Here are my thoughts on reducing our use of oil while we still have some left to play with!
New Scientist (4 July 2007, "Biorefineries: curing our addiction to oil") reports that over 70% of the oil we extract is used for transport fuel. Most of the remainder is burned for energy (and this without including natural gas, another fossil carbon) or used for roads, lubricants and waxes. Just 3.4% is used in the petrochemical industry, to synthesise all the materials we depend on in our everyday lives - e.g., plastics, cosmetics, paints and medicines. Wouldn't it make sense to cut down the 90-odd percent that is used for energy and save the oil for petrochemical manufacture? If we were to do this ahead of "peak oil" then the feedstocks that we need for the synthetic chemical industries could last for centuries.
It is comparatively easy to switch electricity generation over to renewables, including woodchip and pellet technologies used for industrial "cogeneration" or combined heat and power (CHP). Slough Trading Estate has been doing this for several years so your UK Mars Bars are made using sustainable energy. This type of biofuel makes sense and does not compete for agricultural resources with food supply. The biggest problem will be scaling up the supply of woody fuel - perhaps an argument for restoring some of Britain's native woodland cover that was displaced by farming?
It is much harder to make the switch to renewables for the transport fuel we all depend on because few other materials have the energy density of petrol or diesel. Plug-in hybrids could help, if recharged from renewable electricity, but hybrid cars today are really no more than green window-dressing to enhance the reputations of the world's largest car manufacturers, while they continue to flog Chelsea tractors, SUVs, pickups and luxury limos.
Whether it's ethanol from sugar cane ('gasohol' in Brazil) or biodiesel from oilseed crops, production of biofuels for transport displaces food production (witness the soaring price of bread). More importantly, to meet the current transport fuel demands of the developed world, biofuel would have to supplant food production entirely - and then some more!
There is an overwhelming need is to change the way we use transport - both personal and freight. That's a very tall order but nothing else comes close to providing a sustainable solution.
Energy efficiency, both domestic and industrial, offers huge prizes but is barely beginning to be tapped here in England because energy is still far too cheap. There is loads of advice available on improving our domestic energy and I will post the best links I can find to help with this. Retailers and manufacturers have much scope to cut their energy consumption but the economics will need to change before they pay more than lipservice to these opportunities. Massive hikes in the price of oil and gas would drive energy efficiency but this is not going to win elections anywhere in the world and so seems unlikely to happen before we reach peak oil.
Solar thermal power is already highly efficient - vacuum collector tubes can capture over 90% of the solar energy reaching them. Rooftops around the world should be covered in them already but - outside of Germany - they are not.
Solar electricity generation, in contrast, uses only up to 15% of the incident energy. There is plenty of room yet for technological innovation, both the physics of solar energy capture and the manufacturing processes used to produce photovoltaic panels in large quantities and at low cost.
Even nuclear fission is ultimately unsustainable because the uranium reserves are limited and the environmental and human costs of uranium mining are very high. If we could tame nuclear fusion as an energy source we would really be getting somewhere!