Alternative energy sources for cars, such as natural gas, electricity, ethanol, vegetable oil, sunlight, and water, will vie for consumer use in the future. The Clean Air Act of 1990 and the National Energy Policy Act of 1992 created significant new market opportunities for alternative fuels by requiring government vehicles to use cleaner fuels.
The Toyota Prius, top, a four-seat hybrid electric vehicle (HEV), was the first HEV to be marketed when Toyota introduced it in Japan in 1997. The Honda Insight, bottom, a two-seat HEV, followed in 1999 when it was sold in both Japan and the United States. The Prius had its U.S. debut in 2000.
Many vehicle manufacturers now convert existing vehicles or offer factory-built natural gas vehicles (NGV) that burn natural gas and cost less to run than conventionally fueled vehicles do. In many countries, natural gas is cheaper and more available, so NGVs could become popular in the future.
Corn-based gasohol (a combination of unleaded gasoline and ethanol made from corn) reduces fossil energy use by 50 to 60 percent and pollution by 35 to 46 percent. More than 11 percent of all automotive fuels sold in the United States are ethanol-blended, and that percentage may increase in the future. Agricultural sources of fuel have interested carmakers for decades. In 1997 the Veggie Van, a small motor home powered by a diesel motor that runs on a fuel made from used and new vegetable oil (called biodiesel), took a 16,000 km (10,000 mi) journey. The Veggie Van reached speeds up to 105 km/h (65 mph) and achieved a gas mileage of 10.5 km per liter (25 mi per gallon). Some fuel for the Veggie Van was made from used restaurant fryer oil, and its exhaust smelled like french fries.
An experimental electric car from the Massachusetts Institute of Technology is prepared for a test. Innovations in test cars like this one may be adopted in production electric cars.
Many large automakers are now adapting fuel cell technology for automobiles. Fuel cells are cleaner, quieter, and more energy efficient than internal-combustion engines. Fuel cells combine hydrogen and oxygen electrochemically without combustion to supply electricity. Fuel cell engines will likely run on conventional gasoline, but with a fraction of the emissions of a normal engine. The Ford Motor Company announced in December 1997 that it was investing $420 million in fuel cell research.
From 1995 to 1997 Mazda Motor Corporation experimented with a low-pollution hydrogen rotary engine vehicle, which burns hydrogen fuel that will not emit carbon dioxide. Japan reportedly aims to have a hydrogen fuel distribution network in place to support that fuel’s use in transportation by 2010. Scientists are also trying to reduce emissions of existing vehicles and are testing a device that uses electrons to nullify the noxious components of diesel exhaust.
Electric cars, powered by an electric motor and batteries, provide drivers with another alternative. To recharge the batteries, operators plug the car into a 120-volt or 240-volt outlet. A typical electric car averages 60 to 200 km (40 to 100 mi) per charge. Since most car trips are less than 120 km (75 mi), electric cars can help meet the needs of many two- or three-car families. In 1996 GM debuted the EV1, an emission-free electric car that seats two. The EV1 has been slow to catch on, however. Its batteries run out frequently and require several hours to recharge. Moreover, pioneering electric technology makes the EV1 expensive, especially when compared with conventional gasoline-powered cars of comparable size.
Hybrid automobiles combine an electric motor with batteries that are recharged by a small gas- or diesel-powered engine. By relying more on electricity and less on fuel combustion, hybrids have higher fuel efficiency and fewer toxic emissions. Several automakers have experimented with hybrids, and in 1997 the Toyota Motor Corporation became the first to mass-produce a hybrid vehicle. The first hybrid available for sale in North America was offered by Honda Motor Company in 1999. In 2004 the Ford Motor Company became the first U.S. automaker to produce a hybrid vehicle. The Ford Escape Hybrid, introduced for the 2005 model year, was both the first hybrid made in the United States and the first hybrid sport-utility vehicle (SUV).