Clean Power US geothermal FORGE project

Published on July 18th, 2014 | by Tina Casey


100 GW Of US Geothermal Power Will Push US Past Gas

July 18th, 2014 by  

Natural gas has been having a field day in the US energy profile for the past dozen years or so, but it looks like the sleeping giant of US geothermal power is being nudged out of its stupor. Yesterday, the Energy Department announced that it is plunking down $31 million to rev up a cutting edge geothermal demo project that could enable the US to tap into an estimated 100 gigawatts of geothermal power.

The new geothermal project, called FORGE for Frontier Observatory for Research in Geothermal Energy, is just one of a package of clean energy investments that President Obama has been rolling out in recent days.

US geothermal FORGE project

“Virtual reservoir,” US geothermal FORGE project (cropped) courtesy of US DOE.

US Geothermal vs. Natural Gas

Earlier this week the US Energy Information Agency released a new futurecast in which the base scenario calls for almost 75% of all new generating capacity to be from gas-fired power plants. In consideration of the new geothermal announcement, which comes on top of stunning gains in wind and solar power, it looks like EIA has a bit of revising to do.

Here’s the Energy Department enthusing over FORGE:

The FORGE initiative is a first-of-its-kind effort to accelerate development of this innovative geothermal technology that could help power our low carbon future…This field observatory will facilitate the development of rigorous and reproducible approaches that could drive down the cost of geothermal energy and further diversify our nation’s energy portfolio.

Just one caveat. When you check out the details, the words “fluid” and “underground” come to mind, which conjures up fracking, so we’re going to temper our enthusiasm for now.

The FORGE project basically involves finding ways to “effectively stimulate large fracture networks” (so yeah, kind of like fracking). The idea is to tap into areas underground where the rocks are hot, but the heat doesn’t have a natural way up to the surface.

In industryspeak that’s called an Enhanced Geothermal System. Ideally, an ESG would create pathways that enable fluid to circulate efficiently through rock, and return to the surface piping hot.

That means drilling a well into the target area, and then injecting water at high pressure and/or heat to split the rock. You keep doing that until you have a “fracture network” large enough to sustain a reservoir in terms of heat and flow rate.

All that’s left to do is drill a production well into the reservoir. The returning water should be hot enough to transition to steam at the surface. Alternatively, it could be used to heat another fluid to produce vapor. Steam or vapor, there’s your energy for running a turbine.

Here’s a nifty infographic from the Energy Department:

FORGE US geothermal infographic

FORGE US geothermal infographic courtesy of US DOE.

That infographic looks awfully clean but as described above the process of building an ESG is pretty messy.


However, it’s not likely that a boom in ESG construction would lead to the kind of widespread environmental impacts that have characterized the natural gas industry in states with weak regulations for fracking, including the disposal of fracking wastewater.

We’re thinking that’s the case partly because unlike the wildcatting, all-over-the-place nature of the natural gas (and oil) fracking boom, ESG lends itself to the kind of large scale, centralized installations that could fall under federal jurisdiction.

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About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.

  • spec9

    We need a revenue-neutral carbon fee. That will raise the relative value of geothermal sourced electricity (and solar & wind) relative to coal & gas generated electricity. Right now we don’t properly value the advantages of the relatively carbon-free geothermal electricity.

    • JamesWimberley

      A carbon tax would not be enough to get geothermal deployed at scale, as it still considerably more expensive than solar or wind. As I pointed out above, geothermal needs specific financial recognition for its despatchability, which wind and solar don’t have. The issue is below the radar of a carbon tax, which looks increasingly like a cargo cult.

  • Angus Train

    Let’s hope this R&D budget provides better demonstration technology than the current EGS technology they are pushing now. The common presumption that geothermal energy is clean and safe is a false story promoted by industry insiders and powerful politicians, both local and national, like Harry Reid who benefit from industry dollars. By definition of pumping pressure alone, EGS IS FRACKING no matter how the industry wants to play semantic games.

    Simple truth is these so-called “closed loop” systems leak. All the time. Industry knows it. The EPA knows it. Politicians know it and the local communities, impacted by these installations, definitely know it.

    Geothermal fluids do involve many toxic and caustic chemicals that not only threaten natural aquifers but can actually cause well casement failures. Some geothermal industry experts say well casement leak rates are as high as 50%. These chemicals must be continually replenished due to subterranean migration and casement leakage. Where do they go? Industry claims they miraculously miss the aquifer despite the high casement leak rates.

    For those of you who are interested in cleaner energy for long term sustainability of all resources and associated economies, please educate yourselves rather than towing an industry funded party line with a drill drill drill mentality that is caught in the 1950’s. Impacted communities throughout the world and in the U.S. are fighting current geothermal practices as they are demonstrably proven pollute air and freshwater resources.

