Natural Gas

Light-duty natural gas internal combustion engine vehicles are typically dedicated natural gas or bi-fuel vehicles that use either natural gas or gasoline. The acceleration, horsepower, and cruise speed of natural gas vehicles and similar models of conventional vehicles are comparable, but natural gas vehicles generally have a shorter driving range because natural gas has a lower energy density (DOE, 2019). For additional background, see the Alternative Fuels Data Center's Natural Gas Vehicles.

On this page, explore key cost and performance metrics for natural gas internal combustion engine vehicles, including vehicle cost, fuel economy, levelized cost of driving, and emissions. Caveats for comparing powertrains are listed in the Light-Duty Vehicle Comparison page.

Fuel Economy

The chart below shows fuel economy, which depends on fuel type. Fuel economy is also used to calculate levelized cost of driving.

Vehicle Cost

The chart below shows vehicle cost, which is used to calculate levelized cost of driving.

Levelized Cost of Driving

This chart shows levelized cost of driving, a metric that combines vehicle cost, fuel economy, and other assumptions, for the selected fuel.

Notes:

• The levelized cost of driving includes initial costs for the vehicle, fuel costs, and, if applicable, residential charger equipment and installation. It does not include other operations or maintenance costs beyond fuel, or insurance.
• Changes over time are attributable only to projected vehicle cost and performance; the fuel cost and emissions are constant over time based on the selected fuel.

CO2e Emissions

The chart below shows CO₂ equivalent greenhouse gas emissions for the fuel well-to-wheels portion of the life cycle for the selected fuel. Emissions depend on fuel type and fuel economy. Emissions associated with vehicle life cycles are not included here.

Note: Changes over time are attributable only to projected vehicle cost and performance; the fuel cost and emissions are constant over time based on the selected fuel.

Key Assumptions

The data and estimates presented here are based on the following key assumptions:

• The assumptions about fuel economy improvements reflect adoption of lightweighting and engine efficiency technologies consistently across vehicle powertrains for a given trajectory. The cost and fuel economy trajectories are based on the analysis-year Autonomie modeling results for the Conventional Turbo powertrain from Islam et al. (Islam et al., 2020). The ATB Advanced trajectory corresponds to the Base performance, High technology progress case. The ATB Mid trajectory corresponds to the Base performance, Low technology progress case. The ATB Constant trajectory is set to the 2020 values in the Base performance, Low technology progress case and held constant through 2050.
• The estimates from Islam et al. (Islam et al., 2020), and those shown here, represent costs and technology performance at high production volume. Natural gas internal combustion engine vehicles are manufactured at high volume today, and the high-volume estimates should therefore reflect the current state of technology.
• The Transportation ATB presents estimates for a representative, single size of light-duty vehicle (midsize); we do not account for variations in make, model, and trim or for pricing incentives or geographic heterogeneity that influence prices in the market. As a result, representative values shown here may differ from specific models available on the market.
• Advancements in natural gas fuel tank costs contribute to the total cost reductions seen in natural gas internal combustion engine vehicles. Based on Islam et al. (Islam et al., 2020), fuel tank manufacturing costs decrease by $2,500 and $3,400 in the Mid and Advanced trajectories, respectively (which correspond to $3,700 and $5,100 decreases in the purchase cost equivalent shown in the charts above). Fuel tank cost reductions are based on technology advancments, but also improved efficiency requiring lower fuel tank volume.
• Technology advances include changes that may reduce costs or may increase costs while improving performance, which implies that costs do not always decline between less- and more-advanced scenarios.
• Vehicle cost trajectories may exhibit non-monotonic behavior resulting from the combination of advanced technology costs and the impact on engine efficiency. For example, while the engine cost might increase over time due to advanced technologies, the overall engine power required decreases over time due to lightweighting, improved aerodynamics, etc. As a result, while per unit of power engine costs might go up, lower engine power requirements decrease the total engine cost.
• The baseline fuel pathway used for this powertrain in the levelized cost of driving and emissions estimates is natural gas (market). Additional information can be found on the Natural Gas page.
• The fuel price and emissions of the selected fuel pathways (e.g., Baseline, Lowest Cost, Lowest Emissions) are associated with a single year. Because we do not provide a time-series trajectory, here we show fuel price at a frozen level for all years so we can offer a range of fuel price values. In the levelized cost of driving and emissions charts, this approach clearly distinguishes effects of fuels from those of vehicle technologies, because fuels remain constant while vehicle technologies change over time.
• The Transportation ATB assumes the fuel economy (on an miles per gallon gasoline equivalent basis) remains constant when operating on substitutable fuels (e.g., conventional E10 gasoline versus reformulated E15 gasoline). In reality, fuel composition may affect engine performance.
• The vehicles modeled in Autonomie in Islam et al. (Islam et al., 2020)include multiple transmission options. The table below shows the transmission technology and number of gears selected from the model results for the ATB trajectories. The ATB Constant trajectory corresponds to the 2020 values in ATB Mid. Values for 2040 and 2045 are interpolated based on 2035 and 2050 values.

Transmission Technology and Gears from Autonomie Modeling Selected for ATB Trajectories

• The data downloads include additional detail on assumptions and calculations for each metric.

Definitions

For detailed definitions, see:

Emissions

Fuel economy

Levelized cost of driving

Scenarios

Vehicle cost

References

The following references are specific to this page; for all references in this ATB, see References.