The real question is how much power goes into the process. If it requires electricity then you have to evaluate the energy use from the source. Somebody has to produce the electricity.
T.A.N.S.T.A.A.F.L.
Heinlein ping.
Good point! You don't get anything for free.
It will work if they can find an inexpensive source of hydrogen. I believe they were planning to get the hydrogen from fossil fuels. Not exactly inexpensive and back to burning fossil fuels.
On the other hand, if the fuel cell energy conversion process is more efficient than fossil fuels, including all the way back to the original source, then it might be feasible.