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Vehicle Basics Heavy-duty NGVs for long-haul fleets that operate along a route with Natural gas powers about 175,000 fueling stations. Photo from Saturn Lounge Photography, NREL 28496 U.S. vehicles and more than 23 million vehicles worldwide.1 Natural gallons of LNG contains the regulations, including Federal Motor gas vehicles (NGVs) are a good equivalent of a gallon of . Vehicle Safety Standards (FMVSS). choice for high-mileage (high -use) Compared to gasoline and , fleets—such as , medium- How and where is natural gas natural gas has a higher autoignition and heavy-duty , and refuse produced and distributed? temperature, so it takes significantly vehicles—that are centrally fueled Most natural gas is drawn from wells more for the fuel to ignite without or operate within a limited area or or extracted in conjunction with crude oil a flame or spark. This makes uninten- along a route with natural gas fueling production. U.S. production of natural tional ignition less likely. In addition, because it is lighter than air, natural stations. The advantages of natural gas has increased significantly in recent gas dissipates quickly. gas as an include years. Most U.S. natural gas is produced in . The United States its domestic production, established NGV fuel tanks are strong and extremely has a vast distribution system, which distribution network, relatively low puncture resistant, and they undergo can quickly and economically distribute testing according to stringent standards. cost, and emissions benefits. natural gas to and from most locations in Once in use, they must be inspected in the lower 48 states. What is natural gas? a qualified facility every three (RNG), or years (36 months) or 36,000 miles, Natural gas is an odorless, gaseous 4 biomethane, is produced from decaying whichever comes first. The National mixture of —predominantly organic materials like municipal solid Protection Association, U.S. Department (CH ). The fuel is widely used 4 waste from , from waste- of Transportation, and other organizations for heating and cooking, treatment , animal , or provide these and other safety guidelines production, and industrial use. Although waste. After impurities are removed, for NGVs, as well as for fueling equip- it is a proven, reliable alternative fuel that 5 the gas is ready for use in vehicles or for ment. A list of applicable codes and has long been used to power vehicles, distribution through existing pipelines. standards is available on the AFDC less than 1% of natural gas is currently RNG qualifies as a renewable fuel under (afdc.energy.gov/pdfs/48611.pdf). used this way.2 Because it is a gas, it the federal Renewable Fuel Standard must be stored on board a vehicle in (RFS) and a low- fuel under 1 either a compressed or liquefied state. In “NGVAmerica – Vehicles.” Accessed January 2020. California’s Low Carbon Fuel Standard. www.ngvamerica.org/vehicles. the United States, (CNG) is typically stored in a tank at a In 2018, more than 305 million gasoline- 2 “Natural Gas Consumption by End Use,” U.S. Energy Information Administration. Accessed January 2020. pressure of 3,600 pounds per square inch. gallon equivalents of RNG received www.eia.gov/dnav/ng/ng_cons_sum_dcu_nus_a.htm. credits under the RFS.3 This constitutes (LNG) is super- 3 “Spreadsheet of RIN Generation and Renewable Fuel significant progress toward renewable Volume Production by Fuel Type for the Renewable cooled and stored in its form at goals, despite the fact that RNG produc- Fuel Standard,” U.S. Environmental Protection −260°F in insulated tanks. Because liquid tion is still a small fraction of estimated Agency. Accessed January 2020. www.epa.gov/ is denser than gas, more energy can be -registration-reporting-and-compliance-help/ potential. Learn more about RNG on the spreadsheet-rin-generation-and-renewable-fuel-0. stored by volume. This makes LNG Alternative Fuels Data Center (AFDC) favorable for trucks that need a longer 4 U.S. Department of Transportation, National Highway (afdc.energy.gov/rng). Traffic Safety Administration, Compressed Natural Gas driving range. CNG is sold in units of Fuel Container Integrity, 49 C.F.R. 571.304 (Oct. 1, 2011). gasoline- or diesel-gallon equivalents, Are NGVs safe? 5 “NFPA 52: Vehicular Natural Gas Fuel Systems which is based on the energy content of Just like conventional vehicles, NGVs Code,” National Association. Accessed a gallon of gasoline or diesel fuel. LNG January 2020. nfpa.org/codes-and-standards/all- must comply with all applicable codes-and-standards/list-of-codes-and-standards/ is sold as a liquid gallon, where 1.5 detail?code=52. engines are traditionally limited to Purchasing new vehicles heavy-duty applications and can be more To find available OEM NGVs and fuel-efficient than their spark-ignited, engines, see the AFDC Vehicle Search dedicated counterparts. A dual-fuel (afdc.energy.gov/afdc/vehicles/search) system is more complex, requiring or the Natural Gas Vehicles for America diesel exhaust aftertreatment and onboard (NGVAmerica) Vehicle Availability page storage of both types of fuel at all times (ngvamerica.org/vehicles/availability). (whereas bi-fuel vehicles can operate on either fuel exclusively). A variety of In some cases, buyers can order OEM -, medium-, and heavy-duty NGVs models with gaseous-fuel “prep pack- CNG vehicles are fueled with easy- are available and suitable for various ages,” which allow a qualified system to-use, pressure-sealed fueling applications. Buyers can purchase retrofitter or vehicle modifier (QSR or dispensers. Photo by Dennis Schroeder, vehicles through OEM dealerships or QVM) to install the EPA- or CARB- NREL 48723 have in-service vehicles converted. certified fuel delivery system before the vehicle is delivered to the customer. Considerations for CNG tanks How well do NGVs perform? Converting in-service vehicles When purchasing a CNG vehicle, NGVs are similar to gasoline or diesel customers should be mindful of the vehicles with regard to power, accel- Owners should insist upon an EPA- or FMVSS inspection requirements and eration, and cruising speed. Natural CARB-certified system when converting the useful life of the fuel tanks. For used gas has a higher octane number vehicles. System manufacturers may vehicles, it is important to know when than gasoline (120+ compared to 84–93 perform the conversion themselves the fuel tanks were last inspected, the for gasoline), and some OEMs offer or closely with a QSR/QVM. A expiration date, if the vehicle has been in dedicated engines optimized to take well-qualified QSR/QVM will have an accident, and whether the tanks were advantage of this higher rating.6 This can established procedures and technical inspected after. CNG tanks have a useful result in improved performance and fuel training for the installation process, as life of 15, 20, or 25 years, depending on economy over nonoptimized engines. well as best practices. It is important how they were certified by the original The driving range of NGVs is generally to understand these and ask to review equipment manufacturer (OEM). All less than that of comparable gasoline and documentation on emissions compli- CNG tanks carry a label with the expira- diesel vehicles because with natural gas, ance as well as the conversion practices, tion date. This date may also be found on less overall energy content can be stored procedures, warranty, and training. a label near the fueling connector and on in the same size tank. Extra natural gas the label under the hood of the vehicle. storage tanks or the use of LNG can help How much do NGVs cost? increase range for larger vehicles. The of an NGV is higher than Types of NGVs available that of a comparable conventional fuel There are three types of NGVs: How can I find reliable and vehicle; however, NGVs can provide EPA-compliant vehicles? an acceptable return on investment • Dedicated vehicles are designed to run (ROI) for many fleets because of fuel All NGVs must be certified to meet only on natural gas. cost savings. NGVs can cost thousands U.S. Environmental Protection Agency of dollars more than comparable gaso- • Bi-fuel vehicles have two separate (EPA) or California Air Resources Board line- or diesel-powered vehicles. The fueling systems that enable them to run (CARB) emissions standards. For a list price depends on the fuel tank capacity, on either natural gas or gasoline. This of EPA-certified conversion systems number of tanks required, and whether extends overall vehicle range by adding and engines, see the EPA website (epa. the vehicle is purchased new from an the distance that can be driven on each gov/vehicle-and-engine-certification/ OEM or is an in-service vehicle that has fuel separately. lists-epa-compliant-alternative-fuel- been converted. The maintenance and conversion-systems). Consult the • Dual-fuel vehicles use natural gas operation costs are similar to those of Conversions page blended with some diesel fuel for their gasoline or diesel counterparts.7 and the publication What Fleets Need ignition assistance, allowing them For dedicated NGVs, maintenance costs to operate much like conventional to Know About compression-ignition (e.g., diesel) Conversions, Retrofits, and Repowers on the AFDC for additional information on engines. 6 “AFDC Fuel Properties Comparison,” Alternative Fuels conversions (afdc.energy.gov/vehicles/ Data Center. Accessed January 2020. afdc.energy.gov/ Light-duty vehicles are typically config- natural_gas_conversions.html). fuels/fuel_properties.php. ured as dedicated or bi-fuel models, and 7 “Alternative Fuel Life-Cycle Environmental and heavy-duty vehicles are configured as Economic Transportation (AFLEET) Tool 2018,” dedicated or dual-fuel models. Dual-fuel Argonne National Laboratory. afleet-web.es.anl.gov/ afleet.

