Elon Musk, CEO of electric vehicle maker Tesla, said on Sunday that the US company will accept bitcoin payments again when the virtual currency is greener.
The American manufacturer caused a sensation in February when it announced that customers could pay in cryptocurrency, an option that became possible at the end of March.
But then Musk changed his mind, indicating that bitcoin were no longer accepted -- in the interest of protecting the environment.
"When there's confirmation of reasonable (~50%) clean energy usage by miners with positive future trend, Tesla will resume allowing Bitcoin transactions," the billionaire wrote on Twitter Sunday.
Bitcoin are produced by powerful computers that have to solve equations and consume huge amounts of electricity in the process.
The science journal Nature recently published a study showing that China's bitcoin mines, which power nearly 80 percent of the world's cryptocurrency trade and run in part from coal-fired power plants, risk jeopardizing the country's climate goals.
Musk on Sunday reacted to an article raising the possibility that with his tweets, which regularly move the value of bitcoin in one direction or another, he is manipulating market prices for the benefit of his business.
"This is inaccurate," he said. "Tesla only sold ~10% of holdings to confirm BTC could be liquidated easily without moving market.
The US automaker announced in early February that it had invested $ 1.5 billion of its ample cash in bitcoin and has since sold part of it.