The Other Geothermal: Hotter and Deeper

November 22, 2022

There are two kinds of “geothermal” energy. One is the ground source heat pump, that relies on constant temperatures a few feet below ground to warm and cool homes and businesses.
The other is when you use advanced drilling technology to go REALLY deep, where there is hot, hot rock, just about anywhere.

Canary Media:

A leading geothermal energy startup just raised $138 million to build and run a fleet of power plants fueled by the Earth’s heat.

Fervo Energy announced the new funding on Monday. With the latest round, which was led by venture capital firm DCVC, the Houston-based startup has raised $177 million in total investment since launching five years ago.

Fervo aims to lower the cost of developing geothermal power by making it easier to tap heat deep within the Earth to make steam and produce clean electricity. The startup uses the same horizontal drilling techniques and fiber-optic sensing tools as the oil and gas industry, with the goal being to access geothermal resources that are otherwise too expensive or technically complex to reach using existing technologies.

The company is part of a growing effort by startups, research institutions and government agencies to harness geothermal energy from deeper wells and hotter sources. In February, MIT spinoff Quaise Energy raised $40million to develop high-frequency beams that melt and vaporize rocks, in theory allowing developers to extract heat virtually anywhere in the world. In May, Schmidt Futures — the philanthropy run by former Google CEO Eric Schmidt and his wife Wendy Schmidt — backed a new nonprofit, Project InnerSpace, to accelerate geothermal development worldwide.

“Power buyers are interested in geothermal power because they are actively looking for reliable energy sources that can address climate change and rising energy prices,” Tim Latimer, CEO of Fervo, said in a press release. ​“Our mission is to meet that growing demand by putting gigawatts of 24/7 carbon-free energy on the grid.” 

To date, geothermal’s ability to provide around-the-clock baseload electricity has been largely limited by geography. Most projects are located near relatively easy-to-access sites like hot springs and volcanoes. That explains why only about 0.4 percent of annual U.S. electricity generation comes from geothermal plants. Wind and solar power account for 9.2percent and 2.8 percent, respectively.

Fervo’s first commercial project is now under construction. The 5-megawatt site will produce power to support Google’s data center operations in Nevada. Latimer said the latest investment will help Fervo complete its power-plant projects in Nevada and Utah, as well as evaluate new projects in California, Colorado, Idaho, New Mexico, Oregon and internationally. 

“Fervo is poised to make geothermal as important as solar and wind to our energy future,” Matt Trevithick, a partner at DCVC, said in the Monday press release. 

The funding announcement comes a week after President Joe Biden signed into law the Inflation Reduction Act, which authorizes as much as $350billion for new federal loans and loan guarantees for energy and automotive projects and companies. In an interview with The New York Times on Monday, Latimer said the law’s new loan authority could help geothermal development expand more quickly.

“I don’t think we were expecting good news a month ago, but we’re getting more ready for prime time,” he told the NYT. ​“We have barely scratched the surface with the amount of geothermal that we can develop in the United States.”


7 Responses to “The Other Geothermal: Hotter and Deeper”

  1. Lucas Vereline Says:

    I’m not getting what makes Fervo a breakthrough.
    Quaise drilling hopefully works in the super hot rock because there’s no direct contact and it “cauterizes” the drill hole so you don’t have hot rock flowing into the hole.
    Eavor has the closed loop that eliminates a power drain, creates lateral radiators from a single drill hole, and a Rankine cycle to produce power from lower temperature rocks.
    Fervo says they use lateral drilling techniques and fiber optics for better data analytics, but that doesn’t let them get to the super hot rock, or use the more accessible temperatures very differently. Is it just incremental improvements and scale? Or just a price premium?

    • rhymeswithgoalie Says:

      “Fervo says…”
      Ehh, it’s just a glorified press release, aimed at potential investors rather than tech people.

  2. John Oneill Says:

    Geothermal is nuclear for nuclophobes. It’s using the heat mostly left in deep rocks from the decay of uranium 238. The decay is very slow – half has gone over the four and a half billon years of Earth’s existence. It only releases about 20% as much energy per atom, over a series of mutations down to lead, as induced (or spontaneous) fission would give, where the nucleus splits into two much lighter parts, and, in a chain reaction, triggers on average one of its neighbours to do the same.
    Heat is being added at a very slow rate to the rocks, but it also escapes at a very slow rate – a mile of rock is a fairly good insulator. If we run pipes through the bedrock to extract the heat, it will eventually cool below the useable temperature, and stay that way for thousands, or millions, of years. That could be OK, if drilling prices fall far enough – there should be plenty of other volumes to exploit,
    Currently, geothermal is all at tectonic plate boundaries, where the crust is thinner and the heat flux stronger. It’s not very thermally efficient – where supercritical coal or combined cycle (gas turbine plus steam bottoming cycle) can turn 50 or 60% percent of heat to power, current nuclear plants do 37%, and geothermal can be as low as 10%. Deeper, hotter bores would improve that, but that’s much tougher drilling than through softer oil-bearing sedimentary rock.

    • rhymeswithgoalie Says:

      AIUI, the bulk of ongoing heating of the planet has long been radioactive potassium (potassium-40), which, while much less energetic than uranium and thorium, is far more common (potassium being 2.4% of Earth’s crust).

      • John Oneill Says:

        Only 0.012% of naturally occuring potassium is 40K, whereas all uranium is radioactive. Half-life of 40K is 1.25B years, versus 239U (99.7%) at 4.5 B years, and 235U (0.7%) at 0.7B years. Also, potassium only has one decay, whereas either uranium, once it has its first transmutation, goes through a whole chain of decays, emitting an alpha particle, and significant energy, each time. The total energy released by the whole decay chain for either uranium isotope, or thorium, is 40 to 50 Mev, versus ~1.5 for 40K.
        In the early earth, potassium was the main source of heat,'s_radiogenic_heat.svg

        • rhymeswithgoalie Says:

          In the early earth, potassium was the main source of heat….

          Uh, my bad. I won’t short thorium now, that’s for sure.

    • rhymeswithgoalie Says:

      Solar is fusion for nuclophobes.

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