2 can be significantly lower because they do not require complicated exhaust Average Fuel in the United States aftertreatment systems. Fleet managers 4 will also need to consider both the cost of fueling infrastructure, if they do not have access to existing fueling sites, and the potential cost of any upgrades 2 that may be required to their garage/

shop facilities. For more information, Dollars per GGE Gasoline Diesel CNG see the publication Compressed Natural 0 Gas Vehicle Maintenance Facility Apr. 2000 Feb. 2003 May 2006 Oct. 2008 Oct. 2010 Sep. 2012 Oct. 2014 Oct. 2016 Oct. 2018 Modification Handbook (afdc.energy.gov/ cng-handbook). Date of Report Tax credits and other incentives may also be available to help reduce costs. Figure 1. Average retail fuel prices in the United States for gasoline, CNG, and diesel in dollars per gasoline gallon equivalent (GGE). Source: AFDC Average Retail Fuel Prices in Is it easy to fuel an NGV? the United States, afdc.energy.gov/data/10326. CNG vehicles are fueled with easy-to- use, pressure-sealed dispensers. The time Public fueling stations A time-fill CNG station can range in it takes to fill a tank depends on several There are more than 1,000 public natural cost from tens to hundreds of thousands factors, including how the fueling station gas stations across the United States, of dollars, while a fast-fill station may is configured. Time-fill stations fuel including more than 900 offering CNG cost up to several million dollars for vehicles automatically overnight, taking and more than 50 offering LNG. To find large and fleets. For more advantage of smaller, less expensive stations in your area, visit the Alternative information, refer to Costs Associated compression equipment. Fast-fill stations Fueling Station Locator or download with Natural Gas Vehicle Fueling fill vehicles rapidly using larger compres- the Station Locator mobile app from the Infrastructure.8 sion equipment and high-pressure gas- AFDC (afdc.energy.gov/stations). Fleet LNG fueling station costs are highly vari- storage systems. Ambient air temperature managers are often able to negotiate and fill speed also affect the final fill able, ranging from one to several million long-term competitive or bulk pricing dollars.7 Costs are dependent on factors volume in CNG vehicle tanks. See an with natural gas fuel suppliers. interactive animation on the AFDC such as storage capacity, station design, (afdc.energy.gov/cng-animation). and the services needed to build it. All Private fueling stations infrastructure must comply with local LNG stations operate similar to gasoline Fleet managers planning to use a high codes and standards, and it’s important and diesel stations because they deliver volume of fuel may consider building to involve the local authority having to the station via trucks. a fueling station to serve their needs. jurisdiction early in the process. Fueling LNG vehicles requires specific CNG stations are typically located near procedures, training, and protective existing natural gas pipeline infrastruc- How do I calculate the ROI equipment, but the process is not difficult. ture, whereas LNG is transported and for NGVs? delivered to stations via tanker truck As with all vehicles, proper safety The ROI associated with NGVs depends precautions must be taken. much like gasoline and diesel fuel. Stations may be private access, shared on a variety of factors. Because natural or open to multiple fleet customers, or gas is often less expensive than gasoline How much does natural available to the general public. and diesel, fleets with higher vehicle gas fuel cost and where mileage (higher fuel use) will experi- is it available? For current price information, refer ence shorter payback periods. Payback to the Alternative Fuel Price Report is therefore linked to fleet size and type. Historically, the average retail price of (afdc.energy.gov/fuels/prices.html). Tax credits and other incentives may natural gas has been lower and more also be available to help reduce the stable than that of gasoline and diesel How much does it cost cost of natural gas fuel, vehicles, and (see Figure 1). This makes natural gas a good option for fleets that use large to install a natural gas amounts of fuel. Fleet managers should fueling station? 8 Margaret Smith and John Gonzales, “Costs Associated with Compressed Natural Gas Vehicle Fueling carefully consider their options when The cost of installing natural gas infra- Infrastructure, DOE/GO-102014-4471,” U.S. Department deciding whether to build a private structure varies based on size, capacity, of Energy Office of Energy Efficiency and Renewable fueling station or use public fueling sites. Energy, 2014. afdc.energy.gov/files/u/publication/ and the type of natural gas it dispenses. cng_infrastructure_costs.pdf.

