Definitions 

Definitions of common terms in the 2022 Transportation ATB are presented below.

Vehicles

Battery electric vehicles (BEVs) use a battery pack to store the electrical energy that powers the motor. The batteries are charged by plugging the vehicle into an electric power source (DOE, 2019). For additional background, see the Alternative Fuels Data Center's All-Electric Vehicles webpage.

The battery cost assumptions used in the Annual Technology Baseline modeled vehicle price trajectories are shown below and are presented at the battery pack level. Battery costs are shown in constant 2020 dollars per unit of total rated capacity. Please refer to Islam et al. (Islam et al., 2022) for further detail and assumptions about battery performance, energy density, chemistry, and retail price equivalency.

The ATB Mid trajectory corresponds with the Base performance, Low technology progress case in Islam et al. (Islam et al., 2022), which reaches $70/kilowatt-hour in 2050. The ATB Advanced trajectory follows the Base performance, High technology progress case, which reaches around $60/kilowatt-hour in 2050. The ATB Constant trajectory is held constant at the 2022 value for the ATB Mid case. 

 See the Diesel Internal Combustion Engine Vehicle page.

Fuel cell electric vehicles (FCEVs) use fuel cells for energy conversion, which are more efficient than internal combustion engines. FCEVs use hydrogen as the power source, convert the hydrogen to electricity, and emit water vapor and warm air, with no other tailpipe emissions. FCEVs and the supporting hydrogen fueling infrastructure are in an early deployment stage (DOE, 2019). For additional background, see the Alternative Fuels Data Center's Fuel Cell Electric Vehicles webpage.

The fuel cell and hydrogen storage cost assumptions used in the Transportation ATB modeled vehicle price trajectories are shown below. The fuel cell costs and hydrogen storage vessel costs shown include an assumption of low-volume manufacturing today that gradually increases to high production volume manufacturing of these devices. Specific assumed manufacturing volumes for each scenario are below and are based on James et al.  (James et al., 2018). The estimates are input into the Autonomie model, and other vehicle component assumptions (e.g. lightweighting and aerodynamic improvements over time) are consistent with Islam et al. (Islam et al., 2022). The ATB Mid trajectory corresponds to the Base performance, Low technology progress case. The ATB Advanced trajectory corresponds to the Base performance, High technology progress case. The ATB Constant trajectory is set to the 2022 values in the Low technology progress case and held constant through 2050. The final fuel cell and hydrogen storage costs for a vehicle depends on the size of the fuel cell stack and storage tank, which vary depending on the technology progress of the other components and vehicle size as well as the resulting fuel economy.

Assumptions for Light Duty Fuel Cell Vehicle Production Volumes

• Assumed manufacturing volumes in the ATB Constant trajectory are based on current manufacturing volume of light-duty fuel cell electric vehicles today. The ATB Advanced trajectory assumes incremental projected manufacturing growth consistent with the estimated medium- and heavy-duty vehicle adoption in the Ledna et al. Central case  (Ledna et al., 2022). The ATB Mid trajectory assumes volumes midway between Constant and Advanced. Component costs for hydrogen storage and fuel cells are scaled according to the assumed manufacturing volumes and component cost multipliers in the table below. All other vehicle component assumptions (e.g. lightweighting and aerodynamic improvements over time) are consistent with Islam et al. (Islam et al., 2022). The ATB Mid trajectory corresponds to the Base performance, Low technology progress case. The ATB Advanced trajectory corresponds to the Base performance, High technology progress case. The ATB Constant trajectory is set to the 2022 values in the Base performance, Low technology case and held constant through 2050.Light Duty Fuel Cell Electric Vehicle Production Volume and Low-Volume Production Component Cost Multipliers

Assumptions for Medium and Heavy Duty Fuel Cell Vehicle Production Volumes

• Assumed manufacturing volumes in the ATB Constant trajectory and Mid trajectory are based on limited manufacturing volume of medium- and heavy-duty fuel cell electric vehicles today, with no or negligible assumed production increase. The ATB Advanced trajectory assume projected manufacturing growth consistent with the estimated medium- and heavy-duty vehicle adoption in the Ledna et al. Central case  (Ledna et al., 2022). 
• Component costs for hydrogen storage and fuel cells are scaled according to the assumed manufacturing volumes and component cost multipliers in the table below. All other vehicle component assumptions (e.g. lightweighting and aerodynamic improvements over time) are consistent with Islam et al. (Islam et al., 2022). The ATB Mid trajectory corresponds to the Base performance, Low technology progress case. The ATB Advanced trajectory corresponds to the Base performance, High technology progress case. The ATB Constant trajectory is set to the 2022 values in the Base performance, Low technology case and held constant through 2050.Medium and Heavy Duty Fuel Cell Electric Vehicle Production Volume and Low-Volume Production Component Cost Multipliers

See the Gasoline Hybrid Electric Vehicle page.

