Geothermal energy from volcanoes could power the future
Newberry Volcano — the largest volcano in the Pacific Northwest — is the site of an experiment that’s aiming for a breakthrough in geothermal energy.
The experiment is one small step in the high-risk, high-reward world of next-generation geothermal. The goal is to replace fossil fuels with this always-on, renewable energy. The challenge, however, is getting it to work.
To access geothermal energy you need three elements: Heat, water, and permeable rock.
The water flows through gaps in the hot permeable rock, transferring heat from deep underground to the surface. That’s geothermal energy.
The world’s first geothermal resources were the rare places where those three things just happened to come together naturally. Like hot springs or geysers, found in places like the U.S. Mountain West.
Early projects were extremely simple: pumping the water into buildings for heat and hot baths. But eventually, starting in the 20th century, countries all around the world — like Italy, Iceland, and the United States — started using geothermal energy to produce electricity, using steam to power turbines.
This form of energy has one big benefit over other renewables. To understand, let’s compare a geothermal plant and a solar farm, each capable of pumping out the same amount of power.
On the solar farm, let’s say it’s only really sunny for about five hours a day. That means that every day, it only produces 20 percent of its potential. A geothermal plant, on the other hand, can basically produce full power, all day, every day – which makes geothermal a really useful kind of energy: It’s got all the same “always-on” benefits of a fossil fuel power plant, but it’s renewable.
People were understandably excited about geothermal, and the energy source started to take off in the U.S. after the 1970s energy crisis. But for all its benefits, geothermal energy has only ever played a small role on our grid. And, to understand why, let’s compare it to that solar farm again.
To build this solar farm, you need to find sun. And you do that by, like, looking up. But for the geothermal plant, I’d need to find a rare spot that has all three of those geothermal ingredients, hidden under miles of rock. Then, I’d need to pay for expensive equipment and labor, and go through years of permitting, just to get the plant up and running. So, despite all its benefits, and the almost limitless energy in the earth, it’s hard to make a project pencil out.
Because of these challenges, geothermal energy started to slow down around the 1990s. The industry needed something to change.
That change? A new process known as enhanced geothermal. Instead of relying on places where all three of those geothermal ingredients come together naturally, enhanced geothermal allows you to tap into heat, even if you’re missing the other two.
It works by injecting high-pressure water into the ground, forming a network of little cracks for water to flow through and carry heat back to the surface. It’s a similar idea to fracking, but with a lot less pollution.
The technology really opens up the potential for geothermal. To put it into perspective: The U.S. currently produces about 3 gigawatts of geothermal electricity. Enhanced geothermal could theoretically generate more than 5,000 gigawatts of electricity — more than all the fossil fuel plants in the country.
So why isn’t enhanced geothermal powering the world? Despite a few successful pilot projects, the problem, once again, is money.
Right around the time people were getting serious about enhanced geothermal, another energy transition happened: Solar, wind, and natural gas got cheap. While enhanced geothermal could compete with coal, it had trouble with its new competition.
“With the change in the economics of power, the question was how does geothermal compete?” said Geoff Garrison, vice president of research and development at the geothermal company AltaRock.
AltaRock was one of the companies trying to build on the promise of enhanced geothermal, only to be caught off guard by that wave of cheap gas and renewables. In order to be competitive, the only option they saw was to build an even hotter enhanced geothermal project. And that’s what brought them to Newberry Volcano.
“There’s a very large magma body underneath it,” said Garrison. “It contains a tremendous amount of heat.”
AltaRock wanted to reach temperatures of 400 to 450 degrees Celsius (752-842 degrees Fahrenheit) — what the industry calls “super-hot rock.” At this temperature, you get way more energy, and extract it more efficiently.
In a normal location, you’d have to drill down about eight miles to reach these kinds of temperatures. But at Newberry, it’s so hot that you can reach those temperatures at a quarter the depth. AltaRock saw this as a perfect testing ground for super-hot geothermal energy.
If Altarock is going to reach those super-hot temperatures beyond Newberry, they’re going to need to drill deeper. And that’s really hard to do with conventional drills. Instead, they’re hoping to use another type of new technology that sounds like science fiction: A heat ray to melt rocks. It’s called a millimeter-wave — it’s kind of like a laser, in a different part of the spectrum.
The idea came from Paul Woskov, a fusion scientist at MIT. In his research, he’d seen the waves accidentally melt holes in tile walls. Years later, he started studying millimeter waves as a way to melt rock.
After a decade of research, he’s now working with a geothermal company called Quaise to test millimeter waves for geothermal drilling. They’re doing tests at Oak Ridge National Laboratory — essentially, melting holes in rocks.
Eventually, AltaRock hopes to test these millimeter waves in the real world at Newberry.
And, if they’re successful, this new heat ray might make it a little more feasible to reach those super-hot temperatures anywhere.
AltaRock, and other geothermal startups like it have a long and challenging road ahead.
But they also see a big reward.
“We’re talking about replacing every coal plant in the country, or every natural gas plant in the country with geothermal,” said Garrison. “We can do that. That’s the scale of the resource we have at hand.”
It’s certainly not guaranteed to succeed. Odds are, there will be a lot of failures along the way.
But there’s so much heat in the earth, that today’s geothermal energy is just the tip of the iceberg.
How a geothermal breakthrough could transform our energy grid youtu.be
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