Renewable Energy

Biofuel can be broadly defined as solid, liquid, or gas fuel consisting of, or made from recently dead biological material, most commonly plants. This distinguishes it from fossil fuel, which is derived from long dead biological material. Biofuel can be theoretically produced from any carbon source. The most common by far is plants that capture solar energy. Many different plants and plant-derived materials are used for biofuel manufacture. Biofuels are used globally and biofuel industries are expanding in Europe, Asia and the Americas. The most common use for biofuels is as liquid fuels for automotive transport. The use of renewable biofuels provides increased independence from petroleum and enhances energy security.

There are various current issues with biofuel production and use, which are being discussed in the popular media and scientific journals. These include: the effect of moderating oil prices, the "food vs fuel" debate, carbon emissions levels, sustainable biofuel production, deforestation and soil erosion, impact on water resources, human rights issues, poverty reduction potential, biofuel prices, energy balance and efficiency, and centralized versus decentralized production models.

Solar energy is energy from the Sun in the form of heat and light. This energy drives the climate and weather and supports virtually all life on Earth. Heat and light from the Sun, along with secondary solar resources such as wind and wave power, hydroelectricity and biomass, account for most of the available flow of renewable energy on Earth. Solar energy technologies harness the Sun's heat and light for practical ends such as heating, lighting and electricity. These technologies date from the time of the early Greeks, Native Americans and Chinese, who warmed their buildings by orienting them toward the Sun.

Solar power is used synonymously with solar energy or more specifically to refer to the conversion of sunlight into electricity. This can be done with photovoltaics, concentrating solar thermal devices and various experimental technologies.

Wind power is the conversion of wind energy into useful form, such as electricity, using wind turbines. In windmills, wind energy is directly used to crush grain or to pump water. Wind power is produced in large scale wind farms connected to electrical grids, as well as in individual turbines for providing electricity to isolated locations. Wind energy is plentiful, renewable, widely distributed, clean, and reduces greenhouse gas emissions when it displaces fossil-fuel-derived electricity. The random patterns of wind seldom creates insurmountable problems when using wind power to supply a low proportion of total demand, but it presents extra costs when wind is to be used for a large fraction of demand.

Wave power refers to the energy of ocean surface waves and the capture of that energy to do useful work - including electricity generation and the pumping of water (into reservoirs). Wave power is a form of renewable energy. Though often co-mingled, wave power is distinct from tidal power and the steady gyre of ocean currents. Wave power generation is not a widely employed technology, and no commercial wave farm has yet been established. The north and south temperate zones have the best sites for capturing wave power. The prevailing westerlies in these zones blow strongest in winter.