There are many different types of Alternative Fuels available. Some, like E10 or B5, which are traditional fuels blended with low amounts of ethanol or biodiesel, do not require major engine changes. Other fuels, like compressed natural gas and electricity, require special vehicles designed to use them.  Below are some examples of alternative fuels.

• Biodiesel

  Biodiesel is a replacement diesel fuel that is made from renewable sources such as animal fats and vegetable oils. It is a liquid fuel that is typically mixed with conventional petroleum diesel fuel for use in diesel engines. Biodiesel exhibits excellent fuel properties for diesel engines and thus offers significant potential as a diesel fuel blending stock. When blended with petroleum based diesel, the percentage of biodiesel is specified following the letter “B”. So, B5, a common blend level, contains 5% biodiesel and 95% petroleum diesel. Other commonly available blends include B10, B20, and B100, pure biodiesel!

• Electricity

  Electricity can be used as a transportation fuel to power battery electric and fuel cell vehicles. When used to power electric vehicles or EVs, electricity is stored in an energy storage device such as a battery. EV batteries have a limited storage capacity and their electricity must be replenished by plugging the vehicle into an external electrical source. The electricity for recharging the batteries can come from the existing power grid or from distributed renewable sources such as solar or wind energy. Additionally, electric and hybrid vehicles use regenerative braking. This technology engages a generator when the brakes are applied, using some of the kinetic energy of the vehicle to recharge the battery , and slowing the vehicle down at the same time.

• Ethanol

  Ethanol, a clear, colorless liquid, is an alcohol-based alternative fuel produced by fermenting and distilling starch crops that have been converted into simple sugars. Ethanol can be used at low blend levels in most gasoline engines.  The use of higher blend levels requires modifications to the fuel delivery system unless the vehicle was produced as a Flex Fuel vehicle by the manufacturer. Like biodiesel, ethanol blends use the letter “E” followed by a number to specify the amount of ethanol blended with regular gasoline. E10 contains 10% ethanol and 90% gasoline. Blends up to E85, 85% ethanol and 15% gasoline, are available. Ethanol is most commonly used as an additive (up to E10) to increase octane and improve the emissions quality of gasoline. In fact, most of the gasoline sold in Maryland contains 10% ethanol.

• Hydrogen

  Hydrogen gas (H₂) is the simplest and lightest fuel. Hydrogen exists in a gaseous state at atmospheric pressure and ambient temperatures. Hydrogen gas may contain low levels of carbon monoxide and carbon dioxide, depending on the production source. Hydrogen is being explored for use in combustion engines and fuel cell electric vehicles. On a volumetric basis, the energy density of hydrogen is very low under ambient conditions. This presents greater transportation and storage hurdles than for liquid fuels. Vehicle storage systems being developed include compressed hydrogen, liquid hydrogen, and physical or chemical bonding between hydrogen and a storage media (for example, metal hydrides). Hydrogen vehicles are only available in a few select areas for small pilot programs.

• Natural Gas

  Natural Gas is a mixture of hydrocarbons—mainly methane (CH₄)—and is produced either from gas wells or in conjunction with crude oil production. Natural gas is consumed in the residential, commercial, industrial, and utility markets. Use of natural gas in a variety of markets means there is already an infrastructure in place for processing and delivery. The interest in natural gas as an alternative fuel stems mainly from its clean burning qualities, its domestic resource base, and its commercial availability to end users. Because of the gaseous nature of this fuel at ambient conditions, it must be stored onboard a vehicle in either a compressed gaseous state (CNG) or in a liquefied state (LNG) to provide sufficient fuel storage for reasonable driving range. According to Energy Information Association, estimates place our domestic supply of natural gas at more than 50 years assuming current consumption rates.

• Propane

  Propane or liquefied petroleum gas (LPG) benefits from an extensive 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. Propane is a colorless paraffin gas that is compressible to a liquid for safe transport in inexpensive containers. According to the Gas Processors Association’s HD5 specification for Liquefied Petroleum Gas as a transportation fuel, LPG must consist of 90% propane, no more than 5% propylene, and 5% other components (primarily butane and butylene). Propane is produced as a by-product of natural gas processing and petroleum refining. The components of LPG are gases at normal temperatures and pressures.

• Alternative Fuel Comparison Charts

To locate Alternate Fuel Refueling facilities in Maryland please visit the US DOE Website to search by location and fuel type. 

Contact Information

For more information please contact Tim Shepherd at (410) 537-3270 or email tim.shepherd@maryland.gov.​