Geothermal company Fervo Energy announced Thursday morning that it had started selling electricity from its Cape Station power plant to the grid on September 30, one day ahead of schedule.

With it, Fervo becomes the first enhanced geothermal company to reach a key commercial milestone. The power plant synchronized with the grid about a week ago, bringing online the first third of what will soon become a 100-megawatt power plant.

The entire site could be much larger, though, with the potential to generate as much as 4 gigawatts of electricity, Fervo previously told TechCrunch.

“No team has ever built a project like this anywhere in the world, and we did it ahead of schedule,” Fervo co-founder and CEO Tim Latimer said in a statement.

From groundbreaking to commercial operations, the first block at Cape Station took 23 months to complete. As Fervo refines its process, it is aiming to complete future blocks in as little as 18 months.

That sort of speed to power should appeal to power-starved data center operators, who have been scouring every part of the energy sector for generating capacity. Geothermal can also be developed in phases, similar to how data centers are developed, allowing hyperscalers to bring racks online as demand ramps up.

Google, Southern California Edison, and others have committed to buying power from Fervo’s Cape Station project, which is located in Utah.

Fervo is one of several companies developing enhanced geothermal power plants. While traditional geothermal power taps heat sources close to the surface, Fervo and its peers are drilling deeper because deeper rock is hotter, opening more opportunities for development.

Fervo went public in May in an upsized IPO that raised $1.9 billion. It was founded in 2017, bringing drilling techniques and technologies from the oil and gas sector to the development of new geothermal resources. As a startup, the company raised more than $1.3 billion from investors, including Breakthrough Energy Ventures, Congruent Ventures, and Capricorn Investment Group.