Application of OTEC Overcoming Electricity-Fresh Water Crisis in Remote-Outer Islands, Indonesia

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1 Application of OTEC Overcoming Electricity-Fresh Water Crisis in Remote-Outer Islands, Indonesia a) Faculty of Mechanical Engineering, Universiti Teknologi Malaysia b) Ocean and Aerospace Engineering Research Institute, Indonesia J.Koto a,b,* and Rido Bela Negara b *Corresponding author: jaswar.koto@gmail.com, jaswar@utm.my Paper History Received: 5-April-2017 Received in revised form: 25-April-2017 Accepted: 30-April-2017 ABSTRACT Indonesia is an archipelagic country having 13,466 islands extending 5,120 km from East to West and 1,760 km from North to South Indonesia. In small or outermost islands, supplying fresh water and electricity for public are still a serious problem and must be addressed by the government. As Indonesia is an equatorial country located at latitudes less than 20 degrees covered by 77 % ocean, thousand islands, strain and many difference of topography, Ocean Thermal Energy Conversion (OTEC) is very compatible built in Indonesian. This paper discussed the potential areas of 100 kw OTEC to be applied in Indonesia. The simulation results found that Indonesia was high potential for application of OTEC in which electricity and fresh water produced by OTEC are cheaper than the current price market. Ocean Thermal Energy Conversion (OTEC) is a clean and friendly renewable energy with zero-emission. OTEC uses temperature difference between the sea surface and the deep ocean to rotate a generator to produce electrical energy. OTEC is capable of generating electricity day and night, throughout the year, providing a reliable source of electricity. OTEC have installed in certain countries as follows [1]: Saga, Japan produces 30 kw which was operated since 1980 with the purpose of research and development. Gosung, Korea, KRISO produces 20 kw which was operated since 2012 with the purpose of research and development. KEY WORDS: Ocean Thermal Conversion Energy, Electricity, Fresh Water, Indonesia. NOMENCLATURE Ocean Thermal Energy Conversion 1.0 INTRODUCTION Figure.1: OTEC system in Saga University, Japan [2] Réunion Island, France - DCNS produces 15 kw which was operated since 2012 with the purpose of research and development. Kumejima, Japan produces 100 kw with grid connected operated since 2013 with the purpose of research and development and for electricity production. 1 IJERCE Received: 5 April 2017 Accepted: 30 April 2017 February-March 2017 [(6)1: 1-9]

2 Carnot efficiency. (1) Figure.2: OTEC plant at Kumejima, Japan [3]. Where; is Carnot efficiency, is an absolute temperature of the surface water and is absolute temperature of the deep water. The efficiency of the cycle is determined by the temperature difference. The greater the temperature difference, the higher the efficiency. This technology is therefore worth especially in equatorial regions where differential temperatures throughout the year are at least 20 0 C. Hawaii, US under Makai Ocean Engineering produces 105 kw with grid connected operated since 2015 with the purpose of electricity production. Figure.4: OTEC process overview [3]. 3.0 ELECTRICITY AND FRESH WATER CRISIS IN THE REMOTE ISLAND, INDONESIA Figure.3: OTEC plat in Hawaii, US [4] 2.0 OTEC PLANT SYSTEM Ocean Thermal Energy Conversion (OTEC) technology uses a turbine generator to create renewable energy from the temperature difference between cold, deep seawater circulating in the ocean and surface seawater warmed by the sun. In order to produce power with the low temperature range, a working fluid with low boiling point is used. The amount of energy created is reliant on the amount of water available to cool or heat the working fluid. Ocean thermal between water surface and water depth must be converted to reach maximum output from its thermal. The OTEC efficiency value can be calculated using the equation of Indonesia is an archipelagic country extending 5,120 km from East to West and 1,760 km from North to South. According to a geospatial survey conducted between 2007 and 2010 by National Coordinating Agency for Survey and Mapping (Bakosurtanal), Indonesia has 13,466 islands [5]. The isolated islands or outermost islands have a variety of specific natural resources, limited, as well as the environmental carrying capacity is limited. In an effort to protect the country's border areas against foreign territorial claims, the government has declared 111 outer islands [6] as shown Figure 5. In small or outermost islands, both in the West and the East, Indonesia, supplying fresh water in the dry or rainy season and supply of electricity are still a problem difficult and must be addressed by the government. The problem is more complex if the supply of water and electricity associated with integrated regional development plan that includes residential areas, industry, trade, transportation, Hankamnas, and others as shown in Figure 6. Strategic management of remote islands and outermost should be sought so that the water and electricity resources available will 2 IJERCE Received: 5 April 2017 Accepted: 30 April 2017 February-March 2017 [(6)1: 1-9]

