Magma-enhanced geothermal energy
Back in 2009, the Icelandic Deep Drilling Project (IDDP) was conducting a search for high-temperature geothermal resources. Engineers drilled a borehole at Krafla in north-east Iceland, near the explosive volcanic crater Víti. At a depth of just 2.1 km the temperature of the borehole spiked to 1000 °C. The engineers had unexpectedly drilled into magma (molten rock). This had only happened once before, two years previous, in Hawaii.
A steel casing, perforated in the bottom section closest to the magma, was cemented into the well. Water was pumped down into the borehole and steam was produced at a temperature of 450 °C. This super-heated, high pressure steam was fed directly into the existing power plant at Krafla, and demonstrated that a high-enthalpy (high heat) geothermal system could be successfully utilised.
Iceland is not new to the use of geothermal energy. It supplies 65 % of Iceland’s total energy demand. Whilst most geothermal systems use energy from rocks that are cooler than magma, this new borehole was unique in that it allowed the first ever recorded use of actual magma for geothermal energy recovery.
Obviously this feat cannot simply be repeated at other random spots around the world, as most places don’t have an active magma chamber lying just beneath them. However, the process itself was very instructive, and many practical lessons were learned through this remarkable engineering feat.