Study Shows EPA Proposed Replacement for Clean Power Plan May Be Worse for Climate and Health Than No Carbon Regulations
The Bottom Line
A new study published in the journal Environmental Research Letters predicts that, compared to no carbon regulations, the U.S. Environmental Protection Agency’s (EPA) Affordable Clean Energy (ACE) rule would increase greenhouse gas (GHG) emissions in 18 states and Washington, D.C. in 2030 due to an “emissions rebound,” raising questions about the rule’s standing under the Clean Air Act. Sulfur dioxide and nitrogen oxide emissions are also projected to increase in as many as 20 states and D.C.
Emissions rebound occurs when a facility undergoes efficiency improvements, otherwise known as heat rate improvements, then runs more often or for longer periods, increasing the total time it operates and leading to increased emissions.
In August 2018, the EPA proposed to replace the Clean Power Plan with ACE. ACE represents a narrow, source-based approach to carbon standards focused on heat rate improvements. The Clean Power Plan represents a flexible, systems-based approach that sets emissions standards and allows the use of demand-side energy efficiency, renewable energy generation, and emissions trading for compliance.
Author Quotes:
“The key takeaway is that ACE is a free pass for carbon emissions. The agency’s proposal could cause some coal plants to run longer, generating more pollution that drives climate change and harms human health. It’s hard to imagine how a federal plan that increases greenhouse gas emissions in eighteen states could represent the Best System of Emission Reduction required under the Clean Air Act.” —Kathleen F. Lambert, Senior Advisor, Center for Climate, Health and the Global Environment, Harvard T.H. Chan School of Public Health
“On the heels of reports that greenhouse gas emissions in the U.S. rose in 2018, our study shows that EPA’s rollback of the Clean Power Plan could make things even worse. This will throw a wrench into the climate action plans for many states and cities. Under their proposal, cities like San Francisco, Boston, and Portland (Oregon), and states like California, Massachusetts, New York, and Florida will have a harder time meeting their carbon emissions goals.” —Jonathan J. Buonocore, Research Associate, Center for Climate, Health and the Global Environment, Harvard T.H. Chan School of Public Health
Why It Matters
For the nation – Recent reports show that carbon dioxide (CO2) emissions in the U.S. increased approximately 3.5% in 2018. Our study suggests that replacing the Clean Power Plan with ACE could drive emissions higher still, making it even more challenging for the U.S. to meet its previous commitments under the Paris climate agreement and to achieve emissions reductions needed by 2030 to avoid the worst impacts of climate change.
For the courts – The results of the study call into question whether the ACE rule can meet the “Best System of Emission Reduction” requirement under the Clean Air Act given that it is projected to cause an increase in CO2 emissions at 28 percent of the regulated plants compared to no carbon regulations.
For states – Emissions rebound would shift the burden of setting CO2 emissions standards to states and create a patchwork approach with uncertain outcomes. In so doing, it may make it more difficult for states with GHG targets to meet those goals. Six states (California, Florida, Maryland, Massachusetts, Oregon, and New York) plus Washington, D.C. have GHG targets and are projected to experience at least a small increase in CO2 emissions under ACE compared to no carbon regulations.
For health – The study shows that in 20 states ACE is likely to cause an increase in emissions of sulfur dioxide or nitrogen oxides compared to no carbon regulations. Sulfur dioxide and nitrogen oxides contribute to ground-level ozone and fine particulate matter which can harm human health and ecosystems. The EPA’s Regulatory Impact Assessment (RIA) estimated that lower air quality under ACE compared to the Clean Power Plan would result in approximately 1,000 additional premature deaths per year, along with more than 40,000 lost work days due to air pollution-related illness and other effects on asthmatics, individuals with cardiovascular disease, and other vulnerable populations.
Key Findings
- At the national level, CO2 emissions are projected by the EPA to be 0.8% (14 million short tons) lower in 2030 but 0.6% (11 million short tons) higher in 2050 under ACE compared to no policy.
- At the state level, CO2 emissions from the power sector are expected to increase by up to 8.7% in 18 states and D.C., under ACE compared to no policy in 2030.
- At the plant level, CO2 emissions are projected to increase at 28% of the regulated coal-fired power plants under ACE compared to no policy in 2030.