3 not be used beyond the limits of carrying capacity. enormous passive solar collectors as shown in Figure. Figure.7: Potential OTEC in Indonesia. Figure.5: The outmost and remote islands in Indonesia [7, 8]. As the Indonesia has 77 % of total area covered by the ocean, OTEC can be done effectively and on a large scale to provide a source of renewable energy that is needed to cover a wide range of energy issues [9, 10]. This paper discusses performance of closed cycle OTEC applied in several locations in Indonesia such as Mentawai, Sumatera Barat, North of Sulawesi Utara, Maluku Utara and Banda seas as shown in Figure 8. Figure.6: Fresh water crisis in the remote islands, Indonesia [7, 8]. 4.0 POTENTIAL OTEC IN INDONESIA 4.1. Temperature Distribution inn Indonesia OTEC is one of the world s largest renewable energy resources and is available to around the tropical countries including Indonesia. Indonesia is the tropical oceans country, approximately defined by latitudes less than 20 degrees, may be thought of as 4.2. Research on OTEC in Indonesia Some researchers have studied OTEC in Indonesia. Achiruddin, et.al 2010 [11] has mentioned in their study that OTEC plants can be applied in the regions of along southern Sumatra, Java, Bali, Nusa Tenggara archipelago and in eastern Indonesia. In 2015, Donny [12] proposed a strategy to develop OTEC in Indonesia by taken economic and environmental issues. He stated that Indonesia has excellent ocean thermal energy conversion technology resources, especially along southern Sumatra, Java, Bali, Nusa Tenggara archipelago and in eastern Indonesia. Adrian 2015 [13] stated that OTEC could be a solution to produce electricity and also can produce fresh water and cold water for agricultural and cooling purposes especially in the tourist area in Bali. Fanny, et.al 2016 [14] studied potentially of OTEC Installation as Power Plant in West Sumatera, Indonesia. They proposed three potential locations for OTEC application as follows: Pesisir Selatan, Padang and Mentawai Islands. Delyuzar in 2016 [15] has conducted sites seawater temperature measurement in Indonesian waters by MGI Team at the following locations: Mamuju located in the Makassar Strait, Tarakan, Flores Sea, North Bali and Lembata, Nusa Tenggara Timur. 3 IJERCE Received: 5 April 2017 Accepted: 30 April 2017 February-March 2017 [(6)1: 1-9]

4 Figure.8: Bathymetry map of Indonesia [9, 10]. Table.1: Temperatures on the surface and 700 m of depth water at several locations in Indonesia [9]. Location T Max, ( 0 C) T Min ( 0 C) Siberut, West Sumatera North Sulawesi West Papua Morotai Sea South of Maluku Figure.9: Temperature profile in Indonesia [8]. Table 1 shows surface temperature and seabed temperature on several locations in Indonesia which found temperature difference more than 20 degree Celsius. 4.3 Potential OTEC in Siberut Island (1) Geography of Siberut Island Siberut is the largest and northernmost of the Mentawai Islands, lying 150 kilometres west of Sumatra in the Indian Ocean. A part of Indonesia, the island is the most important home for the Mentawai people. Siberut Island has area 4,030 km2 with population 35,091 people. Siberut Island has a hot and humid tropical rainforest climate, with an annual rainfall of 4,000 mm with temperatures range C and humidity averages 81-85%. (2) Temperature, Salinity and Density Profiles Figure 10 shows profile temperatures on January at different water depths in Siberut, Mentawai, Sumatera Barat. As in Sumatera Barat, January is the peak of rainy season, therefore the 4 IJERCE Received: 5 April 2017 Accepted: 30 April 2017 February-March 2017 [(6)1: 1-9]

