The Environmental Challenge: Realising the Potential of the Fifth Fuel Available to Purchase

Post‐war world economic growth has been accompanied by a five‐fold increase in the demand for energy – 80 per cent of it met by oil and gas. However, fossil fuels are not only finite resources; they also contribute to global warming through the build‐up of carbon dioxide emissions. Renewable energy sources, such as biomass, and hydro, solar and wind power, will no doubt have an increasingly important role to play. Yet until technology has released their potential at far lower resource costs, the answer has to lie elsewhere; in energy efficiency– the “fifth fuel”.