    Pumping for energy at the expense of your water supply shows barbaric ignorance of epic proportions. Geothermal may work in the long run but it has a quite a way to go before exposing it to our just as economically precious natural resources.

    • JamesWimberley

      What chemicals? AltaRock are upfront about theirs (link), unlike secretive oil and gas frackers. Other EGS projects don’t use any.

      What groundwater pollution? EGS geothermal works at depths of 5000m. It has to be very deep otherwise the heat stored in the hot lumps of granite would have dissipated up to the surface by now. No aquifers are anything near – that’s why the water has to be injected, unlike conventional hydrothermal. Source your scare stories. Shouting EVIL FRACKING won’t cut it here.

      • Angus Train

        I appreciate your question, though no one said anything about “evil”. Ignorance or denial may be the more prominent issue here. Once you achieve a certain pumping pressure, you fracture the rocks (not always granite) below. Call it what you like. A rose by any other name…

        As for chemicals, some geothermal companies use proprietary chemicals that they do not disclose. In an effort to promote economic growth, since 2005, both Bush and Obama administrations, successfully rolled back Clean Air Act and Clean Water Act chemical disclosure rules to safeguard oil, gas and geothermal industries. It is known, however, that toxic solvents are commonly used in geothermal wells. In Hawaii, for example, it has been disclosed that Ormat uses Isopentane, a gasoline-like solvent with high dispersion rates. Isopentane is associated with reproductive harm and other chronic health issues. Ormat stores 60,000 gallons of Isopentane on site. Why so much? Despite their efforts to avoid disclosure, they were legally forced to disclose that they lose 40-100 gallons a day during pumping operations. Where does it go if not in the ground? If one site is pumping millions of gallons of toxic fluids a day into the earth, it is foolhardy to assume there would be no contaminant migration. Fortunately for Ormat, lax government oversight spares them from comprehensive baseline water analysis to detect contamination.

        Along with these types of chemicals, the drilling and pumping itself brings up other known earth bound contaminants like arsenic, lead, mercury and ammonium bisulfide. In some locations, radionuclides are also drawn into the brine. These types of heavy metals can wreak havoc if ignored. In 2006, EPA announced that 42% of rivers and streams were in poor condition. Not fishable or swimmable. Can we afford to ignore known contamination for some feel-good hype about unproven clean and sustainable energy?

        Depth of drill is irrelevant if you have a 50% chance of casement leakage. A well that passes through the water table does not necessarily protect that water table from pollution if casements are faulty. And they are. EGS, just enhances this problem with higher pressure, as they pump millions of gallons a day of contaminated brine right through precious water resources or near enough to cause migration. Higher pressure brings more migration and more calamitous failures when they occur.

        Finally, your claim that there are no aquifers near EGS is an industry falsehood because often there are not buffer zones to protect those aquifers. Current oversight for test wells is abysmal because there are so many tax funded federal subsidies promoting exploration. Each potential site should require it’s own comprehensive EIS rather than depending on broad indefensible generalities like “No aquifers are anything near – that’s why the water has to be injected.” There is science and there is industry promoted “science.” Guess which gets the most research funding and publicity.

        • Omega Centauri

          Aside from the chemicals injected, you also have chemicals from the rock formations themselves. I think there are proposals for hybrid systems, selling both geothermal energy, and solution mined underground minerals.

  • JamesWimberley

    Tina: “as described above the process of building an ESG is pretty messy.” This is an exaggeration. Google for photos of the original European pilot at Soultz-sous-Forêts in Alsace (link), or Geodynamics’ Habanero wells in the Australian outback.

    For EGS – not ESG – you need to drill at least two deep wells, with standard oil drilling equipment (though Foro Energy are making progress on laser-assisted drills). That gear goes. Then install a high-pressure pump at the down (injection) well or wells for the fracking. This is basically done with water, but AltaRock at Newberry in Oregon (link) have had success with a temporary and degradable blocking agent to fine-tune the process. Monitor for microshocks. Then install a compact generator to use the steam that comes out of the up well. The footprint when you’ve finished is small: no towers, no tall chimneys. no trucks or trains.

    The current plants are medium ugly, but don’t have to be. The industry should hire some hi-tech architects like Norman Foster to make the installations glamorous. This will help bring round the locals in places like Japan, Costa Rica and Bali where’s there’s been opposition to geothermal on aesthetic/religious/environmental grounds.

