Alternative Fuels for Transportation
- The transportation sector can use biogases such as ethanol, methanol and biodiesel. Producers make these fuels through fermentation of food crops --- sugar cane, corn, cereals and others --- or from wood waste. Using these fuels presents a number of concerns, however. Production of these fuels is energy-intensive, which is an issue. Also, growing the crops necessary to produce these fuels requires land that people could otherwise use to grow crops for food. Finally, a limited amount of fuel can be produced this way, which would not meet the transportation sector's needs.
- Hydrogen is an efficient alternative fuel that emits almost no pollutants. Producers derive hydrogen either from water or carbohydrates and convert it into liquid form, allowing others to use it to create electricity to power vehicles. Users of hydrogen may face difficulties as fuel storage requires low temperatures, under high pressure, as it is a gas at normal temperatures and pressures. Producing hydrogen and converting it to electricity is also an energy-intensive process.
- Electricity is an efficient alternative fuel source. It is more efficient than using hydrogen since users have to convert the latter to electricity. Using electricity as a fuel can be greatly beneficial to the environment, as it does not emit the pollutants that gasoline-powered engines produce. An issue with using electricity is the difficulty it presents in storing enough power to achieve speeds and driving ranges comparable to those of vehicles with internal combustion engines.
- Natural gas occurs naturally as a mixture of gases in porous rock formations. Producers make it into a fuel in both liquid and compressed form and must extract, purify and either compress it for storage and transportation or convert it to liquid. Converting a vehicle to run on natural gas can be cost-effective over its life. Using natural gas produces fewer toxic pollutants and greenhouse gases than gasoline or diesel. Transporting and handling compressed natural gas is also easier, reducing spills and other accidents.
