In myths and fantasy drilling deeply enough into the Earth awakens demons or Balrogs, but Icelanders are undeterred. They are digging 5 kilometers (3 miles) into the Earth to wake a sleeping giant, but one they believe they can control to produce vast amounts of electricity.
Iceland is already one of the lowest carbon-emitting countries in the world, with 70 percent of electricity produced from hydroelectric plants, while geothermal makes up the rest. There are also proposals for an undersea cable to supply clean energy to Britain. However, proposals to build more dams in the stunningly beautiful highlands have aroused fierce protests, turning the focus back on geothermal.
A stroke of luck seven years ago has inspired Iceland Drilling to investigate a way to get more energy from the rocks beneath the island using high-temperature geothermal drilling. It's going to drill deep enough to tap the energy from the molten magma that moves under Iceland's rugged landscape.
Geothermal energy provides a source of power in many places where volcanism brings the heat of the Earth's mantle close to the surface. Water, whether from natural reservoirs or added by humans, is turned to steam, which is then used to drive turbines. In 2009, the Iceland Deep Drilling Project (IDDP) conducted what was meant to be a conventional, if unusually deep, drill into hot rocks, which hit a magma reservoir.
The IDDP experimented by putting water into the drill hole and got a well capable of producing 30 megawatts (MW) of power, although corrosion shut it down before it could be connected to the grid. This inspired the idea of deliberately tapping much larger magma reservoirs, such as the one that sits 5 kilometers (3 miles) beneath the Reykjanes peninsula. The peninsula is the only place where the Mid-Atlantic Ridge protrudes above sea level.
Drilling began in August, and reached a depth of 3 kilometers (2 miles) on September 7. The goal is to use the combination of great heat (as much as 1000ºC or 1800ºF) and high pressure (200 atmospheres) to produce supercritical water, which carries much more energy than normal steam. Even after the long journey to the surface, the steam is expected to be 400-600ºC (750-1100ºF).
Typical geothermal stations produce 5 MW per well, but it is hoped that those that reach the magma reservoirs will produce 50 MW. The trial has been named Thor in recognition of its potential power.
The hole would not set a record for depth, but drilling into magma is an entirely different matter from hard rock, and the heat will do terrible things to the equipment.
“Black smokers” where magma encounters sea water along mid-oceanic ridges, are often surrounded by gold and silver deposits. Something similar may be found here under Reykjanes, although mining them would be commercially challenging, to say the least.
Iceland Drilling already has operations at volcanic locations outside its home island. If Thor succeeds, Iceland Drilling hopes to drill even deeper in other parts of the world, providing a new source of renewable energy for the planet.
[H/T: New Scientist]
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