Session: 13-01: OTEC, Applications and Devices

Submission Number: 174734

Hybrid OTEC Technology Implementation on Fernando De Noronha Through Brasil-Japan Collaboration: Benefits and Challenges 

The Fernando de Noronha archipelago, located 354 km off Brazil's coast in the Southern Atlantic Ocean, primarily relies on ecotourism, which accounts for 95% of its economy. In 2024, the island welcomed over 131,000 visitors. The permanent population are more than 3,000 people and around 4,000 temporary workers.

 Our survey data conducted from 2018 to 2024, the island's power supply is predominantly from diesel engines connected to generators, consuming up to 25,000 liters of diesel per day to generate 5 MW. Tank ships from Recife and Natal supply diesel fuel weekly, each carrying 160,000 liters. The diesel storage capacity at the thermoelectric plant on the island is 210,000 liters. To reduce CO₂ emissions, two solar panel plants are installed. Due to drinking water scarcity on the island, up 65% of drinkable water is desalinated from seawater using membrane reverse osmosis (RO) technology at a rate of 72 m³/h, with high energy consumption attributed to this process. The island's proximity to the equator means that split-type air conditioning, commonly used on the mainland, is also utilized on the island.

Ocean Thermal Energy Conversion (OTEC) is a renewable energy technology that exploits the temperature difference between the warm surface waters and the cold deep waters of the ocean. By circulating a working fluid through this temperature gradient, OTEC systems can produce electricity continuously, as long as the temperature differential (usually above 20°C) exists. There are three main types of OTEC systems: (i) Closed-cycle systems, which use a working fluid with a low boiling point (such as ammonia) to drive a turbine. (ii) Open-cycle systems, which use the seawater itself as the working fluid, creating a vacuum to flash-evaporate the surface water. (iii) Hybrid systems, which combine aspects of both closed and open cycles. OTEC is particularly suited for tropical islands and coastal regions.

Fernando de Noronha Island is perfect for OTEC deployment due to its tropical location and temperature differences between surface and deep water is higher than 20C and remain quite stable.  OTEC is considered a mature technology, however, CAPEX is quite high, but on islands, the cost per kWh is quite competitive compared to thermoelectric plant using diesel as fuel. Successful implementation will provide continuous, fuel-free energy 24 hours per day for 7 days per week, and becomes the baseload. So, this technology can reduce fossil fuel dependence, improve water security through Low-Temperature Thermal Desalination (LTTD) process with minimum maritime environment impact due to use less than 2% of surface seawater, and can boost the local economy through new businesses such aquaculture, cosmetics production,  hydrogen generation.

This study examines the benefits and challenges of implementing OTEC of 1 MW to 2 MW taking into consideration a memorandum of understanding (MOU) between Brazilian Universities  and IOES – Institute of Ocean Energy,  Saga University, Japan. The Memorandum of Understanding (MoU) signed between UFPE and IOES on August 5^th, 2024 represents a significant step forward in the quest for sustainable energy solutions and innovative marine applications. This collaboration is expected to yield groundbreaking research, human resource development, technological advancements, and tangible benefits for both Brazil and Japan. By harnessing the power of OTEC and DOW applications, the island of Fernando de Noronha can move towards a more sustainable and prosperous future, benefiting from the expertise and experience of Japan's leading research institute.

Presenting Author: Yasuyuki Ikegami IOES

Presenting Author Biography: Graduate at Engenharia Mecânica from Universidade Estadual de Campinas (1986), master's at Mechanical Engineering from Universidade Estadual de Campinas (1990) and ph.d. at Materials Science and Engineering from University Of Tohoku (1994). Has experience in Material and Metallurgical Engineering, focusing on Ceramics, acting on the following subjects: quartzo sintético, quartzo natural, saxs, x-ray topography and digital radiography

Authors:

Armando Hideki Shinohara Federal University of Pernambuco
Yasuyuki Ikegami IOES
Luiz Alberto Magri UFPE - Federal University of Pernambuco
Moacyr Cunha De Araújo Filho UFPE
Ayako Ono UFPE - Federal University of Pernambuco
Takafumi Morisaki Institute of Ocean Energy, Saga University
Jessica Borges Posterari Institute of Ocean Energy Saga University
Flaminio Levy Neto UNB
João Manoel Dias Pimenta UNB
Segen F. Estefen INPO
Carlos Afonso Nobre USP
Delson Torikai USP
Ricardo Cury Ibrahim USP
Paula Birocchi USP
Celso Morooka UNICAMP
Sergio Nascimento Bordalo UNICAMP
Joel S. Sales Junior UFRJ
Antonio Carlos Fernandes UFRJ
Milad Shadman UFRJ
Vitor Takashi Endo UFSC