Filipinos Draw Power From Buried Heat

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Powering the Philippines on Geothermal Energy

On the Philippine island of Leyte, the development of geothermal energy sources has been highly successful in recent years. Geothermal power now accounts for a third of the electricity generated in the Philippines.

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In a report released this week, the U.S. Geological Survey reassessed the potential for this kind of energy in the United States. It examined 13 Western states, from California to Colorado, Washington to New Mexico, that sit atop a hot geologic zone that is often called the Pacific Ring of Fire. It encircles the Pacific Ocean and includes the Philippines, as well as Indonesia, Japan and several other countries in East Asia.

In the American West, power production from already identified geothermal fields could increase more than 2 1/2 times, the report said.

But new geothermal technology -- which injects water into fractured rock to mine heat -- raises the possibility that small geothermal power plants could be built all over the West. If this technology continues to advance, the Geological Survey report said, there is enough accessible public and private land in the 13 Western states to supply about half the electricity now generated in the United States.

"Geothermal resources have the potential to play a much more significant role in our nation's energy mix," the report concluded.

Nature's Perfect Design

For nearly three decades, the Philippine government has been acting on a similar assumption, despite revolutions and widespread corruption.

The showcase for its long-term commitment is here on the rural island of Leyte, where a government-created company, now privatized, has carefully transformed a vast geothermal field into the linchpin of the country's electricity grid.

The Leyte field, as engineers describe it, is one of nature's most perfectly designed geothermal resources. Located about 1 1/2 miles underground, it is a great pot of boiling water that covers about 416 square miles.

Molten rock heats the pot but is kept separate from the boiling water by a thick layer of impermeable rock. The pot's lid is made of a much softer, more porous rock, which is easy to drill down through. About 90 wells bring up steamy water to run turbines.

Thirty-two re-injection wells shoot cooler water back into the pot to be heated and repeat the cycle. Water filtering down naturally through a mountainous rain forest atop the reservoir also recharges it.

"Leyte is very blessed in the sense that the resource is not common to any other part of the world," said Ruperto R. Villa Jr., a geothermal engineer and a longtime supervisor here.

Villa and other engineers here have made the most of their natural blessings, inventing the world's first large-scale re-injection system. After 25 years of operation, this system has conserved nearly all of the field's heat and steam pressure. Experts say Leyte, if it continues to be well managed, should produce electricity for centuries.

"Once the Philippines government gave its edict to develop geothermal, it was implemented with good management and intelligent engineering," said Horne, the Stanford professor who has traveled often to the Philippines.

A Wild West Show

The United States has the world's largest geothermal resource, the Geysers, 72 miles north of San Francisco. But it has not been nearly as well managed as Leyte, according to Horne and other experts.

From the 1960s to the early 1980s, the Geysers was a kind of Wild West show of multiple owners racing to tap steam before the others did. Lacking federal or state regulation, the Geysers spawned 15 years of lawsuits among the owners. Consolidation of ownership and tighter regulation have since resolved many of the problems, but not before the sustainable power-generating capacity of the field was reduced.

"What happened in the Geysers did not happen in Leyte because of better regulation and central control of management," Horne said.

But experts say the future of geothermal development in the United States depends not on giant sites such as the Geysers but on smaller fields, to be tapped using nontraditional technology that injects water into hot fractured rock and powers turbines with the resulting steam. Creating that technology will require $1 billion of consistent public investment over 15 years, according to a study this year that was commissioned by the Energy Department.

"We have seen something of a turnaround in federal interest in geothermal," said Gawell, of the Geothermal Energy Association. "But companies and investors still don't trust that it will last. There is a lack of confidence that the government is not going to once again turn its back on geothermal."