Carbon dioxide is by far the most prevalent of the greenhouse gases— gases that trap heat in the atmosphere—emitted in the United States, accounting for about 85 percent of emissions. The other principal greenhouse gases are methane, nitrous oxide, and three types of synthetic gases—hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride. Like carbon dioxide, methane and nitrous oxide are released during the combustion of fossil fuels by stationary and mobile sources. Hydrofluorocarbons are emitted from refrigerants that leak from chillers and air-handling units. Perfluorocarbons and sulfur hexafluoride are generally not emitted by legislative branch operations. Each greenhouse gas has a global warming potential—a measure of its heat-trapping ability relative to that of carbon dioxide. For example, methane is 21 times more potent than carbon dioxide, so its global warming potential is 21. Global warming potentials are used to convert emissions of non-carbon-dioxide gases into their carbon dioxide equivalents to allow comparisons of the total cumulative warming effects of different greenhouse gases. Carbon dioxide equivalents are calculated by multiplying the emissions of the non-carbon-dioxide gas by its corresponding global warming potential (see app. I for a list of the global warming potentials of the principal greenhouse gases). The common unit of measure for reporting greenhouse gas emissions is metric tons of carbon dioxide equivalents. Legislative branch operations generate greenhouse gas emissions from the combustion of fossil fuels in the Capitol Power Plant; business travel in government-owned and -leased vehicles; the use of heavy machinery; the release of VOCs in furniture and print shops; fugitive emissions, such as leaks in refrigeration equipment and fuel tanks; the combustion of fossil fuels in emergency generators; and the consumption of purchased electricity, natural gas, steam, and chilled water. AOC, GAO, and GPO have jurisdiction over the majority of these sources through their management of legislative branch property. While AOC operates the facilities within the Capitol complex, LOC, CBO, the Senate, and the House of Representatives are responsible for their own energy consumption. These entities also procure their own office equipment, and own and lease vehicles independent of AOC. In addition, the Senate and House of Representatives run the operations of their own furniture shops that perform wood refinishing, painting, and upholstery, and the Senate operates its own print shops. LOC also leases facilities independent of those managed by AOC. Table 1 shows the number of facilities, vehicles, and other property managed by each entity. The Capitol Power Plant produces steam and chilled water for the majority of the Capitol complex, as well as steam for GPO. Steam is used for heating buildings and hot water, as well as for cooking and humidification. Chilled water is used for cooling buildings and equipment, as well as for dehumidification. Two of the Capitol Power Plant’s seven boilers are coal-fired units with auxiliary gas burners, and the other five run on natural gas or oil. AOC uses a mix of fossil fuels—coal, oil, and natural gas—in the Capitol Power Plant to help ensure continuity of operations in case of a supply shortage or an increase in the price of one of the fuels. Ten chillers in the Capitol Power Plant’s refrigeration plants run on electricity to generate chilled water. In addition to the steam and chilled water produced by the Capitol Power Plant, AOC purchases steam and chilled water from GSA for one building under its jurisdiction (the Ford House Office Building), and GAO also purchases its steam from GSA. GAO has six electric-powered chillers and GPO has three electric-powered chillers that produce chilled water for these agencies. The legislative branch agencies purchase their electricity primarily from Pepco Energy Services and natural gas from Washington Gas. Options to reduce emissions include projects that can be divided into five categories—energy efficiency, renewable energy, adjustment of power plant fuel mix to include less carbon-intensive fuel, energy curtailment, and offsets. Energy efficiency means using less energy to produce a given level of service or an increase in output for the same amount of energy. Energy-efficiency projects include enhancing the energy efficiency of equipment, installing a cogeneration (combined heat and power) system, and upgrading vehicles to more fuel-efficient models. Renewable energy is derived from resources that are generally not depleted by human use, such as the sun, wind, and water movement. In most cases, renewable energy releases less carbon dioxide than fossil fuels. Renewable-energy projects include purchasing renewable energy, generating renewable energy on site, procuring alternative-fuel vehicles, and adjusting power plant fuel mix to include renewable fuels. In addition to adjusting the fuel mix to include renewable fuels, adjustments could be made to the fuel mix to use less carbon-intensive fuel, such as natural gas. Energy curtailment means a decrease in activity to reduce energy consumption, such as turning off lights when not in use. Finally, offsets refer to projects that would reduce or remove emissions outside an entity’s sphere of operations and are generally used to supplement other projects that directly reduce emissions. Legislative branch operations generated about 316,000 metric tons of greenhouse gas emissions (expressed in carbon dioxide equivalents) in fiscal year 2006. Electricity use was the largest source of emissions, accounting for 198,989 metric tons, or approximately two-thirds (63 percent) of total emissions (see fig. 1). Electricity purchased by legislative branch agencies is generated primarily from the combustion of fossil fuels, such as coal, oil, and natural gas. The second-largest source of emissions was the combustion of fossil fuels—primarily coal and natural gas—in the Capitol Power Plant to