When I was managing a small factory almost 20 years ago, I had the guys convert an old Case tractor to propane because it was a pain to fetch gasoline for it, and we had a 1,500 gallon propane tank on the premises. I even joked about converting the lawn mower. Soy diesel seems to be working. Most other vegetable oils would work too. Used oil should only need the French fries fished out. The farmers love it. Hydrogen needs breakthroughs in both storing it, and lowering the cost of electricity. I consider the government program a boondoggle. The one sleeper I see is methanol from plant waste. I think it can be used in fuel cells too. Electricity is still in the real soon now breakthrough in batteries as it has been since the 50's. We need to be looking at things. Eventually oil production will decline. Note, can we combine this thread with the other one on CNG?