Can bitcoin go green? Inside the Norwegian mine that's working to cut waste

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 small town 40 miles west of Oslo.

- Daniel Boffey

Hot air is being pumped into the 12 skips through flues curling out from the warehouse. Despite the snow, the logs will be dry in a few days, after which a local lumberjack, grateful for the free service, will take them off for sale.

The wood is being warmed by some of the so-called 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 a Norwegian company, Kryptovault. The company expects its mining to account for just under 1% of the computing 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 energyintensive. The latest calculation from Cambridge University’s bitcoin electricity consumption index suggests that the sector consumes more energy in a year than many countries, including Argentina, Pakistan and Poland.

Heat is an inevitable waste byproduct. Despite noise from ventilation fans so loud that the company had to spend about £1.5m on insulation after complaints from neighbours, the hot areas in the Hønefoss warehouse can reach 55 C.

For many, at a time of rocketing energy prices, this may be further evidence of the unsustainability of a business that was recently described by Robert McCauley, a senior fellow at Boston University’s global development policy centre, as “worse than a Madoff-style Ponzi scheme”.