Alternative Fuel Vehicles

Alternative fuels are considered non-conventional, and include types of fuel that are not made with petroleum products. Some well known types of alternative fuels include ethanol, biodiesel, and fuel cells and batteries (chemically stored electricity). Alternative fuels are those that can be considered a renewable resource. The need for alternative fuels is becoming more abundant as people are trying to be more environmentally friendly and also save money on petroleum based fuel products. Alternative fuel vehicles are becoming more widely available, with more than 40 million being sold as of July 2010. The following information outlines some of the different types of alternative fuels and alternative fuel vehicles available today.

Ethanol

Ethanol is an alcohol and is the active ingredient in alcoholic beverages though it is also used as an alternative fuel. In the United States, most cars on the road run on a blend of up to 10% ethanol. In some US states the use of 10% ethanol gas is mandated as it helps to cut poisonous exhaust emissions and is therefore better for the environment. Between 2000 and 2007 the worlds ethanol production of transport fuel tripled.

Ethanol is a renewable energy source in which the energy is generated using sunlight, a resource that cannot be depleted. Ethanol creation begins with the process of photosynthesis causing some type of feedstock, such as corn or sugar cane, to grow. These items can then be processed into ethanol. Large scale production of ethanol consists of basic steps: yeast fermentation of sugars, distillation, dehydration, and denaturing. Depending on the crop used to produce ethanol, prior to fermentation they may require saccharification to turn starches into sugars. To convert the starch into sugar, enzymes are used.

Starch and cellulose are converted to sugars for microbial (yeast) fermentation. The ethanol then must go through a distillation process in order to be used as a fuel, so all of the water must be removed. The distillation process makes the purity of the ethanol somewhere between 95-96%. The mixture can be used for fuel alone but in order for ethanol to be mixed with gasoline it must undergo further treatment to burn in combination with gas in engines. Dehydration is the next step in production to remove the remainder of the water from the ethanol. Five dehydration processes have been developed to remove water from ethanol. In order to save energy, the majority of ethanol plants use the molecular sieves process.

Biodiesel

Biodiesel is another type of alternative fuel that is clean burning and can be produced with renewable resources. Biodiesel itself does not contain petroleum but can be mixed with petroleum products to create a biodiesel blend. The use of biodiesel is growing based on the fact that it is nontoxic, basically free of sulfur and other aromatics, and is biodegradable.

Many people are under the impression that biodiesel is the same thing as raw vegetable oil however, fuel grade biodiesel must be produced according to strict specifications to ensure its proper performance, and is therefore not the same as raw vegetable oil. Biodiesel is the only type of alternative fuel that has fully completed the testing requirements of the Clean Air Act Amendments. Biodiesel that meets the testing standards and is registered by the Environmental Protection Agency can be sold legally. Raw vegetable oil does not meet these testing standards so it cannot legally be sold as a motor fuel.

Biodiesel is produced through a chemical process referred to as transesterification. During transesterification, glycerin is separated from vegetable oil or some other type of fat, resulting in two products – glycerin and methyl esters (chemical name for biodiesel).

Biodiesel is much better for the environment than regular gasoline. It is made from renewable resources and has lower emissions than petroleum products. Biodiesel also helps contribute to the United States economy due to the fact that it is made in the US from renewable resources. This also helps to cut down on our dependence on foreign oil. Biodiesel is available nationwide, and while it is only available at a handful of public gas stations, it can easily be purchased from petroleum distributors and biodiesel marketers and producers.

Hybrid Electric Vehicles

Hybrid electric vehicles, or HEVs, are vehicles that are run on fuel and electric power stored in the battery. Hybrid electric vehicles can run on either conventional or alternative fuels along with the electric power in the battery. HEVs are beneficial and environmentally friendly because of their low emissions and high fuel economy. Currently, there are a variety of hybrid electric vehicles available, though they are more expensive than vehicles that run solely on petroleum products, however many states offer incentives and there are federal tax credits available for those that purchase hybrid electric vehicles.

Hybrid electric vehicles are powered by an electric motor and an internal combustion engine. The electric motor uses energy stored in batteries and the extra power from the electric motor allows the car to have a smaller engine. The smaller engine results in better fuel economy but does not negatively affect performance. An HEV does not need a plug to charge its battery, it uses the internal combustion engine along with regenerative braking to charge. Hybrid electric vehicles are designed to capture energy lost during braking in a process that uses the electric motor as a generator and stores the captured energy in the battery which in turn provides extra power during acceleration.

There are two different types of system designs for hybrid vehicles, series or parallel, meaning that two different types of hybrid electric vehicles are available, mild and full. Parallel hybrids are the most common hybrid electric vehicle design, and they have the electric motor and engine connected to the wheels by mechanic coupling. This means that the internal combustion engine and the electric motor drive the wheels of the vehicle directly. Series hybrids are designed so just the electric motor drives the wheels. Series hybrid design is more common with plug-in electric vehicles. Mild hybrids, also referred to as micro hybrids, use an electric motor along with a battery to power the vehicle. Mild hybrids have the ability to shut off the engine when the vehicle stops (at stop signs and traffic lights), greatly improving fuel economy. Mild or micro hybrids cannot run on electricity alone, therefore they cost less than full hybrids but the fuel economy is lower. Full hybrid electric vehicles have far more powerful electric motors as well as larger batteries that allow the vehicle to run on full electric power for short distances when driving at low speeds. Full hybrids have better fuel economy than mild hybrids resulting in a higher price.

