The price of bitcoin jumped about 4% Monday afternoon after Tesla CEO Elon Musk tweeted that he was having active discussions regarding the sustainability of the digital coin.

Bitcoin was trading around $38074, according to Coindesk, when at about 3:42 p.m. ET Musk posted on Twitter: “Spoke with North American Bitcoin miners. They committed to publish current & planned renewable usage & to ask miners WW to do so. Potentially promising.”

Within minutes, the price had shot up to more than $39500. Overall, the coin is up more than 17% in the last 24 hours.