Current energy sources and consumption patterns are reviewed, with emphasis on the UK. A survey is made of the main technological means of energy conservation: more efficient conversion of fuels to mechanical and electrical power; utilisation of waste heat; reducing energy requirements for materials and manufacturing; reducing distribution/storage losses, and heat losses from structures. Potential savings resulting from exploitation of novel energy resources are also considered. Sociotechnical aspects of energy conservation are discussed, with particular reference to transport and per capita consumption of materials/manufactured goods. It is concluded that very substantial savings could be made in these areas. Despite the additional environmental benefits associated with many such savings, their political feasibility is judged to be low. Suggestions are made for realistic legislation that could be introduced to effect savings by individual users with minimum capital expenditure.