produce steam for the majority of the legislative branch buildings. The Capitol Power Plant produced 102,659 metric tons of greenhouse gas emissions in fiscal year 2006, or approximately one-third (32 percent) of total emissions. In addition, the consumption of purchased natural gas, steam, and chilled water each accounted for approximately 1 percent of the greenhouse gas emissions from legislative branch operations. The natural gas was used to heat buildings within the Capitol complex that do not receive steam from the Capitol Power Plant, to operate appliances in GAO’s cafeteria, and as part of the printing process at GPO. Finally, business travel in government- owned and -leased vehicles and the use of heavy machinery, the release of VOCs in furniture and print shops, the combustion of fossil fuels in emergency generators, and leaks in refrigeration equipment at the Capitol Power Plant each accounted for less than 1 percent of emissions. Our analysis of emissions by type of greenhouse gas showed that carbon dioxide represented 99 percent of total emissions from legislative branch operations in fiscal year 2006. Hydrofluorocarbons, nitrous oxide, and methane made up the remaining 1 percent of emissions. Although nitrous oxide and methane emissions were generated from multiple sources and hydrofluorocarbons were generated from a sole source—R-134a refrigerant that escaped from two chillers at the Capitol Power Plant through a gasket leak between June and August 2006— hydrofluorocarbons represented the majority of the non-carbon-dioxide emissions, in part because of R-134a’s high global warming potential. Overall, greenhouse gas emissions generated by legislative branch operations in fiscal year 2006 increased 4 percent from the annual average quantity emitted in fiscal years 1998 through 2001 (see fig. 2). Factors that could have influenced emissions trends—and may continue to influence trends in the future—include emissions reduction projects and changes in square footage of buildings, weather, numbers of employees, operating hours, security measures, sources of production, energy prices, and numbers of vehicles. Despite the overall increase in emissions, there was one notable decrease in emissions during this time period—a 6 percent decrease from fiscal year 2003 to fiscal year 2004. The 6 percent decrease can likely be attributed to AOC’s purchase of renewable energy from Pepco Energy Services during an 8-month period beginning in September 2003. The most recent decrease in emissions (1 percent), from fiscal year 2005 to fiscal year 2006, was likely influenced by two factors: a change in the fuel mix at the Capitol Power Plant that was due to a malfunction in the coal-fired boilers, which required AOC to replace some coal with more expensive—but less emissions-intensive—natural gas; and lower fuel consumption that was due to more moderate temperatures. Emissions trends varied by agency (see app. IV for emissions trends by agency). For example, GPO emissions decreased 28 percent primarily due to a reduction in staff levels. A strategy for reducing emissions includes conducting energy audits to identify and evaluate energy-efficiency and renewable-energy projects, as well as evaluating other emissions reduction projects that may fall outside the scope of energy audits. The strategy would also involve developing an implementation plan that considers cost-effectiveness, the extent to which the projects reduce emissions, and funding options. Conducting energy audits would assist the legislative branch in addressing the largest sources of emissions—the consumption of purchased electricity and fossil fuel combustion in the Capitol Power Plant—because these audits identify cost-effective systemwide energy-efficiency and renewable-energy projects. Energy audits typically include information on projects that could address these emissions sources, as well as projects that could reduce emissions from other sources, such as the consumption of purchased natural gas and leaks in refrigeration equipment. Energy audits also include information on the cost-effectiveness of projects and on the extent to which the projects could reduce emissions, which assist agencies in evaluating and selecting projects. In general, projects identified by energy audits as generating savings sufficient to pay for the capital costs of the projects are deemed cost-effective. Other projects identified through the energy audits may partially pay for themselves and could be considered cost-effective relative to other projects. Energy- efficiency projects are generally more cost-effective than renewable- energy projects because many renewable-energy projects are not cost competitive when compared with more traditional sources of power. There are three main types of energy audits—preliminary, targeted, and comprehensive. Each type is distinguished by the level of detail and analysis required to complete the audit. Less detailed audits include less accurate estimates of project costs and energy savings. Preliminary energy audits are the least detailed and provide quick evaluations to determine a project’s potential. These energy audits do not provide sufficiently detailed information to justify investing in the identified projects. Instead, preliminary audits are primarily used to decide if a more detailed evaluation is necessary. Targeted audits are detailed analyses of specific systems, such as lighting or boiler replacement. Comprehensive audits are detailed evaluations of all major energy-using systems. Targeted and comprehensive audits provide sufficiently detailed information to justify investing in projects. AOC, GAO, and GPO commissioned six preliminary, four targeted, and one comprehensive energy audit of some of their facilities from fiscal years 1998 through 2006. AOC commissioned preliminary audits of the Capitol in June 2000, the Rayburn House Office Building in April 2003 and December 2003, the Hart Senate Office Building in December 2003, and the