Google has signed an agreement to buy 200 megawatts of electricity from a future commercial fusion power plant operated by Commonwealth Fusion Systems, a move signaling growing confidence in next-generation clean energy technology.

The deal, announced Thursday, is among the first large-scale fusion purchase agreements by a major U.S. tech company. Google plans to use the energy to power data centers in the western United States once the Commonwealth Fusion Systems plant becomes operational, which is projected in the early 2030s.

“Fusion energy holds the promise of virtually limitless carbon-free power,” Michael Terrell, Google’s senior director of energy and climate, told The Verge in an interview published Thursday. “We see this as a critical bet to support our 24/7 clean energy goals.”

Commonwealth Fusion Systems, a spinoff from the Massachusetts Institute of Technology, is developing a tokamak-based fusion reactor called SPARC that uses advanced superconducting magnets to contain plasma. The company has raised more than $2 billion from investors including Bill Gates’ Breakthrough Energy Ventures and Temasek.

Fusion technology, which aims to replicate the energy-producing reactions of the sun, has long faced challenges around cost and scalability. But recent progress has drawn interest from commercial buyers seeking alternatives to wind and solar.

Google’s broader clean energy portfolio remains dominated by solar and wind resources, but its new deal reflects a growing appetite for “firm” zero-carbon energy that can run around the clock.

“This is a landmark moment,” said Dennis Whyte, a Commonwealth Fusion Systems co-founder and professor at MIT, in a statement shared with Reuters. “Commercial fusion is closer than many people think.”

No financial details of the agreement were disclosed, and experts caution that fusion’s commercial rollout still faces significant engineering hurdles. Nevertheless, the deal is seen as a strong vote of confidence in a technology long considered science fiction.