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KUMEJIMA, Japan – October 29, 2019: 12pm (Nuku’alofa Times): Kumejima was awesome. It was an experience I will never forget.

This small island, part of Japan’s Okinawa Prefecture, is laid back and simple but a leader in the business of Ocean Thermal Energy Conversion (OTEC) and the use of deep ocean seawater to breed marine resources, culture vegetables and agriculture products, and help in the production of cosmetics.

The OTEC Plant in Kumejima. Photo: NUKU’ALOFA TIMES

OTEC is a marine renewable energy technology that harnesses the solar energy absorbed by the oceans to generate electric power. The sun’s heat warms the surface water a lot more than the deep ocean water, which creates the ocean’s naturally available temperature gradient, or thermal energy.

OTEC uses the ocean’s warm surface water with a temperature of around 25°C (77°F) to vaporize a working fluid, which has a low-boiling point, such as ammonia. The vapor expands and spins a turbine coupled to a generator to produce electricity.

At least that is what I learned during the day’s field trip around the town.


The island’s Vice Mayor, Hideo Toubaru, summed up the continuing migration problem, the rural to urban drift, beautifully.

Palau journalist Leilani Reklai meeting the Deputy Mayor of Kumejima Mr Toubaru Hideo. Photo: NUKU’ALOFA TIMES

People are moving where the pasture is green so to speak, he said.

“The population has reduced to 7,800 from 30,000 some years back,” he told the APIC Japan Journalism Fellowship team at the council office.

In 10 years time they expect that to reduce further by another 1,000.

They are losing their young people who have gone to search for education and are then tied down to jobs in other centres.

They have jobs available but no takers. Their recruitment net has expanded to other Asian countries as well.

Energy and by products

The OTEC plant is a critical part of the Kumejima revival, aimed at boosting its economy and sustaining livelihoods.

Caribbean journalists Christopher Serju (left) and Andre Huie tasting deep seawater bred sea grapes in Kumejima. Photo: NUKU’ALOFA TIMES

While ocean energy is a key, the project has also helped in raising the standards with marine product cultivation, agriculture production,cosmetics and drinking water resource.

In the words of Mr Naoki Ohta, of the Kumejima Town Project Promotion Office, “this is our lifeline.”

“The project has brought a ray of hope to Kumejima,” he told me as he drove us through the streets, moving from one business site to another that is using the deep ocean seawater from the OTEC plant to support their commercial operations.

Kumejima was home away from home.

Simple, laid back.

But with a lot of interesting stories the world over can learn from.


  • Iliesa Tora was part of the APIC Japan Journalism Fellowship team that visited Kumejima.

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