Drilling into a hot volcano

Iceland is already littered with geothermal power stations, producing most of the country’s electricity from steam at around 240C, extracted from boreholes between 600 and 1,000m deep. Later this year, they will put a pressure lining into their borehole and drill on down to more than 4km deep. At that depth, they hope to encounter what is called supercritical water: water that is not simply a mixture of steam and hot water but a single phase which can carry much more energy.

Engineers on the project have calculated that increasing the temperature by 200 degrees and the pressure by 200 Bar will mean that, for the same flow rate, the energy extracted from such a borehole will go up from 5MW to 50MW. Power station manager Albert Albertsson predicts that, by the end of the century, “Iceland could become the Kuwait of the North”, exporting energy in the form of liquid hydrogen as part of a new hydrogen economy.

BBC