Allen Schaeffer wrote me to point out, for lack of a better word, a homelier option. Here's what Schaeffer, executive director of the Diesel Technology Forum, had to say:
Josh--I read your story in the May 2007 Governing Magazine--It was a good intro to the trials and tribulations of the "hydrogen economy." As I remember reading the National Academy of Sciences independent panel on Fuel efficiency and vehicles about 4 years ago--they identified the H2 economy as at least 25 if not 50 years out.
I was hoping I'd see a mention of the possibility of more diesel cars coming to the US in your story - along the lines of more fuel efficient vehicles and ones that can run on renewable fuels - but there was no mention. Diesel is the most energy efficient internal combustion engine and petroleum-based fuel out there today, and it can and does run on biodiesel blends--which incidentally are viewed as better renewables than ethanol for carbon balance and energy density.
As you may know - about 50 percent of all vehicles sold in Europe have diesel engines which are about 20-40 percent more fuel efficient than today's gasoline and in the next year or two will be every bit as clean as gasoline.
