Despite having made his $1,5 billion dollar fortune on fossil fuels, Mika Anttonen is among the most passionate renewable energy champions in Finland. His St1 petrol chain, with some 1500 stations around the Nordics, has made big bets on wind power, biofuels, and now, emission-free deep heat technologies.

Although the latter project, called St1 Deep Heat, put its drilling on hold back in February due to technical issues it has now resumed excavations.

The goal is both simple and breathtaking: drill two 7 kilometer wells deep into the granite bedrock, pump water into one of them, let the 115 celsius environment warm the water and push it back out of the second well.

After feeding the recovered water through a heat exchanger in Espoo, the plant seeks to cover 10% of the district heating needs of the city and produce up to 40 MW of thermal energy. As Finnish heat networks currently rely heavily on fossil fuels, completely emission-free geothermal heat production can mean a large jump towards the goal of reducing CO2 emissions.