Available online at www.sciencedirect.com ScienceDirect

Energy Procedia 100 ( 2016 ) 8 – 13

3rd International Conference on Power and Energy Systems Engineering, CPESE 2016, 8-12 September 2016, Kitakyushu, Japan Successful experience of development in several offshore islands

Jhih-Hao Lina, Yuan-Kang Wub*, Huei-Jeng Lina

aDepartment of Engineering Science and Ocean Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan bDepartment of Electrical Engineering, National Chung Cheng University, No.168, Sec. 1, University Rd., Chiayi 62102, Taiwan

Abstract

Islands incur more difficult and expensive energy supplies; many offshore islands, therefore, develop renewable energy to supply energy and reduce CO2 emissions. However, most of renewable energy sources, such as wind and solar, are intermittent and variable sources of power. To overcome the integration problems, numerous islands have utilized several useful methods. For instance, the island of Gran Canaria applied the pumped storage systems to reutilize energy, and the island of Lolland developed renewable hydrogen community. The operation experience of these islands is extremely worthy to appreciate. This article introduces eight offshore islands and discusses about their present situations, policies, successful experience and challenges about renewable . Those islands include Samso, Reunion, , Crete, King Island, Agios Efstratios, Utsira and El Hierro. The successful experience on those islands can provide useful information for other islands for developing renewable energy. ©© 20162016 The The Authors. Authors. Published Published by Elsevierby Elsevier Ltd. LtdThis. is an open access article under the CC BY-NC-ND license (Peer-http://creativecommons.org/licenses/by-nc-nd/4.0/review under responsibility of the organizing). committee of CPESE 2016. Peer-review under responsibility of the organizing committee of CPESE 2016 Keywords: Offshore Island; Renewable energy; Wind; Solar

1. Introduction

Increasing concern about environmental problems and the shortage and rising costs of fossil fuels have promoted a growing interest in massive integration of renewable energy sources (RES) in power systems. Electrical grids in offshore islands are appropriate for the large scale installation of renewable sources because the fuel cost is very high and there are numerous RES that can be exploited in several islands. However, the integration of a large scale of RES would bring many challenges on power system operation [1-3]. Therefore, this article will introduce the

* Corresponding author. Tel.: +886-5-2720411; fax: +886-5-2720411#33232. E-mail address: [email protected].

1876-6102 © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of CPESE 2016 doi: 10.1016/j.egypro.2016.10.137 Jhih-Hao Lin et al. / Energy Procedia 100 ( 2016 ) 8 – 13 9 development and successful experience of renewable energy, as well as renewable projects, in several offshore islands. The valuable experience would provide significant references to other islands.

2. The development and successful experience of renewable energy in several offshore islands

Many RES, such as wind, solar, hydro, biodiesel and biomass, have been popularly utilized in offshore islands. Table 1 listed several famous offshore islands that develop renewable energy. This article will introduce the renewable energy development in those islands in detail.

Table 1 Famous offshore islands that develop renewable energy

Island Country Location Area Population Density Renewable Energy Samso Denmark Kattegat 112 km2 3,806 (as of 2013) 34.0/km2 Wind, Solar, Biomass Reunion France Indian Ocean 2,512 km2 844,994 (as of 336.4/km2 Wind, Solar, Sea, 2011) Hydropower, Biomass Cyprus Cyprus Mediterranean 9,251 km2 1,141,166 (as of 123.4/km2 Wind, Solar, Biomass, Sea 2011) Bio fuel, Biogas Crete Mediterranean 8,303 km2 623,065 (as of 75.0/km2 Wind, Solar, Sea 2011) Hydropower, Biomass Agios Efstratios Greece Aegean Sea 43 km2 270 (as of 2011) 6.28/km2 Wind, Solar, Hydrogen King Island Australia Tasmania 1,098 km2 1,800 (as of 2013) 1.64/km2 Wind, Solar, Biodiesel Utsira Norway North Sea 6.3 km2 206 (as of 2015) 32.7/km2 Wind, Hydrogen El Hierro Spain Atlantic Ocean 268.7 km2 10,960 (as of 2010) 40.8/km2 Wind, Hydropower

2.1. Samso (Denmark)

The island of Samso has invested heavily on local energy production, including wind, biomass, and generation. The installed capacity of onshore and offshore wind turbines in Sanso is 11 MW and 23MW, respectively, and it achieves 100% renewable energy supply [4-6]. The renewable production not only covers the electricity consumption, but compensates the energy utilized in the transportation sector. The development strategies of Samso are as follows [7]: z Energy savings and increased efficiency in terms of heat, electricity and transport by the introduction novel energy technologies. z Expansion of the district heating supply systems using local biomass resources. z Expansion of individual heating systems using renewable energy. z Construction of onshore and offshore plants. z Gradual conversion of the transport sector from petrol and oil power to electrical power and hydrogen.

