This paper quantifies the costs of controlling SO2, carbon, and NOx emissions from power generation, accounting for interactions between environmental policies and the broader fiscal system. We distinguish a dirty technology (coal) that satisfies baseload demand and a clean technology (gas) that is used during peak periods, and we distinguish sectors with and without regulated prices. Estimated emissions control costs are substantially lower than in previous models of fiscal interactions that assume a single, constant returns technology and competitive pricing. The results are reasonably robust to alternative scenarios, such as full price deregulation and market power in the deregulated sector.