As Congress continues the debate on an appropriate response to the climate change issue, multiple bills have been introduced that would require reductions in greenhouse gas (GHG) emissions. Of these, H.R. 2454 , (the American Clean Energy and Security Act of 2009) has received particular attention. Introduced by Representatives Waxman and Markey, H.R. 2454 passed the House of Representatives on June 26, 2009. Several analyses have been done on the impact of the cap-and-trade provisions, and as of September 2009, seven studies had been released. They are presented below in no particular order. E nvironmental P rotection A gency : A comprehensive analysis has been conducted by the U.S. Environmental Protection Agency (EPA). The report is entitled: EPA Analysis of the American Clean E nergy and Security Act of 2009: H.R. 2454 in the 111 th Congress (June 23, 2009). Beyond a "core" analysis of H.R. 2454 , the report employs a suite of models and reference cases, along with some useful sensitivity analyses. This report will focus on cases from three of the models. The first model is ADAGE: a computable general equilibrium (CGE) model developed by RTI International. The "core" analysis case employing the ADAGE model is designated EPA/ADAGE. The second model is IGEM: a CGE model developed by Dale Jorgenson Associates. The "core" analysis case employing the IGEM model is designated EPA/IGEM. The third model is IPM: a dynamic, deterministic linear programming model of the U.S. electric power sector developed by ICF Resources. The case employing the IPM model is designated EPA/IPM in this report. E nergy I nformation A dministration : A second comprehensive analysis has been conducted by the Energy Information Administration (EIA). The report is entitled Energy Market and Economic Impacts of H.R. 2454 , the American Clean Energy and Security Act of 2009 (August 4, 2009). The analysis employs EIA's NEMS model: a macroeconomic forecasting model with extensive energy technology detail. In addition to conducting a "basic case" analysis of H.R. 2454 using its updated 200 9 Annual Energy Outlook (AEO) Reference , EIA also conducts some useful sensitivity analyses that focus on the upside risk of decreased offset supply (and thus, increased allowance prices) under H.R. 2454 . The basic case H.R. 2454 analysis is designated EIA/NEMS in this report. N ational B lack C hamber of C ommerce : A third analysis has been conducted for the National Black Chamber of Commerce by Charles River Associates (CRA) International. The report is entitled Impact on the Economy of the American Clean Energy and Security Act of 2009 ( H.R. 2454 ) (May 2009). The analysis employs CRA's MRN-NEEM macroeconomic model with extensive electric power sector detail. CRA conducted three scenarios: reference, high, and low. The "reference" scenario analysis is designated NBCC/CRA. In cases where the reference scenario projections were not presented, the low or high case scenario figures (designated NBCC/CRA/LOW and NBCC/CRA/HIGH) are used instead. Heritage Foundation: A fourth analysis has been conducted by The Heritage Foundation, based on projections from the Global Insight model—a macroeconomic model with energy sector modeling. Focused on the economic impacts of H.R. 2454 , the results were first disseminated in a series of "WebMemos" as H.R. 2454 was developed, then released in a report. The analysis is limited to carbon dioxide emission reductions from the energy sector and is designed as HF/GI in this review. Congressional Budget Office: A fifth series of legislative analyses have been conducted by the Congressional Budget Office (CBO) on various aspects of H.R. 2454 during its movement through the House of Representatives. These analyses address budgetary, household, and other impacts of the bill, and are incorporated in this report. American Council for Capital Formation/National Association of Manufacturers: A sixth analysis has been conducted for the American Council for Capital Formation (ACCF) and National Association of Manufacturers (NAM) by Science Applications International Corporation. The report is entitled Analysis of The Wa x man-Markey Bill "The American Clean Energy and Security Act of 2009" ( H.R. 2454 ) Using The National Energy Modeling System (NEMS) . The report states that it includes assumptions about renewable portfolio standards and energy efficiency standards. Employing EIA's NEMS model, the ACCF/NAM study presents a "low cost" case with several restrictions on technology availability, and is designed as ACCF-NAM/NEMS in this review. The analysis also includes a "high cost" sensitivity case that uses some of the most constrained and high-cost assumptions of any of the analyses presented here, and is discussed here as appropriate Massachusetts Institute of Technology: A seventh analysis has been conducted