Bill asks: > In the recent discussion of biofuels, there seems to be a consensus that > producing ethanol from corn has serious adverse consequences both ecological > and economic. However I have not seen anyone address the broader question > what alternatives we have in the long run. Fossil fuels will eventually run > out - oil in a century or so at most, coal in several centuries - and while > there may be some wonderous new technology to fill the gap, we cannot count > on that. I suspect that combustible fuels will always be with us, and I > wonder what they will be.
Ultimately, hydrogen will be the transportable, combustible fuel that we will use. It is essentially an inexhaustable, infinitely recyclable, completely non-polluting fuel source (at least at its point of combustion). The only reason that hydrogen is not used now is its higher cost, vis-a-vis fossil fuels (including the enormous infrastructure changeover costs). But we have the technology in hand now to use it efficiently and well. Indeed, we went to the Moon on hydrogen, combusting it both at high temperatures in the second and third stages of the Saturn V rockets and at low temperatures in the fuel cells of the service propulsion stage, where it produced not only electricity but drinking water as well. Burning any other, more complex molecule only adds a mix of polluting combustion products to the atmosphere. With hydrogen, the only "pollutant" is water. Wirt Atmar
