Geothermal to grow in Japan

Thursday, 20 July 2011

Japan is located on the volcano belt and the tectonic plate boundaries as seen in the map below. . This means higher risk of earthquakes but also a larger geothermal resource. For a country with such a risk and resource profile, one would aspect the electricity sector would be biased towards earthquake-tolerant power generating technologies with a large contribution from geothermal. We know that this is not the case. At the present, renewables (except hydro) constitute only 1% of its energy consumption with only one-fifth of that 1% coming from geothermal. However, it looks like there are moves to increase this fraction. Norio Yanasigawa of the National Institute of Advanced Industrial Science and Technology, Higashi, Japan, in a recent presentation (Geothermal Research Symposium, 23-24 May 2011, Colorado School of Mines), claims that after Fukushima national energy strategies are being re-examined in Japan and as a result of this there is expected to be a lot more attention to be given to geothermal.


World map showing tectonic plate boundaries and volcanoes. The red triangles are arc volcanoes (volcanoes placed along the subduction zones) and the yellow triangles are hot spot volcanoes(isolated locations where magma comes near the surface for various reasons)	The above shows estimated rock temperatures at a depth 2000m. No data are available regarding temperatures at deeper levels

While geothermal energy is the most promising baseload electricity alternative, the Yanasigawa presentation mentions a number of obstacles as

high potential region exists inside of nation park, over 80% of national potential
several hot spring owners resist building of geothermal power plants
long lead time (over 10 years) for geothermal power plant due to legal delays and assessment
high cost due to long lead time and no government incentives for initial development costs

While the problem of access to national parks can be solved by directional drilling, innovative co-generation concepts need to be developed for geothermal power plants co-located with hot spas. The Icelandic experience shows that the power plants and touristic spas are not necessarily in conflict. Yanasigawa presents a concept design where a relatively low-temperature hot spring (70-120^oC) can be used to serve a number purposes including hot baths, water heating for other purposes, and electricity generation.

There are some technical challenges preventing widespread acceptance of such systems such as long-term stability and safety, grid connectivity, scaling and corrosion, lack of reliable designs to enable automated generation, and finally higher costs. There is also raised to be a need for legal changes e.g. the act of electricity, boiler management and environmental protection.

It will be interesting to watch the next few months as Japan takes account of the Fukushima disaster and assesses future electrical power options for the country. It makes sense that geothermal has to be a significant component of this future.

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