5 data was assumed to be acceptable due to temperature of surface seawater on dry season such as June, July August are higher than temperature on January. temperature in the Sulawesi Utara was C, the temperature at 500 meter depth was 6.44 C and difference temperature between surface and deep sea was C. Figure.11: Mean monthly surface and deep seawater temperature profile in Sulawesi Utara-Indonesia [18]. Figure.10: Temperature profile of ocean water in Siberut Island in West Sumatera Indonesia [16]. 4.4 Potential OTEC in Karangkelong Island (1) Geography of Karangkelong Island Talaud region is one of the districts in the province of Sulawesi Utara, Indonesia with a capital city of Melonguane. This region is the most northerly region in eastern Indonesia, borders the Davao del Sur, Philippines. Population of Talaud region at the 2010 census is 83,441 inhabitants. Talaud region is a comprehensive maritime sea around 37,800 km2 which is 95.24% of total area and a land area of 1251 km2. Talaud tribes inhabit the cluster of islands in the regency Sangir-Talaud, Sulawesi Utara. Their area consists of three main islands, namely Karakelong, Salibabu and Kabaruan. Another name of Talaud is Taloda, meaning "the sea". There was also a call Porodisa". The main livelihood of these communities is fisher in the sea only small proportions are farmers in the fields or used as a side job. Their main crop is potatoes, even though it should also be given cultivating rice fields and rice paddies. 4.5 Potential OTEC in Morotai Island (1) Geography of Siberut Island Morotai is a rugged, forested island lying to the north of Halmahera which located at of latitude and of longitude. The Morotai island has an area of some 1,800 square km, stretching 80 km north-south and no more than 42 km wide. A part of Indonesia, the island has population people. (2) Temperature Profile Figure 12 shows profile temperatures at different water depths in Morotai Island, North Maluku. The Halmahera Sea is exposed at its northern end to the South Pacific water adverted into the region by the New Guinea Coastal Current 11). Halmahera Sea sill depth controlling was direct access of South Pacific water to the Indonesian Seas. The South Pacific water column may spread into the southern Halmahera Sea. The Halmahera thermal stratification deviates from the Pacific Ocean with increasing depth below 490 m. (2) Temperature Profile Gordon, et.al, 2003 [17], under Arlindo Project had conducted field measurement of profiles of temperature, salinity and oxygen within the Indonesia seas in Sulawesi Utara, Maluku, and Halmahera, Maluku Utara with CTD equipment and water samples for salinity and oxygen standardization. Figure 11 shows profile of mean monthly temperature on surface and deep water in Sulawesi Utara, Based on the figure the average value of surface 5 IJERCE Received: 5 April 2017 Accepted: 30 April 2017 February-March 2017 [(6)1: 1-9]

