Carbon capture technologies have proven their potential to help accelerate the transition towards a post-carbon future. But one of the main problems preventing the solution’s widespread implementation is that the tech is still relatively expensive and unproven at scale.

In a bid to foster innovation in the field and help scale the technology, Elon Musk has recently unveiled his $100 million XPrize Foundation competition focused on carbon removal technology. The contest will welcome teams around the world and will run for four years.

Over the course of 18 months, judges will select 15 teams for the competition. Each one of them will get $1 million, and 25 separate $200,000 scholarships will be given to student teams who enter. The top three teams will receive $50 million, $20 million, and $10 million, for the first, second, and third place, respectively.

As part of the challenge, participants will have to “demonstrate a solution that can pull carbon dioxide directly from the atmosphere or oceans and lock it away permanently in an environmentally benign way,” according to the XPrize Foundation. Judges will be looking for solutions that can remove a ton of CO2 per day, with the potential to scale that up to a gigaton level.

“We want to make a truly meaningful impact. Carbon negativity, not neutrality,” said Musk in a statement. “This is not a theoretical competition; we want teams that will build real systems that can make a measurable impact and scale to a gigaton level. Whatever it takes. Time is of the essence.”