See the Gasoline Internal Combustion Engine Vehicle page.

See the Natural Gas Internal Combustion Engine Vehicle page.

Plug-in hybrid electric vehicles (PHEVs) use both an electric motor and an internal combustion engine. Batteries power the motor and gasoline, diesel, or another fuel powers the engine or other propulsion source. Operating costs and fuel use are lower than those for conventional vehicles because electricity from the grid is less expensive (see assumptions about electricity costs) and electric motors are very efficient. Greenhouse gas emissions from PHEVs may also be lower, depending on the electricity source (DOE, 2019). For additional background, see the Alternative Fuels Data Center's Plug-In Hybrid Electric Vehicles webpage.

For BEVs, PHEVs, and FCEVs, vehicle ranges are specified because they are an important determinant of modeled vehicle prices. Interactive charts for each of these vehicle powertrain types include a vehicle range filter. Vehicle ranges correspond to those used in the underlying sources cited. As technologies and markets develop, the ranges studied in these references may shift. The following table summarizes the vehicle ranges used in the 2022 Transportation ATB:

The ATB displays vehicle data in two vehicle weight categories: light-duty vehicles, and medium- and heavy-duty vehicles. Each vehicle weight category is subdivided further by vehicle size class.

A representative sample of body types and size classes are represented in the ATB. Definitions and data on other body types and size classes can be found in (Islam et al., 2022),

Fuels

See the definition for Sustainable aviation fuel (SAF). SAF is the term used throughout the ATB, but other sources may also refer to alternative jet fuel, alternative aviation fuel, "biojet," or aviation biofuel. 

Biodiesel is a renewable and biodegradable fuel that consists of fatty acid methyl esters and is manufactured from vegetable oils, animal fats, or recycled restaurant grease (DOE, 2019). For additional background, see the Alternative Fuels Data Center's Biodiesel Fuel Basics webpage.

Biomass is defined in the Bioenergy Technologies Office Multi-Year Program Plan (DOE, 2023), p. vii, as follows: "Biomass is a renewable carbon resource with potential for wide application across industries." "Renewable carbon resources are carbon-based resources that are regularly regenerated, either via photosynthesis (e.g., plants and algae) or through regular generation of carbon-based waste (e.g., the nonrecycled portion of municipal solid waste, biosolids, sludges, plastics, and CO2 and industrial waste gases).” Changes in the market for biomass feedstocks can cause market prices at any given point in time to differ from the biofuels market prices noted in the ATB.  

Blendstock for oxygenate blending (BOB) consists of liquid hydrocarbon components intended for blending with oxygenates (EIA, 2019a). Conventional blendstock for oxygenate blending (CBOB) is blended with oxygenates to produce finished conventional motor gasoline, and reformulated BOB (RBOB) is blended with oxygenates to produce finished reformulated motor gasoline, which is reformulated to reduce emissions.

See the Blendstock for Oxygenate Blending page.

Conventional E10 is a low-level blend composed of 10% ethanol and 90% gasoline (DOE, 2019). For additional information, see the U.S. Energy Information Administration's Gasoline Explained webpage.

Conventional E15 is a blend consisting of 10.5% to 15% ethanol and gasoline (DOE, 2019), with the balance consisting of CBOB. The Transportation ATB assumes ethanol content of 15%.

Conventional aviation fuel is refined from petroleum. This product fuels aviation aircraft engines, and it may consist of kerosene-type aviation fuel (the predominant type) and naphtha-type aviation fuel (EIA, 2019b).

Ultra-low-sulfur diesel is a product of petroleum refining that consists of distillates or blends of distillates with residual oil used in motor vehicles (EIA, 2019b). For additional information, see the U.S. Energy Information Administration's Diesel Fuel Explained webpage.

Conventional marine diesel is fuel supplied to ships. It consists primarily of residual and distillate fuel oil (EIA, 2019b).

See the Electricity page.

See the Ethanol page.

High-blend ethanol fuel contains 51% to 83% ethanol. The blend level of ethanol is selected based on air quality regulations and depends on location and season. This blend level is used in flexible-fuel vehicles (DOE, 2019).

See the Hydrogen page.

See the Natural Gas page.

Reformulated gasoline is a gasoline blend that results in lower emissions of nitrogen oxides (NO_X; see NO_X emissions), volatile organic compounds, and toxic pollutants than conventional gasoline when burned (EPA: "Gasoline Standards: Reformulated Gasoline"). Reformulated E10 contains 10% ethanol, with the balance consisting of Reformulated Blendstock for Oxygenate Blending (BOB). In contrast, conventional E10 gasoline contains 10% ethanol, with the balance consisting of Conventional Blendstock for Oxygenate Blending (BOB).

Reformulated gasoline is a gasoline blend that results in lower emissions of nitrogen oxides (NO_X; see NO_X emissions), volatile organic compounds, and toxic pollutants than conventional gasoline when burned (EPA: "Gasoline Standards: Reformulated Gasoline"). Reformulated E15 contains 10.5%–15.0% ethanol, with the balance consisting of Reformulated Blendstock for Oxygenate Blending (RBOB) (DOE, 2019). The Transportation ATB assumes an ethanol content of 15%.

Renewable diesel is a drop-in replacement for diesel typically produced from fats, oils, and greases. It is chemically the same as petroleum diesel and meets the ASTM D975. As a drop-in fuel, it can be used in all existing infrastructure and engines intended for petroleum diesel. It is also called "green" diesel (DOE, 2019).

Sustainable aviation fuel (SAF), is the term used throughout the ATB, but other sources may also refer to alternative jet fuel, alternative aviation fuel, "biojet," or aviation biofuel. also called alternative jet fuel, alternative aviation fuel, "biojet," or aviation biofuel, is derived from biomass. Up to specified blending limits that vary by pathway, it can be used directly in airplanes that use regular, petroleum-based aviation fuel (DOE, 2019).

There are multiple meanings of the term “SAF.” Specific U.S. and international definitions are provided here because commercial aviation is a global business. We also identify the role of biomass sources and greenhouse gas reduction targets in the SAF definition, including the additional criteria that must be met to make the U.S. definition consistent with the international definition.

For the United States, the U.S. Department of Energy used the following definition in SAF Grand Challenge: “SAF is drop-in liquid hydrocarbon jet fuel produced from renewable or waste resources that is compatible with existing aircraft and engines”  (U.S. DOE, 2022). Although some may consider SAF to refer to pathways that are only derived from oils, in this definition, SAF refers to drop-in hydrocarbon fuel jet from a variety of pathways. 

Further defining SAF in a U.S. context, the Commercial Aviation Alternative Fuels Initiative (CAAFI) defines SAF as Jet A fuel blendstocks that:

1. Reduce net life cycle CO₂ emissions from aviation operations.
2. Enhance the sustainability of aviation by being superior to petroleum-based jet fuel in economic, social, and environmental aspects.
3. Enable drop-in jet fuel production from multiple feedstocks and conversion processes, so no changes are required in aircraft or engine fuel systems, distribution infrastructure, or storage facilities. As such, SAF can be mixed interchangeably (is fungible) with existing jet fuel. (Quoted directly from CAAFI Frequently Asked Questions.)

Internationally, the International Civil Aviation Organization (ICAO) establishes criteria for eligibility for credits under the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA): 

Greenhouse Gas Criterion 1: CORSIA eligible fuel shall achieve net greenhouse gas emissions reductions of at least 10% compared to the baseline life cycle emissions values for aviation fuel on a life cycle basis.

Carbon Stock Criterion 1: CORSIA eligible fuel shall not be made from biomass obtained from land converted after 1 January 2008 that was primary forest, wetlands, or peat lands and/or contributes to degradation of the carbon stock in primary forests, wetlands, or peat lands as these lands all have high carbon stocks. 

Carbon Stock Criterion 2: In the event of land use conversion after 1 January 2008, as defined based on IPCC land categories, direct land use change (DLUC) emissions shall be calculated. If DLUC greenhouse gas emissions exceed the default induced land use change (ILUC) value, the DLUC value shall replace the default ILUC value.(Quoted directly from (ICAO, 2019).)

