Musk decries bitcoin’s ‘insane’ energy use after Tesla payment U-turn

Bitcoin fell more than 10% after Musk, one of its most famous backers, tweeted his decision to suspend its use, less than two months after Tesla began accepting it as payment for its electric cars. Other cryptocurrencies, including ethereum, also fell before regaining some ground in Asian trade.

"Cryptocurrency is a good idea on many levels and we believe it has a promising future, but this cannot come at great cost to the environment," Musk tweeted on Wednesday.

He followed this up on Thursday, tweeting a graph of bitcoin’s power consumption and saying: “Energy usage trend over past few months is insane.”

Tesla revealed in February it had bought $1.5 billion of bitcoin, the world’s biggest digital currency, before announcing it would accept it as payment for its electric cars in March. The company later said it had trimmed its position by 10% in the first quarter.

The announcements turbo-charged the crypto market, driving the price of bitcoin up by about 20%. Yet they highlighted an apparent contradiction with billionaire Musk’s reputation as a champion of low-carbon technology.

Some Tesla investors and environmental campaigners have been increasingly critical about the way bitcoin is created or “mined”; high-powered computers compete to solve complex mathematical puzzles in an energy-intensive process that often relies on fossil fuels, particularly coal.

Musk said he backed that concern, especially the use of "coal, which has the worst emissions of any fuel."