抄録
Kyushu Electric Power Co., Inc. operates six units at five geothermal power stations. Their total capacity is 207.5 MW, accounting for 39% of the installed geothermal power plants in Japan. Hatchoubaru Power Station started operation about 21 years ago with the first unit. Now stable operation on the output of 110 MW (55 MW×2) goes on. On the way to stable operation, we confronted output decline due to reservoir interference by reinjected hot water. In order to recover the output, both steam producing system and power generating system were checked up as a consequent system. The idea is based on our company's fundamental strategy for geothermal development: “consistent development” from upstream to downstream. We carried out optimum reservoir management with more accurate reservoir monitoring data. Also we improved the generation facilities such as turbine and two-phase flow line (NISOURYUUTAIRENRAKUKAN), to utilize existing wells. As a result, these efforts recovered the output successfully and reduced generation costs. We learned that reservoir management is essential to keep stable output of the Hatchoubaru Power Station. We shall make continuous efforts to keep economically stable output by advanced reservoir management, applying the newest simulation technology to balance reinjection with production.
