Speaking of Geothermal

In the previous post I stated the geothermal – a very promising and cost-competitive source of alternative energy – doesn’t get the same kind of press coverage as wind or solar power. Ironically, I hadn’t realized that Google has just announced a >$10 million investment in advanced geothermal technology. It even got quite a bit of press coverage (probably due more to the ‘Google’ factor than anything). Scientific American has one of the better articles I have seen:

Drilling for Hot Rocks: Google Sinks Cash into Advanced Geothermal Technology

Some excerpts:

For $1 billion over the next 40 years, the U.S. could develop 100 gigawatts (a gigawatt equals one billion watts) of electricity generation that emits no air pollution and pumps out power to the grid even more reliably than coal-fired power plants, according to scientists at the Massachusetts Institute of Technology. Now Google.org—the charitable wing of the search engine giant—has chipped in nearly $11 million for this renewable resource: so-called geothermal power, or tapping the Earth’s heat to make electricity.

Amazingly, this is more money than the U.S. government spends on this technology:

That makes Google.org the largest funder of enhanced geothermal research in the country, outspending the U.S. government. The Australian government has pledged $43.5 million for such projects and already has several in the works, as do Europe and Japan.

While there are still technical challenges for advanced geothermal, geothermal itself has been producing cost-competitive electricity for many years in places where surface magma is readily available. In fact, as I have pointed out before, the U.S. is the world’s leader producer of geothermal electricity at around 3 gigawatts of capacity. The difference in advanced geothermal is that they are going after magma that is far beneath the surface, which would greatly increase the geographical area over which geothermal technology could be applied. Therein lies the technical and economic challenges: Drilling rigs are expensive and in short supply, and you use a lot of electricity pumping water down the drill hole.

10 thoughts on “Speaking of Geothermal”

  1. Why drill new holes? Haven’t we drilled hundreds of thousands over the years? Why not just use those?

    Oil companies with old oil fields should go into the geothermal energy business.

  2. Good to see Google sinking their own money into this — and not trying to get some politician to stick the bill to the taxpayer.

    The oil industry has a lot of experience doing the reverse — pumping steam down into heavy oil formations to reduce oil viscosity. Technical reality is that a long pipe is in effect a heat exchanger. Rule of thumb is that heat losses become very significant once the well’s depth exceeds about 2,000 feet — and there are not many suitable hot rocks at shallower depths.

    Geothermal is like hydro-power: not exactly “green”, but a great source of power where natural conditions favor it. Not much use anywhere else. Let’s hope that Google’s money can extend the range of acceptable natural conditions, but let’s keep our hopes within reasonable bounds.

  3. Someone posted at TOD that The Geysers have run down a bit over the years, belying the common impression of geothermal as an eternal maintenance free source of power. Forget the details though, possibly it’s a minor consideration overall.

    Oregon has about 2GW of geothermal potential. The SciAm article mentions the earthquake the Bern facility triggered however, and OR’s biggest source is the Newberry Caldera – an active volcano. Watch what you’re doing, guys!

    Agree about the potential of deep gas wells. Would an NG bore be by definition too “cold” for geothermal potential, however? Or would we just need to go another measily 10k feet down?

  4. Just some guy,

    The reason the old holes generally can’t be used are

    1. Though thousands of wells have been drilled at the end of the wells life the oil companies essentially fill it with cement

    2. There has to be a high amount of available heat. Many of those thousands of wells are to shallow to have much available heat.

    3. It takes large amounts of heat transfer to run a power plant. Heating the water, circulating it back up the wellbore and preventing corrosion damage to materials in the flow path are not trivial issues.

    If you look at a car radiator it has a lot of fins and tubes to increase the surface area available for heat transfer. Same principle is applied in steam boilers.

    That can’t really be created in a cylindrical wellbore.

    Then there is the other problem of what is the heat transfer capacity of the rock surrounding the wellbore. The water will cool it, how long does it take to reheat the rock?


  5. “That can’t really be created in a cylindrical wellbore.”

    They’re using two boreholes. Even superheated steam is less than a third of steels’ melting point,so plain old pipe should work in both holes. The injection hole probably won’t be as deep. They’ll flood fractured rock and recover steam some distance away. The rocks stay hot for at least 30 years. The DOE says this can be done for less than 4 cents kwh. Guess we’ll find out eventually. You’d think one of the oil majors would have gone all in on this. They already drill deep wells,fracture rock,and work with superheated steam. They’d be naturals.

  6. Just one correction – the rock being drilled is heated by internal radioactive decay, not nearby magma. This means that certain kinds of rock tend to be much hotter than others.

    Furthermore, the depths at which the rock is sufficiently hot are beyond most oil and gas well, as I understand it.

    If you want to read more about hot rock geothermal, you could try this company’s website, who are well down the road to installing a prototype in outback Australia (disclaimer: I’m a small shareshareholder). The reason I’m a shareholder is that unlike solar PV and wind, this technology can actually deliver 24 hours a day, 7 days a week, without expensive energy storage.

  7. One attack on the depth issue:


    A 1 page gloss on the Alaskan project at Chena Hot Springs, a natural spa area that has a long (by Alaskan standards) history of use. They do space heat, and grow much of their food in a greenhouse with geothermal. Note the cost of barging diesel several hundred miles up Alaskan rivers after transporting it a distance about the same as that from the Panama Canal to Puget Sound before heading up stream.


    I saw a report they are installing one at a Florida oil well this summer.

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