Ocean Thermal Energy Conversion (OTEC)

The OECC facilitates improving access to international funding for large-scale projects

Many Small Island Developing States (SIDS) rely on imported fossil fuels for their energy sources and are faced with significant challenges in terms of energy price hikes and security. At the same time, in order to respond to climate change, conversion to renewable energy (mitigation) and management against water shortages (adaptation) are also their priorities. Against this backdrop, the OECC is working to promote the use of Ocean Thermal Energy Conversion (OTEC) which is a system that combines a stable renewable energy supply and the benefit of utilizing the deep seawater for a variety of purposes. An OTEC system is being tested on Kumejima Island in Okinawa prefecture and is attracting attention as the “Kumejima Model” that drives new industries and can be further deployed to support the self-sustaining development model for SIDS.

About Ocean Thermal Energy Conversion（OTEC）

The oceans surrounding us have a large temperature difference between the surface and the deeper layers. The power generation system that utilizes this ocean temperature difference is called Ocean Thermal Energy Conversion (OTEC). Its heating source is warm seawater at 25 to 30°C on the surface layer of the ocean, and its cooling source is cold seawater at 5 to 7°C in the deeper layers, 800 to 1,000 meters below the surface. Since 2013, a demonstration facility has been in operation in Kumejima Town, Okinawa. While OTEC supplies sustainable energy without emitting GHGs, it also provides opportunities to foster local industries, as in the “Kumejima Model” where aquaculture fisheries, cool-temperature agriculture, and food products and cosmetics are being developed through the secondary use of deep seawater in collaboration with the local government.

Reference: Public Relations Office – Government of Japan

Roles of the OECC

OTEC requires significant funding for the power generation plant and the intake pipes to pump deep seawater. In obtaining international funds for climate change measures in developing countries, the OECC can act as a guide to ensure that the project proceeds in the right steps. Former engineers in the field of power generation and staff specializing in climate finance provide advice on introducing technologies, conducting economic analyses, and guidance on the procedures to access international climate finance in order to expand the “Kumejima Model” to other island nations.

Our Business

Facilitation for International Climate Financing

The OECC works with the Japanese government and international organizations in supporting the Small Island Developing States and the Japanese private sector to obtain climate finance. For the introduction of OTEC facilities, we support the implementation of Pre-feasibility studies and feasibility studies through multilateral funds such as the Climate Technology Centre and Network (CTCN), the Green Climate Fund (GCF) and other bilateral cooperation schemes provided by the Japanese government.

Projects we were engaged in:

CTCN “OTEC: Ocean Energy Technical Pre-Feasibility Study in Nauru”
JICA, Information Collection and Confirmation Survey regarding Ocean Thermal Energy Conversion and Expansion of the Kumejima Model in Pacific Island States in the Oceania Region
Ministry of Economy, Trade and Industry, “Feasibility Study on GCF/CTCN for Ocean Thermal Energy Conversion in Mauritius”.

Pre-FS report in Nauru formulated by the OECC.

Team up with the Governments in Partner Countries and International Organizations

Utilizing domestic and international networks we have established over the years, the OECC is teaming up with governments and companies of Small Island States, the Japanese government and companies, international organizations, and other relevant parties that are interested in introducing OTEC and water intake pipes.

Conference of the Japanese government and the Mauritian government in COP28 (Dubai)
Reference：UNFCCC flickr

Business Model Development

As the construction of OTEC and intake pipes requires significant upfront capital, it is necessary to establish a business model that can simultaneously recover these costs. To further expand the “Kumejima Model,” the OECC supports the formation of a business model based on the conditions in each island nation that would promote industrial development by utilizing the deep seawater used in OTEC.

Interview at an aquaculture center in Palau

Topics

Experiences Obtained from the CTCN Pre-feasibility study in Nauru

In 2022, a pre-feasibility study was conducted in Nauru using the CTCN scheme. While COVID-19 made it difficult to travel to the site and to measure the actual oceanographic data, we conducted a reanalysis based on the existing global low-resolution ocean observatory data. With the cooperation of the University of Tokyo and Saga University, the oceanographic environment of the waters in the Republic of Nauru was assessed and a method to build the data necessary for designing a 1 MW-scale OTEC plant established. As a result, it became possible to evaluate the potential for OTEC deployment in the entire Republic of Nauru and to select optimal locations by comparing the analyzed data for each point.

Identification Survey for Installation of OTEC Plant in Nauru

Related Information

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