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Clean Power Plan Will Limit Carbon Emissions from U.S. Electricity Generation

The Obama adminstration's Clean Power Plan will use EPA's authority under the Clean Air Act to limit carbon emissions from U.S. power generation. That is if the plan can stand up to the bevy of legal challenges head. 

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


On Monday, the Obama administration announced the final rules for the U.S. Environmental Protection Agency’s (EPA’s) Clean Power Plan, which imposes state-by-state limits on the amount of carbon dioxide emissions that power plants can release into the atmosphere. If the Clean Power Plan can get through the barrage of legal challenges ahead of it, it could stand as a vital first step in U.S. climate policy, and pave the way for the United States to take a more leading role in the global fight against climate change.

The Clean Power Plan leverages EPA’s existing authority under the 1970 Clean Air Act to place new limits on carbon pollution from electricity generation, including existing power plants.  The Clean Air Act empowers the EPA to regulate pollutants that negatively impact public health, such as smog-inducing nitrogen dioxide and acid-rain-causing sulfur dioxide. Since 1970, the law has had a proven track record of success, helping to reduce regulated pollution levels by over 60 percent despite increases in population, gross domestic product, vehicle miles traveled, and total energy consumption. 

Between 1980 and 2013, the Clean Air Act led to a 62 percent decline in aggregate emissions despite increasing gross domestic product, vehicle miles traveled, population, energy consumption, and carbon dioxide emissions. (Source: EPA)


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The Obama administration argues that the Clean Air Act’s definition of harmful pollutants should include carbon dioxide emissions, because the effects of carbon-induced climate change will have a negative impact on public health and welfare in the future. In other words, a direct pollution impact like asthma is tantamount to an indirect impact from climate change such as drought, flooding, or famine. By classifying carbon dioxide as a regulated pollutant, EPA can extend Clean Air Act regulations to cover carbon emissions from both new and existing power plants.

The new regulations on greenhouse gas emissions take the form of future limits on carbon dioxide emissions from electricity generation in each state. EPA calculated state-by-state carbon dioxide targets using a consistent formula that counts up the potential to reduce carbon emissions over time from three “building blocks”: 1) improving the efficiency of existing coal-fired power plants, 2) using more natural gas electricity in lieu of coal, or 3) increasing use of low-carbon electricity sources like wind, solar, and nuclear power. To comply with the Clean Power Plan, states will have to gradually reduce their carbon emissions between now and the year 2030, when the final limits are imposed.

While the state-by-state carbon dioxide limits imposed on each state are derived from EPA’s emissions-reducing “building blocks,” the states are not required to follow EPA’s recommended actions to the letter. If a state thinks EPA’s efficiency targets for coal-fired generation are too stringent, it can build more wind and solar than prescribed by EPA and keep its coal plant online. If a state finds EPA’s renewable energy goals too ambitious, it can use more natural gas or nuclear generation than proposed by EPA. If a state wants to ditch EPA’s recommendations altogether, it can use other methods like carbon capture and storage or energy efficiency to reduce its total carbon emissions. The flexible nature of the Clean Power Plan is one of its strong points, especially when you consider the fact that every state has a different electricity mix and a different potential for renewable energy.

While the Clean Power Plan rules were officially finalized on Monday, states and industry groups are already lined up to fight the provision in the courts. The plan has already faced a legal challenge from Murray Energy Corporation, the nation’s top underground coal mining company, and a coalition of states led by West Virginia. In June, a federal court dismissed the lawsuit as premature, but another legal challenge is sure to result in the wake of Monday’s finalized rules. While the courts have upheld the notion that carbon dioxide can be regulated as a pollutant, it’s unclear if the precise formulation of the Clean Power Plan can get through the barrage of legal challenges that will be thrown at it.

Regardless of whether the Clean Power Plan makes it through the legal battles ahead, it is a vital first step toward not only reducing U.S. carbon emissions, but also affirming the United States as a participant in the global effort to address climate change. As President Obama put it when he announced the Clean Power Plan, “There is such a thing as being too late when it comes to climate change.”

Robert Fares is a AAAS Science and Technology Policy Fellow at the U.S. Department of Energy Building Technologies Office. The views expressed are his own and do not necessarily reflect the views of the U.S. Department of Energy.

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