Exowatt.

Exowatt builds modular solar-thermal energy systems for the AI compute era. Where a photovoltaic panel converts sunlight directly to electricity, the P3 unit captures it as heat, holds that heat in a thermal battery, and converts it to electricity when the customer asks for it. The result is up to 24 hours of dispatchable power.

The customers are utilities and data centers, the two parties most exposed to the gap between AI's appetite for firm power and the grid's ability to supply it. P3 units can be deployed with or without a grid interconnection, which matters when interconnection queues stretch for years. The systems are factory-built in the United States from abundant, low-cost materials, with no rare earth minerals.

What they're building

The P3 is a three-stage machine. Proprietary Fresnel lenses and heat exchangers collect solar heat. A heat battery stores it at high temperature with minimal losses, and a heat engine converts the stored heat to electricity on demand, day or night. The company designs the unit for a 30-year lifespan with minimal maintenance, and because it ships from a factory instead of rising from a construction site, capacity scales by adding units rather than by permitting a new plant.

Around the hardware, Exowatt offers ExoRise: powered land and energy for hyperscale data centers. The offering bundles land sited for utility-scale data centers, colocated solar-thermal generation with long-duration thermal storage, and modular data centers built for high-power AI workloads at gigawatt scale and beyond. The product is the ground the facility stands on as much as the generator.

Why we backed the founders and team

Energy is one of the frontiers we exist to back. The binding constraint on AI has shifted from chips to electrons, delivered firm and around the clock at a price that makes the math work. Photovoltaics plus chemical batteries strain at that job. Exowatt's bet is that storing heat is cheaper than storing electrons, and that a repeatable factory product beats a bespoke construction project.

That bet is won in unglamorous places, in lens yield, heat-engine reliability, and the cost curve of the ten-thousandth unit. Exowatt is assembling lenses, heat, land, and data centers into the thing the next decade of compute actually needs, which is power that shows up. Nothing about thermal storage demos well. It just runs through the night, and that is the entire point.