Thats a very good question Fuzzy. I have seen hydrogen cars here {in Aus}that didn't use "dirty" technology to create hydrogen. I get the impression if it" hasn't been done before in the US" then it doesn't exist. In Aus we are way ahead on these alternative technologies and a lot of them are in use commercially. Every street in Aus has a solar hot water system on a house, gas powered cars is normal and has been around for around 40 years, solar power is common, solar heated swimming pools, wind farms, wave generators, we have the "across AUS solar car race every year. These technologies are the way of the future whether anyone likes it or not, all the nay sayers do is stifle it for a while but eventually it will be the norm.
Mick