Natural gas is comprised mostly of methane which is commonly captured in geologic deposits, such as shale, and from renewable sources such as landfills, wastewater, and agriculture/dairy operations. It is transported to South Carolina through interstate pipelines and compressed or liquified to obtain greater volumetric storage capacity. Many South Carolinians use natural gas every day to cook and heat their homes, but using natural gas in vehicles has proven benefits too. Natural gas is one of the most abundant fossil fuels found in the US. Natural gas, when extracted, is an odorless and colorless gas. To provide added protection, public safety regulations dictate natural gas companies to add an odorizer called mercaptan. This common nose-wrinkling rotten egg smell helps individuals realize gas leaks well below explosive levels and contact the appropriate authorities. Utilizing natural gas for transportation can lower tailpipe emissions, reduce dependence on foreign oil, and boost economic development.
There are light-, medium-, and heavy-duty natural gas vehicles available from original equipment manufacturers, as well as medium- and heavy-duty vehicle options available through qualified system retrofitters. Qualified system retrofitters can convert many vehicles for natural gas operation with aftermarket conversion systems. These aftermarket conversion systems allow the vehicle to operate on natural gas alone or in a dual-fuel or bi-fuel basis with gasoline or diesel. For a listing of vehicle conversion systems, visit the Alternative Fuels and Advanced Vehicles Data Center.
Compressed natural gas (CNG) and liquefied natural gas (LNG) are considered alternative fuels under the Energy Policy Act of 1992. Adsorbed natural gas (ANG) is also an emerging technology for natural gas use in transportation. Sources of natural gas include fossil natural gas and renewable natural gas (RNG).
Find a CNG or LNG fueling station near you.
Fuel Options for Natural Gas Vehicles
Compressed Natural Gas
The use of compressed natural gas, or CNG, as an alternative fuel can reduce emissions of nitrous-oxide, carbon dioxide, particulate matter, and hydrocarbons. Natural gas vehicles (NGVs) use a spark-ignited engine, similar to conventional gasoline-fueled vehicles and have a fuel system designed for natural gas fuel. This means maintenance costs are relatively cheap compared to diesel engines. Historically per unit, CNG costs less than gasoline and diesel and is very stable compared to the high volatility of gasoline and diesel prices.
Learn more about CNG as an alternative fuel.
Learn more about how the outside temperature and fill speeds affect the final volume in CNG vehicle tanks.
Adsorbed Natural Gas
Activated carbon adsorbents for adsorbed natural gas, or ANG, allows natural gas to be stored at lower compression pressures compared to traditional CNG, without adsorbents, at the same pressure. The operating pressure for ANG technology is 900 PSI instead of the traditional 3,600 PSI. Significant savings can be found in the use of ANG rather than LNG or CNG due to the lower cost of tanks and compression. ANG vehicles emit a reduced amount of hydrocarbons, carbon dioxide, and nitrous-oxides from their exhausts.
Learn more from Ingevity, a South Carolina-based company developing ANG
Liquefied Natural Gas
Liquefied natural gas, or LNG, is natural gas that has been super-cooled and cryogenically stored in liquid form for easier and safer non-pressurized storage and transport. Heavy-duty LNG vehicles work much like gasoline-powered vehicles with a spark-ignited internal combustion engine. LNG is usually stored in a light and fuel-efficient tank on the side of heavy-duty trucks, making it ideal for Class 7 and 8 trucks carrying heavy loads and travelling long distances. In comparison to CNG, LNG is typically more expensive, but it has a greater energy density, so more fuel can be stored on the vehicle. This alternative fuel can also be utilized in rail, marine, and off-road vehicles.
Learn more about LNG as an alternative fuel.
Learn more about the key components of an LNG heavy-duty truck.
Sources of Natural Gas
Fossil Natural Gas
The vast majority of natural gas in the United States is considered a fossil fuel because it is made from sources formed over millions of years by the action of heat and pressure on organic materials. Natural gas is commonly extracted from geological deposits through conventional or unconventional methods. The most prolific method is unconventional extraction such as hydraulic fracturing (fracking); producing about 75 percent of United States dry gas in 2019. This method involves drilling into gas-rich layers of sedimentary rock such as shale or sandstone. Water and chemicals are then pumped through the borehole to expand and fracture the porous rock. Methane and other gases are then collected through the flowback of water and gas. Once the raw gas is collected, cleaned, and conditioned to meet natural gas pipeline quality specifications, it can be used within natural gas vehicles.
Natural gas can also be extracted as a by-product of crude oil extraction. In conventional natural gas deposits, the natural gas generally flows easily up through wells to the surface. While involving a borehole, conventional drilling employs a singular well head that goes vertically down. Hydraulic fracturing can house multiple boreholes in one well head that span multiple miles horizontally.
Learn more about hydraulic fracturing
Renewable Natural Gas
Renewable natural gas, or RNG, is the cleanest and lowest carbon natural gas alternative, according to the California Air Resources Board’s (CARB) Low Carbon Fuel Standard program. Using RNG as a transportation fuel can reduce a vehicle’s life-cycle greenhouse gas emissions by 382 percent compared to diesel.
Rather than fossil extraction for natural gas supplies, RNG can be collected from local landfills, wastewater treatment plants, food waste facilities, and agricultural digesters. After engine retrofits and the installation of typical natural gas fueling infrastructure, vehicles can operate using RNG lower than the cost of traditional diesel. Once the raw gas is collected, cleaned, and conditioned to meet natural gas pipeline quality specifications, it can act as a direct substitute for CNG or LNG vehicle fuel. Fleets that already use CNG or LNG can switch to RNG with no additional capital investments. When used as a vehicle fuel, RNG vapor emissions meet the standards of states with strict GHG pollution requirements, and they potentially provide the lowest EER-adjusted well-to-wheel carbon intensity of any on-road motor fuel, including electricity.
Learn more about how RNG is produced.