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Introduction to Alternative Fuels

Posted 8/8/2007
By Jim Linder

As the use of alternative fuels continues to grow, there is a growing need for technicians to be properly educated about alternative fuel sources as they relate to service issues.

As an instructor for Lincoln Schools in the late '70s, I spent a great deal of time researching alternative fuels. Gasoline had started to show some large increases in price, and the search was on for an alternative method of fueling the vehicles we were driving. (It is kind of ironic that I would be requested to write an article on alternative fuels some 30 years later!)

The bad news is that very little has changed over the last 30 years. Doing research for this article, I learned that Henry Ford built the Model T to be an alternative fuel vehicle based on the fact it would run on kerosene or gasoline. Gasoline was considered to be of poor quality and expensive back then. Lamp or "kerosene" oil, as we call it today, was cheaper and more readily available.

Today, almost all of the fuel we use comes from petroleum. Gasoline and diesel fuel account for almost 99 percent of our transportation fuel use. The remaining 1 percent is usually the addition of ethyl alcohol (ethanol) that is used to increase the oxygen content of the fuel for cleaner burning. Federal mandates have made the use of oxygenated fuels standard in some areas that have failed federal air quality testing. Here are the different types of alternative fuels:

  • Ethanol, which is sometimes called "grain alcohol," is generally made in the United States from corn. It can also be made from biomass (organic materials) that include agricultural crops and waste (like rice straw), plant materials left from logging, and trash that includes paper. Brazil is the largest producer in the world of ethanol and produces it from sugar cane. The alcohol found in alcoholic beverages is also considered ethanol. However, the ethanol that is used for fuel is denatured, which means additives are added to prevent human consumption.

  • Methanol, which is called "wood alcohol," can be made from many different biomass resources like wood, as well as coal. However, nearly all methanol is made from natural gas based on a cheaper production cost. Methanol is also very poisonous and harmful if swallowed. Methanol must not be confused with ethanol and as with gasoline, skin contact must be avoided, as it can pass through the skin.

  • Compressed natural gas (CNG) is what many homes across the country cook with each and every day. A vehicle may also be powered with CNG. Natural gas comes from underground and is one of the most environmentally friendly fuels available. CNG is mostly made up of methane (95 percent) with the other 5 percent being comprised of a mixture of butane, propane, ethane and other trace gases. Methane is a hydrocarbon, meaning it is made up of hydrogen and carbon atoms. Its simple composition makes possible nearly complete combustion. Cars, vans, buses and small trucks generally use natural gas that has been compressed and stored in high-pressure cylinders. Several vehicles (such as the Honda Civic CGX and Ford Crown Victoria) are available that use CNG. A vehicle that uses CNG and gasoline is called a bi-fuel vehicle.

  • Electricity-stored batteries in electric vehicles have been around for a long time. In the early 1900s there were more electric vehicles than there were gasoline-powered cars since gasoline was so expensive. It was also difficult to start the early engines. These early gasoline engines were noisy and put out lots of smoke, so electrics were a big hit! As new methods of gasoline production developed - thereby lowering its price - a new invention called a starter was invented, and electric vehicles began to fade away.

    Automobile companies are making cars run cleaner and cleaner. Ten of today's cars would produce the same amount of pollution that would come from one car just 15 years ago. Electric vehicles are still being built and used and often are called zero-emission vehicles (ZEVs). These cars, for example, account for approximately 2 percent of all vehicles sold.

  • Hydrogen fuel cell vehicles lead the race for fuel-cell vehicles, and hydrogen vehicles are also considered to be ZEVs. Fuel-cell vehicles turn hydrogen fuel and oxygen into electricity. The electricity then powers an electric motor; just like the electricity from batteries power the motor of an electric vehicle. To carry gaseous hydrogen on a vehicle, it must be compressed. When compressed (3,000 pounds per square inch) it must be stored in special containers. This is similar to the way compressed natural gas is stored on natural gas-fueled vehicles.

