Only about 16% of Japan’s electricity is produced domestically, but Japan is located on the ring of fire and is rated as the third most geologically active country in the world. This threatens nuclear power with earthquakes, tsunamis, and volcanic eruptions, but is ideal for geothermal energy development. Japan Geothermal Developer’s Council has announced that six Tohoku prefectures could develop a generating capacity of 170 MW and a total of 740 MW in those prefectures, if including sites in national parks, where geothermal plants are presently restricted.
The recent massive earthquake in Japan caused 6800 MW of electricity to go offline. It is estimated that conventional geothermal in Japan may have a combined capacity for 85,000 MW, more than enough to entirely replace its nuclear energy power plants.
“Conventional geothermal” energy development uses volcanically active areas of the Earth to produce steam for a conventionally operated thermal power plant (and uses the thermodynamic Rankine cycle). Both nuclear energy and geothermal energy currently have the highest capacity factor, around 90%, making them good sources of baseload power. CleanTechnica’s Andrew Burger says:
In contrast to fossil fuel electrical power plants, geothermal power plants produce no greenhouse gas emissions, and geothermal is a renewable resource. It’s cost-effective, and in contrast to renewable energy resources, such as wind and solar that produce electricity on an intermittent basis, it provides a steady stream of electricity, or baseload power.
Geothermal energy can also be developed with the Organic Rankine Cycle (ORC) and can then operate at lower differences in temperatures. This is sometimes called “Dry Well Geothermal” because it is proposed for dry oil wells. This type only needs warmer underground temperatures and may use wells 2,000 to 3,000 feet deep. This type is available even in areas that are not volcanically active.
The last type of “geothermal” is used with heat pumps to tap the relatively constant ground temperatures for heating and cooling. This type might use ponds, 6′- to 10′-deep surface loops or wells 200 to 300′ deep. Our planet’s surface heat would be 20 to 30 degrees cooler if it were not for the sun heating the surface. To some extent, this type of “geothermal” is a solar application.
Geothermal in Japan
Japan is heavily dependent upon imports for most of its electrical needs. It is not surprising that nuclear energy was such an attractive option. Like solar and nuclear energy, geothermal has a high initial cost but much lower operating costs.
Mitsubishi Corp, Toshiba Corp and Fuji Electric are leaders in the geothermal equipment industry, supplying nearly 70 percent of all steam turbines and power gear at geothermal plants worldwide.
Geothermal Research Society of Japan provides an 80-year timeline of geothermal development in Japan, but there is only about 530 MW of geothermal energy presently developed. Presently, development is a long and complex process that can take 5 to 10 years. In part, this may be because geothermal energy is viewed as a natural resource that feeds their hot spring resorts (onsens) rather than primarily as a renewable energy resource.
As Japan begins to “…aim for a society that does not depend on nuclear power generation” by phasing out such energy “systematically and in stages” (- Japan’s Prime Minister Naoto Kan), geothermal seems like a great option for new electricity generation. Thus, it is not surprising that
…the government last June eased restrictions on development in national and quasi-national parks. Developers are now permitted to tap into geothermal resources underground if they drill diagonally into the ground from outside national and quasi-national parks, or take other steps to preserve the parks’ landscapes.
Careful legislation will be required to continue to streamline the development process while maintaining the natural beauty of Japan.
- Ring of Fire: USGS
- how geothermal works: NREL via Union of Concerned Scientists
- energy graph: EIA
- Onsen (hot spa:) wiki commons