 (From IS875)

Loadcase 10

For ultimate condition = 1.5(L.C1+L.C2+L.C3+L.C4+L.C5+L.C6+L.C7+L.C8+L.C9) Loadcase 11 For servicability condition = 1.0(L.C1+L.C2+L.C3+L.C4+L.C5+L.C6+L.C7+L.C8+L.C9)

5.2.7.3. Staad Results

S.No Members B.M(kNm) S.F(kN) Deflections(mm) Main 1 beams 10 10.5 3.86

2 Rigids 21 12.166 0.279

3 Sec beams 0.691 1.687 0.736

Main beams & Central Rigid beam

ISMC150 (2Sections faced front to front)

From SP -6

A = 4176 mm2

H = 150 mm

B = 150 mm

D = 132 mm tf = 9 mm

40 tw = 5.4 mm 4 Ixx = 15588000 mm 4 Iyy = 2046000 mm 3 Zxx = 204800 mm 3 Zyy = 38800 mm 4 Zp = 272384 mm r1 = 10 mm

5.2.7.4. Sectional Classification

ε =

= 1

From Table 2 IS 800:2007

d/tw = 132/5.4 = 24.4444 < 84ε 84

Hence the section is plastic

5.2.7.5. Shear Capacity

According to Cl 8.2.1.2 IS 800:2007

V < 0.6Vd

Vd = Vn

γmo

Vn = Av x fyw

Av = Ah (b+h) = 2088 mm 2

Vn = 301385.7

Vd = 273.987 kN

0.6Vd = 164.3922 kN

V < 0.6Vd

Hence the section is safe in shear condition

5.2.7.6. Moment Capacity

M < Md

Md = βb Zpfy

γmo

Since the section is plastic

βb = 1

Md = 62.26977 kNm

M < Md

Hence the section is safe

5.2.7.7. Check for deflections

Allowable deflection

From table 6 IS 800-2007

For Main beams = L/180 = 7.22222 mm For rigid beams = L/300 = 2.06667 mm

Deflection of main beam = 3.86 mm safe in deflection Deflection of rigid beam = 0.279 mm safe in deflection

5.2.7.8. Check for web buckling

Assume bearing length = 0 mm

Ab = (b+n1) tw

n1 = 75 2 Ab = 405 mm Slenderness ratio,λ = 2.5d/t = 61.11111

From Table 9c of IS 800-2007

2 fcr = 167 N/mm Capacity of the section = 67.635 kN

Hence the section is safe against web buckling

5.2.7.9. Check for web bearing

Fw = (b+n2) twfy

γmo

n2 = 2.5(R+tf) = 47.5 mm

Fw = 58.29545 kN Hence the section is safe against web bearing

5.2.7.10. Check for stiffeners

According to Cl 8.6.1.1 IS 800 -2007

d/tw <200ε Not required for stiffeners

d/tw = 24.44444 < 200

Hence transverse and longitudinal stiffeners not required.

5.2.7.11. Check for compression flange buckling

According to Cl 8.6.1.7 IS 800 -2007

2 d/tw < 345 ε

24.444444 < 345

Hence no buckling of compression flange into web occurs.

5.2.7.12. Secondary beams ISMC75 (2Sections faced front to front) From SP -6 A = 867 mm 2 h = 75 mm b = 40 mm d = 67.7 mm tf = 7.3 mm tw = 4.4 mm 4 Ixx = 760000 mm 4 Iyy = 126000 mm 3 Zxx = 20300 mm 3 Zyy = 4700 mm 4 Zp = 24766 mm r1 = 8.5 mm

5.2.7.13. Sectional Classification

ε =

= 1

From Table 2 IS 800:2007

d/tw = 17.04545 < 84ε

Hence the section is plastic

5.2.7.14. Shear Capacity

According to Cl 8.2.1.2 IS 800:2007

V < 0.6Vd

Vd = Vn

γmo

Vn = Av x fyw

Av = Ah (b+h) = 565.4348 mm 2

Vn = 81615.88

Vd = 74.19625 kN

0.6Vd = 44.51775 kN

V < 0.6Vd

Hence the section is safe in shear condition

5.2.7.15. Moment Capacity

M < Md

Md = βb Zpfy

γmo

Since the section is plastic

βb = 1

Md = 5.628636 kNm

M < Md

Hence the section is safe

5.2.7.16. Check for deflections

Allowable deflection

From table 6 IS 800-2007

For secondary beams = L/300 = 4.3 mm

Deflection of secndary beam = 0.736 mm safe in deflection

5.2.8.17. Check for web buckling

Assume bearing length = 0 mm

Ab = (b+n1) tw

n1 = 37.5 2 Ab = 165 mm Slenderness ratio,λ = 2.5d/t = 38.46591

From Table 9c of IS 800-2007

2 fcr = 197 N/mm Capacity of the section = 32.505 kN

Hence the section is safe against web buckling

5.2.7.18. Check for web bearing

Fw = (b+n2) twfy

γmo

n2 = 2.5(R+tf) = 39.5 mm

Fw = 39.5 kN Hence the section is safe against web bearing

5.2.7.19. Check for stiffeners

According to Cl 8.6.1.1 IS 800 -2007

d/tw <200ε Not required for stiffeners

d/tw = 17.04545 < 200

Hence transverse and longittudinal stiffeners not required.

