Pacific's Ring of fire spews geothermal electric power

"Before," said Arturo P. Alcaraz, geothermal power specialist at the National Power Corporation, "we looked at our volcanoes as a possible source of danger. Now we look at them as possibly useful.

"They are benefactors rather than malefactors."

Nearby was the evidence -- the Mak-Ban Geothermal Power Plant. At that moment, steam, surging upward from wells about 5,300 feed deep, was turning turbines producing 165 megawatts (MW) of power. Some of that electricity was flowing 40 miles northwest to Manila.

By now a fourth unit should have been added, providing another 55 MW of power.

Sitting on what is called the Ring of Fire, a chain of dormant and active volcanoes of the Circum-Pacific Belt, whose subsurfaces smoulder with intense heat, the Philippines has turned wholeheartedly to geothermal power.

The Pacific nation is already No. 2 in the world in geothermal power output, producing some 440 MW. It should next year or in 1982 surpass the United States , which produces something over 500 MW of geothermal power.

The Filipino enthusiasm for geothermal power arises from two factors:

1. It replaces expensive imported petroleum. Last year, 74 percent of the nation's electricity was produced in oil-fired thermal plants. Oil the cost the Philippines $1.5 billion last year. This year the oil bill is expected to be substantially more -- $2 billion.

2. Geothermal power is cheap. It is half as expensive as nuclear power; some 80 percent cheaper than oil at last year's prices.

Producing geothermal power has become a relatively simple process -- as long as the underground hot water is available not too deep.

After the National Power Corporation (NPC) and Philippine Geothermal Inc., a subsidiary of Union Oil Company, entered into an agreement in 1970, it took eight years before the first commercial geothermal plant at Tiwi, 55 miles southeast of Manila, was producing power.

Today, once a field has been located by geological, geophysical, and geochemical means, it takes only about 30 months from the start of drilling to the production of power. Thus the NPC's ambitions to step up the output of geothermal power could well be more realistic than it at first sounds.

In 1978 geothermal power provided 3 percent of the nation's electrical power, hydro 24 percent, and oil 76 percent. Last year those percentages were 6, 21, and 74. And in the first half of this year, the percentages had reached 11.5, 20.5, and 68 percent. That is a dramatic change in a short time.

By 1985 the power company plans to get 20.4 percent of its electricity from geothermal, 29.2 from hydro, 19.6 percent from coal, 7 percent from nuclear, and only 23.7 percent from oil.

Because of the rising price of oil, President Ferdinand E. Marcos has called on the company to accelerate its production of geothermal power in the years beyond 1985, noted Jose Jovellanos, senior vice-president of NPC.

Company officials hand out a list of eight more geothermal units scheduled to come into production in the next few years. There will be two more 55 MW units at Tiwi, three 37.5 MW units at a new site at Tongonan, Leyte Island, and three more 37.5 MW units at Palimpinon, Valencia, Negros Oriental.

Several other potential sites for geothermal power have been located.

Once the sites have been located, the drillers have a 92 percent success rate in reaching superhot water that flashes into steam at the lower pressures at the surface level. Each well costs about $750,000. That compares with perhaps a 1 -in-20 success ratio for those drilling wildcat wells for oil and far higher costs for each well.

"The great thing," says Mr. Alacaraz, "is that this is a renewable source, as long as we manage it carefully and do not go beyond what nature provides." After steam has gone through the generators and been turned back into water, it is reinjected into the ground to be heated up once more.

New Zealand also has geothermal power, but the wells lose some of their strength over the years. An official here maintained that by spacing the wells far apart, this is less of a problem. In any case, the field is expected to last at least 50 years.

Philippine Geothermal Inc. owns 45 percent of the project here; NPC owns 55 percent. Union Oil had acquired experience and technology in this area by its operation of a major geothermal plant in California.

Union Oil is guaranteed an 18 percent return on its investment, an NPC official said.