Alternative Fuels

Alternative fuels include and are limited to ethanol, hydrogen, methanol, natural gas, propane and biodiesel. These fuels are being used worldwide in a variety of vehicle applications.

Using these alternative fuels in vehicles can generally reduce harmful pollutants and exhaust emissions. In addition, most of these fuels can be domestically produced and derived from renewable sources.

 

Ethanol

Ethanol is an alcohol-based alternative fuel produced by fermenting and distilling starch crops that have been converted into simple sugars. Feedstocks for this fuel include corn, barley, and wheat. Ethanol can also be produced from "cellulosic biomass" such as trees and grasses and is called bioethanol. Ethanol is most commonly used to increase octane and improve the emissions quality of gasoline.

Ethanol can be blended with gasoline to create E85, a blend of 85% ethanol and 15% gasoline. E85 and blends with even higher concentrations of ethanol, E95, for example, qualify as alternative fuel. Vehicles that run on E85 are called flexible fuel vehicles (FFVs) and are offered by several vehicle manufacturers.

Benefits - E85 is easy to use and handle - E85 fueling equipment is slightly different and of similar cost to equipment used to store and dispense petroleum fuels. In some cases, it may be possible to convert your existing petroleum equipment to handle E85.

Using E85 reduces petroleum consumption - Use of E85 will reduce a fleet's overall use of petroleum and replace it with a renewable-based fuel produced ("grown") in the United States.

E85 is good for the environment - Beyond operational ease, E85 offers considerable environmental benefits.

Flexible Fuel Vehicles (FFVs) are available and affordable - FFVs specifically designed to run on E85 are becoming more common each model year, and FFVs are typically available as standard equipment with little or no incremental cost.

FFVs have flexible fueling options - FFVs may operate on gasoline, and, in fact, most of the 4 million FFVs on US roadways do today. Although that is not a positive from an E85-use standpoint, it does underscore the flexibility FFVs offer fleets. When E85 is not available, or an FFV travels outside the fueling network, a driver may simply fuel with either fuel as the situation dictates.

 

Hydrogen

Hydrogen (H2) will play an important role in developing sustainable transportation in the United States, because in the future it may be produced in virtually unlimited quantities using renewable resources. Hydrogen has been used effectively in a number of internal combustion engine vehicles as pure hydrogen mixed with natural gas.

In addition, hydrogen is used in a growing number of demonstration fuel cell vehicles. Hydrogen and oxygen from air fed into a proton exchange membrane (PEM) fuel cell "stack" produce enough electricity to power an electric automobile, without producing harmful emissions.

Benefits - Widespread use of hydrogen as an energy source in this country could help address concerns about energy security, global climate change, and air quality. Fuel cells are an important enabling technology for the hydrogen future and have the potential to revolutionize the way we power our nation, offering cleaner, more efficient alternatives to the combustion of gasoline and other fossil fuels. Hydrogen's main benefits are:

            *  Stronger national energy security

            *  Reduced greenhouse gas emissions

            *  Improved air quality

            *  Increased energy efficiency.

Methanol

Methanol, also known as wood alcohol, can be used as an alternative fuel in flexible fuel vehicles that run on M85 (a blend of 85% methanol and 15% gasoline). However, it is not commonly used because automakers are no longer supplying methanol-powered vehicles.

Methanol can be used to make methyl tertiary-butyl ether (MTBE), an oxygenate which is blended with gasoline to enhance octane and create cleaner burning fuel. MTBE production and use has declined because it has been found to contaminate ground water. In the future, methanol could possibly be the fuel of choice for providing the hydrogen necessary to power fuel cell vehicles.

Benefits - Methanol's physical and chemical characteristics result in several inherent advantages as an automotive fuel. Some methanol benefits include lower emissions, higher performance, and lower risk of flammability than gasoline. In addition, methanol can be manufactured from a variety of carbon-based feedstocks such as natural gas, coal, and biomass (e.g., wood) and the use of methanol would help reduce U.S. dependence on imported petroleum. On the down side, methanol produces a high amount of formaldehyde in emissions.

