Deep Sea Water Research Institute


The Okinawa Prefectural Deep Sea Water Research Center is located in the Maja district of Kumejima. North of Kumejima the sea bed drops away several hundred meters creating a unique opportunity to study deep seawater, its uses, and properties without having to travel into open water. Using a series of pipes, the center is able to bring the cold, mineral rich water onto Kume Island for study.

The Center has been in operation since 2000, and through research has already found a number of uses for the water, which is being used in local industries. ODRC maintains a number of active experiments while aslo coordinating with other research stations and projects around the world. In 2013, the world's only fully operational OTEC (Ocean Thermal Energy Conversion) Power Plant at the time was completed on the institute grounds to study the use of deep seawater in clean energy production.

While the facility is not open to the general public, tours are now available by appointment and the information and tourist center next door features many products developed from Kumejima's Deep Seawater. Stop by to see live specimines, sample products, and relax in a cool environment.


Water Cooled PlantsThough Kume Island's temperature is relatively stable due to its island geography, the warm climate significantly limits the types of produce that can be grown locally. Since Deep Seawater is brought up at nearly the same temperature as a refriderator, it is a natural resource that can be used in a variety of cooling applications.

On Kume Island, the DSW Research Center has invested the past 15 years in researching different plants that can be grown with soil cooled by deep seawater. Several greenhouses are set aside for this research. Regular water in a closed system is cooled in a heat exhcanger by deep seawater before being pumped through pipes that are placed in soil. The cold water pipes cool the soil enough to ensure that plants can thrive. Though the houses can get very hot, the roots of the plants remain cool.

After years of research, Kume Island locals now grow spinach for local consumption and export to the Okinawa mainland. Kumejima town has also constructed new greenhouses next to the center to study expanded DSW-cooled agriculture. This form of agriculture provides an exciting opportunity to feed the world's growing populations, especially in suptropical regions that have limited growing seasons.


With diminishing wild fish populations, growing human populations, and millions still hungry around the world, it is critical that countries develop ways to create healthier and sustainable food resources. The ODRC is also focusing on finding ways to use mineral rich deep sea water in the cultivation of edible marine species.

Using a combination of surface and deep seawater provides both pristine, bacteria-free water and temperature control for the study of ways to promote growth and health in potential food sources.

Already, Kumejima is using deep sea water to create larger, healthier Kuruma Ebi (A prawn similar to Tiger Prawns) and umi budo (known as sea grapes or green 'caviar'). Above you can see a giant clam that resides at the institue. There are also many fish pools where researchers can study different mixes and temperatures with schools of various fish species.

The water resources are also useful for growing edible sea plants. In particular, Kume Island residents have found that they can produce sea grapes with larger and more uniform 'grapes.' Sea Grapes are a type of seaweed with small green protrutions similar to caviar. They are considered a delicacy in Okinawa, creating another useful industry for the island.


Visit the OTEC Okinawa website for more information on Ocean Thermal Energy Conversion on Kume Island or to make a tour reservation!

OTEC Power Plant

OTEC is an acronymn for Ocean Thermal Energy Conversion, or in simpler terms: a way of harnessing the difference in sea temperature between surface and deep water to turn a power-generating turbine.

The OTEC plant on Kumejima was built by Okinawa Prefecture under advice from Saga University and their Institute of Ocean Energy. It is one of only two fully operational OTEC facilities in the world.

The OTEC plant uses the warm surface sea water as well as cold deep seawater from the Research Center. The seawater is used to cool and heat a working fluid in a closed system to drive a trubine. The only major by-product of the process is seawater that can be used in other industries.

OTEC Flowchart

The OTEC power plant first produced electricity in March of 2013. Researchers utlize the new building to demonstrate technology and gain valuable data for use in the development of larger facilities.

On June 16, 2013 the Okinawa Government and other interested parties celebrated the initialization of power generation with a ceremony and reception at the Research Center.

Other Industries

Deep Sea water can be used for many things. In the fifteen years the Research Institute has operated, a number of new technologies and innovation has led to the creation of new products and industry. Examples include cosmetics at the Point Pyuru company, bottled mineral water, magnesium lights, and many other items. Click "Other Industries" above to see them all.

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