The US Environmental Protection Agency’s move to replace the Clean Power Plan (CPP) will see a flattening of US emissions instead of a downward trend, and poses a lost opportunity to accelerate the current movement toward a decarbonised electricity sector in the US.
The EPA’s new rule is a nail in the coffin for the Obama Administration’s CPP, which has spent years in legal limbo.
The successful implementation of the CPP would have been an important step in strengthening US climate action. The plan set emissions reduction targets for entire states, which would have incentivised systemic changes in the electricity supply system—for example, switching from coal power to renewable power. In contrast, the new regulations proposed by the Trump Administration are expected to allow states to set their own rules, require only modest emissions reductions, and affect only individual power plants, for example through efficiency measures or carbon capture and storage technologies.
Without the CPP, US emissions are likely to be around 160–210 MtCO2e higher in 2030 and level off after the early 2020s, instead of continuing downward. On this path, the US will miss its 2025 climate target under the Paris Agreement, from which the Trump Administration intends to withdraw. However, some states are acting on the CPP anyway and are likely to achieve their CPP targets without the CPP in place (Larsen & Herndon, 2017).
The real loss, however, is the opportunity. Without the Clean Power Plan (or more ambitious measures in the power sector) the US is missing an important window to get its power sector onto a path that is compatible with the Paris Agreement’s goal to limit warming to 1.5°C (2.7°F).
Market forces and actions by states, cities, businesses, and individuals continue to drive up the share of renewables in electricity generation, which are projected to generate 23% of US electricity in 2030 (U.S. Energy Information Administration, 2018).
This, however, is not yet enough to avoid the worst impacts of climate change. In one scenario that is nearly Paris Agreement-compatible, the US would need to increase its share of renewables to at least 33% in 2030, and 66% by 2050 (IEA, 2017). However, this scenario assumes widespread adoption of as-yet unviable carbon capture and storage (CCS) technologies. Without CCS, the renewables share will need to be even higher. These renewable energy capacity installations need to start now, and forward-thinking federal policy could have accelerated the trend towards a decarbonised electricity sector in the US.
 The International Energy Agency’s Beyond 2°C scenario would likely result in 1.75°C warming by the end of the century: 0.25 degrees above the Paris Agreement long-term temperature limit of 1.5°C.
IEA. (2017). Energy Technology Perspectives 2017. Paris, France: International Energy Agency.
Larsen, J., & Herndon, W. (2017). What the Clean Power Plan Would Have Done. Retrieved from https://rhg.com/research/what-the-cpp-would-have-done/
U.S. Energy Information Administration. (2018). Annual Energy Outlook 2018. Retrieved from https://www.eia.gov/outlooks/aeo/