ABSTRACT
Energy is an essential input for social development and economic growth. The socioeconomic impacts on a local economy arising from providing power through renewable resources instead of conventional generation technologies are very important. Liquid biofuels (mainly ethanol and biodiesel) have been investigated as alternative resources to resolve the demanding consumption of conventional gasoline and diesel fuels from fossil fuels. Social, political, economic, and environmental aspects related to biofuels are overviewed and issues associated with future liquid fuels demand are proposed to encourage energy experts to contribute to the emerging field of energy research. The promising transportation fuels are ethanol, biodiesel, hydrogen, biogas, and natural gas. Electricity and hydrogen are principal energy carriers which can be produced from all primary energy sources.