Interest in geothermal energy is heating up

On the edge of the San Andreas fault, near a dormant volcano and the banks of the super-salty Salton Sea, planners are working on yet another anomaly in this desert farming community: the world's biggest geothermal energy plant.
By tapping into the hot water and steam a mile or more beneath the Earth's surface, CalEnergy Operating Corp. plans to power a turbine big enough to constantly produce 185 MW of electricity -- enough for about 185,000 houses.

If the plant opens as expected in about three years, it would supply much of the power used by California's Imperial Valley, making an agricultural region known for wasting huge amounts of water and spilling fertilizer into the Salton Sea one of the few places to get electricity without burning fossil fuels or damming rivers.
"This is truly renewable energy," said Vince Signorotti, director of CalEnergy's real estate assets. "We're not just depleting nature of oil or gas or coal to make electricity."

In the family of energy supplies, geothermal has always been something akin to a crazy uncle. It doesn't have the sex appeal of wind or solar power, and it isn't portable like the hydrogen fuel cells President Bush wants the country to develop.
The hot liquid needed to drive geothermal plants can be easily reached only in a few places in the Western United States for now. As result, only four states -- California, Nevada, Utah and Hawaii -- now have geothermal power plants, according to the Geothermal Resources Council, an industry group. They generate about 2,700 MW, less 3 % of the nation's electricity.

But amid spiking natural gas prices and tenuous oil supplies, interest in geothermal is heating up. Developing geothermal resources is part of Bush's national energy policy. The Department of Energy wants to double the number of states with geothermal electricity plants by 2006, and supply at least 7 mm homes with geothermal power or heat by 2010. States it is eyeing for significant development include Arizona, Nevada, Idaho and New Mexico.
To help attract private investors and spur development, the Energy Department and Congress are also considering industry-backed incentives such as tax breaks, grants and funding for new technology. The aim is to reduce operating costs for geothermal plants to 3 to 5 cents per kWh over the next few years, bringing costs in line natural gas and other traditional sources of power.

The government also wants to consider tapping into the Earth's natural energy in national parks and other Department of Interior lands, where it now powers such attractions as the Old Faithful geyser in Wyoming's Yellowstone National Park).
What has held the industry back since it got its start in the early 1960s in Northern California is its high costs and low returns for investors, said Ted Clutter, executive director of the Geothermal Resources Council. That could be changing, though, along with the potential of geothermal energy. The biggest shareholder in CalEnergy, for instance, is the world's best-known investor, Warren Buffett.
"With proper government assistance, we can see a resurgence in this industry," Clutter said.

According to Oregon Institute of Technology's Geo-Heat Centre, 271 cities in 10 Western states stretching from Texas to the Pacific could use geothermal energy better. Water hot enough to power small geothermal operations is accessible as far east as the Georgia-Alabama border, according to the centre.
Most sites identified by the centre can tap the Earth's heat for relatively small uses, such as providing heat for houses or schools. But some of the sites in Western states have the potential for power plants like the one being developed by CalEnergy.
"Geothermal energy is everywhere," said David Blackwell, a geologist and geothermal expert at Southern Methodist University in Dallas.

The problem, he explained, is while hot water and steam can be tapped at relatively shallow depths along fissures like the San Andreas Fault and in volcanic areas in California and elsewhere, they're much deeper in other parts of the country. In Texas, for example, a few areas in the westernmost part of the state and along the Gulf Coast may hold major sources of water for geothermal plants if drillers could get to it, Blackwell said.
But most potential geothermal sites are smaller -- more like the one in Marlin, Texas, between Austin and Waco, where about 20 years ago the local hospital tapped into the hot water trapped beneath the city for heating, creating a prototype for geothermal heat pumps.

Harnessing geothermal energy is a relatively simple process. A well is drilled a few thousand feet to where geothermal liquid -- water saturated with minerals and elements -- is tapped. When it comes out of a wellhead at temperatures of 500 degrees or more, big tanks and pipes separate the steam from the liquid and use it to drive a turbine generator. The remaining liquid is pumped back into the ground to be reheated and used again.
The biggest geothermal site in the country is at the Geysers in Northern California, with nearly 30 power plants. The Imperial Valley area is the second-biggest site, with 17 plants -- 10 of them owned by CalEnergy -- generating nearly 1,000 MW of power. Most of these plants produce 50 MW or less, less than a third what the new plant will generate.
"We're basically super-sizing it," Signorotti said. "This will be a prototype for other plants eventually built here."

While power companies and the Department of Energy consider geothermal a clean, renewable technology that does little to harm the environment, it does come with concerns that geologists and others are only beginning to understand. At the Geysers, for instance, years of over-pumping may have produced unexpected side-effects. US Geological Survey studies have found that it may have contributed to an increase in earthquakes in the region in recent years.
Signorotti said all geothermal power companies have learned lessons from over-production at the Geysers. Everything from the temperature of liquid coming from the Earth to the pressure of the rocks around it are constantly monitored in an attempt to ensure geothermal fields aren't being significantly depleted.
"Maintaining the integrity of (the field) is almost as important as accessing it," Signorotti said. "We have always tried to look beyond just what we're doing today."