6 International Journal of Environmental Research & Clean Energy 30nd April Vol.6 No.1 (2) Temperature Profile Figure 6 shows profile temperatures at different water depths in Seram Island, Maluku retrieved from NOAA. The Seram Sea is a relatively small basin with an expected short deep residence time 11). The shallow Halmahera Sea (see Figure 13 lower part) sill allows saline South Pacific lower thermocline water to enter the Seram Sea. Temperature profile of ocean water in Seram Island, Maluku, Indonesia Water Depth (m) Temperature (C) Figure.12: Temperature and salinity profiles of ocean water in Halmahera, North Maluku-Indonesia [17, 19]. 4.6 Potential OTEC in Seram Island (1) Geography of Siberut Island Seram is the largest island in southern Maluku Province located at of latitude and of longitude as shown in Figure 13. According to local beliefs it is the "Nusa Ina" or Mother Island where all the people of Central Maluku once came from. The population of the island in the 2010 Census was 434,113 people, administered among 3 regencies as follows: Maluku Tengah Regency had 170,392 people on Seram island and 191,306 on the lesser islands, the entirety of Seram Bagian Barat Regency and Seram Bagian Timur Regency. Figure.13: Temperature and salinity profiles ocean water in Seram Island in Maluku-Indonesia [17, 20] KW OTEC IN INDONESIA 5.1 Simulation and Results The performance of OTEC system was simulated using Subsea 6 IJERCE Received: 5 April 2017 Accepted: 30 April 2017 February-March 2017 [(6)1: 1-9]

7 Pro as shown in the Figure 14. The software was developed by Ocean and Aerospace Research Institute, Indonesia. The simulation was based on following assumptions: Surface temperature inlet was assumed 28 0 C (the lowest surface temperature in Indonesia) and the temperature outlet was setup 25 0 C. The evaporation and condensation ammonia pressures rose and decreased were assumed 0.06 bar. The surface and deep seawater pressures decreased were assumed 0.3 and 0.72 bar respectively. The evaporation and condensation ammonia temperatures were set up 25 and 8 0 C The outlet surface and deep sea water temperatures were set up 25and 9 0 C Turbine and generator efficiencies were assumed 75 and 94 %, respectively Working fluid was using pure ammonia Depth of inlet sea water was 700 meter energy. The low temperature of ammonia is pumped with 62 kw from solar energy The results simulation shows that the suitable mass flow rate of the working fluid is 21 kg/sec. The surface and deep seawater flow rates were founded 2100 and 2300 kg/sec. The simulation shows several founding as follow: Long Mean Temperature Difference (LMTD) is Investment for generating electrical power is $/kwh The OTEC system can produce 0.21 km2 of green-house cooling system The system can produce 7400 m 3 per day of fresh water for drink after distillation. The system can also produce 2300 kg per second seawater which can be used for fish farming. The Carnot efficiency of ammonia saturation is 6 percent The cycle efficiency of ammonia saturation is 0.17 percent The electricity and fresh water tariffs produced by OTEC are lower than current (Indonesian National Electricity Company) PLN s rate and market as shown in Figures 16 and Figure 17. These were due to return value from waste surface and deep seawater used for fresh water and cooling system. It is clear to picture that the OTEC system will save million USD national economic impact compared using diesel energy. The OTEC system is more sustainable because the energy resource is taken from seawater surrounding the electric station. Figure.14: Subsea Pro Simulation Software In the simulation, the principal components are the heat evaporator, condenser, turbine and generator, and seawater supply system. They did not included ancillary devices such as separators to remove residual liquid downstream of the evaporator and subsystems to hold and supply working fluid lost through leaks or contamination. Figure 15 shows results of simulation for 100 kw of Net Output Power (NOP) in Indonesia. In the simulation, the inlet surface and deep sea water temperatures are 28 and C, respectively. Heat transfer from high temperature occurs in the evaporator, producing saturated ammonia. The hot water is required 46 kw to pumped from surface seawater. Electricity is generated when this ammonia gas expands to lower pressure through the turbine. Latent heat is transferred from the vapor to the low temperature from deep sea water in the condenser and the resulting liquid is pressurized with a pump with 51 kw from wind Figure.15: OTEC simulation results in Indonesia. 7 IJERCE Received: 5 April 2017 Accepted: 30 April 2017 February-March 2017 [(6)1: 1-9]

