Bitcoin miners use increasingly powerful, specially designed computer equipment, or rigs, to verify Bitcoin transactions in a process that produces newly minted Bitcoins.
“If you are using Bitcoin you do not see the environmental cost,” says Alex de Vires, founder of Digiconomist, which tracks Bitcoin emissions. “There are 319 kilograms of carbon emissions per transaction, equivalent to watching over 50,000 hours of YouTube. It is an insane amount.” Cryptocurrency mining is the hidden process that powers the transactions that keep accounts on cryptocurrency apps such as Coinbase ticking along. The process is built into the very fabric of digital currencies.
In its simplest terms, Bitcoin transactions are verified by a huge network of independent computers. They perform complex calculations in a process called Bitcoin mining. Once the calculation is complete, the network is rewarded by new Bitcoin.
“You can compare it to a lottery. Every 10 minutes a ticket is drawn, and lucky miners will have the winning ticket,” says Michel Rauchs, of the Cambridge Centre for Alternative Finance.
At first, mining was easy. It could be done in a bedroom with a graphics-processing computer. There were almost no Bitcoin miners out there, so early miners were able to mint thousands of coins. Now, there are thousands of miners and very few Bitcoins left. This makes the calculations vastly more difficult. The more difficult the transaction, the more computing power is needed, with factories filled with graphics processors and “Antminer” rigs crunching numbers and burning power.
According to Digiconomist, around 77 terawatt hours of electricity annually are needed by the Bitcoin network, roughly the electricity used by Chile, emitting 37 megatons of carbon, the same as New Zealand.
Miners have turned to wind or geothermal energy power to avoid traditional power costs.
Peter Wall, of London-listed miner Argo Blockchain, says its own operations rely on hydroelectric power in Canada and the US. He says: “The sector is still maturing and I expect we will see a lot of miners follow our lead.”
In Iceland, meanwhile, Genesis Mining, led by Marco Streng, has been harnessing the northern nation’s geothermal energy to power its data centres.