What is 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 (NO_x) 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.

How is Natural Gas Made?

Most natural gas consumed in the United States is domestically produced. Gas streams produced from reservoirs contain natural gas, liquids, and other materials. Processing is required to separate the gas from petroleum liquids and to remove contaminants. In addition, natural gas (methane) can also come from landfill gas and water/sewage treatment.

First, the gas is separated from free liquids such as crude oil, hydrocarbon condensate, water, and entrained solids. The separated gas is further processed to meet specified requirements. For example, natural gas for transmission companies must generally meet certain pipeline quality specifications with respect to water content, hydrocarbon dewpoint, heating value, and hydrogen-sulfide content.

A dehydration plant controls water content; a gas processing plant removes certain hydrocarbon components to hydrocarbon dewpoint specifications; and a gas sweetening plant removes hydrogen sulfide and other sulfur compounds (when present).

Natural Gas 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 NO_x relative to commercial diesel engines.