On June 29, 2006, the Senate Committee on Appropriations reported H.R. 5427 , the Energy and Water Appropriations bill for FY2007 ( S.Rept. 109-274 ). This bill includes funding for the Department of Energy (DOE) Renewable Energy Program, which is conducted by the Office of Energy Efficiency and Renewable Energy (EERE). Compared with House-passed funding, the FY2007 Senate Appropriations Committee recommendation seeks an increase of $66.1 million (5%). Table 3 shows other differences, most notably those for Biomass & Biorefinery, Geothermal, Hydro, and Weatherization programs. Compared with FY2006 funding, the Senate Committee recommends an increase of $240.4.8 million for R&D and deployment programs. This reflects support for the Advanced Energy Initiative, including increases for Hydrogen ($34.2 million), Biomass/Biorefineries ($59.3 million), and Solar ($65.3 million). The main cuts include the Weatherization program (-$42.6 million), Facilities (-$20.2 million), Industrial programs (-$9.3 million), and Program Management (-$9.9 million). (The renewable energy provisions in the Energy Policy Act of 2005 [ P.L. 109-58 , H.R. 6 ] and other bills of the 109 th Congress are discussed in the " Renewables in the 109 th Congress " and " Legislation " sections below. A list of all renewable energy bills introduced in the 109 th Congress is provided in CRS Report RL32860, Energy Efficiency and Renewable Energy Legislation in the 109 th Congress , by [author name scrubbed].) Renewable energy is derived from resources that are generally not depleted by human use, such as the sun, wind, and water movement. These primary sources of energy can be converted into heat, electricity, and mechanical energy in several ways. There are some mature technologies for conversion of renewable energy such as hydropower, biomass, and waste combustion. Other conversion technologies, such as wind turbines and photovoltaics, are already well developed, but they have not achieved the technological efficiency and market penetration that many expect they will ultimately reach. Although geothermal energy is produced from geological rather than solar sources, it is often included as a renewable energy resource (and is treated as such in this report). Commercial nuclear power is not generally considered to be a renewable energy resource. According to the Energy Information Administration's (EIA's) Annual Energy Outlook 2006 , renewable energy resources (excluding wood used for home heating) supplied about 5.7 Q (quadrillion Btu's, or quads) of the 99.7 Q the nation used in 2004, or about 6.0% of national energy demand. More than half of renewable energy production takes the form of electricity supply. Of this, most is provided by large hydropower. However, from 1998 through 2001, a drought-driven decline in hydroelectric availability led to a major drop in national renewable energy use. Industrial use of renewables, supplied primarily by biofuels, accounts for most of the remaining contribution. Some note that renewable energy, after more than 25 years of federal support, has achieved neither a high level of market penetration nor a growing market share among other energy sources. A 1999 review of renewable energy studies by Resources for the Future ( Renewable Energy: Winner, Loser, or Innocent Victim? ) concludes that the lower-than-projected market penetration and flat market share were due primarily to declining fossil fuel and electricity prices during most of that period. In contrast, however, it notes that the costs for renewable energy technologies have declined by amounts equal to or exceeding those of earlier projections. Nevertheless, the costs are still higher than those for conventional energy. Even wind energy, which has a much lower cost than solar energy technologies, owes its recent commercial success to support from the federal renewable energy production tax credit and the renewable portfolio standard (RPS) that many states have put in place. EIA's Annual Energy Outlook 2006 projects that current policies would yield a 1.8% average annual increase in renewable energy production to 9.0 Q through 2030, resulting in a 57% total increase. This would amount to about 6.7% of the projected 134 Q total demand in 2030. Our Common Future , the 1987 report of the United Nations World Commission on Environment and Development, found that "energy efficiency can only buy time for the world to develop 'low-energy paths' based on renewable sources." Though many renewable energy systems are in a relatively early stage of development, they offer "a potentially huge primary energy source, sustainable in perpetuity and available in various forms to every nation on Earth." The report suggested that a research, development, and demonstration (RD&D) program of renewable energy projects is required