"Already in 1874, Jules Verne in his novel The Mysterious Island, lets the engineer Cyrus Harding reply when asked what mankind will burn instead of coal, once it has been depleted: water decomposed into its primitive elements. ... and decomposed doubtless, by electricity ... Yes, my friends, I believe that water will one day be employed as fuel, that hydrogen and oxygen which constitute it, used singly or together, will furnish an inexhaustible source of heat and light, of an intensity of which coal is not capable. Today's energy and transport system, which is based mainly on fossil fuels, can in no way be evaluated as sustainable. In the light of the projected increase of global energy demand, concerns over energy supply security, climate change, local air pollution and increasing prices of energy services are having a growing impact on policy making throughout the world. At present, oil, with a share of more than one third in the global primary energy mix, is still the largest primary fuel and covers more than 95% of the energy demand in the transport sector."