NUCLEAR FACTS

Environment

How nuclear energy contributes to clean air compliance

U.S. Clean Air Act standards assume nuclear energy
The U.S. Clean Air Act of 1970 and related regulations set federally mandated limits on the emission of certain pollutants for states and regions of the country. Both nuclear and fossil power plants operate in those states and regions. Air quality standards established under the Clean Air Act have been calculated, in fact, presuming that 20 percent of the nation's electricity will continue to be produced by non-emitting nuclear energy, and that 30 percent total will be non-emitting generation. This is on a national basis. The percent actually varies from state to state, with many states in "non-attainment" areas that have been unable to achieve air quality standards being more heavily dependent on nuclear energy.

Nuclear plants help regions meet air pollution standards
Air pollution compliance regulations are actually being enforced against the total supply of electricity, not just facilities that emit pollutants. Both emission caps and permits under ambient air quality standards represent a predetermined level of pollution rights available to a range of industrial activities, one of which is electricity production. These restrictions remain fixed, even if the total amount of electricity needed to satisfy demand in the affected regions of the country rises. A state or region can more easily remain within its emission limitations and still meet its energy needs when emission-free sources are used to satisfy a portion of demand.

Nuclear plants reduce the cost of air pollution control for emitting facilities
But emission-free sources like nuclear energy do more than help in meeting air pollution standards. When some of the electricity generating units do not need air emission permits—like nuclear facilities, which are non-emitting—more allowable tons remain available to emitting facilities in the same location. Reducing the scarcity of allowable tons lowers their price, or reduces the capital expenses needed to reduce emissions. Non-emitting nuclear generation reduces competition for a limited amount of rights to pollute created by law. So, they reduce the actual capital cost of air pollution controls for emitting generation in the same location.

Nitrogen oxides as an example
Nitrogen oxides, a precursor of ground-level ozone, provides a good example of how nuclear energy helps fossil generation meet its clean air compliance. Under a recent rulemaking, the Environmental Protection Agency established a cap on this controlled pollutant for 21 eastern states. The so-called NOx SIP Call Rule allocates this total cap as an emission limit for each state. The cap for all of these states is 565,000 tons, while actual NOx output in 1997 was 1,346,350 tons. If electricity generation sources that emit harmful gases were to replace nuclear, these states would produce an additional 131,867 tons, even if their emission rate meets the level required by the SIP Call Rule. That replacement generation alone would use up 31 percent of the combined caps for each state even before all other industries are brought into the calculation. Some states would face a significantly greater burden—South Carolina would lose 86 percent, Connecticut 65 percent, Illinois 47 percent, Virginia 46 percent, Pennsylvania 41 percent, and New Jersey 40 percent of their respective caps without nuclear energy.

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