Warning: Soapbox follows!!
:soap:
None of the "alternative" energy sources are nearly mature for production. The problem with hydrogen is that it's not an energy source. You can't go out and find hydrogen to burn. You have to pry the H's out of water, or out of a hydrocarbon. This takes as much (actually more than as much) energy as you will get out when you burn it. Hydrogen is just a (sorta) convenient way to store energy.
I was somewhat interested in Biodiesel as well, until I learned how much organic material is required to manufacture it. We just don't have the acreage and farm resources to make this stuff a viable mass source. That and production is ridiculously unwieldy.
The only viable alternative energy source we have ready to go right now is nuclear fission. Modern reactor technology is orders of magnitude safer than any of the currently operating commercial plants in the US, none of which was designed within the last thirty years. Even with the older plants operating, how many casualties have we had in the US nuclear industry?
That's certainly more than you can say for the conventional power industry, even if you neglect the (literally) tons of ash, CO2, CO, Sulfur, NOx, and other nasties they emit every day. I think it's absolutely laughable that environmentalists campaign against zero emission nuclear power when the alternative is what it is.
We as a country need to get over our doomsday hollywood fears of catastrophic nuclear meltdown, and take advantage of the best thing 20th century science gave us. BTW, nuclear fuel costs are practically nil when compared to fossil fuels. Plant operations and startup capital are a little higher, but if we were primarily dependent on nuclear power, we would see a STEEP decline in energy costs.
Once we're there, then technology like Hydrogen will help us to unplug ourselves from oil: Hydrogen will allow us to package up the energy we get from our nuclear reactors and pour it into a tank so that we can take it on the road. If we were to convert to a Hydrogen infrastructure tomorrow, we would still need the fossil fuels (actually more so, since energy is lost in Hydrogen manufacture), so we would get no reduced dependence, and no reduced emissions.
Sorry, but we have hit upon an area about which I am a little passionate. Actually, I would like to go into nuclear management and/or policy, to help get the US commercial nuclear industry back onto its feet.