Science, technology, and all things awesome with Ian Steadman


Icelandic scientists tap into molten magma for record geothermal energy production

An accidental breakthrough into a chamber beneath the Earth's crust has led to a possible breakthrough in geothermal energy production.

The Krafla geothermal power plant, Iceland. (Photo: Wikimedia Commons)

Imagine you’re drilling into the ground. Quite deeply - you’re looking for sources of geothermal energy, where the heat from deep in the Earth is warm enough to turn water into steam, and thus turn turbines, creating electricity. Imagine realising that you’ve not just drilled deeply into the crust, but that you’ve accidentally broken straight into a chamber of molten magma more than 5km below the surface.

That happened in Iceland in 2009. It’s the only the second time that it’s known to have happened, the other being in Hawaii in 2007. Both places are hotbeds of volcanism, and while the magma chamber wasn’t an expected discovery (it was only 2.1km deep), scientists in Iceland and Hawaii chose different paths of action. In Hawaii, they plugged the hole with concrete. In Iceland, they left it open, wondering if it could be of use for geothermal research - and a study published this week has confirmed that, yes, it has been.

The Icelandic Deep Drilling Project, IDDP, and the country’s National Power Company reinforced the borehole, called IDDP-1, with a steel casing. The temperatures of up to 1000oC built-up, generating super-hot vents of steam that sustained temperatures as high as 450oC. That far exceeds the standard heat geothermal power plants are able to use, and the borehole was estimated to be able to produce 36MW of power by itself. That’s more than half of the existing 60MW Krafla geothermal plant nearby.

In the study, published in the journal Geothermic, could herald a new method for producing geothermal energy - of particular interest in Iceland, a country that relies upon geothermal for 65 percent of its energy, with more than 90 percent of homes being heated by geothermal energy. It might be possible to use magma chambers to get water to a supercritical state. That's when the normal rules of liquid and gas no longer exist, and its molecules hold extraordinary amounts of energy. Harness that, and energy yields might go even higher.

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