The SAF pathways presented in the ATB are intended to meet the CAAFI definition as well as the ICAO CORSIA greenhouse gas criterion of 10% GHG reduction. (The CAAFI definition does not state a specific target for GHG reduction relative to Jet A.) The SAF Grand Challenge targets a GHG reduction of 50% relative to Jet A, which is a greater reduction than SAF as defined here. If biofuels in the United States will be derived from biomass resources that are identified in the 2016 Billion-Ton Report (U.S. DOE, 2016), this would not include resources from old-growth forestland, consistent with part of ICAO CORSIA carbon stock eligibility criterion 1. If the other ICAO criteria are satisfied, then the SAF pathways that are shown in ATB would be compliant both domestically and globally.

Scenarios

Vehicle Scenarios

Vehicle scenarios in the Transportation ATB incorporate assumptions on both the level of technology advancement achieved in each powertrain (e.g., lightweighting and engine efficiency) and the projected costs for the assumed technologies through 2050. Assumptions for assigning values in the Advanced and Mid trajectories reflect the project teams' judgement. Given the rapid pace of technology improvement and market advancement the assumptions here may not reflect the most recent trends. As data become available, ATB data are updated to reflect updated cost and performance trajectories.

In the Advanced trajectory, technology advances occur with breakthroughs, increased public and private R&D investment, and other market conditions that lead to significantly improved cost and performance levels, but the technologies do not necessarily reach their full technical potential. Vehicle technologies advance substantially and achieve high performance, low cost, or both. Attaining this level of cost improvement is assumed to be very uncertain.

In the Mid trajectory, technology cost and performance improve at moderate levels, with continued industry growth and R&D investment (both public and private). Vehicles include moderate technology advancements (in between the currently manufactured technology and the Advanced trajectory) to achieve higher performance, lower costs, or both, and attaining this level of cost improvement is assumed to be moderately uncertain.

In the ATB Constant trajectory, technology cost and performance from the base year are shown through 2050, without further advancement in R&D or markets. This cost level is extended through 2050 for reference only; it does not imply frozen costs and performance are anticipated.

Technology advances include changes that may reduce costs or may increase costs while improving performance, which implies costs do not always decline between less-advanced and more-advanced scenarios. However, while technology advancements that improve performance may increase vehicle cost, they may also result in a lower levelized cost of driving due to potential fuel savings.

Fuel Scenarios

In the Current Market scenario, fuel price and emissions data are shown for fuels that are commercially available; the exact source, timing, averaging, and other details are described in the references. Current Market fuel prices are primarily based on data from the U.S. Energy Information Administration. Current Market fuel prices include taxes, but may differ from observed retail prices because of market volatility and local market conditions. See specific notes and references on the fuels pages for specific dates and averaging methods.

In this scenario, fuel metrics are based on techno-economic modeling of the current technology at current market production volume of the specific fuel pathway as specified in the notes and references on the fuels pages.

In this scenario, fuel metrics are based on techno-economic modeling of the current technology at high market production volume of the specific fuel pathway. Timing of this scenario depends on when high production volume is achieved.

In this scenario, fuel metrics are based on a future technological state modeled at low market production volume of the specific fuel pathway, as might be the case for a pioneer plant.

In this scenario, fuel metrics are based on a future technological state, based on engineering-economic modeling at high market production volume of the specific fuel pathway, often called "n^th plant." Timing of this scenario depends on when high production volume of the specific fuel pathway is achieved.

Select subsets of fuels are shown on the vehicle charts for the Transportation ATB and include three fuel pathways:

• Baseline fuels are meant to best represent current fuels available for each powertrain today. Due to the variability of current hydrogen prices, current modeled costs are used as the baseline fuel instead of current market costs for hydrogen for fuel cell electric vehicles.

• The Lowest Cost fuels correspond to the fuel pathways with the lowest cost of those included in the ATB for each powertrain.

• The Lowest CO₂e Emissions fuels correspond to the fuel pathways with the lowest CO₂e emissions of those included in the ATB for each powertrain.

The fuel pathways used for each powertrain for each fuel subset are shown in the table below. While the charts on the Transportation ATB only include these select fuels, the full set of fuels can be downloaded and explored.

Inflation Reduction Act of 2022

The Inflation Reduction Act of 2022 (IRA) includes many provisions and tax credits affecting the cost of clean energy and transportation. Most source data and modeling in the ATB do not include the provisions in the IRA. The exception is the reference for FCEV refueling/H₂ prices. This discrepancy is noted in charts and web pages where hydrogen fuel price is used.

