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Hydrogen Intermodal Transporation
A Foundation for All Nations to Compete in the Global Economy
End use
The underlying premise of a hydrogen economy is that fuel cells will replace internal combustion engines and turbines as the primary way to convert chemical power into motive and electrical power. The reason to expect this changeover is that fuel cells, being electrochemical, can be more efficient than heat engines. Currently, fuel cells are very expensive, but there is active research to bring down fuel cell prices.
Fuel cells work with hydrocarbon fuels as well as pure hydrogen. If and when fuel cells become cost-competitive with internal combustion engines and turbines, one of the first adopters will be large gas-fired powerplants.
These are currently being built in large numbers by a highly competitive industry, their owners can work with operational constraints (tight temperature ranges, low shock, slow power ramps, etc), power to weight is not an issue, and even small efficiency gains are worth quite a lot. If reforming natural gas into hydrogen and then using that hydrogen in a fuel cell is somehow more efficient than burning the natural gas, gas-fired powerplants will do that instead. But there is no serious discussion of fuel-cell powerplants.
Much of the popular interest in hydrogen seems to attach to the idea of using fuel cells in automobiles. The cells can have a good power-to-weight ratio, are more efficient than internal combustion engines, and produce no damaging emissions. If cheap fuel cells can be had, they may make sense in an advanced hybrid automobile.
So long as methane is the primary source of hydrogen, it will make more sense to fill specialized car tanks with compressed methane and run the fuel cells directly off that. The resulting system uses the methane energy more efficiently, produces less total CO2, and requires less new infrastructure.
A further advantage is that methane is much easier to transport and handle than hydrogen. Methane used for fuel cells cannot have traces of methanethiol or ethanethiol, which are smelly chemicals injected into natural gas distributions to help users find leaks.
The sulfur component of the odorant will destroy the membranes of the fuel cell. Since the technology for running internal combustion engines directly from methane is well developed, low polluting, and leads to long engine life, it is more likely that compressed natural gas (CNG) will be used for transportation in this way rather than in fuel cells for the near future.
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