美国国家公共电台 NPR The Forgotten Renewable: Geothermal Energy Production Heats Up（在线收听）

The Forgotten Renewable: Geothermal Energy Production Heats Up

MICHEL MARTIN, HOST:

We're going to hear now about a different natural resource - geothermal reservoirs. They are all across the American West, and they could be used to power millions of homes. But extracting energy from them is not easy. From member station KVCR in San Bernardino, Benjamin Purper reports.

BENJAMIN PURPER: Three and a half hours east of Los Angeles lies the Salton Sea. It was created when a canal broke in 1985 and the Colorado River flooded the desert. The windy oasis became a tourist attraction for a while, but now it's drawing people in for other reasons.

JIM TURNER: So what you're looking at is - this is the playa that we...

PURPER: Jim Turner works for a company looking for buried treasure. He's the chief operating officer of Controlled Thermal Resources, the company that came all the way to the Salton Sea from Australia. The reason?

TURNER: We're standing on top of what's probably the most robust geothermal resource in the United States.

PURPER: Geothermal energy - it means using the Earth's natural heat to create electricity. It's renewable, and it generates clean energy around the clock, unlike wind and solar.

COLLIN WILLIAMS: The fundamental way in which geothermal energy works is taking advantage of hot water where it's accessible near the Earth's surface.

PURPER: Collin Williams is a geothermal expert for the U.S. Geological Survey. He says you can extract geothermal energy by taking that hot water and turning it into steam, which powers a turbine and produces electricity. Right now, you can only do that in reservoirs that have a lot of hot, wet rock, like the Salton Sea.

But Williams says there's a new technology in development called enhanced geothermal systems. It takes dry rock and cracks it just enough for hot water to pass through. That would essentially create new reservoirs, enough to someday take the country's geothermal energy production from 3,000 megawatts to almost 500,000.

WILLIAMS: To put that in perspective, the entire electric power-generating capacity in the United States is about a million megawatts.

PURPER: So if there's that much clean energy just waiting in the ground, what's taking so long?

ALLYSON ANDERSON BOOK: You never really hear people call it geothermal. They call it the forgotten renewable.

PURPER: Allyson Anderson Book directs the American Geosciences Institute. She says technical and social challenges have made it difficult for geothermal to catch up with the likes of wind and solar energy. Enhanced geothermal systems isn't really viable yet. And even the more traditional plants take a lot of time and money to get built.

ANDERSON BOOK: There's a lot of different factors that play in. And so they're looking - so the Department of Energy right now is spending a lot of time and energy in something called the FORGE project.

PURPER: FORGE would create a test site dedicated to making enhanced geothermal systems a reality. The idea is if engineers can make this process easy, geothermal energy production would skyrocket. But back at the Salton Sea, Controlled Thermal Resources isn't waiting on new technology. It's hoping to exploit what's already here right now.

ROD COLWELL: So this video here, as that's receding, as that drone is moving away, that's exposing some of the best geothermal resource, not in the U.S., but on the planet - right there.

PURPER: In his office, CEO Rod Colwell shows me an aerial video of the playa I visited earlier where his first geothermal plant will be. It's still in the permitting stages, and it's going to cost a lot of money to get built - around a billion dollars. But if it's successful, Colwell plans to build more plants, enough to reach 1,000 megawatts, which could power about 800,000 homes. And with California looking to phase out its use of fossil fuels, that's no small number.

COLWELL: Particularly, in California, we will not be able to import any carbon-fired energy after 2025. So it's important that geothermal is that integral value in the mix.

PURPER: Geothermal's got a long way to go, but Colwell and others are betting that new technology and the demand for clean energy will someday bring this forgotten renewable to the forefront of clean power. For NPR News, I'm Benjamin Purper at the Salton Sea in California.

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