  • Bob_Wallace

    Geothermal fracking doesn’t require the bothersome chemicals that oil and natural gas wells use. Last year AltaRock, a geothermal company, fracked (they prefer the word sheered) a geo well at three different levels using CO2 based products.

    • Adam Grant

      Fracking would be more acceptable if everyone involved were forced to list the substances they’re pumping into the ground, pay for 3rd party monitoring of emissions and water-table contamination, and post large bonds in case of mishaps. Effective regulation of techniques used, materials standards and practices would be desirable.
      If it does turn out that the current fracking boom is an unsustainable financial bubble, the resulting bust will be a good opportunity to tighten drilling regulations, i.e. while the oil industry’s captive politicians’ eyes are off the ball.

    • Omega Centauri

      Someone was proposing geothermal, with CO2 used as the working fliud. The claim is a lot of the CO2 would be lost underground, essentially sequestering it and making the project carbon negative. Anyone heard anything recently?

  • DGW

    Hot Rocks Rule!

  • PCalith

    Using a lot of the same techniques, but not a lot of the same environmental failures – might be a better transition for fracking rigs and jobs than anything else.

  • Timetohelp998

    Everyone, please take a second to tell the EPA “NO” to
    raising the amounts of radiation released from nuclear power plants.

    The EPA is asking for public comments on this.

    In case you don’t know, radiation is released from nuclear
    power plants during their “normal” operations

    This radiation is linked to all kinds of cancers, heart disease,
    miscarriages, birth defects, etc.

    Studies found higher incidences of breast cancer and
    childhood leukemia in people living around nuclear power plants.

    This radiation stays in the environment from tens to hundreds
    of years and has been found in the rain, snow, ocean, food, milk, etc.

    Here is the link to tell the EPA your opinion on this. Your comment is anonymous, quick and easy to do.!submitComment;D=EPA-HQ-OAR-2013-0689-0001

    Thank you!

    • RamboSTiTCH

      Tell me you didn’t up-vote your own comment and then do it again with your smartphone…

  • brad

    In an immensely wealthy country of billionaires and multi-millionaires, a government investment of $31 million is lauded to the heavens.

    I wonder how many Americans spend more on art for their second or third homes.

    • CP

      Yes, but if the demonstration technology project proves effective, then the private sector will invest tens of billions. This is an appropriate role for Government, to fund basic research and high risk new tech that the private sector will not fund before proven out, particularly in a highly regulated environment like energy production.

      • brad

        Thanks for the informative comment. Point I made rather poorly is that investment is too low because consumption by all, especially the wealthy, is too high.

        • RamboSTiTCH

          Hey, let’s tax the super-rich just a little bit more (what’s 3% of $10,000,000?) and earmark it for renewable energy. I’m sure the Republicans would be okay with it… they’re starting to come around.

          • Bob_Wallace

            Republicans are coming around because they see opportunity for them, personally, to make or save money.

            Ask them to contribute a fair share? What are you? Some kind of Commie?

        • CP


      • urbanegorilla

        It is being used is parts of the US and makes an obvious choice for the right areas as our dams no longer provide the necessary power we’re used to. There was one installation above Santa Rosa, CA that I know of. It’s presently closed, but Hawaii has functional thermogeneration. Obviously, their proximity to active volcanoes is a consideration, but we also have volcanic areas in Yellowstone for example. i think it’s a great idea.

        • Omega Centauri

          California was just under 900MW of geothermal currently, mostly at The Geysers area. I think a few new wells are being drilled in the Imperial valley. I think a few decades back the state had 2GW, but the Geysers couldn’t produce sustainably at that rate.

          Currently geothermal is used for baseline power, but at least in theory you could store the steam or hotfluid and make the power dispatchable (i.e. load following).

          • urbanegorilla

            I vaguely recall lack of sustainable activity was why they shut down the operation above Santa Rosa. However, I do believe geothermal would be a nice addition to California’s needs. In fact the US Energy Dept is funding $31 Million for geothermal (last week’s news).

          • Omega Centauri

            More would be a big plus. Especially if we ran it as dispatchable rather than baseline.

          • Bob_Wallace

            You mean the Geysers?

            There are 21 plants there. About 70 miles north of SF. There are 1517 MW of plants operating with a 63% CF.

            “The Geysers is now recharged by injecting treated sewage effluent from the City ofSanta Rosa and the Lake County sewage treatment plant. This sewage effluent used to be dumped into rivers and streams and is now piped to the geothermal field where it replenishes the steam produced for power generation.”

            There are 15 geothermal plants (570 MW) at the Salton Sea, east of San Diego. The brine from these plants is going to be used as a lithium source.


          • urbanegorilla

            Interesting thanks. Nice Lithium angle too,

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