Exowatt’s core product is the P3 unit, a shipping-container-sized metal box topped with lenses that concentrate sunlight onto heat-retaining bricks. A fan carries the heat to a Stirling engine and generator, enabling each thermal battery to store energy for up to five days and deliver round-the-clock electricity. The system’s efficiency rivals photovoltaic solar plus lithium-ion storage, while its compact, modular design is intended to unlock mass manufacturing learning curves. Exowatt is targeting production of one million units per year, a scale that management says will let it hit its one-cent-per-kilowatt-hour cost goal. Demand appears strong: the company reports a backlog of roughly 10 million P3 units, equivalent to 90 GWh of capacity. Longer term, Exowatt intends to deploy millions—and eventually billions—of units to power the rapidly expanding fleet of AI data centers in sun-rich regions. The approach repurposes decades-old concentrated solar technology but packages it for low-cost, large-scale manufacturing.

Total raised

$140M

Funding rounds

4

Latest round

Series A

Latest activity

Nov 2025