Earth's heat that once cooked bananas now powers televisions

Not all volcanoes blow their tops, as Mt. St. Helens did. Some, like angry giants, can just let off a little pent-up steam, as Southeast Asian nations are discovering.

Seething heat lies not too far below the earth's surface in nations along the "Pacific ring of fire," whose continental edges are home to more than 300 active volcanoes. That subterranean energy could be the "first alternative" to replacing oil imports for several nations, officials say.

The Philippines, which has 12 active volcanoes, is going full-steam ahead to boost its geothermal power from 4.2 percent to 12.2 percent of its electricity supply by 1985, in an urgent quest to cut oil use. (One megawatt replaces 540, 000 barrels of oil a year.)

Already, 440 megawatts are generated from the steam heated by volcanic magma, screaming to the surface with the sound and force of jet engines and quieted to a dull thunder by tubal silencers. The surrounding air reeks with earthen sulfur, and nearby trees are killed by the mineral-rich fumes. Turbines convert the steam into electricity for a long trip by wire to major cities. By next year the Philippines is expected to surpass the United States and become the world's leader in geothermal power.

In Indonesia, where almost 100 years ago the volcanic island of Krakatau blew up with the force of 1,000 H-bombs, the government plans to tap dozens of potential sites in its archipelago. The first plant, to be built by Mitsubishi of Japan and controlled by Geothermal Energy New Zealand Ltd., could go on line by 1982 at Kamojang, in West Java.

Japan's geothermal potential is 4,000 megawatts, with 10 active volcanoes and about potential 200 sites. At present, Japan produces only 168 megawatts, or 0. 13 percent of the nation's total electricity, near Mt. Iwate in the north. With a potential of providing only 1.8 percent of Japan's electrical needs, geothermal has yet to receive much backing.

And in Thailand, officials are just beginning to consider geothermal in talks with Union Oil, the American company recognized as the world leader in commercial geothermal power and the primary developer of California's geysers.

Union Oil, which has developed the Philippine's 440 megawatts of geothermal power under the local name of Philippine Geothermal Inc., plans to boost production here by 110 megawatts a year.

But the local manager, Mack I. Horton, warns that the country could be facing a power surplus in years ahead as coal and nuclear plants come on line. Consumer demand, he adds, may barely increase. Thus, Union Oil could be cutting back its geothermal schedule. "The question is, when do all those plants come on line?" Mr. Horton says.

"Without a doubt, the Philippines ranks No. 1 [in geothermal potential]. If the demand is there, the country could develop all its sites," he adds.

Last year, the Philippines government changed its target date for new large-scale energy projects from 1990 to 1985, raising questions on whether it could come up with enough capital to back the various coal, nuclear, geothermal, and other energy projects. While it is inviting foreign investors into joint ventures on geothermal, so far its terms have not proved too inviting.

The national target for geothermal is 1,700 megawatts, costing more than $400 million to drill about 400 wells. The present 440 megawatts required 32 wells.

Union Oil's future share of production will be about 1,000 megawatts, with the rest drilled by the government's new Energy Development Corporation. Mr. Horton says Union Oil made its first profit in the Philippines last year, after seven years of large-scale production.

Drilling costs range from $800,000 to $1 million per hole, with 6,000 to 7, 000 average depths. Some are as shallow as 800 feet and others go down 10,000 feet, Mr. Horton says.

In his office in Metro Manila, Mr. Horton's wall is covered with large blue maps, marked with yellow and pink areas showing reserves. Red dots show wildcatting sites, which move closer and closer up to volvano cones as drill rigs hit "dry" holes. An average productive hole produces 120,000 pounds of steam an hour.

Asia's geothermal steam tends to have more water and corrosive elements than the clean wells of California, thus raising costs.

For the Philippines, the hot springs and bubbling caldrons are in isolated rural areas, where the natives still toss bags of bananas, corn, or even a chicken onto the hot rocks for cooking. More than half the Philippine's geothermal power, which is generated on the island of Leyte, will have to be exported to the more populated islands of Luzon and Mindanao. Present plans call for a submarine cable across the Strait of Surigao to Mindanao. The government plans to build copper, aluminum smelting, and fertilizer plants near the steam sites, but there will still be excess capacity requiring expensive transmission lines.

As the brightest spot on the Philippines energy future, geothermal is expected to help cure Manila's frequent brownouts in electric supply.