Transportation Deep Decarbonization Initiative Synthesis

The report argues that deep decarbonization of transportation requires a diverse set of solutions across technology, policy, and behavior, as no single technology can address all subsectors. Key strategies include the deployment of battery electric vehicles (BEVs) for light-duty and short-haul freight, hydrogen and ammonia for heavy-duty and marine transport, and sustainable aviation fuels (SAFs) for aircraft. The authors emphasize that efficiency improvements are a critical near-term tool across all modes. A central policy recommendation is the adoption of a performance-based, adaptive framework, specifically a Low Carbon Fuel Standard (LCFS) transitioning to a Zero-Carbon Fuel Standard (ZCFS) by 2050, to allow various fuels and vehicles to compete while reducing overall carbon intensity. The report also highlights the daunting nature of infrastructure transitions and the uncertainty of consumer behavior and automated vehicle impacts.

• Current business-as-usual projections from the IEA, WEO, and EIA suggest a modest transition to alternative fuels that is insufficient to limit planetary warming to 2 degrees Celsius, with gasoline, diesel, and jet fuel projected to account for over 90% of fuel consumed in OECD countries through 2050.
• A diverse set of solutions is necessary for deep decarbonization because different subsectors face different constraints; BEVs are promising for light-duty vehicles, while hydrogen is better suited for heavier vehicles, and carbon-neutral ammonia is a promising fuel for marine applications.
• Aviation presents the most significant technical challenges for fuel switching due to energy density requirements; consequently, the report suggests prioritizing limited sustainable biofuel supplies for aviation over other subsectors.
• Synthetic net-zero-carbon 'drop-in' fuels are technically feasible for existing infrastructure but are currently prohibitively expensive, costing between $5 and $15 per gallon of gasoline equivalent (GGE).
• The report recommends a performance-based, adaptive policy framework, specifically a Low Carbon Fuel Standard (LCFS) that evolves into a Zero-Carbon Fuel Standard (ZCFS) by 2050, as the most viable way to move the sector away from oil.
• Efficiency improvements can provide significant GHG reductions in the near term; for light-duty vehicles in OECD countries, a 50% decrease in fuel consumption relative to 2020 levels is possible by 2040+ using gasoline-electric hybrid powertrains.
• The impact of automated vehicles (AVs) on emissions is uncertain, as they could either decrease emissions through fleet efficiency and ridesharing or increase them by raising total vehicle miles traveled (VMT) due to increased accessibility and empty vehicle repositioning.
• Decarbonizing the freight sector requires different strategies based on the goods moved: consumer goods can be largely decarbonized through efficiency and logistics, whereas bulk goods require fundamental changes to vehicle design and operations.
• Infrastructure transitions are a major barrier; while electricity is ubiquitous in developed nations, hydrogen requires a massive scale-up of production, storage, and delivery systems, creating a significant “chicken and egg” investment problem.

APA

Greenwald, J., & Lewis, J. (2021). Transportation Deep Decarbonization Initiative Synthesis. Clean Air Task Force. https://cdn.catf.us/wp-content/uploads/2021/07/21092223/CATF_TransportationDecarbonization_Synthesis.pdf

Chicago

Greenwald, Judi, and Jonathan Lewis. Transportation Deep Decarbonization Initiative Synthesis. Clean Air Task Force, 2021. https://cdn.catf.us/wp-content/uploads/2021/07/21092223/CATF_TransportationDecarbonization_Synthesis.pdf.

Wikipedia

{{cite report |last1=Greenwald |first1=Judi |last2=Lewis |first2=Jonathan |title=Transportation Deep Decarbonization Initiative Synthesis |publisher=Clean Air Task Force |date=July 2021 |url=https://cdn.catf.us/wp-content/uploads/2021/07/21092223/CATF_TransportationDecarbonization_Synthesis.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{greenwald2021transportation, author = {Greenwald, Judi and Lewis, Jonathan}, title = {{Transportation Deep Decarbonization Initiative Synthesis}}, institution = {Clean Air Task Force}, year = {2021}, month = jul, url = {https://cdn.catf.us/wp-content/uploads/2021/07/21092223/CATF_TransportationDecarbonization_Synthesis.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }