Nuclear engineer Lonnie Johnson worked on NASA’s Galileo mission, has more than 140 patents, and invented the Super Soaker water gun. But now he’s working on “a potential key to unlock a huge power source that’s rarely utilized today,” reports the Atlanta Journal-Constitution.

Waste heat… The Johnson Thermo-Electrochemical Converter, or JTEC, has few moving parts, no combustion and no exhaust. All the work to generate electricity is done by hydrogen, the most abundant element in the universe. Inside the device, pressurized hydrogen gas is separated by a thin, filmlike membrane, with low pressure gas on one side and high pressure gas on the other. The difference in pressure in this “stack” is what drives the hydrogen to compress and expand, creating electricity as it circulates. And unlike a fuel cell, it does not need to be refueled with more hydrogen. All that’s needed to keep the process going and electricity flowing is a heat source.

As it turns out, there are enormous amounts of energy vented or otherwise lost from industrial facilities like power plants, factories, breweries and more. Between 20% and 50% of all energy used for industrial processes is dumped into the atmosphere and lost as waste heat, according to the U.S. Department of Energy. The JTEC works with high temperatures, but the device’s ability to generate electricity efficiently from low-grade heat sources is what company executives are most excited about. Inside JTEC’s headquarters, engineers show off a demonstration unit that can power lights and a sound system with water that’s roughly 200 degrees Fahrenheit — below the boiling point and barely warm enough to brew a cup of tea, said Julian Bell, JTEC’s vice president of engineering. Comas Haynes, a research engineer at the Georgia Tech Research Institute specializing in thermal and hydrogen system designs, agrees the company could “hit a sweet spot” if it can capitalize on lower temperature heat…

For Johnson, the potential application he’s most excited about lies beneath our feet. Geothermal energy exists naturally in rocks and water beneath the Earth’s surface at various depths. Tapping into that resource through abandoned oil and gas wells — a well-known access point for underground heat — offers another opportunity. “You don’t need batteries and you can draw power when you need it from just about anywhere,” Johnson said. Right now, the company is building its first commercial JTEC unit, which is set to be deployed early next year. Mike McQuary, JTEC’s CEO and the former president of the pioneering internet service provider MindSpring, said he couldn’t reveal the customer, but said it’s a “major Southeast utility company.” “Crossing that bridge where you have commercial customers that believe in it and will pay for it is important,” McQuary said…

On top of some initial seed money, the company brought in $30 million in a Series A funding in 2022 — money that allowed the company to move to its Lee + White headquarters and hire more than 30 engineers. McQuary said it expects to begin another round of fundraising soon.

“Johnson, meanwhile, hasn’t stopped working on new inventions,” the article points out. “He continues to refine the design for his solid-state battery…”