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Published on June 18th, 2014 | by Guest Contributor


Spain & Portugal Could Survive Just On Geothermal Energy

June 18th, 2014 by  

A version of this article was originally published on Sinc in Spanish.
By Luis Gonzalez



Spain could obtain all the energy the country needs just from the heat under the ground. No solar, no wind is needed. Nor from the old nuclear plants the Spanish government and the electric companies want to restart. There is the potential to produce up to 700 GW, but currently none is produced by this means.

The resource is geothermal power, a growing market that hasn’t reached the Iberian Peninsula yet, and is barely used in Europe. A new study from the University of Valladolid (UVa) published in the journal Renewable Energy with the title “An estimation of the enhanced geothermal systems potential for the Iberian Peninsula,” highlights the big capacity of Spain and Portugal to benefit from this natural resource.

The idea of geothermal energy is very simple; use the heat of the Earth to boil water, like any nuclear or thermal plant does, and use the steam to produce electricity. 24 hours a day, constantly. The heat is coming from the core of the planet, where the temperature is approximately the same as at the surface of the Sun (5,430°C). That is 6,371 kilometers under your feet, but in some areas of the so called Earth crust, the temperature might get up to 370°C due to portions of the mantle convecting upwards.

And there is the potential of the Iberian Peninsula, areas where the temperature reaches high values at shallow depths. According to the study, the areas of Galicia, western Castilla y León, the Sistema Central mountains, Andalusia, and Catalonia have the greater geothermal potential because at a depth of between 3,000 and 10,000 meters the temperature exceeds 150°C, and that is enough to get a geothermal plant to work.

The big number is 700 GW. Five times the current electrical power installed in Spain. This is obtained from calculations that consider wells with a depth between 3,000 and 10,000 meters and by means of enhanced geothermal systems (EGS). Although hard to get there, this depth is in the range of oil perforations. The number goes down to 190 GW for a maximum depth of 7,000 meters and 30 GW above 5,000 meters. To touch a sore spot, there are currently demonstrations in the Canary Islands (Spain) against offshore drilling for oil. The depth estimated for this perforation is 3,500 meters.

But there is something evil behind “enhanced” geothermal system. Enhanced means “to inject a fluid (water or carbon dioxide) under pressure” into a dry rock, creating fractures where the water is stored and heated up. Then, the hot water under pressure is extracted and cycled through a heat exchanger system (aka binary geothermal system) where electricity is produced. So, is this a kind of fracking?

Technically, it is, although it won’t be a legal problem in the case of Spain, since fracking is not forbidden there. In terms of water contamination and spills, it is believed that EGS uses a less aggressive technique based on degradable chemicals and lower pressure, and that the water reservoir is made, in principle, in a hot dry rock with no access to natural water resources.

In any case, more studies should be carried out to address this concern before annoying mother Earth, since another problem, also blamed on fracking, that has been reported from EGS is earthquakes. In 2009, Switzerland resolved to cancel an EGS plant in Basel after several studies stated that the enhanced seismic activity in the area was generated by the EGS power station. It must be said at this point that the plant in Basel was constructed on a known seismic fault.

The alternative to EGS is to exploit geothermal energy in a sustainable way, harnessing the heat that reaches the crust naturally. In that case, Iberia could profit from 3.2 GW of capacity. “It seems low, but it is the equivalent to three nuclear plants,” César Chamorro has declared, who is one of the authors of the study.

In a scenario where EGS could be put into practice without major risks, the main problem relies on the need of appropriated perforation techniques, a technical issue the oil companies are investing a lot of money and efforts to improve. They might be digging, literally, their own grave.

The authors have made use of the information collected in the Atlas of Geothermal Resources in Europe and surface thermal data available from NASA to publish this report and another paper in the journal Energy with the title “Enhanced geothermal systems in Europe: An estimation and comparison of the technical and sustainable potentials,” offering a similar study for Europe.

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  • dondolo06

    Are you sure that geothermal energy is really successful? In Germany, the thermal water systems (~150 °C) have only an efficiency of about 10..12 % – gross. When you consider the demand of electricity for pumping the water from the underground, operate the cooling tower fans amd operate the pumps for re-injecting the water, there is a loss of 50 .. 75% of the electricity produced. So – only about 5% of the heat from the earth is available as electricity, 95% are lost! And how about the same calculation when you drill 10,000 m deep? OK, the temperature will be higher and the electrical output will be higher, too. But what are the risks of drilling 10 km deep?

  • Alan

    Actually also Italy, which is the country with the most geothermal sources in the world only after Iceland, could live with only geothermal energy. The problem is only investment, we should rebuild the grid according to the new sources of energy, and NIMBYs.

  • JamesWimberley

    The mini-quake in Basel was an early mistake. Nobody in geothermal today would repeat the experiment of drilling under a city which suffered a major earthquake in historical times (1356). The successful EGS pilot 100km down the Rhine at Soultz (a village) created 10,000 microshocks, mostly undetectable to humans – but not even a broken window. This is a tiny and manageable risk.