 Inclusion of IRA Provisions

Metrics

Base year: This version of Transportation ATB generally adopts 2020 as the base year, which is the base year for our major data sources, such as the U.S. Energy Information Administration's 2021 Annual Energy Outlook (EIA, 2021), (Islam et al., 2022), and NREL Standard Scenarios.

Dollar year: All costs are converted to 2020$ using the gross domestic product implicit price deflator (FRED, 2022).

Data: The ATB includes empirical fuels data (labeled "current market"), modeled fuels and vehicle prices that represent historical years that have been validated against contemporary empirical data ("current modeled"), and model results that represent projected values for future years ("future modeled"). All of these categories are generally described as "data," and are distinguished by their labels. 

Vehicle Metrics

For the purposes of the Transportation ATB, fuel economy is tank-to-wheels fuel economy, reported in miles per gallon gasoline equivalent, and it represents how efficiently a vehicle converts fuel during operation (Elgowainy et al., 2016). For light-duty vehicles, fuel economy values represent adjusted real-world, on-road estimates, based on a harmonic average of 55% city (Urban Dynamometer Driving Schedule cycle) and 45% highway (Highway Fuel Economy Test cycle) driving for all vehicle powertrains. For medium- and heavy-duty vehicles, fuel economy values represent a harmonically weighted average of the ARB, EPA55, and EPA65 MDHDV test cycles, and weights for each vehicle class are from (Burnham et al., 2021) (Islam et al., 2022). (The ARB test cycle is developed by the California Air Resources Board; the EPA test cycles are developed by the U.S. Environmental Protection Agency.)

For plug-in hybrid electric vehicles, the fuel economy is the combined utility-factor-weighted fuel economy averaged across charge-depleting and charge-sustaining modes. This is consistent with the results provided by Islam et al. (Islam et al., 2022). (The breakout of utility-factor-weighted average electricity and liquid fuel economy for plug-in hybrid electric vehicles is included the downloadable data.) The combined utility-factor-weighted fuel economy is calculated using this equation: 

$$ \text{PHEV_FE [in mpgge]} = \dfrac{1}{\mathrm{UF} * \dfrac{\text{EC}_\text{CD}\text{[in Wh/mi]}}{33700} + \dfrac{1-\text{UF}}{\text{FE}_\text{CS}\text{[in mpgge]}}} $$

where

• UF is the utility factor representing the fraction of miles traveled on electricity
• EC_CD is the charge-depleting electricity consumption (in Wh/mi)
• FE_CS is the charge-sustaining fuel economy (in mpgge).

We convert Wh to gge assuming 1 gge = 33,700 watt-hours (EPA, 2011). Assumptions for utility factor are below.

Modeled vehicle price represents an estimated cost to the consumer to purchase a new vehicle, based on modeling that includes manufacturing costs and profit. Costs are based on manufacturing production volume of vehicles by powertrain category. Changes in modeled vehicle price reflect potential changes to manufacturing costs. The trajectory of modeled vehicle prices in ATB are not intended to estimate actual retail price trajectories, which may differ due to external market drivers not included in the Transportation ATB (e.g., automotive market supply and demand imbalances, original equipment manufacturer regulatory compliance and pricing strategies, taxes, and dealer incentives). Similarly, government incentives, subsidies, or tax credits are not included.

Studies of industrial learning-by-doing (or impact of R&D and spillovers from other industries) have found that industries tend to improve with production volume, and the resulting learning curves can be used to estimate future improvement based on historical trends. The effects of learning curves saturate, declining as the volume of production increases. In the Transportation ATB, learning effects are considered for both vehicles and fuels. 

For vehicles, the threshold for high volume is 200,000 vehicles/year, as assumed by James et al.  (James et al., 2018) and Adams et al. (Adams et al., 2019). Above this threshold, additional volume of vehicle production is assumed not to have an effect on modeled vehicle price. This threshold is a small fraction of light-duty vehicle sales in the United States. In the light-duty market, hybrid, plug-in-hybrid, and battery electric vehicles have already reached this threshold as of 2022 and are therefore assumed to be manufactured at high volume. We also assume medium and heavy duty hybrid, plug-in hybrid, and battery electric vehicles benefit from the economies of scale achieved by light-duty battery electric vehicles. Not all powertrains may reach high production volume if certain powertrains appeal to the same, smaller consumer segment. Notably, fuel cell electric vehicles are assumed to be produced at low volumes and their costs include a low production volume cost multiplier that decays with increasing assumed production volume. The details are discussed above in the definition for Fuel Cell Electric Vehicles.

