Making hydrogen fuel, however, is not emission free: today, making most hydrogen fuel involves natural gas in a process that releases CO2 into the atmosphere. (sciencedaily.com)
There's also currently no cost - effective way to capture the carbon dioxide produced in making hydrogen from natural gas on site at a fueling station, which would undermine any climate benefits. (scientificamerican.com)
Scientists are also investigating the possibility of using high - temperature nuclear reactors to make hydrogen for fuel cells. (sciencemag.org)