- Increased generation from coal-fired power plants accounts for the increase in emissions in 14 of the 18 states. Increased natural gas emissions are responsible for the increase in emissions in the remaining four states and D.C.
- National sulfur dioxide emissions are projected by EPA to be 0.7% lower, and nitrogen oxide emissions are estimated to be 1% lower under ACE compared to no policy in 2030.
- At the state level, emissions of sulfur dioxide are projected to increase by up to 148% in 19 states, and nitrogen oxide emissions are estimated to increase by up to 9% in 20 states and D.C. under ACE compared to no policy in 2030.
- Compared to the Clean Power Plan, national CO2 emissions are projected by the EPA to be 3.5% higher, sulfur dioxide emissions are projected to be 6% higher, and nitrogen oxide emissions are expected to be 5% higher under ACE in 2030.
State Impacts
Table: Change in power sector emissions for states with increased emissions for one or more pollutants under ACE compared to no carbon regulations in 2030. States with an asterisk have GHG reduction targets that may be more difficult to achieve under ACE.
| State | Carbon dioxide increase(thousand short tons) | Sulfur dioxide increase(short tons) | Nitrogen oxides increase(short tons) |
| Alabama | 988 | 464 | 513 |
| Arkansas | 499 | 2,282 | 381 |
| California* | 1,415 | 0 | 109 |
| Connecticut | -16 | 0 | 3 |
| District of Columbia* | <1 | 0 | <1 |
| Florida* | 400 | 1,770 | 264 |
| Georgia | 56 | -60 | 212 |
| Kentucky | 168 | 82 | 54 |
| Louisiana | 196 | 1,784 | 163 |
| Maryland* | 790 | 416 | 25 |
| Massachusetts* | 73 | <1 | 9 |
| Minnesota | -44 | -139 | 106 |
| Mississippi | 224 | 260 | 547 |
| Nevada | 2 | 3 | 25 |
| New York* | 67 | 2 | 12 |
| North Carolina | 564 | 340 | 898 |
| Ohio | -836 | 309 | 331 |
| Oregon* | <1 | <1 | <1 |
| South Carolina | -263 | 514 | <-1 |
| Tennessee | 597 | 346 | 200 |
| Texas | 782 | 2,412 | -236 |
| Virginia | 677 | 274 | 68 |
| Washington | -66 | <1 | -6 |
| Wisconsin | 975 | 309 | 356 |
The Fine Print
This study corroborates previous findings by the EPA and others that carbon standards focused on individual power plants can produce emissions rebound. This study takes the analysis a step further than earlier efforts by mapping the rebound on a state-by-state basis and by quantifying how much of the rebound is attributable to increased electricity generation from fossil-fuel fired power plants.
This work also demonstrates that system-wide emissions standards, like the Clean Power Plan, can have greater health benefits than standards that act on individual sources, like the proposed ACE rule.
The study is based on data published by the EPA in its RIA for ACE for the central illustrative case which assumes a heat rate improvement of 4.5% at the cost of $50 per kilowatt-hour. While the emissions rebound is evident in the EPA’s data, the Agency did not account for the state and local impacts of emissions rebound in their cost-benefit analysis. The EPA has stated that it expects to finalize the carbon standards regulation in March 2019.
About the Study
The Affordable Clean Energy Rule and the Impact of Emissions Rebound on Carbon Dioxide and Criteria Air Pollutant Emissions. Published in Environmental Research Letters. January 2019.
The study was led by researchers from the Center for Climate, Health, and the Global Environment at the Harvard T.H. Chan School of Public Health, Resources for the Future, Syracuse University, and Boston University School of Public Health.
Amelia T. Keyes, Research Assistant, Resources for the Future
Kathleen F. Lambert, Senior Advisor, Center for Climate, Health and the Global Environment, Harvard T.H. Chan School of Public Health
Dallas Burtraw, Darius Gaskins Senior Fellow, Resources for the Future
Jonathan J. Buonocore, Research Associate, Center for Climate, Health and the Global Environment, Harvard T.H. Chan School of Public Health
Jonathan I. Levy, Professor and Chair, Department of Environmental Health, Boston University School of Public Health
Charles T. Driscoll, University Professor of Civil and Environmental Engineering, Syracuse University
Public Comments on ACE from the Authors to EPA
Media contact: Liz Purchia, lizpurchia@hsph.harvard.edu, 315-794-6943.