For fuels, we specify high or low volume of production of the specific fuel pathway; see Fuel Scenarios.

The levelized cost of driving (LCOD) is an indicator of the cost of driving a vehicle on a per-mile basis. As defined and calculated in the Transportation ATB, LCOD includes initial costs for the vehicle, fuel costs, maintenance and repair costs, and if applicable, residential charger equipment and installation. It does not include any other costs, such as insurance, registration, tolls, or driving labor. LCOD here assumes a typical first and single owner over an assumed vehicle life and does not consider depreciation and resale value. 

Note that changes in LCOD over time are attributable only to vehicle technology changes, because fuel costs for a specified pathway are held constant over time in the ATB.

LCOD should be interpreted as a simplified estimate that is an indication of the per-mile cost to purchase and operate because it does not include all real-world costs of purchasing and operating a vehicle, unlike more comprehensive total cost of ownership calculations. LCOD only includes specific key cost components for the purpose of simplified comparisons of powertrains costs. The LCOD methodology is parallel to the levelized cost of electricity (LCOE) methodology of amortizing capital costs in Electricity ATB. 

The LCOD estimates are calculated using the following equations and definitions, with quantitative values shown in the tables below for light-duty and medium- and heavy-duty vehicles:

$$ \begin{aligned}
&\text{LCOD }\left[\dfrac{\$}{\text{mi}}\right]=A+B+C\\\\
&A: \text{Capital (Vehicle & Charger) Cost}\\
&B: \text{Fuel Cost}\\
&C: \text{Maintenance Cost}\\\\
&A=\dfrac{\text{vehicle_cost} + \text{charger_cost}}{\text{discounted_VMT}}\\\\
&B=\dfrac{\text{fuel_price}}{\text{TTWFE}*\text{fueling_efficiency}} \\\\
&C=\dfrac{\sum\nolimits_i^t\left(\dfrac{\text{VMT}_i}{(1+\text{discount_rate})^i} \right)*\text{maintenance_cost}_i}{\text{discounted_VMT}}\\
\end{aligned} $$

where

• fuel_price is the price of fuel delivered to vehicles (constant over time for each selected ATB Fuel Pathway). In some electricity cases, such as residential or depot charging, the price is for energy drawn from the grid, and in these cases, a corresponding fueling efficiency to account for efficiency loss incurred by the vehicle operator is applicable. In other electricity cases, such as public charging, the price is for energy delivered to the vehicle, and therefore, no applicable fueling efficiency loss is incurred by the vehicle operator.
• TTWFE is Tank-To-Wheels Fuel Economy.
• fueling_efficiency is the proportion of the energy delivered to the vehicle fuel storage relative to the energy drawn from the fuel supply chain.
• discounted_VMT is the present value of total vehicle miles traveled over the vehicle lifetime, computed as \( \sum\nolimits_i^t\dfrac{\text{VMT}_i}{(1+\text{discount_rate})^i} \).
• \(i\) is the index for vehicle life year.
• \(t\) is vehicle lifetime.
• \(\text{VMT}_i\) is the VMT for each vehicle life year.
• \(\text{maintenance_cost}_i\) is the per-mile maintenance and repair costs for each vehicle life year.

Additional Notes

• Fuel economy for light-duty vehicles are in units of mpgge, and fuel economy for medium-and-heavy-duty vehicles are in units of miles per diesel gallon equivalent (mpdge).
• Fuel economies are computed from duty-cycle-weighted sums of fuel usage.
• Fuel costs for PHEVs are computed as a utility-factor-weighted sum of fuel usage and costs.
• Maintenance costs are first computed into net present value and then levelized, due to their mileage dependence and escalating maintenance schedule (i.e., varies by year), whereas fuel prices for each ATB Fuel Pathway do not vary by year.

