Engineering details aside, my doubts about the feasibility of most schemes to widely use H as a fuel go beyond favoring low temperature/pressure production methods over high.
I’m more concerned that the most popular technology for the consumer-end – proton exchange membrane fuel cells – can’t, based on reasonable assumptions, be more widely used, at anything approaching an acceptable cost. Since a material required for their manufacturing – platinum - is actually scarce, an increase in manufacturing volume would likely increase, not decrease, their cost. The next most popular technology, alkaline fuel cells, avoids prohibitive manufacturing costs, but require prohibitively expensive H and O purity.
There is, of course, an obvious and well developed method of getting work from ordinary, low-purity H and O – combustion. While inelegant compared to fuel cells, and, while very clean compared to other combustibles, not zero-emission (most of the exhaust is H2O, but unless the supplied H and O is uncontaminated, combustion byproducts similar to gasoline combustion are produced), burning H is immediately feasible. Distributed H can be used both for combustion, and in fuel cells, so combustion doesn’t negatively effect the use and advancement of fuel cells, only fills in the large nitch where they’re not economically viable.
I’m nearly at a loss to explain why H combustion has, since the late 1970s, practically disappeared from popular literature. It’s as if the major proponents of H – Ford and GM, for example – want to fail due to economic infeasibility.
IMHO, proponents of a shift from oil to H should steer clear not only of centralized H production (including nuclear), but of fuel cell consumption. Low cost should be the order of the day, avoidance of expensive materials the mantra. My modest proposal is:
1) Generate electricity via solar thermal means (example:
http://www.enviromission.com.au/index1.htm )
2) Generate H at the point of dispense with reverse alkaline fuel cells (no example exists to my knowledge, but similar to
http://www.ovonic.com/PDFs/fuel_cell...04_toronto.pdf )
3) Consume the generated H by combustion. (a hobbyist can do this)
