Can Bitcoin Go Green?

A giant Norwegian crypto-mining operation is recycling its waste heat, pushing back against criticism of the famously energy-intensive industry

- Daniel Boffey

A line of large blue skips full of chopped wood sit at the back of a site belonging to Norway’s biggest bitcoin mining operation, a 5,000 sq metre warehouse on the outskirts of Hønefoss, a town 65km northwest of Oslo.

Hot air is pumped into the 12 skips through bendy, corrugated pipes curling out from the warehouse. Despite the snow, it will only take a few days for the logs to be dried out, after which a lumberjack, grateful for the free service, will take them away to be sold.

The wood is being warmed by some of the “waste heat” being emitted from thousands of stacked-high computer servers, known as miners, working away inside the warehouse. It is one of two such sites owned by the Norwegian company Kryptovault. The company expects its mining to account for just under 1% of the computing and process power in the global bitcoin network later this year.

Bitcoin mining, the process of earning cryptocurrency by solving complex computational maths puzzles and verifying transactions in the process, is famously energy-intensive. The latest calculation from Cambridge University’s bitcoin electricity consumption index suggests that, as a result, the sector consumes more energy in a year than many countries, including Argentina, Pakistan and Poland.

Heat is an inevitable waste by product. Despite noise from ventilation fans so loud that the company had to spend about $2m on insulation after complaints from neighbours, the hot areas in the Hønefoss warehouse can reach 55 C.