to attain the level of primary energy now obtained from a mix of fossil, nuclear, and renewable energy resources. The Agenda 21 adopted at the 1992 United Nations Conference on Environment and Development (UNCED, "Earth Summit") concluded that mitigating urban air pollution and the adverse impact of energy use on the atmosphere—such as acid rain and climate change—requires an emphasis on "clean and renewable energy sources." The U.N. Division on Sustainable Development oversees implementation of Agenda 21. The 2002 U.N. World Summit on Sustainable Development (Johannesburg Earth Summit) adopted a Political Declaration and a Plan of Implementation , which includes "Clean Energy" as one of five key policy actions. Subsequently, in 2003, the U.S. Department of State implemented a $42 million Clean Energy Initiative and the European Union committed to a $700 million energy partnership. Nevertheless, EIA estimates that renewable energy's share of global energy consumption through 2030 will remain limited to less than 9% for the next two to three decades. The oil embargo of 1973 sparked a quadrupling of energy prices, major economic shock, and the establishment of a comprehensive federal energy program to help with the nation's immediate and long-term energy needs. During the 1970s, the federal renewable energy program grew rapidly to include basic and applied R&D and federal participation with the private sector in demonstration projects, commercialization, and information dissemination. In addition, the federal government instituted market incentives, such as business and residential tax credits, and created a utility market for nonutility-produced electric power through the Public Utility Regulatory Policies Act ( P.L. 95-617 ). The subsequent failure of the oil cartel and the return of low oil and gas prices in the early 1980s slowed the federal program. Despite Congress's consistent support for a broader, more aggressive renewable energy program than any Administration, federal spending for these programs fell steadily through 1990. Until 1994, Congress led policy development and funding through legislative initiatives and close reviews of annual budget submissions. FY1995 marked a noteworthy shift, with the 103 rd Congress for the first time approving less funding than the Administration had requested. The 104 th Congress approved 23% less than the Clinton Administration request for FY1996 and 8% less for FY1997. However, funding turned upward again during the 105 th and 106 th Congresses, and stayed relatively flat through the 107 th and 108 th Congresses and the first session of the 109 th Congress. From FY1978 through FY2005, the DOE spent about $13.4 billion (in 2005 constant dollars) for renewable energy R&D. Renewable energy R&D funding grew from less than $1 million per year in the early 1970s to more than $1.4 billion in FY1979 and FY1980, then declined steadily to $148 million in FY1990. By FY2005, it reached $380 million in 2005 constant dollars. This spending history can be viewed within the context of DOE spending for the three major energy supply R&D programs: nuclear, fossil, and energy efficiency R&D. From FY1948 through FY1977 (in 2005 constant dollars), the federal government spent about $42.6 billion for nuclear (fission and fusion) energy R&D and about $14.1 billion for fossil energy R&D. From FY1978 through FY2005, the federal government spent $33.9 billion for nuclear (fission and fusion), $21.1 billion for fossil, $13.4 billion for renewables, and $12.4 billion for energy efficiency. Thus, total energy R&D spending from FY1948 to FY2005, in 2005 constant dollars, reached $140.0 billion, including $76.5 billion, or 55%, for nuclear; $35.2 billion, or 25%, for fossil; $13.4 billion, or 10%, for renewables; and $12.4 billion, or 9%, for energy efficiency. In FY2006, as part of a restructuring of the appropriations committees, Congress merged appropriations accounts for the DOE Energy Efficiency Program, which previously had been under the Department of Interior and Related Agencies Appropriations Bill, with the appropriations accounts for the DOE Renewable Energy Program under the Energy and Water Development Appropriations Bill. As a result, appropriations for some subprograms of the Renewable Energy Program, such as Hydrogen and Program Management, are commingled with those for the Energy Efficiency Program and are no longer reported separately. In place of the former totals for the Renewable Energy Program, this report now shows a subtotal of appropriations for all of the renewable energy technology subprograms, namely Biomass and Biorefinery, Solar, Wind, Geothermal, and Small Hydro subprograms (see Table 3 ). The total for these subprograms was $242.5 million for FY2005 and $236.2 million for FY2006. The Energy Tax Act of 1978 ( P.L.