Fuel were present at the sites. As a fuel, wood has remained in use up until the present day, although it has been superseded for many purposes by other sources. Wood has an energy density of 10–20 MJ/kg. Recently biofuels have been developed for use in automotive transport (for example Bioethanol and Biodiesel), but there is widespread public debate about how carbon efficient these fuels are. Fossil fuels are hydrocarbons, primarily coal and petroleum (liquid petroleum or natural gas), formed from the fossilized remains of ancient plants and animals by exposure to high heat and pressure in the absence of oxygen
Home fuel cell plants and transmission lines. Putting a home fuel cell system into homes has the potential to get people off-the-grid, play a significant role in energy efficiency, and reduce US dependence on foreign energy imports. Home fuel cell A home fuel cell or a residential fuel cell is a scaled down version of industrial stationary fuel cell for primary or backup power generation. These fuel cells are usually based on combined heat and power-CHP or micro combined heat and power MicroCHP technology, generating both power and heated water or air. A commercially working cell is called Ene-Farm in Japan and is