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Friday, December 17, 2004

THE HYDROGEN ECONOMY

The hydrogen economy has been one of the Green's Holy Grails for years. Basically if you burn hydrogen rather than petrol the only pollution you get is water vapour. To make the hydrogen in the first place all you need is to run an electric current through water.

What many of the less numerate Greens haven't realised is that you arn't getting electricity free in the first place it has to be generated & the nature of the universe being what it is, you get less energy out than you put in.

Researchers at a government nuclear laboratory and a ceramics company in Salt Lake City say they have found a way to produce pure hydrogen with far less energy than other methods, raising the possibility of using nuclear power to indirectly wean the transportation system from its dependence on oil..........Experts cite three big obstacles to a hydrogen economy: manufacturing hydrogen cleanly and at low cost, finding a way to ship it and store it, and reducing the astronomical price of fuel cells.

"This is a breakthrough in the first part," said J. Stephen Herring, a consulting engineer at the Idaho National Engineering and Environmental Laboratory, which plans to announce the development tomorrow with Cerametec Inc. of Salt Lake City. ..................The heart of the plan is an improvement on the most convenient way to extract hydrogen, which is to run electric current through water, splitting the H2O molecule into hydrogen and oxygen, called electrolysis.

The new method involves running electricity through water that has a high temperature. As the water molecule breaks up, a ceramic sieve separates the oxygen from the hydrogen.

The idea is to build a reactor that would heat the cooling medium in the nuclear core, in this case helium gas, to about 1,000 degrees Celsius. The existing generation of reactors, used exclusively for electricity generation, use water for cooling and heat it to only about 300 degrees Celsius.

The hot gas would be used two ways. It would spin a turbine to make electricity, which could be run through the water being separated. And it would heat that water. But if electricity demand on the power grid ran extremely high, the hydrogen production could easily be shut down for a few hours, designers say.

If this works at about twice the efficiency of conventional electrolysis it could very well be that using off peak nuclear power, which already has a very low marginal cost, could produce hydrogen which would be cheaper per energy unit, than petrol. Nuclear power is difficult to switch on & off quickly & the most efficient way to run it is continuously at full power. On the other hand our electricity needs vary. Thus a system which can make use of off peak is desirable.

This puts us in the situation where we can go over to 100% cheap nuclear electricity & end most oil imports on the margins & all much cheaper than invading Iraq.

To be fair all the arguments about producing hydrogen from nuclear work equally well with using off peak wind power - except, of course, that wind could never come close to matching nuclear's & thus oil's cost.

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