For light-duty vehicles:

• We use the mileage schedule provided by the National Highway Traffic Safety Administration for the annual VMT (NHTSA, 2006). The administration reports that new vehicles (first year of ownership) are driven on average 14,231 miles/year, which gradually declines to 9,249 miles/year for vehicles 15 years old. Total mileage during the 15 years is 178,102 miles. In this calculation, the annual VMT are then discounted based on the assumed discount rate of 5% to bring all costs to a present value (reflecting that the costs associated with miles driven in the earlier years of vehicle ownership contribute more to the levelized cost than the cost of miles driven in later years). This methodology is used for consistency with other U.S. Department of Energy analyses (Elgowainy et al., 2016). The total discounted mileage over a 15-year life is 132,946 miles.
• The fuel price is converted to U.S. dollars per gallon gasoline equivalent.
  • The various fuel prices are detailed on the Fuels page. The selected fuel pathways for Baseline, Lowest Cost, and Lowest CO₂e Emissions fuels are shown in the Transportation ATB charts.
• TTW FE is the tank-to-wheels fuel economy in miles per gallon gasoline equivalent. 
  • In the case of plug-in hybrid electric vehicles, separate fuel consumption metrics for charge-sustaining and charge-depleting modes are first combined with their respective fuel prices (typically conventional fuel for charge-sustaining and electricity for charge-depleting); those costs are then combined using utility factor assumptions, based on Islam et al. (Islam et al., 2022) and are consistent with SAE J1711.
• We include residential charger equipment and installation costs for battery electric vehicles and plug-in hybrid electric vehicles in the LCOD. The following charging assumptions are based on Borlaug et al. ((Borlaug et al., 2020)) and are also discussed on the electricity  page. We assume (1) 50% plug-in hybrid electric vehicles use Level 1 chargers and 50% of them use Level 2 chargers, and 2) 16% of battery electric vehicles use Level 1 chargers and 84% of them use Level 2 chargers. Residential Level 1 costs are assumed to be zero and Level 2 costs are assumed to be $1,836 ($550 for equipment and $1,286 for installation). Based on these assumptions, we add a charger cost of $918 for plug-in hybrid electric vehicles and an average charger cost of $1,542 for battery electric vehicles when calculating the LCOD. We assume any owner of a battery electric vehicle and plug-in hybrid electric vehicle will own a residential charger; thus, its capital costs are included in the LCOD. We note that this assumption of residential charging ownership might not be fully applicable in future scenarios with widespread adoption of electric vehicle where some EV owners may not necessarily own a charger and might rely solely on public or workplace charging. For select electricity pathways, we assume a blend of residential, workplace, and public charging that also assumes near-term charging behavior (primarily home charging) and may be different in future scenarios.

The table below summarizes the assumptions used for LCOD for Light-Duty Vehicles.

Levelized Cost of Driving Assumptions for Light-Duty Vehicles

For medium- and heavy-duty vehicles:

• We use the mileage schedule from HDStock (Brooker et al., 2021) based on original data from VIUS. In this calculation, the annual VMT are then discounted based on the assumed discount rate of 5% to bring all costs to a present value (reflecting that the costs associated with miles driven in the earlier years of vehicle ownership contribute more to the levelized cost than the cost of miles driven in later years). This methodology is used for consistency with other Department of Energy analyses (Elgowainy et al., 2016).
• The fuel price is converted to U.S. dollars per diesel gallon equivalent.
  • The various fuel prices are detailed on the Fuels page. The selected fuel pathways for Baseline, Lowest Cost, and Lowest CO₂e Emissions fuels are shown in the Transportation ATB charts.
• TTW FE is the tank-to-wheels fuel economy in miles per gallon diesel equivalent. 
  • In the case of plug-in hybrid electric vehicles, separate fuel consumption metrics for charge-sustaining and charge-depleting modes are first combined with their respective fuel prices (typically conventional fuel for charge-sustaining and electricity for charge-depleting) and then those costs are combined using utility factor assumptions, based on ANL BEAN/TechScape.
• We do not include charger costs for MDHD vehicles and assume the associated infrastructure costs of charging are included in the fuel price.

The table below summarizes the assumptions used for LCOD for MDHD vehicles.

Levelized Cost of Driving Assumptions for 

Medium- and Heavy-Duty Vehicles

Fuel Metrics

Diesel gallon equivalent (dge) is the volume of fuel that contains the same amount of energy as a gallon of diesel. We use a value of 128,450 Btu, which is the amount of energy in a gallon of U.S. conventional diesel on a lower heating value basis from GREET 2021.

This cost is a calculated estimate of what the cost of a fuel might be with either current or future technology at either low or high production volume of the specific fuel pathway. See Key Assumptions on the fuels pages and references for details.

