Currently the fuel used in most cars and trucks – gasoline and diesel – is based on oil (petroleum). Since the oil from which gas and diesel are refinanced primarily comes from non-Western countries, unfortunately that means the US, Europe, and many other countries are vulnerable to forces outside their control, forces that currently include the war in Iraq, internal conflicts in Nigeria, and the latest political showdown in Venezuela.
Oil is also a major pollutant, meaning that vehicles that burn petroleum-based products add to global warming. Plus oil is what is called a non-renewable energy source. Once these fossil fuels have been used, they can not be replaced, so we will actually run out of oil someday.
All this obviously means that finding alternative fuels – particularly ones that are more "earth friendly" – and developing alternative fuel vehicles is in everyone's best interests.
Currently the most common alternative fuels for vehicles are ethanol, bio-diesel, and electric. In fact, you may even be driving a type of Flexible-Fuel vehicle and you do not even know it. There are even hydrogen cars, but they are currently cost millions of dollars so are out of range of most people's pocketbooks! Steam-powed and solar-powered cars are also being developed.
Hybrid cars, such as the Toyota Prius, run on a combination of gas and electric power. They use gas engines in combination with electric motors, a combination that results in dramatically improved gas mileage as well as significantly reduced CO2 emissions. They are particularly useful driving in town where you can often drive solely on the electric power generated and use no gas at all. They are, however, noticeably more expensive that non-hybrids.
Bio-diesel is another common alternative fuel. Diesel fuel burns far more efficiently than gasoline, leading to better gas mileage. However, diesel is still a petroleum-based fuel. Bio-diesel, on the other hand, is made from vegetable oils, not petroleum oil. And, because it's made from plants, and plants use carbon dioxide for photosynthesis, bio-diesel reduces net carbon emissions by as much as 60%. Most diesel vehicles, including buses, farm vehicles and cars, can also run on bio-diesel.
Ethanol is probably the most commonly used alternative fuel today. Ethanol, as a biofuel, can be made from a wide variety of common natural materials, such as corn, sugarcane, and switchgrass. Most cars today can run on a combination of gasoline and up to 10% ethanol (a combination called E10) with no special equipment. A real downside of bio-fuels is the environmental costs of growing and refining the material used. However research in using algae to make ethanol holds promise.
Alternative fuel vehicles allow us to reduce dependency on foreign oil and reduce pollutants even with the downsides. Is an alternative fuel car right for you? That is the question we must ask ourselves.