    There are many different methods of getting the hydrogen to the fuel cell, but most are somewhat expensive. At present, fuel-cell vehicles are considered to be in the pre-prototype stage. This means there are few in existence, although many of the manufacturers have a prototype of one kind or another.

  • Hybrid vehicles - The word hybrid means something that is mixed together from two things. A typical hybrid is the Honda Insight, which can get up to 68 mpg on the freeway. The car uses a small gasoline engine with an ultra thin electric motor. Its primary power comes from the gasoline engine, but it uses the electric motor when it is accelerating or climbing hills. The electric motor does not need an external power supply for recharging. Regenerative braking recharges its batteries. That means energy from forward momentum is captured during braking. This energy is then used to recharge the batteries. Most auto companies are working on a hybrid or already have at least one hybrid on the road today.

  • Liquefied natural gas (LNG) - Natural gas comes in three forms. One is the low- pressure form you use to cook or heat a home. It comes to you in a pipe from the local gas company. Another form is compressed natural gas (CNG). This form is compressed into high-pressure cylinders to power a car or truck. It comes from special CNG fuel stations. The third form is liquefied natural gas. LNG is made by refrigerating natural gas to condense it to a liquid. The liquid form is much more dense that natural gas or CNG. It has more energy for the same amount of space it takes up. This makes LNG good for vehicles to travel long distances. LNG is cooled to minus 260 degrees Fahrenheit below zero!

    Liquefied petroleum gas (LPG) - Propane is what LPG is commonly called. That's because LPG is mostly made up of propane. Actually, propane is made up of a mixture of propane and other types of hydrocarbon gases. Different batches of propane may have slightly different hydrocarbon molecules. These hydrocarbons are gases at room temperature, but turn to liquid when they are compressed. A propane tank is usually about 200 pounds of pressure. LPG-fueled engines pollute less than gasoline and diesel engines. LPG usually costs less than gasoline for the same amount of energy.

  • Liquids made from coals - Not all gas comes from petroleum. There are ways to make gasoline, diesel fuel, methanol and other fuels from coal. Other countries (such as South Africa) have been making gasoline and diesel fuel from coal for many years. These processes can be used today, but it is expensive. It's cheaper to use inexpensive crude oil pumped from the ground below.

  • Biodiesel is not your regular vegetable oil and is not safe to swallow. However, biodiesel is considered biodegradable, so it is considered to be much less harmful to the environment if spilled. Biodiesel also has been shown to produce lower tailpipe emissions than regular fuel. The best thing about biodiesel is that it is made from plants and animals, which are renewable resources.

Energy balance is basically the difference between the energy produced (biodiesel, ethanol, etc.) and the energy necessary to produce it (transportation, refining, etc.). The net energy gain is defined as the difference between the energy in the fuel product (output energy) and the energy needed to produce the product (input energy).

Estimated net energy gain for corn ethanol is between 25 percent and 35 percent. Further improvements in agricultural practices and ethanol plants should increase the net energy gain to 47 percent in the near future. Using these calculations, a better, fairer assessment can be made about how these alternative fuels relate to each other in actual cost. In later articles, we will discuss the energy balance of all these fuels.

Editor's Note: This article is the introductory article to alternative fuels. More details and actual examples will be covered in later issues of AutoInc. Don't miss a three-hour class discussion (to include case studies of each fuel) at the Congress of Automotive Repair and Service show in Las Vegas in November. For details, visit

Types of Alternative Fuel

Alternative fuels are fuels that aren't made from petroleum. There are many different kind of fuels that vehicles can use that aren't made from petroleum. The U.S. Department of Energy identifies "alternative fuels" as the following:

  • Alcohols - ethanol and methanol
  • Compressed natural gas (CNG) - natural gas under high pressure
  • Electricity stored in batteries
  • Hydrogen (considered a special gas)
  • Liquefied natural gas (LNG) - natural gas that is very cold
  • Liquefied petroleum gas (LPG) - called propane, it is hydrocarbon gas under low pressure
  • Liquids made from coal - gasoline and diesel fuel that isn't made from petroleum
  • Biodiesel - diesel fuel made from plant oil or animal fat

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