Experimental power plant in Kunigami dismantled

Electric Power Development Co., Ltd. (J-POWER) has dismantled its Yanbaru experimental seawater pumped storage power station in Kunigami.

The plant, the first of its kind in the world, created electricity by pumping during the night seawater into a tank up on a hill 150 meters above the sea level, and then returning the water into the sea through a power-creating turbine during daytime when the electricity demand is at its peak.

The Japanese Ministry of Economy, Trade and Industry built the power station in 1999 to explore the possibility of oceanic renewable energy at a cost of ¥3.2 billion. J-POWER has used it as a testing facility, but they could not put it in practical use because the demand for electric power in Okinawa has not grown as predicted, and the plant was not profitable as a business.

J-POWER says that the station was originally built as a testing facility, and the company was able to obtain beneficial results from more than 10 years of study, before a decision to close the plant was made after considering every aspect of the operation.


  • JonathanMaddox

    This is a great shame. Okinawa gets its electricity almost entirely from burning imported fossil fuels, but it is a sunny place which could obtain much of its power from sunshine and sea breezes, which arrive free of charge. A pumped storage facility such as that at Yanbaru would usefully have complemented the variable contribution of solar and wind generation.

    • https://scottishscientist.wordpress.com/ Scottish Scientist

      Really? Well what’s the point of building a pumped-storage hydro scheme if there’s no supply / demand imbalance that needs balancing with an energy store?

      I just assumed, like everyone else maybe, that Okinawa must have had unresponsive base-load, like from nuclear power, or intermittent renewable generation, like solar and wind, that needed balancing.

      If they’ve got dispatchable fossil fuel power stations only, that never need much by way of supply-demand balancing, then WHAT’S THE POINT?

      What on Earth happened to the famed “Japanese efficiency”?

      World’s biggest-ever pumped-storage hydro-scheme, for Scotland?


      • https://scottishscientist.wordpress.com/ Scottish Scientist

        * Double Tidal Lagoon Baseload Scheme
        * Off-Shore Electricity from Wind, Solar and Hydrogen Power
        * World’s biggest-ever pumped-storage hydro-scheme, for Scotland?
        * Modelling of wind and pumped-storage power
        * Scotland Electricity Generation – my plan for 2020
        * South America – GREAT for Renewable Energy

        Scottish Scientist
        Independent Scientific Adviser for Scotland

      • JonathanMaddox

        Alas no. Okinawa’s power supply is almost entirely generated by burning imported oil and liquid natural gas, mostly in modern and highly flexible facilities. There is an increasing penetration of solar power, which serves to reduce the existing daytime demand peak and the variation required from the existing generators, but only very little wind power.

        Okinawa may find itself in a “duck curve” situation eventually as solar PV uptake increases, which would certainly present an opportunity for renewed storage investment, but it is not yet as affected by that as some paces like Hawaii and California.

06:32 17 Apr , 2024