Japan’s power-from-seawater project attracts global attentionーNHK WORLD-JAPAN NEWS
generating roundthe-clock clean electricity straight from the sea. That’s the promise of ocean thermal energy conversion or OTAC. The technology taps temperature gaps in seawater to generate a power and a test facility on a remote Japanese island is attracting international attention. The facility sits next to the sea on Kumijima Island in Okinawa Prefecture. This white pipe contains deep ocean water. Okinawa and Kouima funded construction of the plant based on Saga University research and technology. OTCH takes advantage of the 20° temperature difference between surface seawater and colder water pumped up from more than 600 m. The warmer water is used to turn liquids with low boiling points, such as ammonia, into vapor to spin a turbine and generate power. The colder water turns the vapor back into liquid. So, the cycle continues. The test plant produces just 100 kow, but it has provided a stable electricity supply for over 10 years. Saga University professor Iikami Yasuyuki is a leading expert on OTCH. When I open this vapor valve, the pressure will rise and rapidly spin the turbine. This is how it generates electricity. The university has studied ocean energy for about 50 years to find alternative sources to fossil fuels. It identified Kumijima as an ideal site where warmer and deep ocean sea water is easily available. The biggest advantage of the system is it can generate stable electricity supply 24 hours a day regardless of the weather. This is how it provides a base load power source. The next stage is to expand the test facility to a commercial use plant. A shipping company has joined with the university to achieve this. However, OTCH is a costly method for generating power. The university started recycling seawater to offset these costs. Cold sea water warms up after use and becomes ideal for marine farming. It’s being used on Kumijima to grow a type of edible seaweed known as sea grapes. The island is now Okinawa’s leading producer. The water is also used for onshore oyster farming. Another facility opened in spring to use the water to farm other types of seaweed used in food and medicine. These businesses generate about $17 million a year and have created about 140 jobs. The additional revenue helps cut the cost of generating power. Japan’s research into OTCH is benefiting other nations. A facility designed by Saga University started operation in Malaysia in October last year. Officials from the Pacific Island nation of Palao visited Kouima and plan to build their own plant. I would like the research at Saga University to help not just people in Kajima but many others around the world. There are many people struggling from shortages of electricity. The technology nurtured over decades in Saga University is now doing its part to build a world based on sustainable energy.
Generating round-the-clock sustainable electricity straight from the sea? That’s the promise of ocean thermal energy conversion, or OTEC. Will it work?
More stories on business and technology: https://www3.nhk.or.jp/nhkworld/en/news/tags/60/
Please subscribe HERE: http://www.youtube.com/channel/UCSPEjw8F2nQDtmUKPFNF7_A?sub_confirmation=1