Clearly, the need to make our cars and trucks run cleaner is driving innovation.
Today, several technologies compete to replace our current dependence on fossil fuels, which are environmentally unfriendly and will eventually run out. Renewable fuels including biodiesel and ethanol have made significant inroads on the premise that we can always grow more. But these fuels are also controversial. A strong debate is brewing about the science and ethics of using crops to make fuel rather than food. (Soybeans provide the raw material for biodiesel while corn is used to produce ethanol.)
You've no doubt at least heard of hybrid cars, that is, if you don't already drive one yourself. Hybrids combine a traditional internal combustion engine with an electric motor to deliver increased fuel efficiency. Expect hybrids to be around for some time, even when all-electric cars such as the Tesla Roadster have come to dominate the roads. Since many of today's cars last much longer than those of a decade or two ago, they'll likely continue to require the support of the gasoline filling station infrastructure.
Currently, all-electric cars are the "Holy Grail" of clean transportation. They produce zero direct emissions and automakers have made wall-socket recharging capability a must on the vehicles they plan to release to the public. What's even more enticing about electric cars is the potential to make them completely non-polluting by recharging them with emissions-free solar or wind energy. Currently, coal-burning power plants make up the vast majority of electricity-producing facilities in the United States.