In 2009, approximately 4 trillion kilowatt hours of electricity were generated by the U.S. power sector. By 2035 electricity generation is expected to rise to more than 5 trillion kilowatt hours, a roughly 25% increase from 2009 levels. The fuel mix for U.S. electricity generation includes four primary categories: (1) coal, (2) natural gas, (3) renewables, and (4) nuclear. As illustrated in Figure 1 , coal is the largest electricity generation fuel source for both actual (2009) and projected (2035) generation. However, EIA projects that natural gas and renewables are the only fuel sources that would experience growth, in terms of percentage of the electricity generation mix, over the projection period. During his January 25, 2011 State of the Union speech, President Obama proposed a Clean Energy Standard (CES) policy framework that would result in 80% of U.S. electricity generation coming from "clean energy" sources by 2035. "Clean energy," as described by President Obama, would include renewables, nuclear power, and partial credits for clean coal and efficient natural gas. While there is no official definition, a federal Clean Energy Standard might be defined as a requirement to generate a percentage of electricity from certain energy sources. It is a policy designed to encourage U.S. electricity generation from "clean" or "cleaner" energy sources within a certain time period. Many CES proposals require individual utility companies to comply with a federal CES, although some utilities may be exempt from CES requirements based on their total amount of annual electricity sales. Generally, utilities can comply with CES requirements through a combination of (1) electricity generation from qualified clean energy sources, (2) purchasing clean energy credits, and (3) making alternative compliance payments (ACPs). Each of these will be discussed below. Previous CES proposals have addressed multiple policy design parameters, including (1) technologies that qualify, (2) base quantities of electricity, (3) goals and requirements, (4) alternative compliance payments. Understanding the implications and inter-relationships of these parameters is an important element of CES policy design and will assist Congress with considering if overall objectives such as increasing clean energy generation, minimizing rate payer impacts, and job creation are likely to be achieved. This report evaluates design elements of previous CES proposals, summarizes the Administration's CES policy framework, provides state-level baseline CES compliance analysis, and presents several policy options that Congress might consider as part of a CES debate. During the 111 th Congress several Clean/Renewable Energy Standard policies were proposed, although none became law. In order to provide background on previously proposed CES legislation, four proposals were analyzed and compared against multiple design parameters (See Table 1 ). A more detailed analysis of these proposals is presented in a side-by-side comparison matrix that can be found in Appendix A . All proposals were compared in order to assess areas of commonality and divergence. While not an all-inclusive or exhaustive list, following is a brief overview and discussion of the design elements considered for this analysis. The base quantity of electricity is a critical Clean Energy Standard design element as it establishes the amount of electricity, typically measured in kilowatt-hours, that applies to CES goals and requirements. Proposals analyzed have base quantity definitions that range from 100% of utility power sales to sales less the amount of power generated by hydro-electricity and municipal solid waste (MSW) incineration. A hypothetical example of how different utilities might derive their respective CES base quantities in the latter case is provided in Table 2 . Clean Energy Standard targets and goals set the percentage of electricity that must be generated from clean energy sources by a certain date. The percentage articulated in a CES proposal is applied to the base quantity of electricity to calculate the number of kilowatt-hours that must be generated from clean energy sources in order to achieve compliance by a certain date. Examples of CES targets/goals include (1) 50% of base quantity by 2050, (2) 15% of base quantity by 2039, and (3) 15% of base quantity by 2020. Defining and determining which energy sources will qualify under a CES proposal could be a design element worthy of consideration. A clear definition of qualifying sources is important as it allows a utility company to determine which electricity generation options are available for compliance. Each of the four proposals analyzed in this paper include typical renewable energy as qualified sources. All four proposals also include coal-mine methane and landfill gas as qualifying sources. Differences among the proposals, generally, are associated with the inclusion and definition of qualified hydropower and incremental geothermal as well as the inclusion/definition of waste-to-energy, qualified nuclear, advanced coal/fossil with carbon capture and storage, and re-powering/co-firing biomass at existing coal generation facilities. Energy efficiency/savings typically refers to reductions in electricity consumption at end-use consumer facilities that are served by an electric