They actually might in certain cases, using off-peak power at peak times.
The province of Ontario, Canada, is looking at introducing hydrogen-powered commuter trains as part of its commitment to get off diesel and go electric. Does this make sense?
For a very long time, I have been skeptical of hydrogen as a fuel, because it isn't a fuel so much as it is a form of battery. Right now, most hydrogen is reformed from natural gas, so it is a fossil fuel. The fans of hydrogen are pushing electrolysis, which uses a lot of electricity, so it was often promoted by the nuclear industry as a justification for building more reactors. It would then be turned back into electricity in fuel cells and drive electric motors, which is what batteries do. But hydrogen is a tiny molecule that is hard to keep bottled, and the whole process seems less and less efficient or straightforward when batteries keep getting better and cheaper.
But this proposal to run hydrogen trains is actually interesting. Firstly, because they are not pretending that it is a fuel, but are actually calling it a form of battery or "energy carrier." From the province's discussion paper:
Why is hydrogen considered a form of electrification?
Electricity is used to split water into hydrogen fuel which is then pumped into the vehicle’s tank. The hydrogen is then used to generate electricity on the vehicles using fuel cells. Finally that electricity is used to drive electric traction motors to move the vehicle. There is no combustion in this process. Hydrogen acts an ‘energy carrier’ between electricity generated using renewable technologies and electricity driving electric motors.
Also, the province of Ontario has a lot of hydro-electric power and a few nuclear reactors that run all night, making more power than the province actually can use. Sometimes they even pay American companies to take it off their hands. Ben Spurr of the Toronto Star notes:
Because the fuel is stored for later use after it’s produced, it could be produced during off-peak periods overnight, which would lower the cost and allow the province to tap into its considerable electricity surplus. Hydrogen would also allow Metrolinx to run clean trains while avoiding the expensive and disruptive work of erecting overhead wires along hundreds of kilometers of track.
Those are both key points; hydrogen as battery could use off-peak power to run trains at peak times. It could help flatten out demand and help pay for those multi-billion dollar refits of the nuclear fleet.
It would also avoid eating that massive conversion bill all at once, which is not just about hanging wires, but also rebuilding bridges that currently aren't high enough for the catenary wires and pantographs on the roofs of the trains. Another benefit is that the province doesn't have to eat the giant expense of hanging the wires and buying new trains all at once, but could introduce them gradually, since they do not need additional infrastructure on the rail network.
Is this a fantasy? According to Spurr, hydrogen trains are being deployed in Europe, "where the French company Alstom performed successful tests of a hydrogen-powered train earlier this year. The company announced Thursday it had sold 14 of the trains to the German state of Lower Saxony, with an expected in service date of late 2021."
But others are not so sure. John Michael McGrath was not impressed, writing for TVO:
A more basic anxiety around all this is that Ontario is, once again, pursuing a shiny bauble when tested technology we need is sitting on the shelf waiting to be used. The basic parameters of the rail expansion plan are well-known. Everything, including the name, has been borrowed from France and other jurisdictions that have done it well for decades. Hydrogen fuel cells may do wonders in the future, but they’re totally unnecessary right now. Ontario doesn’t need to reinvent the steel wheel, but we seem to love doing so.
McGrath thinks that the province should "stick with the overhead wires that get the job done." But the idea of using off-peak power at peak times is interesting. I have often complained that hydrogen is nothing but a battery, but perhaps this kind of battery makes sense on trains.