By Riley Kaminer
Hannan Happi knows energy. The mechanical engineer built his career at Siemens, General Electric, and Tesla before co-founding his first startup, a drone technology company that went through Y Combinator and eventually sold to a defense contractor.
But in late 2022, he found himself in Miami, brought in by the venture studio Atomic to tackle a challenge that’s growing exponentially: how to power the AI revolution.
The problem is simple to understand but massive in scale. AI demands energy — lots of it. Data centers worldwide are scrambling for power, and traditional electricity sources aren’t cutting it. Renewable energy is key, but solar and wind are intermittent, making them unreliable without expensive storage solutions. Happi and his team at Exowatt saw an opportunity to change that.
“We started thinking about ways that we could power data centers using renewable energy in a sustainable way,” Happi told Refresh Miami. “We set a very aggressive goal for ourselves: to generate electricity at one cent per kilowatt hour, which is by far the cheapest you can generate electricity today.”
To get there, Exowatt focused on two principles: modularity and solar efficiency. The company’s flagship product, the Exowatt P3, is a shipping container-sized module that collects and stores solar energy in the form of heat.
Instead of relying on traditional batteries, Exowatt’s system uses a dense thermal storage method – essentially superheated solid blocks – that can retain energy far longer and at a fraction of the cost. When power is needed, an integrated heat engine converts that stored energy back into electricity, making it a reliable, round-the-clock power source.
“We went through over 50 different configurations before landing on the final design,” Happi said. “It’s a combination of concentrated solar power, efficient thermal storage, and a dispatchable energy system that can provide power 24 hours a day.”
The Exowatt P3 is designed to bypass many of the bottlenecks that slow down renewable energy adoption. Traditional solar and wind projects often require years of permitting, infrastructure upgrades, and grid connections before they can go online. Exowatt’s modules, by contrast, can be deployed quickly, operating independently of the grid or supplementing existing renewable projects. That’s a huge advantage for data centers looking to expand their capacity without waiting years for utilities to catch up.
Happi described Miami as an unexpected but ideal place to launch Exowatt.
“When we started, there were people who doubted we could build a hardware-intensive company here,” he said. “But we’ve found it to be a great place to grow. We’ve hired amazing engineers from universities in and around Miami, and we’re expanding our team rapidly.”
Exowatt, currently at around 25 employees, plans to double or even triple in size by the end of the year.
The company has also attracted major backers. In April 2024, its $20 million seed round was led by Sam Altman and Andreessen Horowitz, two of the most influential names in AI and venture capital. More funding announcements might be on the way, Happi hinted.
For now, the focus is on scaling production and meeting the growing demand for Exowatt’s technology. The company is manufacturing its first batch of modules in the U.S., staying true to its commitment to domestic sourcing and production. While its initial customers are data centers, Happi sees applications for commercial and industrial power users as well.
Looking ahead, he envisions a future where modular, scalable renewable energy solutions reshape how power is generated and consumed.
“We’re just scratching the surface of what’s possible,” he said. “The ultimate goal is to build millions of these modules and deploy them as fast as possible.”
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