Ambrosia Energy Starts Work on 10 GWh Texas Battery Plant for Off-Grid Data Center Power

Longmier said that volume would allow the company to build roughly a 300-megawatt power plant a year at its field sites. The factory will occupy 150,000 square feet, and Ambrosia expects to reach full production in two to three years.

The startup came out of stealth in June with a plan to build power plants for data centers at a cost of $100 per megawatt-hour. Longmier and co-founder Sara Spangelo settled on solar plus batteries as the cheapest option that could be deployed fastest. Solar panels serve the load during the day and charge the batteries, which discharge at night and on cloudy days so the data center keeps running around the clock. Before founding Ambrosia, the two started the satellite constellation company Swarm, which they sold to SpaceX.

Ambrosia is also beginning work later this year on its first commercial power plant, in West Texas. That facility will pair 300 megawatts of solar panels with 660 megawatt-hours of batteries to deliver 30 megawatts of continuous power, with a goal of 99.3% uptime. Even with the overbuilding of solar and batteries required to deliver uninterrupted power, Longmier said the company can be profitable at $100 per megawatt-hour, which he said makes it competitive with the natural gas turbines many hyperscalers plan to use at their data centers.

Sections of Ambrosia's first pilot-scale power plant have operated continuously for more than 100 days, Longmier said. The pilot can generate 200 kilowatts of electricity around the clock.

To hit its cost targets, Ambrosia has been simplifying components including solar mounts and battery packs. Cutting part counts and manufacturing many components in its own factory have reduced costs relative to buying from outside suppliers. "We buy existing cells and we make our own pack in-house, and it has the fewest parts by a factor of about 100 compared to any other competitor we've seen," Longmier said. "We've been able to get to about 1.3x the cost of the bare cell compared to about a 5- or 7x for most stationary storage systems."