It was announced today that the US Dept of Energy is dropping further research into using fuel cells in automobiles. Research into stationary fuel cells will continue. Does anyone know if this is just because of the difficulty of safely storing enough H2 onboard a car to make the idea practical? Or are there basic problems with fuel cells themselves (reliability, maintenance, etc)?
From the New York Times, “Cars powered by hydrogen fuel cells, once hailed by President George W. Bush as a pollution-free solution for reducing the nation’s dependence on foreign oil, will not be practical over the next 10 to 20 years, the energy secretary said Thursday, and the government will cut off funds for the vehicles’ development.”
Slightly more detail is here, from the Washington Wire blog of the Wall Street Journal.
This recent article at energy.gov makes me think that H2 storage is the tougher problem:
Secretary Chu Announces $41.9 Million to Spur Growth of Fuel Cell Markets
It sounds like they’re still pushing fuel cells, just not fuel cells for cars. Naturally, YMMV on the interpretation.
Hydrogen has a huge chicken and egg issue, in that very few will buy a hydrogen fueled car if there isn’t anywhere to fuel it up, and very few will build a hydrogen fuel stations if no one has hydrogen cars. Now, this problem isn’t insurmountable, as gasoline & diesel fuel were once in the same boat, but it would cost an a huge amount of money to put in hydrogen fueling stations everywhere - imagine how much it would cost to put in new gas pumps everywhere.
Meanwhile, battery powered electric cars don’t need a massive amount of new infrastructure to be built - they can use the already existing electric grid, which should be sufficient for the bulk of the country -IIRC, the DOE estimated that ~85% of the cars in the US could be switched to electric power without any changes aside from having existing coal and natural gas plants burn more fuel at night. (This assumes the cars will be set on timers to recharge at night.) The West Coast would need more power plants, though.
This isn’t really true; the existing national power grid infrastructure, such as it is, is already pushed to the limit, and as regional brownouts in the last few years have demonstrated, sometimes beyond. In order to support the additional load the whole grid would have to be retooled. Mind you, this isn’t really a bad thing; the system is desperately overdue for an overhaul anyway, and a large, fully integrated program to modernize and homogenize the national power grid would be money well spent for future demand, and could be design to be cellular to limit the impact of local failures and support further expansion. It would certainly be easier than building a hydrogen distribution infrastructure, and possibly more energy efficient as well.
As for shifting to either a hydrogen or electric power for transportation, while this will mitigate dependence on foreign oil it is still an interim solution to the problem of fossil fuel depletion and carbon emissions. Note that while electric powered vehicles are suitable for suitable for most commuter transportation use, in anything like current form they won’t provide enough juice for OTR cargo/heavy haul, air transportation, and probably not enough for blue ocean transportation, for which diesel and kerosene fuel will still be needed.
To address the question of the o.p., the biggest problem with fuel cells is that the practical storage of hydrogen for mobile application is limited by mass density; even in “pure” form of gaseous diatomic hydrogen the density is a couple of orders of magnitude lower than gasoline or other petrofuels. Even bound into a solid metal-organic matrix the density is still too low to support long range transportation. (There was an article in Scientific American a couple of years ago that had a handy chart discussing the efficiency and energy density of various fuel cell types, but I can’t find it online.) Hydrogen stored in liquid or slurry form comes fairly close to the energy density of petrofuels but is cryogenic and thus can’t be stored this way for long periods of time, and requires active cooling or highly adiabatic storage. There are proposals for using nanoscale materials for greater energy density but these are still unproven and probably two decades away from practical application. The promise of energy density storage in batteries, while showing a lower ultimate ceiling than hydrogen fuel cells, is more practical for the near term.
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