2.2. Reunion (France)

The island of Reunion has high potentials of RES such as solar, wind, geothermal, sea energy, biomass and hydropower. Two renewable-related projects - PRERURE and GERRI were launched in 2000 and 2008, respectively. They have indeed promoted investments to achieve an with 100% renewable energy sources by 2025 through incentive mechanisms such as tax exemptions, direct subsidies and advantageous feed-in tariffs [8, 9]. The hydropower with an installed capacity of 146 MW spread over six sites is the main renewable resource of the island. An additional capacity of 50 MW should be deployed by 2020. The biomass potential of Reunion is important. Solar energy is also an abundant energy resource. The current installed capacity of photovoltaic solar energy is 130 MW. The southeast and the northeast regions of the island are suitable for wind power generation. There are two wind farms with the installed capacity of 16.5 MW in Reunion; however, the potential of wind power generation is estimated up to 60 MW [10-12]. 10 Jhih-Hao Lin et al. / Energy Procedia 100 ( 2016 ) 8 – 13

2.3. Cyprus

The electrical system in Cyprus is isolated; therefore, its electricity generation relies entirely on imported fossil fuels [13]. A plan aimed at the promotion of RES for the period 2002-2010 was developed to promote investments in the field of energy savings and energy production from RES through financial incentives [5]. Another plan during the years 2009-2013 was approved to promote large renewable energy facilities, further fostering energy conservation and RES installations. The RES capacity in Cyprus’s plans includes 165 MW of wind, 25 MW of solar thermal, 14 MW of large PV systems, 4 MW of biomass and 3MW of biogas [14]. Based on the assessment of the International Renewable Energy Agency (IRENA), renewable energy could provide 25-40% of Cyprus’ total electricity supply by 2030. Additionally, the deployment of renewable energy in Cyprus has the potential to create between 11,000 and 22,000 jobs [15]. However, the most significant barriers for developing RE in this island are the limited potential of wind resources and the limited availability of land.

2.4. Crete (Greece)

The island of Crete is one of the Greek islands with high penetration of renewable energy, it hosted more than 50% of all renewable energy projects situated in Greece; mainly on wind power generation. Crete is situated in the south- east Mediterranean, and its potential for wind, solar and agricultural biomass is high due to the island’s geography and prevailing climatic conditions. Crete supplies around 19.5% of the annual electricity consumption from renewable sources, in which more than 90% of renewable energy is from wind energy. Biomass is mainly used in the island to produce heat. The biomass electricity generation is estimated to be 360 GWh per year [16, 17]. On the other hand, 455,000 m2 of solar thermal collectors and the biomass provides about 6% of the total final energy consumption. The generation portfolio in Crete has a mix of steam, diesel, gas and combined cycle based power plants. Diesel and gas turbines, unlike steam turbines, present some advantages for flexible operation such as lower minimum operation point and can be started quickly to react to changes in load and wind generation [18]. Owing to a large amount of wind power integration, the determination on reserve margins, voltage profiles, dynamic stability, and even wind curtailment rates is significant in this island.

2.5. Utsira (Norway)

The Utsira is a small island with the area of 6 Km2. It uses a wind/hydrogen energy demonstration system as power sources, in which hydrogen is used as the medium [19]. This project aimed to demonstrate how a hybrid renewable energy system can provide a safe, continuous, and efficient energy supply to remote areas. In windy seasons, when the wind power generation exceeds the load demand, the excess power is used to produce hydrogen in an electrolyser. The hydrogen is then compressed and stored. If the wind generation is low, the hydrogen engine with the fuel cell system uses stored hydrogen to produce the necessary electricity. This system can ensure a continuous and reliable energy supply to the demand for up to three days when wind power is not available. Despite the successful demonstration and operation of the system, several challenges have been identified. In this project, the wind energy utilization was only 20%, revealing a need for the development of more efficient electrolysers, as well as improved hydrogen-electricity conversion efficiency. The fuel cell experienced some technical problems that did not allow it to be fully integrated into the system, including leaking of the coolant fluid, damage to the voltage monitoring system during assembly, and frequent false grid failure alarms. In addition, the fuel cell experienced very rapid degradation and was operated for less than 100 hours over the duration of the project. The low efficiency of the hydrogen engine indicates that hydrogen would run out during windless periods [20].

