An alternative fuel is one that is used in place of the normal fossil fuels in a given situation. It might be a different fossil fuel, or it might be a totally different source of power. Generally, alternative fuels are discussed when oil prices begin to soar or shortages are thought to be just over the horizon. Alternative fuels tend to have one big problem. Compared to oil, they are very expensive until oil prices rise above $100 a barrel. At those prices for oil, some alternative fuels can be manufactured for sale at a competitive price.

In many cases, this term is used to describe the use of fuels such as ethanol or various vegetable based oils in place of gasoline or diesel. This may or may not be a mixture with the original fuel. The purpose is to work toward reducing the need or dependence upon a specific type of fossil fuel that is thought to have limited reserves. These mixtures right now range in the 10% to 25% alternative fuel with the rest being the original fossil fuel. Because of the huge quantities of fuel consumed daily, even these lesser percentages can have a major impact on fossil fuel consumption and emissions.

Electric motors while not an internal combustion engine offer a use of alternative fuel by using electricity in combination with a gasoline engine. The hybrid car allows a driver to greatly extend the miles per gallon of fuel consumed. In the short term, combining hybrid technology with a mixed fuel gives maximum improvement on conservation of fossil fuel usage. The problem here is that hybrids are not nearly as efficient as they could be and far too costly to be really competitive with comparably sized gasoline or diesel vehicles.

Technology that breaks water down into burnable hydrogen and uses the oxygen during combustion while yielding water as the byproduct is the most promising alternative fuel today. The problem is to make these cars safe while still burning the extremely combustible hydrogen.

In non-automotive uses, wind, sea wave action, and solar are gaining ground every day. Cars get the big attention for alternative fuel usage, but electrical generation is another big user of fossil fuels. As more areas of life involve the use of electricity, it becomes critical to learn to produce it with as little carbon residue as possible. With grave concerns about the