The fuel price represents the market or retail price at which commercial fuels are sold. Taxes are included for all fuels currently taxed. See notes and references on each fuels pages for details.

Gasoline gallon equivalent (gge) is the volume of fuel that contains the same amount of energy as a gallon of gasoline. We use a value of 116,090 Btu, which is the amount of energy in a gallon of gasoline blendstock on a lower heating value basis from GREET 2021.

The lower heating value is the amount of energy that is released per unit of fuel that is burned, not including the heat of vaporization of the water contained in the fuel. The lower heating values from the GREET model are used for gasoline gallon equivalent conversions. Values in Btu/gal or Btu/kWh are shown below.

The following values are used for taxes and distribution cost of gasoline and diesel fuel. Values are based on the U.S. Energy Information Administration's Annual Energy Outlook (EIA, 2021), where taxes include federal, state, local, and energy taxes.

Miles per gasoline gallon equivalent (gge).

Additional Fuel Metrics

The following fuel metrics are available from the BETO Techno-Economic Analysis Database.

This revenue is the value derived from sale of products than fuel.

This is the investment in the durable physical plant for fuel production.

This is the cost of operating the fuel production facility.

This is the cost of feedstock at the throat of the reactor once a mature supply industry has been established.

This is the cost of expendable inputs needed for fuel production that are not converted into fuel.

The fuel price, which is synonymous with the minimum fuel selling price, is the price at which fuels are sold at the plant gate. It does not include distribution costs or taxes.

This is the value derived from the sale of electricity coproduced with fuel.

This is the volume of feedstock that can be processed per unit of time.

This is the sum of the yield of each valued product from the fuel production process.

Emissions Metrics

Emissions for CO₂e, NO_X , SO_X, and PM₁₀ are estimated for well-to-tank and well-to-wheels portions of the fuel life cycles, not including emissions associated with vehicle production. The Transportation ATB only reports absolute values of physical emissions and does not account for the social cost of carbon or other associated impacts. Note that the changes over time are attributable only to vehicle technology changes; emissions associated with fuels are held constant at the values for the selected fuel.

CO₂e is the carbon dioxide equivalent of greenhouse gas emissions. The Transportation ATB considers greenhouse gas emissions from CO₂, CH₄, and NO_X, consistent with GREET. The global warming potentials are also based on GREET model default values, which are based on the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) (IPCC, 2014). GREET model defaults do not include effects on soil organic carbon. Values (from defaults) for induced land use change are used when the biomass resource is corn or soybeans, but not for feedstocks from wastes.  

NO_X are nitrogen oxides.

SO_X are sulfur oxides.

PM is particulate matter. In the Transportation ATB, we report PM₁₀, which consist of particles that have aerodynamic diameters of less than 10 microns. These metrics are reported in GREET model results.

Tank-to-wheels emissions are emissions from fuel consumption during the operation phase of the vehicle (Elgowainy et al., 2016).

Well-to-tank emissions include emissions from fuel production at the primary source of energy (feedstock) to its delivery to the vehicle's energy storage system (e.g., fuel tank or battery) (Elgowainy et al., 2016).

These are emissions from both the well to the tank and the tank to the wake (which includes fuel consumption during operation of an aircraft).

These are emissions from both the well to the tank and the tank to the wheels. Well-to-wheels emissions are presented in different units depending on the data shown.

For fuels, we present the well-to-wheels in g/mmBtu (on lower heating value basis). This represents the emissions associated with each unit of energy used onboard the vehicle; it does not incorporate vehicle fuel economy. This methodology is consistent with the Renewable Fuel Standards (RFS2), which evaluate fuels on a gram per unit energy basis (EPA, 2015); (EPA, 2010).

For vehicles, we present the well-to-wheels emissions in g/mi, which incorporates both the fuel emissions and the vehicle fuel economy. This methodology is consistent with regulations that account for potential fuel economy improvements of advanced powertrains, such as California's Low Carbon Fuel Standard (California Air Resources Board, 2019).

Transportation Metrics

Passenger-mile is a unit used to indicate one mile traveled by one passenger. 

Seat-mile is a unit used to indicate one mile traveled by one seat, typically on a commercial aviation flight or public transportation mode. This is calculated by multiplying the number of miles an airplane or other vehicle travels by the available number of seats on that vehicle.

Vehicle-mile is a unit used to indicate one mile traveled by one vehicle.  

References

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