utility company as well as reductions in distribution system losses. Some proposals also include output from combined heat and power systems as energy efficiency/savings. In order to qualify for energy efficiency/savings credits, utility companies may have to institute programs that result in consumer demand reductions. One example of such a program might be subsidies for high efficiency air conditioning systems. All four proposals analyzed allow for energy efficiency/savings credits, although some proposals place limits on how much energy efficiency/savings credits can be used to comply with a broader Clean Energy Standard. For example, one proposal allows utility companies to use energy efficiency credits to satisfy up to 25% of the CES target. Therefore, 75% of a utility company's CES target must be met by generating electricity from qualified sources, purchasing CES credits, or making alternative compliance payments. One challenge associated with energy efficiency/savings credits might be determining a baseline for calculating energy efficiency and therefore the number of credits that result from various energy efficiency programs. Alternative compliance payments (ACPs) can be paid by utility companies in lieu of generating qualified clean energy or purchasing clean energy credits. Typically expressed in cents per kilowatt-hour, ACPs provide utility companies with some degree of flexibility associated with meeting the targets/goals of a Clean Energy Standard. From a policy perspective, determining the value of ACPs can be somewhat complicated. Setting the ACP too low could potentially result in minimal development of "clean" electricity generation because some companies might choose to pay the ACP instead of generating or purchasing qualified clean energy. At the same time rate payer costs may increase as utility companies seek to recover their compliance costs. However, setting the ACP value too high might result in relatively large electricity rate increases in areas/regions that lack clean energy resources. Nevertheless, ACPs are basically a cost containment mechanism that effectively place a cap on the value of clean energy credits. Determining the value of ACPs will likely involve comparing the cost of generation from all qualified sources to the lowest generation cost from any fuel (e.g., coal, natural gas, nuclear, renewable) source. Some proposals suggest that funds generated through receipt of ACPs will be used to provide grants in support of new "clean energy" electricity generation projects. Under most of the four Clean Energy Standard proposals, utilities would be awarded credits for each kilowatt-hour of electricity generated from qualified clean energy sources. Utility companies can submit clean energy credits as a means of compliance with annual CES requirements. If a utility has more CES credits than are required for a given year, the utility may either "bank" the excess clean energy credits for a certain period of time or the utility can trade the excess credits, in exchange for cash, to other utilities. For those proposals that allow energy efficiency to count towards CES compliance, energy efficiency credits are typically handled in a similar manner. Details regarding the mechanics of how CES credit trading may work are not clearly defined in the four proposals analyzed and responsibility for establishing trading programs is delegated to the Secretary of Energy. Three of the four CES proposals analyzed include provisions for double and triple credits. Multiple credits could be an approach that further incentivizes certain types of clean energy projects or the development of projects in certain locations. Some examples of projects that might receive multiple credits include (1) projects on Indian lands, (2) on-site electricity generation, (3) first five advanced coal facilities that sequester 1 million tons per year of carbon dioxide (CO 2 ), among others. Some CES proposals include provisions that allow demonstration projects to receive clean energy credits. For example, S. 20 would provide clean energy credits for advanced coal demonstration projects, based on the amount of CO 2 that is captured and sequestered. Providing credits for demonstration projects might be viewed as an incentive to develop, deploy, and commercialize emerging clean technologies. Most CES proposals include a civil penalty for utilities that fail to comply with CES requirements. Civil penalties are typically computed by multiplying the annual kilowatt-hour target shortfall times a multiple of the alternative compliance payment (e.g., 200% of the ACP—inflation adjusted). In some cases, CES proposals may exempt certain utility companies from compliance. Two of the four proposals analyzed exempt utilities that sell less than 4 million megawatt -hours of electricity in the preceding year. All utility companies in Hawaii are also exempt. Some CES proposals empower the Secretary of Energy to make loans to support the development of qualified clean energy projects. The purpose of the loans is to assist with CES compliance and reduce cost impacts to utilities and retail consumers. On January 25, 2011, during the State of the Union address, President Obama announced a clean energy goal for the country: "By 2035, 80% of America's electricity will come from clean energy sources."