When Hannan Happi started thinking about how to solve the AI power crisis, he had one number in mind: 1 cent per kilowatt-hour.
“We looked at all kinds of configurations and designs,” Exowatt co-founder and CEO Happi told TechCrunch. “They all look different from each other. We tried to learn from all of them. How can we reduce construction costs? How can we reduce maintenance costs? How can we optimize this?”
After years of brainstorming and building, Exowatt took its first step toward that goal with a simple box the size of a shipping container topped with a transparent awning. The inside is equally simple. If Exowatt can deliver on its promise of providing cheap solar power that is generated 24/7, it could revolutionize the data center market and the broader energy world by providing 24-hour power at a very low cost.
To scale production to meet its 1 cent per kWh goal, Exowatt has raised an additional $50 million in an extension of its $70 million Series A round that closed in April, TechCrunch has learned exclusively.
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 had no intention of raising additional capital after the April round, but was driven by the “strong momentum we saw in the market” and “strong investor interest” to receive new funding at a higher valuation.
Exowatt’s backlog currently stands at approximately 10 million P3 units, representing 90 gigawatt-hours of capacity, he said. “The goal is to scale up to millions and eventually billions of units as quickly as possible,” he said. Happi said the company should hit its 1-cent goal if production reaches about 1 million units a year.
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Exowatt is essentially repackaging technology that has been around for decades. Known as concentrated photovoltaics or thermal photovoltaics, it uses solar energy to heat materials that are good at storing or transporting thermal energy. If that thermal energy is stored for long periods of time, these materials tend to be derived from or resemble rocks, giving the technology the nickname “stone in a box.”
Each P3 device consists of a metal box with a lens attached to the top that focuses sunlight into a narrow beam. That beam then heats special bricks inside the shipping container. A fan blows air over the bricks, transporting 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 install more P3 boxes. “Everything is designed to be very simple,” says Happi.
Each thermal battery can retain heat for up to 5 days, ensuring continuous operation. Exowatt connects multiple thermal batteries together to power a single power generation unit. How much electricity to produce depends on how fast and how much electricity the customer wants to produce. The system’s efficiency is comparable to solar panels and slightly better than solar power combined with lithium-ion batteries, Happi said.
Other companies are building different approaches to the same technology, but most have failed to compete with solar power and lithium-ion batteries, both of which have surprised experts with their rapidly declining costs.
Happi argued that the P3’s small size and Exowatt’s iterative approach set it apart. He said there are just over 100 solar thermal or concentrated solar power projects planned, built or decommissioned around the world. “When you compare this to the fact that we produce 1.5 billion solar panels a year, you see that the learning curve effects are very far apart from each other.
“What Exowatt aims to do is take a modular system that we know works in principle, scale its manufacturing in practice, and apply the manufacturing learning curve.”
Exowatt is not considered cost-effective everywhere, and the number of P3 units needed to power a data center can require vast amounts of land. Additionally, it performs best in the sunniest areas, potentially limiting its widespread impact.
But Happi counters that there is “significant overlap” between where Exowatt’s P3 excels and where new data centers are being built. “There’s no shortage of projects to do,” he says.
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