Could Super-Hot Magma Be Used as Energy?

Geothermal energy is hardly a new invention. In fact, Iceland already garners around 25% of its total energy consumption from underground reserves of water heated by nearby volcanoes. However, the nation is looking to take its techniques to the next level by drilling down farther than ever before.

At present, geothermal energy production techniques are only able to handle waters of temperatures up to 300°C and that have been sourced within 2km of the Earth’s surface. This new project from Icelandic scientists aims to far surpass those limits by tapping into “supercritical” water reserves found in excess of 4km below the Earth’s crust, with temperatures reaching a whopping 1,000°C.

Why so hot?

If current techniques are only able to sustain water up to a certain temperature, why are scientists investing so much time, effort and money into investigating water which surpasses that threshold by over three times?

The reason is that studies show that these supercritical water reserves exist in a different state of matter to that which we are accustomed; it’s not quite liquid, not quite gas – and it retains an incredible amount of potential energy. Indeed, experts estimate that water at supercritical temperatures is capable of delivering as much as 10 times the amount of power that contemporary geothermal techniques can muster.

Reykjavik is already considered one of the greenest cities in the world, but if it was able to harness the power of this super-hot magma-water, the implications for its environmental energy generation are obvious.

Flies in the ointment

Of course, there is a long way to go before we arrive at the finished article. At present, the huge expense and effort involved in drilling down to retrieve these water sources does not make it economically viable.

Traditionally, the Earth's temperature rises by roughly 25°C for each kilometre that is plumbed. However, geothermal energy production only makes financial sense if that figure is two or three times higher. This means that scientists must look in precise locations to find areas where either the mantle is thinner (thus making access to the water easier) or there are geographical features such as volcanoes in the vicinity, which facilitate the heating of the water and its movement to the Earth’s surface.

While much research has been done into volcanic gas emissions using a wide array of new instruments and techniques, we are only just beginning to understand the implications this could have for geothermal energy generation. In 2009, the Icelandic Deep Drilling Project (IDDP) was founded to explore water reserves below 4km and on their maiden drilling venture, they accidentally ruptured a pocket of magma and were able to create the hottest ever stream of geothermal water, reaching temperatures of up to 450°C.

Looking further afield

If the techniques being pioneered in Iceland are successful, the potential for their deployment around the world is huge. Indeed, it might surprise you to learn that while the Nordic nation has one of the highest percentages of energy consumption from geothermal, it’s not even in the top five for total capacity.

In fact, the nation with the greatest geothermal potential is actually the United States, with fault lines all up the west coast offering a plethora of drilling opportunities. Similarly, the volcanic terrain of the Philippines and Indonesia means that they are second and third respectively, while Mexico and New Zealand close out the top five. Iceland trails in seventh place, one behind Italy.

Clearly, if this tiny nation is capable of gleaning a significant share of its energy needs from such a clean, renewable source, these bigger nations should be able to follow suit. That would spell excellent news for the environment and for concerns over the imminent energy crisis in general.