Anthropic has agreed to buy roughly 470 megawatts of onsite power equipment from ERock for its artificial-intelligence infrastructure, giving the newly public power-generation company its largest contract yet as developers race to secure electricity before the grid can deliver it.

The order is for RockBlock generators, ERock's modular gas-fired power units, ERock told Barron's. The deal is incremental to the $1.2 billion backlog ERock reported around the time of its June IPO, Chief Executive John Carrington said in an interview.

Houston-based ERock sells modular natural-gas power systems to data centers and other large electricity users. Its pitch is that the equipment can be installed faster than conventional power plants and later paired with utility service once grid connections are complete.

Carrington told Barron's that Anthropic has not yet selected a site for the generators. While a timeline has not been disclosed, ERock said the deal extended production commitments into 2028.

The initial order does not include the engineering, construction, operations, and maintenance services that ERock often provides alongside its equipment, Carrington said.

ERock expects to exit this year with an annual assembly run rate of 1.2 gigawatts. Carrington said the company can add another 1.2 gigawatts of assembly capacity for about $15 million because it installs its own technology on engine blocks it buys, rather than building engines from scratch.

The contract gives ERock a high-profile AI customer just weeks after a difficult public market debut. ERock went public in June at $21.50 a share, valuing the company at roughly $5.8 billion, but the stock has fallen by about half since then.

ERock is scheduled to report second-quarter results after the market closes Tuesday. In 2025, ERock generated $183.1 million in revenue and ended the year with $1.18 billion in contracted power-system sales backlog. First-quarter revenue was $31.7 million, while backlog had risen to $1.28 billion.