Abstract: Progress of Geothermal Energy Exploration and Development in Philippines

Arthur Saldivar-Sali, E. V. Olympia

In 1978 the Philippines will join the other countries along the Circum-Pacific belt in the use of geothermal energy for power generation. The Tiwi geothermal field in Albay, operated by Philippine Geothermal, Inc. (Union Oil), is expected to generate its first 110 Mw of power by mid-year and Makiling-Banahaw in Laguna will start operating its first 55-Mw power plant before the end of the year. In July 1977, a 3-Mw noncondensing power plant was installed in Tongonan, Leyte, and is supplying the power needs of Ormoc City. Largescale production of 55-Mw capacity will be started in 1980. Other areas in various stages of development are Palimpinon-Dauin in Negros Oriental and Manat-Masara in Davao. Geoscientific studies are being conducted in the fields of Mambucal in Negros O cidental and Manito in Albay.

The Philippine archipelago lies on a high-heat-flow region with areas of past and recent volcanism, a geologic advantage that has given the country its present vast geothermal resources. Reservoir rocks are generally lava flows of andesitic to dacitic composition associated with pyroclastic rocks. Possible heat sources are Quaternary dormant volcanoes. Secondary porosity in the form of fractures caused by volcano-tectonic systems seems to be the dominant control of the hydrologic system. Geochemical analyses and well data show a hot-water dominated system in every area being explored and developed. Flow tests gave well capacities as high as 18 Mw, and an average of 6 Mw per well.

A nationwide inventory of geothermal resources is being conducted to define more priority areas for further exploration and development. From this bold program, a total of 1,595 Mw of power is expected to be generated by geothermal energy in the year 1987.

AAPG Search and Discovery Article #90962©1978 AAPG 2nd Circum-Pacific Energy and Minerals Resource Conference, Honolulu, Hawaii