Start-ups working on fuel cells for the auto industry (Ballard Power, Plug Power) became the darlings of investors in the 1990s and 2000s, but in the intervening two decades hybrids and EVs started to take over the auto sector instead of cars powered by hydrogen, and fuel cell makers shifted most of their attention to the aviation industry. So, what happened? Why aren’t we all driving around in fuel cell cars today?One major hurdle was the lack of a refueling infrastructure. Internal combustion cars and trucks (and hybrids) can get gasoline at just about every other corner and highway exit across the country. Meanwhile, EV drivers just need an electrical outlet, one of the most ubiquitous pieces of “infrastructure” in our world, to recharge their cars’ batteries for the next 80-200 miles.But if you do happen to drive one of the 300 fuel cell vehicles sold (or leased) in the…