3 Fuel Tank (compressed natural gas)

Electronic Control Module (ECM)

Internal Engine (spark ignited) Pressure Relief Valve

Fuel Injection System Pressure Gauge Fuel Filler

Fuel Filters Fuel Line

This illustration shows a typical heavy-duty, Class 8 CNG truck. The various components of the CNG fuel system are highlighted. Illustration by Josh Bauer, NREL infrastructure, thereby shortening the controls. According to Argonne payback . For more information, National Laboratory’s Greenhouse contact your local Clean coalition , Regulated Emissions, and Energy (cleancities.energy.gov/coalitions) and use in Transportation (GREET) model, see the AFDC Federal and State Laws light-duty vehicles running on natural and Incentives section (afdc.energy. gas can reduce lifecycle greenhouse gov/laws). gas emissions by 11% (83% if running on RNG). In addition, because CNG Two helpful tools include the Alternative fuel systems are completely sealed, the Fuel Life-Cycle Environmental and vehicles produce no evaporative emis- Economic Transportation (AFLEET) Tool sions. For details, see the AFDC Natural (greet.es.anl.gov/afleet), which estimates Gas Vehicle Emissions page (afdc.energy. Technical Response Service use, emissions, and cost of gov/ng-emissions). 800-254-6735 • [email protected] ownership of light-duty and heavy-duty vehicles for a variety of fuels; and the Prepared by the National Vehicle and Infrastructure Cash-Flow Where can I learn more Laboratory (NREL), a National Laboratory of the U.S. Department of Energy, Office of Energy Evaluation (VICE) model (afdc.energy. about natural gas? Efficiency and Renewable Energy; NREL is oper- gov/vice_model), which can be used to To learn more about natural gas as ated by the Alliance for , LLC. evaluate ROI and payback period for a transportation fuel, visit the AFDC both NGVs and infrastructure. Natural Gas Fuels and Vehicles pages (afdc.energy.gov/fuels/natural_gas.html). How do NGV emissions You can also contact your local Clean compare with gasoline and Cities coordinator (cleancities.energy. gov/coalitions) or visit the NGVAmerica diesel vehicle emissions? website (ngvamerica.org). For NGV case Tailpipe emissions from new NGVs (or studies, see the AFDC Case Studies page any new alternative fuel vehicles) are (afdc.energy.gov/case). comparable to those of gasoline and For more information, visit: diesel vehicles from the same model afdc.energy.gov year equipped with modern emissions DOE/GO-102020-5247 • March 2020

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