	Introduction

Electric utility generating facilities are a major source of air pollution. The objective would be to balance the environmental goal of effective controls across the pollutants covered with the industry goal of a stable regulatory regime for a period of years. The Bush Administration's Proposals

In February 2002, the Bush Administration announced two air quality proposals to address the control of emissions of SO 2 , NOx, Hg, and CO 2 . The first proposal, called "Clear Skies," would amend the Clean Air Act to place emission caps on electric utility emissions of SO 2 , NOx, and Hg. Implemented through a tradeable allowance program, the emissions caps would be imposed in two phases: 2010 (2008 in the case of NOx) and 2018. Revised versions of Clear Skies legislation were introduced in the 109 th Congress as H.R. 227 and S. 131 . The second Administration proposal initiates a new voluntary greenhouse gas reduction program, similar to ones introduced by the earlier George H. W. Bush and Clinton Administrations. Instead, the plan focuses on improving the carbon efficiency of the economy, reducing 2002 emissions of 183 metric tons per million dollars of GDP to 151 metric tons per million dollars of GDP in 2012. Proposed Legislation and Legislative Action in the 110th Congress

In the 110 th Congress, five bills have been introduced that would impose multi-pollutant controls on utilities. They are all four-pollutant proposals that include carbon dioxide. S. 1201 , introduced by Senator Sanders, and S. 1554 , introduced by Senator Collins, are similar but revised versions of S. 150 , introduced in the 109 th Congress. All of these bills involve some form of emission caps, beginning in 2009-2012 time frame. S. 1168 , S. 1177 , and S. 1201 include a second phase beginning in 2013-2015; H.R. They would employ a tradeable credit program to implement the SO 2 , NOx, and CO 2 caps while all but H.R. 3989 permit plant-wide averaging in complying with the Hg requirements. The provisions concerning SO 2 , NOx, and Hg in the five bills are generally more stringent than the comparable provisions of S. 131 of the 109 th Congress. It is difficult to compare the CO 2 caps contained in these bills with the Administration's proposal concerning CO 2 —both because the Administration's proposal is voluntary rather than mandatory and because it is broader (covering all greenhouse gas emissions rather than just utility CO 2 emissions). 3989 ). All except S. 1554 and H.R. Comparison of Multi-Pollutant Control Proposals
With the prospect of new layers of complexity being added to air pollution controls, and with electricity restructuring putting a premium on economic efficiency, interest is being expressed in finding mechanisms to achieve health and environmental goals in simpler, more cost-effective ways. The electric utility industry is a major source of air pollution, particularly sulfur dioxide (SO2), nitrogen oxides (NOx), and mercury (Hg), as well as unregulated greenhouse gases, particularly carbon dioxide (CO2). At issue is whether a new approach to environmental protection could achieve the nation's air quality goals more cost-effectively than the current system.
One approach being proposed is a "multi-pollutant" strategy—a framework based on a consistent set of emissions caps, implemented through emissions trading. Just how the proposed approach would fit with the current (and proposed) diverse regulatory regimes remains to be worked out; they might be replaced to the greatest extent feasible, or they might be overlaid by the framework of emissions caps.
In February 2002, the Bush Administration announced two air quality initiatives. The first, "Clear Skies," would amend the Clean Air Act to place emission caps on electric utility emissions of SO2, NOx, and Hg. Implemented through a tradeable allowance program, the emissions caps would generally be imposed in two phases: 2008 and 2018. "Clear Skies" was re-introduced in the 109th Congress as S. 131. The second initiative begins a voluntary greenhouse gas reduction program. This plan, rather than capping CO2 emissions, focuses on improving the carbon efficiency of the economy, reducing 2002 emissions of 183 metric tons per million dollars of GDP to 151 metric tons per million dollars of GDP in 2012.
In the 110th Congress, five bills have been introduced that would impose multi-pollutant controls on utilities. They are all four-pollutant proposals that include carbon dioxide. S. 1168 and S. 1177 are revised versions of S. 2724, introduced in the 109th Congress. S. 1201 and S. 1554 are expanded and revised versions of S. 150, introduced in the 109th Congress, while H.R. 3989 is a new proposal. All of these bills involve some form of emission caps, beginning in the 2009-2012 time frame, with all but S. 1554 including a second phase in 2013-2015 (CO2 only for H.R. 3989). They would employ a tradeable credit program to implement the SO2, NOx, and CO2 caps; all but H.R. 3989 permit plant-wide averaging in complying with the Hg requirements. The provisions concerning SO2, NOx, and Hg in the 110th Congress bills are generally more stringent than the comparable provisions of S. 131 of the 109th Congress. It is difficult to compare the CO2 caps contained in these bills with the Administration's proposal concerning CO2—both because the Administration's proposal is voluntary rather than mandatory and because it is broader (covering all greenhouse gas emissions rather than just utility CO2 emissions).