Accelerating Clean Energy Ambition

The document details the technical methodology used by the Union of Concerned Scientists to model US energy system transitions. It outlines targets for reducing energy and industrial CO2 emissions by 47.5% by 2030 and 100% by 2050, alongside specific targets for non-CO2 gases. The analysis employs seven scenarios, including reference cases and various net-zero pathways, incorporating the impacts of the Inflation Reduction Act (IRA) and the Infrastructure Investment and Jobs Act (IIJA). Key assumptions include the total retirement of coal generation by 2030 in net-zero scenarios and 100% zero emissions vehicle sales by 2035.

• The modeling framework targets a cumulative US carbon dioxide equivalent (CO2e) budget of 74 gigatons between 2021 and 2050 to align with Paris Agreement commitments.
• Specific emissions reduction targets include reducing energy and industrial CO2 emissions by 47.5% below 2005 levels by 2030 and 100% by 2050, and reducing methane, nitrous oxide, and fluorinated gases by 32% by 2030 and 41% by 2050.
• The analysis assumes the US land sink remains constant at 2019 levels of 0.79 gigatons per year through 2050 due to high uncertainty regarding whether these sinks will increase or decrease.
• In all net-zero scenarios, the model assumes that all coal generation is retired by 2030.
• For net-zero scenarios, the model assumes 100% zero emissions vehicle (ZEV) sales for all vehicles by 2035, with battery electric vehicles making up the majority of sales by 2050 (ranging from 73% for heavy-duty trucks to 95% for cars).
• The modeling incorporates specific IRA and IIJA incentives, including a Production Tax Credit (PTC) of $26 per MWh and an Investment Tax Credit (ITC) of 30%, both with potential bonus credits for domestic content and energy communities.
• The framework utilizes a combination of the EnergyPATHWAYS model for demand-side analysis, the Regional Investment and Operations model for supply-side options, and the EPA's CO-Benefits Risk Assessment (COBRA) model to calculate public health impacts.

APA

Clemmer, S., Cleetus, R., Martin, J., Moura, M. C. P., Arbaje, P., Chavez, M., & Sattler, S. (2023). Accelerating Clean Energy Ambition. Union of Concerned Scientists. https://www.ucs.org/sites/default/files/2023-11/accelerating-clean-energy-ambition-appendix.pdf

Chicago

Clemmer, Steve, Rachel Cleetus, Jeremy Martin, Maria Cecilia P. Moura, Paul Arbaje, Maria Chavez, and Sandra Sattler. Accelerating Clean Energy Ambition. Union of Concerned Scientists, 2023. https://www.ucs.org/sites/default/files/2023-11/accelerating-clean-energy-ambition-appendix.pdf.

Wikipedia

{{cite report |last1=Clemmer |first1=Steve |last2=Cleetus |first2=Rachel |last3=Martin |first3=Jeremy |last4=Moura |first4=Maria Cecilia P. |last5=Arbaje |first5=Paul |last6=Chavez |first6=Maria |last7=Sattler |first7=Sandra |title=Accelerating Clean Energy Ambition |publisher=Union of Concerned Scientists |date=November 2023 |url=https://www.ucs.org/sites/default/files/2023-11/accelerating-clean-energy-ambition-appendix.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{clemmer2023accelerating, author = {Clemmer, Steve and Cleetus, Rachel and Martin, Jeremy and Moura, Maria Cecilia P. and Arbaje, Paul and Chavez, Maria and Sattler, Sandra}, title = {{Accelerating Clean Energy Ambition}}, institution = {Union of Concerned Scientists}, year = {2023}, month = nov, url = {https://www.ucs.org/sites/default/files/2023-11/accelerating-clean-energy-ambition-appendix.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }