When Hannan Happi started thinking about how to solve the AI power crisis, he kept one number in mind: one cent per kilowatt hour.
“We went through all kinds of configurations and designs,” said Happi, co-founder and CEO of Exowatthe told TechCrunch. “They all look different from each other. We tried to learn from each of them: How can I reduce structural costs? How can I reduce maintenance costs? How can I optimize for that?”
After years of brainstorming and building, Exowatt’s first step toward that goal is a simple container-sized box covered with a transparent awning. The interior is equally simple. If Exowatt can deliver on its promise of providing cheap solar power that produces electricity 24-7, it could disrupt the data center market and the wider energy world by providing 24-hour power at very low cost.
To scale production in pursuit of its goal of one minute per kWh, Exowatt raised an additional $50 million in a $70 million Series A round expansion that closed in April, TechCrunch exclusively reports.
The expansion was led by MVP Ventures and 8090 Industries with participation from Atomic, BAM, Bay Bridge Ventures, DeepWork Capital, Dragon Global, Florida Opportunity Fund, Massive VC, New Atlas Capital, Overmatch, Protagonist and StepStone. Previous investors include Andreessen Horowitz and Sam Altman.
Happi said Exowatt was not looking to raise additional capital after the April round, but “the strong momentum we saw in the market” and “strong investor interest” encouraged him to take the new money at a higher valuation.
Exowatt’s backlog is currently about 10 million P3 units representing 90 gigawatt hours of capacity, he said. “The goal is to scale as quickly as possible to millions and eventually billions of units,” he said. The company should hit the one-cent target when production reaches about 1 million units a year, Happi said.
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Exowatt essentially repackages a technology that has been around for decades. Known as concentrated solar energy or thermal solar energy, it uses the sun’s energy to heat materials that are good at storing or transporting thermal energy. In cases where this thermal energy is stored for an extended period of time, these materials tend to come from or look like rocks—hence the technology’s nickname “rocks in a box.”
Each P3 device consists of a metal box with lenses that focus sunlight into a tight beam. This beam then heats a special brick inside the shipping container. A fan blows air over the brick to transfer the heat to another box containing a Stirling engine (a piston-driven device that converts heat into mechanical energy) and a generator. To store more power, developers would install more P3 boxes. “Everything is designed to be super simple,” Happi said.
Each thermal battery can retain heat for up to five days, ensuring continuous operation, and Exowatt will connect several together to power a single generator unit. How much depends on how fast and how much electricity a customer wants to generate. The system’s performance is on par with photovoltaic solar panels and slightly better than photovoltaics combined with lithium-ion batteries, Happi said.
Other companies have created different approaches to the same technology, though most have failed to compete with photovoltaic solar cells and lithium-ion batteries, both of which have surprised experts with how quickly their costs have fallen.
Happi argued that the P3’s small size and Exowatt’s iterative approach set it apart. There are just over 100 solar thermal or concentrated solar power projects being planned, built or decommissioned around the world, he said. “If you compare that to the fact that we produce 1.5 billion solar panels a year, you can see that the learning curve phenomena are very, very far apart.
“What Exowatt is about is taking a modular system that we know works in principle and really scaling the manufacturing of that and then implementing the learning curves of the manufacturing.”
Exowatt is unlikely to be cost-effective everywhere, and the number of P3 units needed to power a data center could require huge amounts of land. Additionally, it works best in sunnier areas, which could limit its wider impact.
But Happi counters that there is a “high overlap” between where Exowatt’s P3 excels and where new data centers are being built. “We have no work to do,” he said.
