TODAY’S STUDY: THE HEALTH IN EMISSIONS CUTS
Health Co-benefits of Carbon Standards for Existing Power Plants; Part 2 of the Co-Benefits of Carbon Standards Study
September 30, 2014 (Harvard University and Boston University)
Executive Summary – Part 2: Health Co-Benefits of Carbon Standards
The U.S. Environmental Protection Agency (EPA) released the nation’s first-ever carbon pollution standards for existing power plants on June 2, 2014. The EPA-proposed Clean Power Plan would achieve a 30% reduction in carbon emissions from U.S. power plants below 2005 levels by 2030 (USEPA 2014a). Carbon dioxide (CO2) is an important greenhouse gas and a major driver of human-induced global climate change. Fossil-fuel-fired power plants are the single largest source of anthropogenic CO2 emissions in the U.S. They emitted 2.2 billion tons of CO2 in 2012 (AOE 2014) and currently account for 39 percent of total U.S. CO2 emissions (USEPA 2014b).
Standards to address global climate change by reducing CO2 emissions from power plants can spur significant improvements to public health and the environment by also curbing other emissions from this source such as sulfur dioxide (SO2), nitrogen oxides (NOx), particulate matter (PM) and mercury (Hg). SO2 and NOx emissions contribute to the formation of fine particulate matter (PM2.5) sometimes referred to as “soot”. NOx emissions are also a major precursor to ground-level ozone (O3), sometimes referred to as “smog”. For human health, these pollutants increase the risk of premature death, heart attacks, severity of asthma, and other health effects. For ecosystems, these pollutants contribute to acid rain, the over-fertilization of surface waters and many types of ecosystems, ozone damage to trees and crops, and the accumulation of toxic mercury in fish.
The Co-Benefits of Carbon Standards Study
Scientists from Syracuse, Harvard, and Boston Universities launched a three-part1 co-benefits study in 2013 to quantify the: (1) air quality, (2) public health, and (3) environmental co-benefits of three different carbon policy scenarios based on projected changes in power plant emissions of SO2, NOx, and PM. The term “co-benefits” refers to the added improvements that occur from implementing a policy, beyond those associated with the primary target. In this case, the primary target is the reduction of CO2 emissions and the co-benefits are the improvements associated with ancillary decreases in the other emissions. Since this study is strictly an analysis of co-benefits, it does not quantify the direct health benefits of mitigating climate change, such as anticipated decreases in future heat-related illness.
The three policy scenarios for power plant carbon standards assessed in this study are described on the following page and on pages 7 and 8. The three scenarios represent differing CO2 emissions reduction stringencies, flexibility in compliance options, and investments in demand-side energy efficiency. These scenarios were designed prior to the release of the Clean Power Plan, and capture a broad range of alternatives that can inform the final rule. The analysis isolates the co-benefits that are solely attributable to the carbon standards by comparing power plant emissions under the policy scenarios to the emissions that would have occurred under a business-as-usual reference case in the year 2020. The reference case includes the implementation of existing air pollution control policies.
Scenario 1: Power Plant Improvements (low stringency, low flexibility/no user efficiency)
This scenario focuses on heat rate upgrades and other improvements in the operating efficiency of existing power plants. It represents what is commonly referred to as an “inside the fence line” approach favored by some industry groups and states. It does not include new end-user energy efficiency.
Scenario 2: Electricity Sector Improvements (moderate stringency, high flexibility/high user efficiency)
This scenario includes state-based CO2 emission targets, flexible compliance options, and significant program investments in new end-user energy efficiency. This scenario is most similar to the EPA-proposed Clean Power Plan.
Scenario 3: Cost of Carbon Improvements (high stringency, moderate flexibility/no user efficiency) This scenario compels power plants to implement all upgrades and CO2 pollution controls up to a cost of $43 per ton of CO2 reduced. This scenario allows some shift to renewables but does not include new investments in end-user energy efficiency.
Summary of Results
In Part 1 of the study, changes in air quality in the U.S. were evaluated in response to expected changes in power plant emissions for each policy scenario in the year 2020 (Driscoll et al. 2014). The top-performing option for air quality was Scenario 2: Electricity Sector Improvements. It results in an estimated 24% decrease in U.S. power plant carbon emissions from the 2020 reference case (Driscoll et al. 2014). This is equivalent to a 35% decrease from 2005 levels, the baseline year used by EPA in the Clean Power Plan. For the other pollutants, Scenario 2 results in an estimated decrease in power plant emissions from the 2020 reference case of 27% for SO2, 22% for NOx, and 27% for Hg. The decrease in emissions in Scenario 2 results in widespread air quality improvements of up to 1.35 micro-grams per cubic meter (µg/m3 ) for annual average PM2.5 and up to 3.6 parts per billion (ppb) for the 8-hour maximum summertime ozone by 2020.
In Part 2 of the study, we analyzed the health co-benefits of the air quality changes under each of the three scenarios. The results are summarized here and presented in detail in the sections that follow.
