The availability and environmental impact of energy resources will play a critical role in the progress of the world’s societies and the physical future of our planet. The majority of human energy needs are currently met using petrochemical sources, coal and natural gases but these fossil fuels are approaching depletion and their continued use has had damaging environmental consequences. Worldwide energy consumption has increased more than 20-fold in the last century and, with the exception of hydroelectricity and nuclear fusion energy, all current major energy sources are finite. At present usage rates, these sources will soon be exhausted 1 and this has contributed to soaring fossil fuel prices. As the demand for energy has grown, so have the adverse environmental effects of its production. Emissions of CO2, SO2 and NOx from fossil fuel combustion are the primary causes of atmospheric pollution. 2 The accumulation of carbon dioxide and other greenhouse gases in the atmosphere is thought to be responsible for climate change, which is predicted to have disastrous global consequences for life on this planet. 3