| Abstract |
NEDO (New Energy and Industrial Technology Development Organization) is currently engaged in the development of a binary cycle power plant, as part of MITIs New Sunshine Project. A binary cycle power plant for geothermal power generation has two major advantages as compared to the conventional geothermal power generation. That is, a binary cycle power plant can utilize untapped geothermal energy such as great volume of geothermal hot water reinjected into underground in the conventional geothermal power plants. Although the conventional geothermal power generation is one of clean energy resources, a binary cycle power plant generates electricity under a closed system and therefore no carbon dioxide or other gases are emitted during operation. One main component of a binary cycle power plant under developing is a downhole pump (DHP). The feature of this pump is equipped with motors to drive a pump; therefore, deeper geothermal water resources could be utilized by using this DHP compared to other types of DHP. However, there exist many challenges have to be developed, since the pump must be operated at high temperature and pressure conditions in order to pump up hot water with medium and high temperature (from 150 to 200 Åé). In addition, it needs to withstand erosion in corrosive geothermal water environments. And, its motor with a slim and long-shaped configuration must have high output, because the pump is installed in a slim deep well and is used to pump up geothermal water at high discharge rate. To develop this submersible type DHP, we conducted factory and field tests using a test pump No.3 with an actual size between 1990 and 1992. In each test, the test pump No.3 operated successfully for about 1000 hours under hot water environment at the temperature of 200 Åé. Preceding to the development of a binary power plant, we will conduct a long-term hot water cycle test at Sugawara test site in Kyushu from 1999 to 2000. The main objects of this test are to evaluate the performance of the DHP developed etc. |