“When there’s confirmation of reasonable (~50 percent) clean energy usage by miners with positive future trend, Tesla will resume allowing Bitcoin transactions,” he said in a tweet.
Bitcoin rose 5.1 percent to US$37,360.63 on Sunday, adding US$1817.87 to its previous close, after Musk’s tweet.
Musk also said that Tesla sold about 10 percent of holdings to confirm bitcoin could be liquidated easily without moving market.
He announced in May that Tesla would no longer accept bitcoin for car purchases, citing long-brewing environmental concerns for a swift reversal in the company’s position on the cryptocurrency.
Bitcoin fell more than 10 percent after his tweet.
The billionaire said that he believed cryptocurrency has a promising future, but it cannot be at great cost to the environment.
In February, Tesla revealed it had bought US$1.5 billion of bitcoin and would accept it as a form of payment for cars.