Tesla Inc. is suspending vehicle purchases using Bitcoin over concerns about “rapidly increasing use of fossil fuels for Bitcoin mining and transactions,” Chief Executive Officer Elon Musk said Wednesday in a Twitter post.

Tesla, known for its high performance electric cars, is one of the leading brand names in the clean energy sector. The company disclosed in February that it purchased US$1.5 billion in Bitcoin and planned to accept it as a payment earlier this year, adding credence to the cryptocurrency as a newly added member of the blue chip S&P 500 stock index.

Bitcoin mining is consuming 66 times more electricity than it did back in late 2015, and the carbon emissions associated with it will likely face increasing scrutiny, according to a recent Citigroup Inc. report.