by Archer Gilliam
Alternative vehicle fuels, including biodiesel, ethanol, batteries, fuel cells, and hydrogen, are becoming more important to people and companies in the world, but especially in the United States, as a way to save money as well as the environment. Two recent reasons are the fuel crisis of summer 2006, which brought gasoline prices creeping above $3.00 a gallon, and the January 2007 US State of the Union speech, in which the President outlined his ideas for increasing the supply of renewable and alternative fuels to 35 billion gallons by the year 2017.
Alternative fuels are important because oil (or petroleum), which produces the gasoline that powers most vehicles these days, is a non-renewable energy resource and will one day be used up if people keep on using as much as they do now. The use of gasoline as a vehicle fuel also produces carbon dioxide, a “greenhouse gas” which contributes to global warming and global climate change.
Oil is non-renewable because it is formed from the remains of very old plankton (tiny sea animals) and algae (tiny sea plants) that have settled in large quantities to the bottom of the ocean. Over thousands of billions of years these plants and animals, mixed with mud, are buried under heavy layers of sediment. High levels of heat and pressure cause the remains to change into liquid and gas, which move upwards through rock layers until they become trapped within porous rocks, called reservoirs, near the surface. This forms an oil field, from which drilling and pumping can extract the oil. Once an oil field is empty, there is no way to create the oil again.
Biodiesel is a diesel-like fuel made from vegetable oils and animal fats. It can be pure biodiesel (B100) or blended with regular diesel fuel (B20 would be 20% biodiesel/80% diesel). Using biodiesel reduces emissions of carbon monoxide and other pollutants, and pollutant emissions are reduced more as more biodiesel is blended into the fuel. B100 reduces carbon dioxide by 75%, while B20 reduces carbon dioxide emissions by 15%. B20 can generally be used in any diesel engine, but using B100 may require some engine modification.
Ethanol (ethyl alcohol or grain alcohol) is made from crops such as corn, sugar beets, sugar cane, barley and wheat. All gasoline-powered vehicles are able to run on gasoline/ethanol blends with up to 10% ethanol, and many states require use of up to 10% ethanol fuel because it reduces carbon dioxide emissions. However, real ethanol vehicles, called flexible fuel vehicles (FFVs), are specifically manufactured to run on up to 85% ethanol (E85). FFVs include vehicles such as compact cars, sport utility vehicles and pickup trucks, and can run on gasoline if there is no ethanol available. Most of the 150 existing E85 fueling stations are in the Midwest, making delivery to the coastal areas an issue. Another problem with ethanol is the worry that if countries grow more crops only for ethanol, their people may not have enough food to eat.
Electricity is another alternative to the use of oil for vehicle fuel, by using it to power battery electric and fuel cell vehicles. Benefits of electric vehicles (EVs) include no carbon dioxide emissions, lower "fuel" costs than gasoline-powered vehicles, and less maintenance. EVs have less moving parts to service and replace, except for battery replacement every three to six years. Also, national and state governments offer financial encouragements to buy alternative fuel vehicles. A problem with EVs is that, although the vehicles themselves do not emit pollution, electric power plants do emit pollution. EVs use electricity from energy storage devices such as batteries, which have a limited storage capacity. Plugging the vehicle into an electrical source, which can be either from existing power outlets or from renewable energy sources such as solar or wind energy, renews EV battery electricity.
Hydrogen provides the cleanest, most efficient alternative to the use of oil. Fuel cell vehicle electricity is produced by a reaction that takes place when hydrogen and oxygen combine as they are fed into a proton exchange membrane (PEM) fuel cell "stack". This process produces enough electricity to power an electric automobile, without producing harmful emissions, leaving only heat and water. Hydrogen can also be used in internal combustion engine vehicles as pure hydrogen mixed with natural gas. Hydrogen may be very important for future development of sustainable transportation because of its possible ability to be produced in limitless quantities using renewable resources. Hydrogen's main benefits are stronger national energy security, reduced greenhouse gas emissions, improved air quality and increased energy efficiency.
The energy future of the world may depend on our ability to develop safe, cleaner, more efficient alternatives to oil as a base for vehicle fuel. The amount of oil available for everyone to use is not unlimited, and the countries in which the oil can be found have the ability to control the rest of the world by controlling distribution of the oil. The sooner we can develop the technology to run vehicles on other fuels, for a reasonable amount of money, the better for all people as well as for the environment of the planet. |
