No. 72: Prospect of natural energy in Japan – wave power generation (July 4, 2011)

In Japan, ocean energy is not positioned as new energy in the law designed to promote the utilization of new energy, nor is it subject to the buyback system. In Europe, three ocean power generators have been running offshore Portugal since September 2008 as the world’s first commercial wave ocean generation. In fact, Japan is 10 years behind from western countries in the development of wave power generation, though it started to work on wave power generation in the oil shock in 1975. However, Japan is moving now, even though very slowly.

A venture company from Kobe University conducted the substantiative experiment of wave power generation offshore Wakayama Prefecture. Circular discs rotate by the force of waves and run the generator to generate electricity when they get back to the original position. The research team confirmed that this generator has the maximum generation capacity of 50 kW with higher generation efficiency. Tokyo University and Mitsui Engineering and Shipbuilding will start the substantiative experiment of wave power generation offshore the Izu Island chain starting in 2014. They have already confirmed that they can get more than 15 kW for every 1 m width of a wave. They plan to employ a buoy type generator with a generation capacity of 80 kW and confirm whether or not they can get a generation cost of about 40 yen per KW.

The project team established by the Tokyo metropolitan government and Tokyo University estimates that ocean wind generation and wave power generation combined will have a generation capacity of 20-30 million kW that is equivalent to the power generated by 20-30 nuclear power generators. It suggested to the Japanese government that the nation should boost up the capacity of ocean energy to 1 million kW by 2020.

Responding to the above activities, the Japanese government launched the 5-year ocean energy research and development project with a budget of 1 billion yen, and will recruit private companies shortly. The project aims to develop the technology that realizes a generation cost of about 20 yen per kW by 2020.

Despite the fact that Japan is surrounded by the sea, the Japanese government was not fast enough to stimulate the development of generation technology that uses wave, temperature difference of seawater, and tidal currents. Japan is about to come to the surface again the in the field of ocean energy development again considering that a bipartisan commission formed by Diet members submitted an urgent proposal recently.

No. 71: Prospect of natural energy in Japan – Geothermal generation (July 1, 2011)

Japan is a country of volcanoes. It has the world’s third largest geothermal resources following Indonesia and the U.S., and it has excellent technology for geothermal generation because it has 70% share in the geothermal generation turbine market. If Japan can use all its geothermal resources for generation, it will have a generation capacity close to 24 million kW that is equivalent to the same output by 23 nuclear plants. Nonetheless, Japan’s current geothermal capacity stays at 0.5 million kW which is the 8th largest in the world. Why? The answer is simple. Nearly 80% of geothermal energy sources are located inside national parks.

In 1972, two Japanese government agencies concerned reached an agreement not to promote the development of geothermal energy sources inside national parks for the time being. The phrase of “for the time being” means 40 years for Japanese government agencies. The environment Agency, one of the two agencies, decided to deregulate the development inside the national parks last June. It allowed developers to dig a hole outside of a national park toward inside it at an angle. Tohoku Electric Power started a project to dig a hole in this way at its Sumikawa Geothermal Power Plant in Akita Prefecture. If you dig a hole outside the national park at an angle toward inside it for 2.5 km, you can get inside the national park in about 100-200 m to reach a heat source. The heat source inside is higher than 300 degrees C that is enough for a highly efficient heat source.

According to the Environment Agency, possible thermal generation capacity from outside heat sources alone is 2.2 million kW, but it will increase to 6.4 million kW if digging at an angle toward inside is allowed for a distance less than 1.5 km. If the distance is doubled, it will be 10.3 million kW that is equivalent to the power generated by 10 nuclear power plants, and 43% of Japan’s total heat sources for geothermal generation can be utilized.

Hot springs generation is scheduled to be made practicable pretty soon. Geothermal Energy Research & Development will start the substantiative experiment in a hot spring coming November. The system heats ammonia water using hot spring water and runs the turbine using the resulting steam. A system of hot springs generation with a generation capacity of 50 kW can secure the same output by the photovoltaic generation of 100 households.

A high operating rate also characterizes geothermal generation. Photovoltaic generation has an operating rate of 12% and wind generation 20%, but geothermal generation has an operating rate of more than 90%. However, the demonstration equipment for hot springs generation is 100 million yen. As always, cost is the greatest obstacle for the spread.