A quick note on hydrogen

I just have to make a comment on what Bill said about hydrogen at the 9min 39sec mark:

a hydrogen powered vehicle that is powered by hydrogen that comes from natural gas which, is where 99% of the hydrogen comes from on earth now, actually produces about 6-8 times more CO2 than does burning gasoline in a regular vehicle now

By my calculations, this isn't true.

To make 1kg of hydrogen from natural gas by steam reforming produces roughly 5.5kg CO2:

(2kg) CH4 + (4.5kg) 2H2O <=> (1kg) 4H2 + (5.5kg) CO2

The fuel efficiency of a hydrogen car is hard to come by but from this review of the Honda FCX, the hydrogen fuel cell car goes 190 miles on 3.8kg hydrogen. The target efficiency set by the Department of Energy for a hydrogen fuel cell car is roughly 300 miles per 5kg H2. This means that to drive 300miles in the Honda FCX today using hydrogen produced from natural gas steam reforming will emit 32kg of CO2, worst case. With the DOE target efficiency, a hydrogen car with hydrogen produced from natural gas would produce 28 kg CO2.

Gasoline has a CO2 content of 8.9kg CO2/gallon. So, let's just say we have a car that has a fuel efficiency of 30 miles per gallon. Then the total CO2 produced by that 30mpg car driving 300 miles is 89kg CO2 (2.8 times higher than hydrogen fuel cell car today). In order for a gasoline powered car to produce the same amount of CO2 as a hydrogen fuel cell car, the gasoline car must have a fuel efficiency of 83 miles per gallon.

Note that in this analysis, for both hydrogen and gasoline cars, I only considered tank-wheel CO2 emissions, not well to wheel which would make both cases look slightly worse.

So, in conclusion, a fuel cell car today powered by hydrogen from natural gas will produce less CO2 than your most efficient car available today. I'll make this the topic of an upcoming column. Battery cars are more efficient than hydrogen fuel cell cars though and the future must be efficient.