8 Figure.16: Electricity rate using OTEC compared with PLN s rate. Figure.17: Fresh water price using OTEC compared with current market. 5. CONCLUSION This paper has discussed potential of OTEC in Indonesia. The results founded that several locations in Indonesia has gradient temperature more than 20 0C. They are Siberut Sumatera Barat, Karangkelong, Sulawesi Utara, Seram Maluku and Morotai, Maluku Utara. 100 kw of OTEC has been simulated and the results founded fresh water and electricity produced by OTEC was lower than current market price. ACKNOWLEDGMENT The authors would like to convey a great appreciation to Ocean and Aerospace Engineering Research Institute, Indonesia and Universiti Teknologi Malaysia for supporting this research. REFERENCES 1. Ocean Thermal Energy Conversion (OTEC), Currently operating OTEC plants 2. Institute of Ocean Energy, Saga University, Japan [IOES], 3. OTEC Okinawa, 4. Makai Ocean Engineering, 5. National Geographic Indonesia, Hanya ada Pulau di Indonesia, 8 February The Jakarta Post, Indonesia declares more outermost islands, March 12, Wattech, Informasi Lengkap Reverse Osmosis di Indonesia 8. Koto, J, 2017, Overcoming Electricity-Fresh Water Crisis in Remote-Outer Islands, Indonesia, Presented in ITS, Indonesia 9. Koto, J, Potential of Ocean Thermal Energy Conversion in Indonesia, International Journal of Environmental Research & Clean Energy, Vol.4 (1), pp.1-7, NOAA Atlas NESDIS, World Ocean Atlas 2009, Volume 1:Temperature, Achiruddin, D., K.Saito. and G.C. Nihous, Feasibility Study of OTEC Plants in Indonesia, Trans. Of the West Japan Soc of Naval Architects, No. 94, August Donny Achiruddin, Strategy to Develop Indonesian Ocean Thermal Energy Conversion (OTEC) Resources, Renewable Energy and Energy Conversion Conference and Exhibition, Bali, Indonesia, Adrian Rizki Sinuhaji, Potential Ocean Thermal Energy Conversion (OTEC) in Bali, Renewable Energy and Energy Conversion Conference and Exhibition, Bali, Indonesia, Fanny Octaviani, B. Muswar Muslim, C. Danny Faturachman and D. Ayom Buwono, 2016, Study of Ocean Thermal Energy Conversion (OTEC) Generation as Project of Power Plant in West Sumatera-Indonesia, International Journal of Systems Applications, Engineering & Development, Vol.10, pp Delyuzar Ilahude, 2016, Result of Ocean Thermal Energy Conversion Research in Indonesian Waters and The Future Planning Research Location in 2017, International Seminar of Ocean Energy, Bandung 8 December Koto, J and Ridho Bela Negara, Preliminary Study on Ocean Thermal Energy Conversion in Siberut Island, West Sumatera, Indonesia, Journal of Aeronautical -science and engineering-, Vol.6, pp.1-7, Arnold L. Gordon, Claudia F. Giulivi and A.Gani Ilahude, Deep topographic barriers within the Indonesian seas, Deep- Sea Research II 50, pp , Ridho Bela Negara and J. Koto, Potential of 100 kw of 8 IJERCE Received: 5 April 2017 Accepted: 30 April 2017 February-March 2017 [(6)1: 1-9]

9 Ocean Thermal Energy Conversion in Karangkelong, Sulawesi Utara, Indonesia, International Journal of Environmental Research & Clean Energy, Vol.5 (1), pp.1-10, Koto, J, Ridho Bela Negara, 2016, Study on Ocean Thermal Energy Conversion in Morotai Island, North Maluku, Indonesia, Journal of Aeronautical -science and engineering-, Vol.7, pp Koto, J and Ridho Bela Negara, Study on Ocean Thermal Energy Conversion in Seram Island, Maluku, Indonesia, Journal of Aeronautical -science and engineering-, Vol.8, pp.1-8, IJERCE Received: 5 April 2017 Accepted: 30 April 2017 February-March 2017 [(6)1: 1-9]