Biomass fuels currently supply around 15 per cent of the World's energy. Much of this is in the form of traditional fuelwood, plant residues and dung, which are often inefficiently used and can be environmentally detrimental. There is great potential for the modernization of biomass fuels to produce convenient energy carriers, such as electricity, gases and transportation fuels, while continuing to provide for traditional uses of biomass; this is already happening in many countries. When produced in an efficient and sustainable manner, biomass energy has numerous environmental and social benefits compared with fossil fuels. These include waste control, nutrient recycling, job creation, use of surplus agricultural land in industrialized countries, provision of modern energy carriers to rural communities of developing countries, improved land management, and a reduction of CO2 levels. Using biomass to substitute for fossil fuels is afar more effective use of available land than simply growing trees as a carbon store. Biomass fuels can form part of a matrix of renewable fuel sources that increases the energy available for economic development in developing countries. In OECD Europe it is calculated that a potential of 9.0–13.5 EJ could be produced in 2050 on available land, which represents 17–30 per cent of projected total energy requirements.