    “The alternative to EGS is to exploit geothermal energy in a sustainable way”. This is also a canard. The sustainable character of geothermal depends on the replacement of the extracted heat by natural processes in the Earth’s crust and mantle, over a horizon of about a century. It’s nothing to do with fracking or not.

  • djr417

    It would seem that the closed system would eliminate the fracking/ earthquake issue,but what is the trade off in costs/ yield? I would think with all the bad press fracking is now getting, that the safest route would be by far the easier sell, avoid the NIMBY crowd as much as possible.

  • Kyle Field

    I was not aware that they frac for some forms of geothermal. I guess as long as they dont use crazy chemicals when they do it…I’m honestly ok with some earthquakes to create the basin if it has a reasonable lifespan before more fracking is needed to create another one…(assuming that happens?)

    • eject

      That is not avoidable. You need to fill the fractures you crate with sand so the stay open. Sand and water obviously doesn’t really mix so you need some stuff in the water to help suspend the sand and lower the viscosity of the resulting slurry.

    • Bob_Wallace

      Enhanced geothermal uses fracking, but they prefer to call it shearing. Recently AltaRock successfully sheared rock at multiple levels in a single bore using CO2 to break up the rock and allow water passages.

      I haven’t heard of ‘wet rock’ geothermal fracking/shearing. They look for a source of super hot water and tap in.

  • Paulo

    Portugal has many places with thermal spas facilities and lots of hot springs. They are mainly used for medical purposes and relaxation. of course it could be used to create energy, but besides Azores archipelago, Portugal hasnt got volcanic activity. And, believe me, portuguese are completely addicted to their cars. abandoning that culture and changing it by electric mobility would give us a huge surplus in our national budget

  • 2783iuq

    I’m from Spain and I don’t want Fracking, not for oil or for geothermal energy.

    • Kyle Field

      coal, natural gas, nuclear, geothermal…take your pick

      • eject

        If those would be the only choices you would have a point. But Spain has huge wind and solar resources, theoretically also tidal and wave since it features a lot of coast. What Spain needs (and the rest of Europe) would be a some more capable grid connectors to France so the power can be traded on the EPEX (European Power Exchange).

        • Kyle Field

          let’s see…21% nuclear, 15% coal, 10% combined cycle, 12% cogen (presumably natural gas)…with wind at a respectable 21%, solar PV and thermal together at 5%. So yes, they are making progress and geothermal coupld play a role in that. the difference between geotherm and most other renewables is that it provides the desirable baseload…or constant, predictable supply of energy whereas solar is when the sun is out (obviously storage needs to come in to play here) and wind is not constant. Agree, it’s not ideal but it’s better than the status quo.

      • 2783iuq

        In 2013 in Spain, the primary source of energy was wind energy with 20.1% (second was nuclear with 20%), we have a lot of sun and hydroelectric power, and no problem with natural gas (are from Argelia, not from Russia). We dont need coal or geothermical.

  • Jacob

    All energy sources are finite. Even solar. However, red dward stars keep shining for 10 trillion years from their formation, and will keep being formed for several hundreds of trillions of years from now at least, so we should be able to eke things out for a little while yet.

    In the nearer future, geothermal is a good way of tiding us over the next few hundreds of millions of years.

  • vadik

    Geothermal is not renewable, it is finite.
    We will all die when Earth cools off inside as the magnetic field will disappear.
    It is a stupid technology given that Spain is doing all right in real renewables.

    • Offgridmanpolktn

      But then again it is renewable because from my reading the magma and earth’s core are constantly (excuse the layman’s term) sloshing around due to the spin of the planet. Also the total heat potential of our planet would seem to be high enough for us to utilize some of it without harm.
      Yes you are right in that we do need to make sure that over the long term nothing is done to permanently decrease the earth’s core temperature. But with such a massive resource could it not be part of a comprehensive conglomeration of solar, wind, hydro, ocean tidal and current, and geothermal?

      • LookingForward

        Haven’t we learned anything from the movie “Man of steel” where Krypton blows up because of exasive geothermal use, oh, the horror!

      • eject

        The Earts core is not just hot by having trapped heat down there. This heat is constantly generated by radioactive decay.

        My problem with large scale geothermal is the release of H2S (poisonous gas, also causing acidic rain), Methane and leakage of radioactive material. While the leakage of radioactive material wouldn’t matter if you do it somewhere where there is no connection to water tables we rely on a massive tapping making a dent in the human energy use will have negative effects on the atmosphere. Weather this would create an actual problem or the trade of would be worth it I don’t know due to lack of information or me bothering to do the research. But geothermal certainly isn’t clean.

    • Dwane Anderson

      Geothermal is not going to cool the earth’s core. They’re only talking about dig down at most 10 kilometers. Take a meter stick and stand it on end. If the bottom end of the stick is at the earth’s core and the top is the earth’s surface, 10 km is only about 1.6 millimeters from the top. Not 1.6 centimeters, 1.6 MILLIMETERS! This is not going to impact the core or even the mantle at all.

