Elon Musk tweeted that Tesla could enter the lithium mining and refining business directly and at scale because the cost of the metal, a key component in battery manufacturing, has become too high.

“The price of lithium has reached insane levels,” Musk tweeted. “There is no shortage of the element itself, as lithium is almost everywhere on Earth, but the pace of extraction/refinement is slow.”

The chief technology officer of Tesla and SpaceX was responding to a tweet that showed the average price of lithium per tonne over the last two decades, which showed a massive increase in prices since 2021. According to Benchmark Mineral Intelligence, the cost of the metal has gone up plus. 480% in the last year.

In fact, there are lithium deposits throughout the United States, according to the US Geological Survey, a division of the US Department of the Interior.

Lithium is valuable in electric vehicle batteries because it is the lightest metal and least dense solid element. That means batteries made with lithium have a high power-to-weight ratio, which is important when it comes to transportation.

Friday’s tweet is not the first time Musk has floated the idea of Tesla mining its own lithium.

In 2020, Tesla secured its own rights to mine lithium in Nevada after a deal to buy a lithium mining company fell through, according to Fortune, which was reaching out to “people familiar with the matter.”