Renewable energy

Biofuel is produced from biomass resources to make liquid fuels like ethanol, methanol, and biodiesel, and gaseous fuels such as hydrogen and methane (see Biogas). Biofuels are primarily used to fuel transportation vehicles, but they can...

Biogas from digesters is typically 60–70% methane and 30–40% carbon dioxide. Biogases fuel engine-generators or gas turbines to produce electricity. They also fuel boilers to produce heat or steam. Biogas utilization has increased in...

Geothermal reservoirs located deep underground provide powerful sources of heat energy. Drilling a geothermal well to a reservoir brings hot water and steam to the surface where it can be put to many uses. Geothermal level...

Hydropower is electricity produced from flowing water. Hydropower produces approximately 7% of U.S. energy (19% of world energy) and accounts for 45% of total renewable energy in the U.S. Newer technologies harness energy in ocean tides,...

Solar Technologies use the sun's energy to provide electricity, hot water, process heat and cooling. Solar power presently provides less than 1% of U.S. energy needs but this is expected to increase with the development of more efficient...

Wind energy is one of the fastest-growing forms of electricity generation in the world. U.S. wind power market share is expected to reach 3.35% by 2013 and 8% by 2018. More optimistic industry experts predict that wind energy will meet 20%...