This paper discusses how carbon abatement policies interact with the tax system, and how these interactions affect the overall costs of carbon controls. We provide formulas for adjusting cost estimates of auctioned and grandfathered carbon emissions from partial equilibrium energy models into rough estimates of general equilibrium costs that account for fiscal interactions. In the basic model with a tax on labor income, the general equilibrium costs of (revenue-neutral) auctioned permits are around 25% higher than the partial equilibrium costs; those of grandfathered permits, which do not directly raise revenues for recycling, are typically more than 100% higher. However, when allowance is made for complicating factors, such as the effect of tax subsidies on raising the distortionary costs of the tax system, the efficiency gains from recycling revenues from auctioned permits are larger. Indeed the general equilibrium costs of (revenue-neutral) auctioned permits can be negative for modest abatement levels.