by the Massachusetts Institute of Technology (MIT) Joint Program on the Science and Policy of Global Change. The report is an appendix to a more comprehensive analysis of cap-and-trade programs released in April 2009. The appendix is titled: Appendix C : Analysis of the Waxman-Markey American Clean Energy and Security Act of 2009 ( H.R. 2454 ) . The appendix employs MIT's EPPA CGE model and presents sensitivity analyses of H.R. 2454 's offset provisions. The case that incorporates a gradual increase in available offsets (entitled " H.R. 2454 with Medium Offsets") is designated MIT/EPPA in this report. Beyond these more comprehensive studies of H.R. 2454 , there have been numerous more focused efforts, generally targeting specific economic issues. These reports are generally presented in short presentation formats with limited documentation. Most have to do with electricity price impacts and are discussed at an appropriate time later in the report. Beyond specific caveats each of these analyses has, there are some more general caveats the reader should keep in mind when comparing them to each other: First, the different studies analyze the impact of H.R. 2454 at different stages of its development. The NBCC/CRA analysis is of the bill as introduced in April 2009. The EPA analyses is of the bill as reported by the Energy and Commerce Committee in May 2009. The EIA, ACCF/NAM, and MIT analyses are of the bill as passed by the House. The version analyzed by the Heritage Foundation depends on the date of the WebMemo or other presentation of the results, although its allowance allocation scheme is generally based on a memorandum by Representatives Waxman and Markey dated May 14, 2009. Likewise, analyses by CBO reflect the legislative point in the debate where the analysis was done. At each stage of the legislative process, changes were made to the bill that affect the compliance costs and the distribution of allowance value. Second, H.R. 2454 is a comprehensive energy and environmental bill (not just a cap-and-trade bill), and the studies differ in terms of the scope of their analyses . The NBCC analysis focuses on the cap-and-trade program (including bonus allowances for carbon capture and storage, and the impact of free allowance allocations on regional and U.S. welfare impacts) and the combined renewable energy and energy efficiency standard for electricity (RES) in Title I of the bill. The EPA analyses include these areas, along with State Energy and Environmental Development (SEED) accounts, and an explicit analysis of the allocation of allowances to trade-exposed, energy-intensive industries. The EIA analysis includes the cap-and-trade program, the combined energy efficiency and renewable energy standard for electricity, carbon capture and sequestration provisions, and various energy efficiency provisions (e.g., lighting standards). The Heritage Foundation study is limited to carbon dioxide emissions from the energy sector; other sectors are not incorporated in their analysis. The ACCF-NAM analysis discusses the impact of H.R. 2454 in terms of the cap-and-trade provisions, renewable portfolio standards, energy efficiency standards, and supposed low-carbon fuel standards. The MIT analysis includes the combined renewable energy and energy efficiency standard for electricity in Title I along with the cap-and-trade provisions in Title III. Third, the studies examined in this report are published with different levels of documentation, making comparative analysis difficult. Each study's sponsor has selected features or impacts it is particularly interested in highlighting, and presentations of projections that emphasize those points. In order to increase the comparability of the various cases examined here, CRS has converted all publicly available data presented by the cases to 2005 dollars (where appropriate) and interpolated missing data where possible. Likewise, where studies have stated they used specific projections as a reference case (such as EIA's Annual Energy Outlook 2009 projections), CRS has assumed those assumptions have not been altered except as specifically stated by the study. In some cases, the authors of the reports were contacted in order to clarify assumptions or results. Finally, CRS has attempted to present projections in the most comparable fashion possible . Fourth, a special note with respect to the RES is appropriate . As noted above, seven cases (EPA/ADAGE, EPA/IGEM, NBCC/CRA, EIA/NEMS,ACCF-NAM/NEMS, CBO, and MIT/EPPA) clearly included the RES in their analyses. EPA and CRA do not highlight any significant cost increases directly resulting from implementing RES, while EIA states that no additional costs are entailed by compliance with the RES as sufficient renewable energy is incorporated in the baseline. Likewise, CBO finds that the RES requirement is not binding.