I have said before that hydrogen's usefulness is more as a storage medium than as a source of energy in its own right. But here's a well-referenced assessment of the science by Alice Friedemann, suggesting it isn't of any value even for storage:
The laws of physics mean the hydrogen economy will always be an energy sink. Hydrogen’s properties require you to spend more energy than you can earn, because in order to do so you must overcome waters’ hydrogen-oxygen bond, move heavy cars, prevent leaks and brittle metals, and transport hydrogen to the destination. It doesn’t matter if all of these problems are solved, or how much money is spent. You will use more energy to create, store, and transport hydrogen than you will ever get out of it.
And the conclusion? The energy and environmental challenges facing the world are far too serious to spend effort on dead-end technologies. Policy needs to guide investment based on a firm grasp of both science and geopolitical realities. The risk is that lobby groups will sway government to create misguided incentives, such as the US corn subsidies aimed at ethanol production.
Creating an energy store and storing it is always going to use more energy than you can get from it, simple law of thermodynamics, but that is not the idea of hydrogen fuel cells. The creation of hydrogen fuel cells would use excess electricity from renewables to create the hydrogen fuel store; electricity that would otherwise be lost. One must remember that electricity is very difficult to store and energy from renewables (apart from HEP and some geothermal) must be used when and where available. If there is a supply of excess electricity why not use it to make the fuel cell- how else are you going to create a low carbon portable fuel source?
Posted by: Tom469 | 24 July 2008 at 04:50 PM