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Renewable energy is being deployed throughout the country to reduce air pollution and greenhouse gases. Reliance on increasing amounts of renewable energy, however, may lead to significant unanticipated increases in pollution because of the likelihood of fossil fuel facilities starting, stopping, and running more often to back up renewable resources. Estimates show that these emissions increases can drastically undercut the potential emission benefits of increased renewable penetration. To date, this changing role of fossil fuel facilities has not been thoughtfully evaluated in Clean Air Act permitting decisions for new and modified sources, even though the Act requires consideration of all methods to reduce air emissions. This Article describes why the Clean Air Act requires permitting authorities to fully evaluate the changing role of utilities in permitting decisions.

This Article further describes why this evaluation should necessarily consider all available methods for reducing backup emissions, which includes energy storage and renewable energy resources. Consideration of energy storage or renewable energy to minimize ancillary emissions is consistent with the definition of Best Available Control Technology, and does not lead to a redefinition of the source.