Geothermal Power Setbacks in Iceland

[The Silence and I]

Link

We usually think of geothermal energy as a clean, renewable energy alternative to burning dirty fossil fuels. But new reports from the Inter Press Service reveal that geothermal plants in Iceland are creating environmental problems of their own, suggesting that the energy source may not be the best pollution solution.

When Iceland’s Hellisheidi geothermal plant began operation in 2006 there were immediately noticeable changes in the town of Reykjavik, which sits 18 miles downwind. Residents began having to clean their silverware every three to four days instead of every three to four months, as their possessions became covered in black soot. Truck drivers needed to have rubber in their steering and suspension systems replaced after one year instead of after five years, since the rubber hardened faster and became fragile. People suspected the plant of accelerating these processes, but nothing was ever looked into or publicized.

Years later, people began to notice the unusual decay of moss vegetation around the Hellisheidi plant. While geothermal plants emit steam that is 99.6 percent water, 0.4 percent of the vapor contains gases. 83 percent of the gas mixture is the greenhouse gas carbon dioxide (CO2), and 16 percent is hydrogen sulphide (H2S).

The Reykjavik Energy Company started to do tests on the patches of dead moss at Hellisheidi and two other Icelandic geothermal plants in order to determine what had caused the loss of moss. The tests showed that sulfur, derived from H2S, had poisoned the plants; more shocking, however, was that mercury was also found among the dead moss. Mercury and hydrogen sulphide in large doses are deadly, and Reykjavik has been exposed to them for years.

The Environment Ministry is now mandating a maximum permissible level of H2S emissions from geothermal plants, which should cut down the amount of contaminant exposure and environmental degradation, but the future for the energy source in general looks grim. The Hellisheidi plant is currently testing a project of pumping the H2S back into the system, but this has many uncertainties. Other various methods to reduce H2S emissions can be implemented, but these are very costly and still result in emissions of pure sulfur, sulfuric acid, and gypsum. Lastly, geothermal energy is not absolutely renewable, since it extracts more heat than is replaced. With your home-efficiency improvements, solar panels might be the better way to go.

I imagine this would be a problem for any other site on Earth as sulfur is quite common around hot spots IIRC.

[General Havoc]

Lastly, geothermal energy is not absolutely renewable, since it extracts more heat than is replaced.

This part confuses me. Extracts more heat than is replaced from what? From the earth's mantle? If so that seems rather like a specious argument to me. It's like saying that Solar power is not renewable because the sun will one day burn out.

Moreover, if 99.6% of emissions from a geothermal plant are in the form of water vapor, and only 1/5 of the remaining 0.04% of emissions are in the form of this sulfur, then I'm afraid I have a hard time seeing geothermal plants as particularly onerous polluters. Compare 0.01% sulfur emissions to any of the fossil fuel power plants around.

[The Minx]

Um, the link doesn't work for me. :/

This part confuses me. Extracts more heat than is replaced from what? From the earth's mantle? If so that seems rather like a specious argument to me. It's like saying that Solar power is not renewable because the sun will one day burn out.

Moreover, if 99.6% of emissions from a geothermal plant are in the form of water vapor, and only 1/5 of the remaining 0.04% of emissions are in the form of this sulfur, then I'm afraid I have a hard time seeing geothermal plants as particularly onerous polluters. Compare 0.01% sulfur emissions to any of the fossil fuel power plants around.

The heat from a geothermal plant is not taken directly from the mantle, but from a hot-spot in the crust. The heat ultimately comes from the mantle of course, but that doesn't mean you can't take more out of the hot spot than is going in to it.

Still, I really can't see that this should be seen as a negative, almost all green sources of energy have drawbacks - hydro-electrics screw up your waterfalls, and hence river systems, windmills and solar take up huge space (though the mills can be placed at sea) and photovoltaics are expensive and pollute when they are produced.

I also call shenanigans on the emissions from geothermal - surely it is possible to scrub this like other emissions if that were necessary?

[Mayabird]

It's quite possible to have closed loop systems that don't have emissions, and yes they could have scrubbers if they do have emissions, and even without the amount of CO2 and sulfur released is a fraction of the amount that a fossil fuel burning plant of equivalent size would release. And if they're really going to try to claim unsustainability because of the negligible amount of energy extracted from the Earth's interior by power plants (which is more than made up by simple radioactive decay of elements in the mantle and core), then EVERYTHING is unsustainable. The sun will burn out entirely in upteen billion years! Oh noes!

I call solar wanking here. Because Iceland and its polar winters would be a great place to go entirely solar. Yessiree.