Comment Re:Why isn't the U.S. doing things like this? (Score 1) 156
Well, efficiency informs us on cost. Let's couple those costs with efficiency and use the same fuel source.
Natural gas power stations vs hydrogen (from reformed natural gas)
Gas power station = 60% efficient [1]
So a battery vehicle powered by electricity generated from natural gas :
Gas turbine efficiency * transmission line efficiency * battery cycle efficiency
0.6 * 0.94 * 0.95 = 53%
Fuel cell vehicle powered by hydrogen reformed from natural gas
Natural gas is primarily methane. Methane releases 810kJ per mole [2] on burning, and contains 4 moles of hydrogen atoms which would form 2 moles of hydrogen gas. Assuming we remove the carbon from a mole of methane, we get 2 moles of hydrogen molecules. Energy of combusion of hydrogen gas is 286kJ/mol [3], so that's 572kJ/mol per mole of methane or just over 70% of the energy. I'm going to be very generous and assume that steam reformation costs no energy and that no hydrogen is lost in the process.
Methane reformation to hydrogen efficiency * fuel cell efficiency
0.7 * 0.5 = 35%
Therefore starting with the same fuel as an energy source, storage tank to wheels, the fuel cell car requires at least 50% more fuel. Therefore it costs more per mile, and that's before any of the other engineering considerations.
Please don't try to tell me that the cost of electricity produced from natural gas is completely decoupled from the cost of hydrogen produced from natural gas.
[1] Gas turbine plants
[2] https://www.wou.edu/las/physci...
[2] http://en.wikipedia.org/wiki/H...