“Solar and wind projects don’t create a lot of jobs on a continuous basis,” Marsh tells Forbes in a distinctive southeast Pennsylvania accent. “There's jobs in producing hydrogen. Much more than if you build a battery plant.”

For decades hydrogen has been a “water on the road” mirage: an enticing, limitless clean fuel that’s always just up ahead but never quite in reach. Critics like Elon Musk think it always will be. Billions of dollars were funneled into hydrogen fuel cell programs by major carmakers starting in the 1990s, yet today in California, the top market for such vehicles, fewer than 15,000 are in operation—compared with the Golden State’s nearly 900,000 battery and plug-in hybrid autos. But powering transportation is not the direction Marsh, who’s led Plug Power for 14 years, is taking.