1. Power plant carbon standards can improve air quality and provide substantial health co-benefits. The carbon standard that is moderately stringent has the greatest health co-benefits of the three analyzed (Scenario 2). The high compliance flexibility and high end-user energy efficiency in Scenario 2 results in the greatest number of premature deaths avoided overall and per ton of CO2 reduced. This scenario is most similar to the EPA-proposed Clean Power Plan in its design and resulting CO2 emissions. It yields the following estimated health co-benefits in the U.S. in 2020 compared to the business-as-usual reference case:
• 3,500 premature deaths avoided each year (that is equivalent to 9 premature deaths avoided every day).
• 1,000 hospital admissions avoided from heart and lung disease each year.
• 220 heart attacks prevented each year.
It would also lead to additional health benefits not quantified here, including reduced asthma symptoms and other health benefits for children, the elderly, and vulnerable adults.
2. The geographic distribution of health co-benefits in the top-performing scenario (Scenario 2) is widespread with all lower 48 states receiving some benefit. The 12 states with the greatest estimated number of premature deaths avoided are those where there are a large number of exposed people and air quality improves the most. They are (in order): PA, OH, TX, IL, MI, NY, NC, GA, MO, VA, TN, and IN. The 12 states with the greatest estimated percent increase in premature deaths avoided are (in order): PA, OH, WV, MO, MI, KY, MD, DC, IL, DE, IN, and AR.
3. The carbon standard with the lowest stringency has the lowest health co-benefits (Scenario 1). Its low flexibility and focus on improving power plant heat rates and operating efficiency results in little to no benefit with a slight increase in estimated premature deaths and heart attacks per year in the U.S. from the 2020 reference case.
4. The carbon standard with the highest stringency (Scenario 3) has high health co-benefits but they are lower than Scenario 2. It results in fewer estimated premature deaths avoided per year in the U.S. from the 2020 reference case and nearly half as many avoided per ton of CO2 reduced as Scenario 2.
5. Overall, the study shows that the health co-benefits of power plant carbon standards can be large but the magnitude depends on critical policy choices. The carbon standard scenario that combines moderately stringent carbon targets with highly flexible compliance options and more end-user energy efficiency (Scenario 2) has the greatest estimated health co-benefits.
The results of this study indicate that carbon standards for existing power plants that are aimed at addressing the long-term issue of global climate change can bring substantial near-term state and local health co-benefits. They also demonstrate that the specific policy design choices for power plant carbon standards have a critical influence on the magnitude and distribution of the health co-benefits that occur. The improvements in air quality that accompany a carbon standard can result in nearly immediate benefits to human health. Extended implementation timelines would delay the accrual of these benefits. For the U.S. and other nations with significant greenhouse gas emissions and air quality challenges, local health co-benefits could be an important additional motivator for taking action on climate change.
Power Plant Pollution: Emissions, Air Quality, and Health
Power plants are the single largest source of CO2 (39%), SO2 (71%), and Hg (53%) emissions in the U.S. (NEI 2011, USEPA 2014b). They are also the second largest source of NOx emissions (14%) (NEI 2011). Carbon pollution standards for existing power plants would not only help address the challenge of global climate change, they would also confer substantial near-term state and local health co-benefits by reducing power plant emissions of SO2, NOx, Hg, and directly emitted particulate matter (PM). Emissions of SO2 and NOx contribute to the formation of fine particulate matter (PM2.5) and tropospheric ozone (O3; referred to here as “ozone”)…
Study Approach…Three Scenarios for Power Plant Carbon Standards…Air Quality Results…Air Quality Results…Health Co-benefits Results…
Fossil-fuel-fired power plants are the single largest source of anthropogenic CO2 emissions in the U.S. (~39%). They emitted approximately 2.2 billion tons of CO2 in 2012. Fossil-fuel-fired power plants are also the single-largest U.S. source of SO2 and Hg emissions, and the second largest source of NOx emissions. The results from this study show that carbon pollution standards for existing U.S. power plants can provide the added bonus of substantial near-term health co-benefits for by reducing emissions of co-pollutants (SO2, NOx, Hg and PM) and improving air quality.
The results of this health co-benefits analysis suggest that carbon standards that have stringent CO2 emissions reductions targets but are flexible and include new investments in energy efficiency, offer greater and more widespread health co-benefits than the other alternatives examined here. Scenario 2, which is most similar to the EPA-proposed Clean Power Plan, has the greatest estimated health co-benefits of the three scenarios analyzed. The results also show that carbon standards focused strictly on power plant retrofits could increase emissions and little to no health co-benefits nationwide. The results underscore that the design of power plant carbon standards strongly influences the magnitude and distribution of air quality improvements and health co-benefits that accrue to states and to local communities. For the U.S. and other nations with significant greenhouse gas emissions and air quality challenges, quantifying and valuing local benefits could be an important additional motivator for taking action on climate change.