Compressed Natural Gas (CNG)

CNG is found in underground reserves and is stored as a compressed gas. It is used in many types of vehicle classes. CNG vehicles demonstrate a reduction in ozone-forming emissions (CO and NOx) compared to some conventional fuels. CNG is domestically produced and extracted from the United States' vast natural gas reserves. More than 1,100 CNG stations can be found across the country and California has the highest concentration of CNG stations. Additionally, home fueling is now available through a product from FuelMaker called Pfill. High-pressure tanks require periodic inspection and certification, but these tanks are safe and have been designed to withstand severe impact, high external temperatures, and automotive environmental exposure.

Propane (LPG)

Liquefied petroleum gas (LPG) consists mainly of propane, propylene, butane, and butylene in various mixtures. However, in the United States, the mixture is mainly propane. It is produced as a by-product of natural gas processing and petroleum refining. The components of LPG are gases at normal temperatures and pressures. LPG is a by-product from two sources: natural gas processing and crude oil refining. Most of the LPG used in the United States is produced domestically. When natural gas is produced, it contains methane and other light hydrocarbons that are separated in a gas processing plant. Because propane boils at -44°F and ethane boils at -127°F, it is separated from methane by combining increasing pressure and decreasing temperature. The natural gas liquid components recovered during processing include ethane, propane, and butane, as well as heavier hydrocarbons. Propane and butane, along with other gases, are also produced during crude refining as by-products of the processes that rearrange or break down molecular structure to obtain more desirable petroleum compounds.

Liquified Natural Gas (LNG)

LNG (Liquefied Natural Gas) is stored as a liquid and used in medium and heavy-duty trucks and buses. LNG vehicles can demonstrate a reduction in ozone-forming emissions (CO and NOx) compared to conventional fuels. LNG is domestically produced and it typically costs less than gasoline and diesel fuels. Public LNG stations are limited (only 35 nationally), but LNG is available through several suppliers of cryogenic liquids. High-pressure tanks require periodic inspection and certification and cryogenic fuels require special handling procedures and equipment to properly store and dispense.

Biodiesel

Biodiesel is created from soy bean oil, waste cooking oil, animal fats, and rapeseed oil. Its energy ratio compared to gasoline is 1.1 to 1 or 90% (relative to diesel). This fuel is designed to run in any vehicle that runs on diesel today-no modifications are needed for up to 5% blends. Many engines are also compatible with up to 20% blends. The environmental impact of this fuel is reduced overall, due to lower levels of particulate matter and global warming gas emissions compared to conventional diesel. Biodiesel is domestically produced and has a fossil energy ratio of 3.3 to 1, which means that its fossil energy inputs are similar to those of petroleum. It is available in bulk from an increasing number of suppliers currently there are 22 states that have some biodiesel stations available to the public. It is less toxic and more biodegradable than conventional fuel, and can be transported, delivered, and stored using the same equipment as for diesel fuel.

Ethanol

Ethanol (E85) is produced from corn, grains, or agricultural waste. It is used in light-duty vehicles, medium and heavy-duty trucks and buses. E-85 vehicles can demonstrate a 25% reduction in ozone-forming emissions (CO and NOx) compared to reformulated gasoline. Ethanol is produced domestically and it is renewable. Most of the E-85 fueling stations are located in the Midwest, but in all, approximately 150 stations are available in 23 states. Special lubricants may be required, but practices are very similar, if not identical, to those for conventionally fueled operations. In accidents, ethanol is less dangerous than gasoline because its low evaporation speed keeps alcohol concentration in the air low and non explosive.

Electricity

Electricity is primarily created from coal, but nuclear, natural gas, hydroelectric, and renewable resources can also be used. It is currently used in neighborhood electric vehicles (EV's), bicycles, light-duty vehicles, medium and heavy-duty trucks and buses. EV's have zero tailpipe emissions and electricity is generated mainly through coal fired power plants. Coal is the United States' most plentiful fossil energy resource and our most economical and price-stable fossil fuel. Most homes, government facilities, fleet garages, and businesses have adequate electrical capacity for charging, but, special hookup or upgrades may be required. Service requirements are expected to be reduced. However, the batteries must be replaced every 3-6 years. OEM EVs meet all the same vehicle safety standards as conventional vehicles.

Hydrogen

Hydrogen (for use in fuel cells) is created from natural gas, methanol, and other energy sources - the process of extracting water from hydrogen is currently being evaluated. No vehicles are available for commercial sale yet, but some vehicles are being leased for demonstration purposes. There are zero regulated emissions for fuel cell-powered vehicles, and only NOx emissions are possible for internal combustion engines operating on hydrogen. Hydrogen can help reduce U.S. dependence on foreign oil by being produced by renewable resources. There are only a small number of hydrogen stations across the country and most are available for private use only. When hydrogen is used in fuel cell applications, maintenance should be very minimal. Hydrogen has an excellent industrial safety record; codes and standards for consumer vehicle use are under development.