The Environment Ministry is set to approve later this month the practice of drilling diagonal wells in national parks as part of efforts to promote for geothermal power plants.
The government has been trying to increase geothermal power generation since the outbreak of the crisis at Tokyo Electric Power Co.'s Fukushima No. 1 nuclear plant, but drilling in national and quasi-national parks is strictly regulated for developing geothermal plants, despite the great potential.
According to the ministry, it would relax the regulations to approve diagonal drilling, a form of drilling where wells can originate outside the regulated area in a national park and tap into supplies in the regulated area. Also, the ministry will approve binary power generation using hot spring water, ministry officials said.
A notification on the matter will be issued by the ministry this month, they explained.
Concerning geothermal power generation, the Government Revitalization Unit has submitted a deregulation proposal demanding relaxation of existing rules. The ministry will also study the possibility of allowing a large-scale power plant within regulated areas in the national and quasi-national parks, officials said.
A geothermal power plant generates electricity by drilling a well to extract geothermal steam from underground, and then using it to turn a turbine.
Diagonal drilling is currently used at Tohoku Electric Power Co.'s Sumikawa geothermal power plant in Kazuno, Akita Prefecture, located in the Towada-Hachimantai National Park stretching over Aomori, Akita and Iwate prefectures. Development permission was issued by the Environment Ministry in April last year. The power plant is expected to supply electricity for the equivalent of about 12,000 households.
The permission for the plant, however, was issued as a special case. To date no clear standards have been established for allowing diagonal drilling. Hereafter the ministry will officially approve the technique for national and quasi-national parks, officials explained.
Binary geothermal power generation utilizes ammonia vapors, which occur at a low boiling point in nearly 100 C hot spring water, to produce steam to turn a turbine.
This system has the advantage of being able to utilize "waste heat" after adjusting the temperature of hot spring water when it is too hot.
An experiment demonstrating this system was just introduced by the ministry at the Matsunoyama Onsen hot spring resort in Tokamachi, Niigata Prefecture, in December.
At Kyushu Electric Power Co.'s Hatchobaru geothermal power plant in Kokonoe, Oita Prefecture, a similar geothermal power generator was introduced in 2004 to use lower temperature steam that is not viable for regular geothermal power generation. The power output capacity of the device is 2,000 kilowatts.
The ministry will approve construction of similar plants in special restricted areas in the parks, where previously this type of construction was prohibited.
According to estimates by the National Institute of Advanced Industrial Science and Technology, an independent administrative institution, Japan's geothermal power generation reserve is 23.47 million kilowatts, which is the third largest in the world.
However, only 18 geothermal power stations in the country are currently in operation, with a total output capacity of 540,000 kilowatts. The electricity generated accounted for merely 0.2 per cent of the national total as of fiscal 2010.
In the wake of the Fukushima nuclear crisis, the Government Revitalization Unit has introduced a policy to simplify procedures for approval of geothermal power plant development under the Natural Park Law and Hot Springs Law, in an effort to promote the use of geothermal power in the nation.
The Economy, Trade and Industry Ministry, together with geothermal power plant operators, have thus far been supporting geothermal power development with vertical drilling, as they say diagonal drilling has higher development costs. Because of this, it has been suggested that further deregulation may occur in the future.