Transportation Energy Landscape in the United States

Joshua Barsoian
December 8, 2024

Submitted as coursework for PH240, Stanford University, Fall 2024

Overview

Fig. 1: A DC public charging port. As global EV charging infrastructure expands, the 2022 Inflation Reduction Act (IRA) helped expand charging infrastructure in the United States. (Source: Wikimedia Commons)

The U.S. transportation sector is the largest contributor to national greenhouse gas (GHG) emissions, responsible for approximately 33% of the total in 2022. [1] Addressing the energy and emissions profile of this sector is critical to achieving national climate goals.

Energy Consumption in U.S. Transportation

In 2022, the U.S. transportation sector consumed approximately 1.5 billion metric tons of fuel, equivalent to 6.28 × 1018 Joules of energy. This staggering energy consumption highlights the sector's dependence on petroleum-derived fuels, which accounted for 90% of total use. Light-duty vehicles, including passenger cars and SUVs, were the primary contributors to emissions (49%), followed by medium- and heavy-duty trucks (21%). [1,2] Biofuels like ethanol and biodiesel offer a smaller but growing contribution, offsetting about 7% of oil demand in 2023. They play a vital role in sectors like aviation and freight, where electrification is challenging. Renewable diesel and biojet fuels are expected to grow in importance, although their adoption remains limited. [1,3]

Fuel Consumption Trends

Contrary to assumptions about declining fuel use, historical data reveal an increase in fuel consumption over the past decade. Between 2010 and 2022, transportation fuel consumption grew by approximately 4%. Given that the U.S. transportation sector consumed approximately 1.5 billion metric tons of fuel in 2022, we can calculate that fuel consumption jumped from approximately 1.442 billion metric tons of fuel in 2010 by about 58 million metric tons of fuel over a 12-year span. This growth, driven by increased freight movement and personal vehicle use, underscores the urgency of accelerating decarbonization efforts. [1,2]

Decarbonization Trends

Decarbonization in transportation is advancing through a combination of biofuel deployment, electrification, and efficiency improvements. Policies such as the Inflation Reduction Act (IRA) have spurred growth in renewable diesel and biojet fuel production, but additional efforts are needed to scale adoption. Electrification has also made significant strides, particularly in the light-duty vehicle sector. Battery electric vehicle (BEV) adoption rose sharply, with BEV-related jobs increasing by 27% in 2022. These gains have been supported by expanded EV charging infrastructure and clean vehicle incentives under the IRA. [1,2] (See Fig. 1.) Efficiency improvements and modal shifts are critical to reducing emissions per mile traveled. Expanding public transit and rail systems offers substantial emission reductions compared to single-occupancy vehicles and freight trucks. However, freight trucking remains a significant challenge, with emissions from this mode growing by 83% between 1990 and 2021. Shifting freight to rail and maritime options, which have lower emissions per ton-mile, is a key strategy for reducing overall transportation emissions. [1]

Government Initiatives and Future Outlook

The U.S. government has implemented several initiatives to decarbonize the transportation sector and promote alternative fuels. The 2021 Bipartisan Infrastructure Law allocated $27 billion specifically for programs to reduce greenhouse gas emissions in transportation. [2] The 2022 Inflation Reduction Act introduced policies to accelerate electric vehicle adoption and production of alternative fuels. [2] The Department of Energy's Clean Cities program, which covers 90% of the U.S. population, brings together coalitions to advance policies reducing dependence on petroleum-based fuels. [2] These efforts aim to reduce transportation greenhouse gas emissions by about 25% to around 6 Gt by 2030, in line with net-zero emissions targets. [1]

Conclusion

In conclusion, while the U.S. transportation sector remains heavily dependent on petroleum products, there is a clear push towards more efficient and cleaner technologies. The success of these initiatives will be crucial in reshaping the transportation energy landscape and meeting climate goals in the coming decades.

© Joshua Barsoian. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.

References

[1] "DOT Report to Congress: Decarbonizing U.S. Transportation," U.S. Department of Transportation, July 2024.

[2] "United States Energy and Employment Report 2023," U.S. Department of Energy, DOE/OP-0020, June 2023.

[3] "Renewables 2023," International Energy Agency, January 2024.