In the United States, growing awareness of greenhouse gas (GHG) emissions and the possible implications for global climate change have combined with recent high energy prices and economic uncertainty to rekindle interest in renewable energy. Fossil fuels have long met the needs of economic growth, which has been a primary driver of energy demand worldwide. But with half of electric power in the United States currently generated from coal, electric power generation is responsible for 40% of domestic carbon dioxide emissions (the primary anthropogenic GHG), and over one-third of all U.S.GHG emissions. The prospect of federal climate change mitigation policies is seen as spurring the growth of renewable energy in the near future. Renewable energy technologies generate electricity from resources such as the sun, wind, or biomass, with essentially no net GHG emissions. Approximately 567,000 people are employed in the utilities sector in the United States. With renewable energy technologies accounting for about 10 percent of total U.S. energy production, jobs in renewable energy currently represent a small part of this overall workforce. President Obama has declared a goal for the United States to become the world's leading exporter of renewable energy technologies, setting out policy objectives for the development of related "green jobs" and the investment of $150 billion over 10 years in energy research and development (R&D) for the next generation of energy technologies. The American Recovery and Reinvestment Act of 2009 (ARRA, P.L. 111-5 ) included more than $60 billion for clean energy investments, including $6.3 billion for state and local efforts in renewable energy and energy efficiency, and $500 million for jobs training to help prepare workers for careers in energy efficiency and renewable energy. Other drivers are also pushing the growth of renewable energy and energy efficiency. Renewable energy technologies can provide clean electricity to help meet regional air quality standards. Goals of energy independence and energy security can also be advanced if trends in fuel efficiency continue and automotive vehicles become significantly powered by electricity from renewable sources. Additionally, as part of corporate social responsibility, many corporations are embracing sustainability as a core principle and consider "green," renewable energy goals as part of the same concept. Industrial processes and supply-chain operations are being examined and redesigned to key on low carbon emission, environmentally-friendly solutions as part of the corporation's perceived overall responsibility to its customers and the communities impacted by its operations. If such changes are adopted across the economy and incorporated into business norms, green, sustainable practices will then become standard for business operations. This report will examine the current debate on green jobs, looking at the different renewable energy technologies to provide a context for the discussion of the potential for green jobs and issues associated with maximizing growth in the renewable electricity sector. Current policy discussions of shifting the nation toward greater use of renewable sources of energy production almost inevitably have included the subject of green jobs. Although there is no consensus on the term's meaning, it often has been defined to include at a minimum jobs that result directly from increasing reliance on renewables for generating electricity and powering vehicles as well as jobs that result directly from achieving greater energy efficiency. Less often, green jobs have been defined to also include employment that results directly from reducing and mitigating pollution and from conserving natural resources (e.g., water). To this direct employment (i.e., direct jobs), indirect and induced employment are sometimes added as well. A variety of researchers, usually with the financial support of advocacy groups, have operationalized the diverse definitions of green jobs in order to estimate the number of green jobs at present or at some time in the future. The estimates are based on varying assumptions about, for example, the percentage of U.S. electricity that will be generated by different combinations of renewable resources in the coming decades or the level of public and private sector investments in various renewable energy sources. Less often, the job estimates are based on firm-specific information about the number of persons who are currently employed producing green goods (e.g., solar panels) or providing green services (e.g., energy audits). As a consequence of differences in definitions, assumptions, and methodologies, analysts have produced widely divergent estimates of current and prospective green jobs. Complicating the estimation of the number of green jobs is the absence of an authoritative data source. Federal statistical agencies, such as the Bureau of Economic Analysis and the Bureau of Labor Statistics (BLS), categorize the data they collect according to the North American Industry Classification System (NAICS). In the case of the utility industry, for example, NAICS disaggregates firms into the categories of hydro, fossil fuel, nuclear and "other" sources. NAICS does not disaggregate the "other" category into those that use renewable sources of electricity production such as wind, solar and biomass. Because