      • Offgridmanpolktn

        As I said with the total heat potential of the planet it seems like we can use some of it without causing harm. But also tried to be polite in addressing his concerns.
        When you get sarcastic with a denier they are just going to shut you out and hold more tightly on to their position.
        We are not going to get anyplace in changing our world by telling the other side they are stupid with shows of numbers, even if it is how we feel inside.

        • Dwane Anderson

          I understand your concern. I was not being sarcastic, I was providing an illustration of just how shallow 10 km really is relative to the size of the earth. Most people don’t realize this. My comment was actually intended more for the benefit of other people reading the original comment rather than the commenter himself.

          • Offgridmanpolktn

            Thanks, and excuse me too. Something funky happened with disqus as with my first check back your reply was top of the list, making the read through a little different.

          • vadik

            If you take a meter stick and shove it … inside a refrigerator with one end even a millimeter, the other end will ínevitably get cooler over sufficient time frame. Energy does not appear from nowhere, there will inevitably be a drain, and this drain comes from the molten core.
            One geothermal well is not going to cool the planet significantly, but what if the technology gets off and there are going to be millions of them in a hundred years? It is dangerous and should be stopped at inception.
            We know so little about what is going inside and have yet no fear to potentially damage the Earth forever. Eg one current theory says that magma is crystallizing rapidly and there is not much time left till game over.
            I see parallels to nuclear power discussion. You say nuclear power is dangerous, they say you are an idiot and laundry list all the technical measures and safety gimmicks. You say they keep blowing up and they say it is good they blew up because now we know and it will never blow up again. And then the whole circle again till they blow up anew and the whole circle long you stay an idiot.

          • Bob_Wallace

            “One geothermal well is not going to cool the planet significantly, but what if the technology gets off and there are going to be millions of them in a hundred years?”

            It would be difficult to measure the drop in core temperature. A long line of zeros on the left side of the decimal before you saw a non-zero number.

          • Mint

            Heat generated in the earth leaves through the surface anyway. All geothermal does is let us take that heat, turn some of it into electricity, then put it through our gadgets to become heat at the surface.

            In the end, the heat at the surface of the earth (from sunlight, geothermal energy, and manmade heat) is what determines the temperature gradient that conducts heat out of the earth’s core. Even if the earth was literally entirely covered with geothermal plants 10km deep which cooled that part of the crust down to the surface temp (which is both impossible and counter productive), the worst that will happen is 0.1% faster extraction of heat (I did the math for conduction through a sphere). The core is still 6000 degrees after 4 billion years, so cooling 1% faster isn’t going to matter.

            If you want a refridgerator analogy, think of it this way: you dent your fridge 50 microns so that the insulation thickness shrinks by 0.16%. Even if you do it a million times, the difference is insignificant.

          • Dwane Anderson

            “If you take a meter stick and shove it … inside a refrigerator with one end even a millimeter, the other end will ínevitably get cooler over sufficient time frame.”

            Actually, no it won’t. The first several centimeters will be cooled, but the other end won’t change temperature at all. I’m assuming a regular wooden stick, although it probably would be the same no matter what it’s made of. Of course the reason is that the stick is a decent insulator and the other end of the stick will be warmed by the room. This is very different from the situation inside the Earth, so it doesn’t prove that the Earth wouldn’t be cooled. But it does show that this is a very poor analogy.

            “You say nuclear power is dangerous, they say you are an idiot and laundry list all the technical measures and safety gimmicks. You say they keep blowing up and they say it is good they blew up because now we know and it will never blow up again. And then the whole circle again till they blow up anew and the whole circle long you stay an idiot.”
            In the above, you called someone an idiot for saying that reactors are dangerous, and then they blow up repeatedly, proving him right. How does that make him an idiot?

    • LookingForward

      the earth crust is constantly heated by the core, the sun and the atmosphere keeps the surface warm which in turn keeps the crust warm.

      Geothermal without fracking at key locations is a perfectly fine form of renewable energy, don’t believe everything you here about renewables, geo being finite is just propagenda from the fossil fuel industry.

      Wind and solar is great, but we still need more baseload renewables around the world and geothermal is great for that.

    • Bob_Wallace

      Wiki’s take…

      “Renewable energy is generally defined as energy that comes from resources which are naturally replenished on a human timescale such as sunlight, wind, rain, …”

      Geothermal is one of those dots….

    • just_jim

      By that criteria solar is not renewable either. In several billion years, the sun will stop producing light, so let’s not use it.

      Geothermal will “only” last several hundred million years.

      Really? that’s your argument?


  • spec9

    Well . . . get busy drilling. Nothing wrong with doing solar and wind too. Perhaps they can build an economy exporting electricity to the rest of Europe. Move to electric cars and stop wasting money on gasoline.

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