The problem with oil alternatives is that petroleum is damn near the perfect fuel source for vehicles, energy-wise. There really isn't much else that stores the same amount of energy in the same amount of space under simple and safe storage conditions.

- Batteries can't do it, nor will they ever unless there's some radical new invention that's utterly different from any battery we know.

- The main problem with hydrogen (and LPG) is storing enough of the stuff to get the required energy density per storage volume - these gases have to be stored at immense pressures, which requires seriously strong pressure tanks to store them. And unlike a leaky petrol tank which can be patched with chewing gum in an emergency, I wouldn't like to be anywhere within a block of one of these things getting a crack in the tank, or to be in a hydrogen/LPG car that gets rear-ended (the word would be "shrapnel" when umpty-tum atmospheres of gas blows the tank to pieces, and then there's the flammable gas to deal with as well).

- And diesel is all very well, but the particulates from that aren't good news for the environment.

Of course, the prediction of a 75% increase in oil usage assumes that consumers will still use it at the same rate. Once OPEC start running dry, the price is going to go way high, and demand will crumble. US consumers will get the idea when their 4-litre SUV starts hitting them in the pocket, and SUVs will become as much of an anachronism as all the other gas-guzzling American cars to date.

On the subject of solar panels, I assume we're talking about solar panels heating water? Photovoltaic solar panels producing electricity are a losing proposition - a recent Which? article reckoned they won't pay back their cost for 20 years. They use some really nasty chemicals in their manufacture as well.

Graham.