This paper examines the reasons why the nonoil producing Republic of the Philippinesand the oil producing Republic of Indonesia in the South Pacific, are both developingtheir geothermal energy. The related technical assistance of Japan in each country is briefly reviewed.Because there are no known oil reserves in the Philippines, the use of imported oilgreatly affects the balance of imports and exports.Therefore, the Philippine Government is planning to develop its domestic energy suchas hydro-electric, coal, geothermal and renewable energy and to decrease its consumption of oil.As a result of her efforts, the Philippines had become the second largest producerof geothermal energy in the world by 1983.Japanese technical assistance on geothermal energy began in the Buguias area, LuzonIsland, the Philippines in 1980, but it has stopped because of domestic unrest and restarted at Acupan-Itogon area near Baguio city, Luzon Island.Acupan and Itogon are the names of two gold mines. Acupan is one of the largestmines in the world and hot water and steam are presently spouting out of fractures andtesting bore-holes on the walls of the galleries. A project to divert the steam and hot water from the mine, and thereby improving the underground environment by means of a geothermal well, has not yet been completed.In Indonesia, the balance of trade is continueing to be positive because of the export of oil. However the Indonesian Government is making an effort to promote the development of hydro-electric, coal and geothermal energy etc. in order to export as much oil as possible.The development of geothermal energy in Indonesia is not advanced at present, butis promising because of its large geothermal reserves throughout her many Islands.Japanese technical assistance on geothermal energy had been made use of in theLempur area, Sumatra Island from 1979 to 1983. The Lempur area is located at thesouth-east of Mt.Kerinch, one of active volcanoes along Sumatra in parallel with thetrench of the Java plate. In this area, the construction of a geothermal power plant is expected to help meet the demands of a tea factory and of the general public. Although the Philippines and Indonesia are different from each other in respect todomestic oil reserves, both countries have following common characteristics;(1) They are composed of many islands and have no systematic networks of highpower cables(2) They have no huge factories consuming large amounts of electric power and nolarge cities with big civilian demands, and therefore(3) It would be advisable for them to make many rather small 50 MW class geothermal plants for local energy demands.Japanese technological assistance has helped some in the past and we expect thatit will be more helpful in the future as these countries continue to develop.

※（目次表記別名タイトル）Geothermal Energy in the South Pacific and Related Co-operation of Japan