Geothermal Wells to Utilize Magma

February 13, 2014

The problem of finding reliable source of energy is a topic which is widely speculated nowadays. There are many perspectives in front of the solar power as the Sun provides huge amounts of energy to its planetary system and the human technology is able to capture just small part of it. Biofuels are another option, but they require more efforts for growing cultures with high fuel potential.

magma[Image Source: Wikimedia]

Although this option is known for tens of years ago, it is somewhat neglected by the society. This option is located right below our feet – we walk and live on the outer shell of a nuclear reactor. Iceland is a pioneer country in utilizing the Earth energy. The island is positioned right on the line where two tectonic plates meet. This is why ¼ of the island is an active volcanic zone and local people created geothermal power plants there.
A couple of accidents inspired the scientists to harvest energy from volcanic magma. The first occurred in 1985 during digging for geothermal well in Iceland. Then a blast of high-pressure steam erupted from the drilled whole. Scientists explained that the drilling probe pierced the rocky wall of an underground water reservoir. The water accumulated there was overheated by the magma below, but there wasn’t enough space to turn the water into steam and remained liquid. Water reaches such “supercritical state” when the pressure reaches 222 bars and the temperature is at least 374°C. If the pressure decreases its amount the water turns into steam and starts “seeking” for the surface.
The second accident occurred in 2009, in Iceland again. Then drillings for searching such supercritical fluid deposits hit a pocket of magma. Drillings were held by Icelandic Deep Drilling Project (IDDP), a union of energy companies and scientists, including Wilfred Elders, emeritus professor at the University of California, Riverside. The magma destroyed their tools, but the scientists discovered that the heating of the magma could improve significantly the amount of energy yielded from a regular geothermal well. According to Professor Elder, “There is an enormous energy potential, orders of magnitude greater than can be produced from conventional geothermal systems at 200 to 300°C,”
There’s no need of direct drilling into the magma to produce electricity. Water could be heated by rock lying near the magma, or steam could be generated by injecting water from the surface. IDDP built the first supercritical geothermal well in 2011. The facility was built right above the magma river and proved its effectiveness by generating 35 MW of electricity. Regular geothermal wells generate between 5 and 10 MW. Unfortunately, the facility stopped working due to technical failure because of the extreme conditions it worked for over two years.
There are many difficulties regarding such type of electric generators, and the extreme thermal conditions are just one of them. Active volcano is an obligatory condition for building supercritical well, and even if it is available it is not an easy task to find magma suitable for that purpose. However, the potential of the idea is big enough to stimulate IDDP for further researches in Iceland, and also Japan and New Zealand develop the idea on their own.