The federal government is betting on a new technology to curb global warming. It's called green hydrogen. So what is that? Colorado Public Radio's Sam Brasch went to find out.
SAM BRASCH, BYLINE: If you want to understand hydrogen, head to the National Renewable Energy Laboratory in Golden, Colo. It's raining on the day I visit. For Keith Wipke, who leads the lab's hydrogen research, that rain looks a lot like a future energy source.