5.2.7.20. Check for compression flange buckling

According to Cl 8.6.1.7 IS 800 -2007

2 d/tw < 345 ε

17.045455 < 345

Hence no buckling of compression flange into web occurs.

5.2.7.21. Welded Connection design

Connection between the rigid beams and main beams

S.F = 10.5 kN B.M = 10 kNm Factor of safety = 1.5 (from table 6 of IS 800 -2007) Web connection Maximum size of weld = 3.9 mm (table 21 of IS 800-2007) Minimum size of weld = 3 mm Assume weld size of = 3.5 mm Throat thickness,t = 2.45 mm Strength per 1mm length of weld = 386.6436 N/mm Length of the weld = 27.15679 mm

mm along the Hence provide weld of 3.5 mm for a length of 30 web

Flange connection V = 66.7 kN Maximum size of weld = 7.5 mm (table 21 of IS 800-2007) Minimum size of weld = 3 mm Assume weld size of = 6 mm Throat thickness,t = 4.2 mm Strength per 1mm length of weld = 662.8176 N/ mm Length of the weld = 100.5807 mm

mm along the Hence provide weld of 6 mm for a length of 104 flange

Connection between the secondary beams and main beams

S.F = 1.687 kN Factor of safety = 1.5 (from table 6 of IS 800 -2007) Web connection Maximum size of weld = 4.4 mm (table 21 of IS 800-2007) Minimum size of weld = 3 mm Assume weld size of = 3 mm Throat thickness,t = 2.1 mm Strength per 1mm length of weld = 331.4088 N/mm Leng th of the weld = 5.09039 mm

mm along the Hence provide weld of 3 mm for a length of 8 web

6. Installation procedure The steel Monopiles will be fabricated and transported to the site from shore with the help of barges. Approximate weight of the pile is around 50tonnes. These piles are constructed from welded steel tubular sections which are driven vertically into the sea bed. The piles support the weight of the platform and the instruments primarily using the friction between the pile walls and the sea bed. The monopile will be fabricated at a suitable fabrication yard and transported to site. A brief typical installation sequence is as follows:

 Transportation of monopile to offshore site via vessel, barge or float-out  Up-ending the pile by Jack-up crane vessel with buoyancy assistance if required  Monopile is lowered to seabed location, while pile weight provides initial sea bed penetration.  Hammering the pile till the desired depth. (Soil plugging if any will removed till desired depth is achieved).  Installation of platform at the top which is followed by the installation of LiDar equipments.

Transporting to location Lifting with crane

Launching Positioning

Driving by hammer Completion of Driving Monopile

Removing of Hammer after driving Fig. 16 Installation methodology for wind mast 6.1. Decommissioning procedure For the wind mast it is envisaged that the foundation pile would be cut to below the natural level of the seabed to such a depth to ensure that the remains are unlikely to become uncovered. Complete removal of the pile below the seabed is considered neither practical nor environmentally desirable. The appropriate depth of removal will depend on the sea-bed conditions and site characteristics at the time of decommissioning which is in line with IMO standards as complete removal of the foundations would involve an unacceptable risk to the marine environment and are likely to involve extreme cost. If an obstruction exists above seabed following the decommissioning which is attributable to the Met Mast, it will be marked so as not to present hazard to other sea users.

Decommissioning of pile structure:

 Divers are deployed to inspect pile footing and reinstate lifting attachments if necessary  Jack-up barge or heavy lift vessel is mobilized to the site  Any scour protection that has been placed around the support structures should be removed  Crane hooks are deployed from decommissioning vessel and attached to the lift points  The pile is cut below the natural seabed, following the pile removal the seabed is inspected for debris and any found is subsequently removed.

6.2. Construction and operational impact assessment

6.2.1. Noise level The noise and the disturbances created during construction phase is very minimal. Noise level generated by pile driving for such a small diameter is <50dB. Hence the noise generated during the construction phase will not affect the aquatic environment nearby. Transport of construction material to the site will restricted in daytime.Use of personal protective devices such as ear-muff, ear-pugs etc. will be enforced wherever necessary.Periodic maintenance of Construction machinery and transportation vessels will be undertaken to reduce the noise impact. Since the construction phase is for very short term it will have negligible effect.

6.2.2. Air Environment There will not be any dust emission during a pile driving in sea water. There will be no on- site burning of any waste arising from any construction activities. However Nose masks will be provided to construction workers, while carrying out operations.

6.2.3. Water Environment As the construction phase is for short period and also the number of workers involved is of less quantity impact on water quality is negligible. Sanitation facilities will be made available for disposal of sewage generated by the workers as per SPCB norms. Since, the construction activity happens with the help of vessels proper sanitation facilities will be provided in order to maintain hygienic condition of labourers.

6.2.4. Fishery There are not much commercial fish trawling operations off Jakhau port. However drifts and other local nets are commonly used by local fishermen community. These operations are not hampered much during construction as well as operational activities.

7. Project Schedule and cost estimates

7.1 Project Schedule The period of completion for the project is about 60days. Preparation of drawing, design will constitute about 20 days .Fabrication of the structure and mobilization to the site is will take about 40days. Installation will take about another 30days.

7.2 Cost estimate The total cost of the project including Wind Profiler, mobilization, demobilization and installation is Rs 493 lakhs.