In addition, methanol can easily be made into hydrogen. Some researchers are currently working to overcome the barriers to using methanol as a hydrogen fuel source. So methanol may potentially be used to create hydrogen for hydrogen fuel cell vehicles in the future.

Natural Gas

Natural gas is domestically produced and readily available to end-users through the utility infrastructure. It is also clean burning and produces significantly fewer harmful emissions than reformulated gasoline or diesel when used in natural gas vehicles. In addition, commercially available medium- and heavy-duty natural gas engines have demonstrated over 90% reductions of carbon monoxide (CO) and particulate matter and more than 50% reduction in nitrogen oxides (NOx) relative to commercial diesel engines. Natural gas can either be stored onboard a vehicle as compressed natural gas (CNG) at 3,000 or 3,600 psi or as liquefied natural gas (LNG) at typically 20-150 psi. Natural gas can also be blended with hydrogen.

Benefits - Natural gas is one of the cleanest burning alternative fuels available and offers a number of advantages over gasoline. In light-duty applications, air exhaust emissions from natural gas vehicles are much lower than those from gasoline-powered vehicles. In addition, smog-producing gases, such as carbon monoxide and nitrogen oxides, are reduced by more than 90% and 60%, respectively and carbon dioxide, a greenhouse gas, is reduced by 30%-40%.

For heavy-duty and medium-duty applications, natural gas engines have demonstrated more than 90% reduction of CO and particulate matter and more than 50% reduction of NOx relative to commercial diesel engines.

Propane

Propane or liquefied petroleum gas (LPG) is a popular alternative fuel choice for vehicles because there is already an infrastructure of pipelines, processing facilities, and storage for its efficient distribution.

Besides being readily available to the general public, LPG produces fewer vehicle emissions than gasoline. Propane is produced as a by-product of natural gas processing and crude oil refining.

Benefits - Propane vehicles can produce fewer ozone-forming emissions than vehicles powered by reformulated gasoline. In addition, tests on light-duty, bi-fuel vehicles have demonstrated a 98% reduction in the emissions of toxics, including benzene, 1,3 butadiene, formaldehyde, and acetaldehyde, when the vehicles were running on propane rather than gasoline.

The cost of a gasoline-gallon equivalent of propane is generally less than that of gasoline, so driving a propane vehicle can save money. In addition, propane is the most accessible of all alternative fuels. In the United States approximately 3,000 publicly accessible facilities offer propane.

Approximately 85% of all propane used in this country comes from domestic sources, so driving a propane vehicle can help reduce U.S. dependence on imported oil and strengthen national energy security.

Biodiesel

Biodiesel is a domestically produced, renewable fuel that can be manufactured from vegetable oils, animal fats, or recycled restaurant greases. Biodiesel is safe, biodegradable, and reduces serious air pollutants such as particulates, carbon monoxide, hydrocarbons, and air toxics. Blends of 20% biodiesel with 80% petroleum diesel (B20) can generally be used in unmodified diesel engines; however, users should consult their OEM and engine warranty statement. Biodiesel can also be used in its pure form (B100), but it may require certain engine modifications to avoid maintenance and performance problems and may not be suitable for wintertime use. Users should consult their engine warranty statement.

Benefits - Because little fossil energy is required to move biodiesel, it is a substitute or extender for traditional petroleum diesel, and special pumps or high pressure equipment for fueling are not needed. In addition, it can be used in conventional diesel engines, so special vehicles or engines to run biodiesel do not need to be purchased. However, users should always consult with the OEM and engine warranty statement before using biodiesel.

Scientists believe carbon dioxide is one of the main greenhouse gases contributing to global warming. Neat biodiesel (100% biodiesel) reduces carbon dioxide emissions by more than 75% over petroleum diesel. Using a blend of 20% biodiesel reduces carbon dioxide emissions by 15%.

Biodiesel also produces fewer particulate matter, carbon monoxide, and sulfur dioxide emissions (all air pollutants under the Clean Air Act).

Since biodiesel can be used in conventional diesel engines, the renewable fuel can directly replace petroleum products; reducing the country's dependence on imported oil.

Biodiesel offers safety benefits over petroleum diesel because it is much less combustible, with a flash point greater than 150°C, compared to 77°C for petroleum diesel. It is safe to handle, store, and transport.