Iceland is drilling a hole to a depth of 5 km (3.1 miles) with the purpose of tapping energy from the hot magma beneath the crust. In the world’s hottest man-made hole, temperatures go up to 1000 °C (1800 F).

Krafla geothermal power plant in Iceland. Image credits: Ásgeir Eggertsson

Geothermal energy is heat energy generated and stored in the Earth’s depths. Since the Roman times (and even before), people have used geothermal energy to heat their homes. In more modern times, geothermal energy has been used for generating electricity as well as heating homes and for other industrial or agricultural processes. Geothermal power is cost-effective, reliable, sustainable, and environmentally friendly, but the thing with it is that it’s geographically limited to countries close to tectonic plate edges, where the temperature gradient is high. Iceland using geothermal energy is nothing new — due to their location, they are one of the best places in the world for geothermal — but they’ve never done it so deep.

Albert Albertsson, assistant director of HS Orka, an Icelandic geothermal-energy company involved in the project comments:

“People have drilled into hard rock at this depth, but never before into a fluid system like this,” says Albertsson. He says the team could find the landward equivalent of “black smokers”, hot underwater springs along the ridge saturated with minerals such as gold, silver and lithium.

Typically, Iceland’s geothermal wells go up to 2.5 km or so (1.5 miles) and yield a power equivalent to approximately 5 MW. Going two times deeper won’t make the well two times better — it will make it ten times better. The high temperatures and pressures at that depth will generate ‘supercritical steam’ substantially increasing the turbine efficiency.

“If they can get supercritical steam in deep boreholes, that will make an order of magnitude difference to the amount of geothermal energy the wells can produce,” says Arnar Guðmundsson of Invest in Iceland, a government agency that promotes energy development.

Iceland is already generating virtually all its energy through renewable sources. The country is not only the world’s largest green energy producer per capita but also the largest electricity producer per capita, yet geothermal still plays second fiddle to the world’s largest energy sector: hydro. This is why this drills like this have great potential.

There are significant environmental concerns about hydro energy, and the infrastructure is already becoming old. Furthermore, if this well is successful, it will not only generate more cheap, sustainable, and eco-friendly energy but it could also be significant for other parts of the world. In other words, it could make geothermal viable in places where we previously thought this wasn’t possible. The increased efficiency is no joke, and with the US being the world’s largest raw geothermal energy production, the approach could definitely yield fruit.