Tesla will resume accepting bitcoin as payment once the cryptocurrency’s power-hungry miners go halfway green, CEO Elon Musk tweeted Sunday. The news appears to have driven up the price of bitcoin and other cryptocurrencies.

• Musk halted Tesla’s months-old crypto foray in mid-May citing environmental concerns. But “when there’s confirmation of reasonable (~50%) clean energy usage by miners with positive future trend, Tesla will resume allowing bitcoin transactions,” he said in the tweet.
• It is unclear how Musk will fact-check miners‘ clean energy usage as there is widespread debate over where the industry currently stands. Even so, the comments provide a first benchmark for reinstating bitcoin payments at Tesla.
• Musk’s tweet also reiterates his defense of having sold 10% of the electric vehicle maker’s bitcoin stash in Q1 and would also seem to indicate the company hasn’t sold any of the rest.

• Musk’s tweet may have been what propelled the price of bitcoin sharply higher about an hour after the tweet was sent. In recent trading, bitcoin was changing hands at $39,200.21, up 9.66%, and leading other cryptocurrencies higher.

UPDATE (June 14, 03:00): Adds that the price of bitcoin may have been boosted by the news.