renewables are part of the "other" category, no government series provides data on their output and employment. Analysts consequently have developed ways to address the data deficiency, although their methods usually are not clearly articulated. For its part, the government agency responsible for labor force statistics, BLS, has requested funding for FY2010 to develop data on the number of green jobs and their characteristics (e.g., wages, training requirements) by industry and occupation. Industry statistics are expected to be available in FY2011. In addition, much of the empirical research has estimated only the numbers of green jobs. Estimation or discussion of the net impact on total U.S. employment generally is lacking. Net estimates take into account jobs throughout the economy eliminated or forgone in addition to those created to advance toward a low-carbon environmentally friendly economy. Similarly, the literature does not take into account factors, such as supply constraints (e.g., a tight labor market) and improvements in labor productivity (i.e., output per hour worked), that could affect attainment of estimated levels of green employment. A review of several analyses of the number of green jobs associated specifically with the use of renewable energy sources is presented below. The distinctions between definitions, assumptions and methodologies of green job studies are addressed when possible. (1) Management Information Services, Inc. (MISI) prepared the report Defining, Estimating, and Forecasting the Renewable Energy and Energy Efficiency Industries in the U.S. and in Colorado for the American Solar Energy Society. The economic research firm developed the following definition of the renewable energy (RE) "industry": an employee working in one of the major RE technologies included in this report – wind, photovoltaics, solar thermal, hydroelectric power, geothermal, biomass (ethanol, biodiesel, and biomass power), and fuel cells and hydrogen. In addition, in this study, jobs in RE include persons involved in RE activities in the federal, state, and local governments, universities, trade and professional associations, NGOs, consultants, investment company analysts, etc. MISI estimated that there were 217,600 direct jobs in the domestic RE industry in 2007. The great majority (154,100 or 70%) were in the biomass segment, chiefly ethanol and biomass power. MISI further estimated the number of indirect and induced jobs supported by the RE industry to be more than twice the number of direct jobs. Although MISI included induced jobs, it acknowledged that some jobs are less green than others (e.g., "ancillary jobs created across the street from a factory producing solar collectors shortly after it opens, such as a doughnut shop, fast food restaurant, dry cleaner, etc. whose customers are primarily the workers at the renewable energy factory"). Based on this broad definition, the report states that there were a total of 503,500 (direct, indirect and induced) jobs in the RE industry in 2007. MISI took the analysis further by specifying, in vague terms, three scenarios for the future use of RE and projecting associated job creation. The base case is a "business as usual" scenario "based loosely on the EIA [Energy Information Administration] reference case." The base case scenario yields a direct, indirect, and induced job total of 1.3 million in 2030. The moderate scenario, which assumes among other things an increase over the base case in government RE initiatives, produces a total of 2.8 million jobs in 2030. The advanced scenario "pushes the envelope" in terms of what might be economically and technologically feasible as a result of greatly heightened government support for RE through 2030. Under the study's most ambitious assumption of RE utilization almost 20 years in the future, 7.3 million direct, indirect and induced jobs might be created. The analysis does not estimate the impact of labor market conditions on achieving the job projections. If the unemployment rate is low in 2030, there might not be sufficient numbers of jobless workers to fill the projected RE positions. RE employment would either be less than forecast or the jobs would be filled largely by individuals working elsewhere in the economy. In the latter case, job growth in the RE industry would to some degree come at the expense of employment in other industries. The study also does not estimate the number of jobs that might be forgone or lost due to reduced production of energy from fossil fuel sources. (2) The Renewable and Appropriate Energy Laboratory (RAEL) at the University of California-Berkeley prepared Putting Renewable s to Work: How Many Jobs Can the Clean Energy Industry Generate? The researchers developed three scenarios which assume that a 20% Renewable Portfolio Standard (RPS) would be attained by 2020, and that electricity demand in 2020 would remain unchanged from 2002 (with gains in efficiency offsetting the usual 2%-3% annual increase in demand). The difference between the three scenarios is the proportions of the RPS composed of biomass (wood and waste) electricity, wind energy and photovoltaic (PV) solar. Two additional scenarios were developed in which the 20% of electricity produced by renewables in the first three scenarios is instead produced by different mixes of fossil fuels. All five scenarios are shown in Table 1 .