2.6. El Hierro (Spain)

The island of El Hierro develops a wind-hydro-diesel hybrid electrical generating system, which transfers an intermittent energy source into a controlled and continuous supply of electricity. Most of the energy in this island is Jhih-Hao Lin et al. / Energy Procedia 100 ( 2016 ) 8 – 13 11 generated by the hydroelectric plant, and most of the wind energy is used to pump water from a lower reservoir to an upper reservoir as potential energy. The diesel power plant will only be used in exceptional or emergency situations when there is insufficient wind energy. The wind-hydro system provides around 77% of the energy demanded yearly in the island. The target of this island is to develop renewable energy as a major energy source and to reduce risk sensitivity to increasing oil pricing. Although the hybrid system is a highly capital intensive technology compared to a diesel plant, the diesel plant is being approximately 4 times more expensive to run than the hybrid system when it comes to operations and maintenance [21]. According to the experience on those islands, it is worth noting for the trend of local investments on renewable energy. That is, a large number of local investors would build renewable generation facilities because renewable energy may be a source of income and economic development for remote communities such as islands [22]. For example, BONUS Energy completed construction of the Samso Offshore Wind Farm with 10 turbines, in which only 15% of the wind farm is owned by outside investors. The example of Samso in Denmark shows how such a plan, assisted by substantial local support as well as responsive energy policies, may lead an island community to successfully implementing a renewable energy system.

3. The renewable energy projects by Agios Efstratios and King islands

3.1. Agios Efstratios (Greece)

Agios Efstratios is a small island with annual energy demand of 1073 MWh, maximum power demand of 360 kW, and average daily consumption of 4 MWh. The project of “Green Island - Agios Efstratios” is a research- demonstration plan aiming to achieve 100% RES electricity penetration in the island. In this project, wind generators, photovoltaic systems, and biomass plants were constructed to replace some of the oil power stations. Even the traditional transportation was replaced by electric vehicles. Moreover, energy efficient technologies were applied to buildings and transport sectors. The details of this project include [23]: z Electricity production - The electrical supply in this island includes the existing thermal station and the RES- based hybrid system, which includes wind turbines, PV station, energy storage system, electrolysis unit for hydrogen production, hydrogen storage tank, hydrogen power generating pairs, and central system for monitoring and control. z Transport sector - Electric vehicles, electric scooters and hydrogen vehicles. z Autonomous stationary applications - Fuel cells for the outdoor lighting and the operation of an electric refrigerator. z Use of RES for heating and air-conditioning - Installation of RES systems for heating/air-conditioning and sanitary hot water for the primary school and several buildings. z Improvement of energy efficiency in buildings - Use of environmental friendly materials in public buildings.

3.2. King Island (Australia)

The project - King Island Renewable Energy Integration Project (KIREIP) includes the use of renewable generation in combination with new energy storage devices and enabling technologies. The aim of the KIREIP project is to allow the system to rely less on diesel generation and provide a reliable and stable electricity supply. In this island, the power station comprises of three 1600 kW diesel generators, one 1200 kW diesel generator, three Nordex N29 wind turbines (rated at 250 kW each), two Vestas V52 WTGs (rated at 850 kW each), 800 kWh Vanadium Redox Battery (VRB) storage rated at 200 kW, supervisory control sequencer, and 1500 kW Resistor for frequency control [24]. The detailed scopes for KIREIP include [25] the installation of bio diesel generators, two diesel uninterruptible power supply (D-UPS) engines with flywheel, wind generators, battery energy storage system with 3MW capacity, and smart-grid management system. The D-UPS and storage systems are utilized to store excess wind energy. 12 Jhih-Hao Lin et al. / Energy Procedia 100 ( 2016 ) 8 – 13

4. Conclusions

Due to offshore isolation condition, islands incur more difficult and expensive energy supplies; however, offshore islands are usually granted with a variety of RES. Each island needs to choose the optimal hybrid energy system technically and economically. To achieve a 100% renewable energy system, several significant strategies should be planned in advance. They include efficiency improvements on renewable generation, the design of energy storage systems, and possible energy savings on the demand side [26, 27, 28].

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