Plug-In Hybrid Electric Vehicles

Plug-in electric hybrid vehicles, or PHEVs, are powered by a combination of fuels and electric power that is stored in a battery. Like basic hybrid electric vehicles, plug-ins have an electric motor and an internal combustion engine, both of which use energy that is stored in batteries. Plug-in hybrids have a much larger battery pack than standard hybrid electric vehicles, and this allows the car to run on only electricity for a good distance (generally between 10 and 40 miles). During short trips such as to and from work, it is possible for the car to run on only electricity, it is then plugged in at the end of the day and charged up for the next trip. Longer trips require the use of the vehicles internal combustion engine as opposed to just the electric motor. Plug-in hybrids can be charged by plugging into an outside power source or through regenerative braking and the internal combustion engine like standard hybrids.

All Electric Vehicles

All electric vehicles use only a battery to store any electrical energy that powers the motor. All electric vehicles can be charged by plugging the vehicle into the correct power source. All electric vehicles are considered to be zero emissions vehicles because the motors produce no emissions or exhaust. Electric vehicles also use no fuel so they cut down on the need for petroleum products and are one the most environmentally friendly alternative fuel vehicles. Manufacturers are looking to develop all electric vehicles that can run about 100 miles before needing to be recharged.

Compressed Air Cars

Vehicles that are powered by compressed air are alternative fuel vehicles that use a motor powered with compressed air. The technology of compressed air cars is new and still being perfected so they are not yet available for purchase in most places. Compressed air cars can be powered with a combination of air and fuel (ethanol, gasoline, or diesel) or they can run solely on compressed air. Engines of these cars are fueled by a tank of compressed air as opposed to the traditional engines that run on an ignited fuel air mixture and pistons. Simply stated, compressed air cars are powered through the expansion of compressed air. The first commercial compressed air vehicle was developed by an ex Formula One engineer by the name of Guy Negre. According to manufacturers, when the car does become available it will be practical and priced reasonably. While compressed air vehicles will likely be available in various countries, they may never become available for purchase in the United States. Due to the construction of the air car, it is not likely to pass crash tests in the United States, making unfit for sale.

Fuel Efficiency

The rising prices of gas as well as the desire to be more environmentally friendly are leading people to do everything they can to make sure their vehicles are fuel efficient. Even if you do not have the means to go out a purchase a hybrid or other type of alternative fuel vehicle, there are things you can do to increase your fuel efficiency which in turn helps you be more environmentally friendly while saving money on gas.

  • Drive Sensibly – Aggressive driving can waste a large amount of gas and lower your gas mileage by up to 33% on the highway and up to 5% when driving around town. Driving sensibly not only helps with fuel efficiency but is also much safer for yourself and other drivers on the road.
  • Observe The Speed Limit – When you drive your car above 60 miles per hour it will rapidly decrease your gas mileage. Driving slower will help increase your gas mileage.
  • Remove Excess Weight – Keeping unnecessary, heavy items in your car can reduce your gas mileage. Even an extra 100 pounds in your car can decrease your gas mileage by 2%.
  • Use Cruise Control – Using cruise control when possible helps maintain a constant speed which in turn will save you gas.
  • Keep Your Engine Tuned – Keeping your car tuned on average will save you up to 4% on your gas mileage, and fixing more serious problems can improve your gas mileage by as much as 40%.
  • Keep Tires Properly Inflated – Besides being safer and lasting longer, properly inflated tires can increase your gas mileage by more than 3%.
  • Use The Recommended Oil – Using the right type of motor oil will increase your gas mileage by up to 2% while using the wrong motor oil can decrease your gas mileage by about 2%.
  • Commuting – Traveling in a carpool or working from home if possible are great ways to be fuel efficient and cut down on your gas costs.
  • Choose A More Efficient Vehicle – There are many different makes and models of vehicles available that have great gas mileage and are better for the economy.

Emissions

Vehicle emissions generally refers to the by-products that come out of a vehicle's exhaust system but can also include other emissions such as gasoline evaporation. Vehicle emissions greatly contribute to air pollution and play a large role in creating smog in many large cities. There are various emissions that come out of a vehicle that are regulated. These emissions include mono-nitrogen oxides, volatile organic compounds, carbon monoxide, carbon dioxide, and other toxic air pollutants.

Vehicle emissions control is the study and practice of reducing vehicle emissions. Vehicle emissions have been shown to have a variety of different, often times negative effects on public health as well as the environment. Hydrocarbons, for example, are a major contributor to smog and can also contribute to liver disease, cancer, and asthma. It wasn't until the 1950's and 1960's that federal and state governments in the United States started studying the sources of air pollution. These studies concluded that a major portion of air pollution can be attributed to vehicles emissions. During this time there were very minimal emissions regulations. It wasn't until 1970 that the United States Environmental Protection Agency was created, with one of their tasks being to help create and enforce emissions regulations. Similar agencies exist in a number of other countries that have similar tasks. Emissions standards have come a long way since the 1950's and advances in vehicle and engine technology have greatly reduced vehicle emissions.

Resources

AFDC - The Alternative Fuels & Advanced Vehicles Data Center from the US Department of Energy Efficiency & Renewable Energy.

Alternative Fuels - Some in-depth information on some of the different types of alternative fuels including ethanol, biodiesel, natural gas, propane, and hydrogen.

Alternative Fuel Vehicles - A guide for students looking to do research on alternative fuel vehicles, includes information and resources.

Alternative Fuel Conversion - Information from the US Environmental Protection Agency on converting basic vehicles into alternative fuel vehicles.