Founded in Akron in 2007, Hydrogen Energy Systems, LLC develops hydrogen-fuel technology for internal-combustion engines, centered on its patented Hydrogen Mixing Block™. The device replaces a carburetor or electronic fuel injector so small engines can run mechanically on 100% compressed hydrogen, and the company has tested the system across engines from 6 to 13 horsepower. HES has also demonstrated the technology in a portable generator and a six-passenger golf shuttle prototype.