LOC Madison Building in May 2005. These audits identified cost-effective projects, meeting the definition of cost-effectiveness found at 10 CFR §§ 436.18-436.22. For example, the energy audit of the LOC Madison Building identified 12 cost- effective projects with savings-to-investment ratios ranging from 1.02 to 3.87. It was estimated that these projects would reduce emissions from electricity by approximately 4,760 metric tons per year. However, according to agency officials, AOC has not followed up with energy audits that provide sufficiently detailed information to justify investing in projects at these facilities because of fiscal constraints. There are also approximately 27 buildings under AOC’s jurisdiction that have not had any type of energy audit. In the fiscal year 2008 budget, AOC requested $1.1 million to fund the first two years of a five-year plan to perform energy surveys of all its facilities. In addition to the energy audits, AOC has conducted Facility Condition Assessments and other studies of facilities in need of upgrades and repairs, which identified projects that would yield potential energy efficiency improvements. However, most of these projects have not been implemented. Since 2004, AOC has evaluated the viability of changing the Capitol Power Plant to cogeneration, which could provide steam, supplementary electricity, and backup power to the Capitol complex and reduce emissions by more efficiently capturing the energy output. AOC also began a project in 2001 to evaluate the clean coal technology alternatives to supplement or replace the existing Capitol Power Plant steam generating facilities to reduce emissions from burning coal. In addition, AOC took initial steps in response to legislation that required the agency to develop and implement a cost-effective energy conservation strategy. For example, AOC purchased a building automation system that will be used to operate mechanical and electrical systems more efficiently throughout the Capitol complex, purchased energy-efficient chillers to supplement production of chilled water at the Capitol Power Plant, and is evaluating proposals from contractors for installing energy conservation measures, including on-site renewable energy, on the rooftop of the Dirksen Senate Office Building. In 1999, GPO had a preliminary energy audit and chose to implement two of the projects identified as cost-effective—the replacement of its chillers and 15,000 light fixtures–after a targeted energy audit of the chillers in 2000. According to officials, GPO pursued only those projects with the shortest payback periods because of its limited budget and plans to relocate. GPO does not have a regular schedule for conducting energy audits. GAO had a comprehensive energy audit in 2002 and plans to have another comprehensive energy audit by fiscal year 2009. GAO also conducts a targeted energy audit of its facility every 2 years as part of its building assessment report. GAO has implemented the majority of the projects identified through its audits, such as installing optimization controls for the air-handling system and installing specialized software to decrease electricity use during periods of peak demand. In addition, GAO routinely considers other opportunities taking into account technology, price, and available funding. Legislative branch agencies have three methods for financing energy audits and implementing projects: energy savings performance contracts (ESPC), utility energy savings contracts (UESC), or direct appropriations. Congress authorized agencies to use ESPCs to privately finance energy- efficiency and renewable-energy projects in 1986. Under an ESPC, agencies enter into a long-term contract (up to 25 years) with a private energy services company under which the company conducts a comprehensive energy audit of the agency, then finances and implements projects approved by the agency. The agency then repays the company with the resulting energy savings. The energy audits of the Rayburn and Hart buildings were done through an initial proposal for an ESPC. UESCs are similar to ESPCs, but are offered by electric and gas utilities and can cover smaller projects. The third financing mechanism is direct appropriations. While GPO’s preliminary audit was conducted by Pepco Energy Services under an initial proposal for an UESC, GPO opted to fund the projects with direct appropriations. According to GPO officials, the projects cost $6 million and reduced the agency’s energy bills by $1 million a year. GAO funds its energy audits through direct appropriations and seeks funding for implementing projects in its annual budget requests. In 1995, DOE’s FEMP initiated the SAVEnergy Program, which provided funding for energy audits of federal facilities but not for project implementation. FEMP funding for SAVEnergy audits was eliminated in fiscal year 2006. Three energy audits—for the Capitol and the Rayburn and Madison buildings—were conducted under the SAVEnergy Program. In addition to projects identified through energy audits, a strategy would include evaluating other projects to reduce emissions that may fall outside the scope of energy audits, such as (1) projects to reduce electricity emissions by curtailing energy use, purchasing high-efficiency appliances, using renewable electricity, and considering the energy efficiency of facilities when constructing new facilities and before entering into leases; (2) projects to reduce emissions from the combustion of fossil fuels in the Capitol Power Plant by adjusting the fuel mix; (3) projects to reduce vehicle emissions by acquiring fuel-efficient vehicles and vehicles that run on renewable fuel; and (4) projects to reduce overall emissions by purchasing offsets. The cost-effectiveness, emissions reductions, and funding options for each of these projects would have to be evaluated on a case-by-case basis. Compared with projects identified through energy audits, several of these projects cost more to implement but could reduce emissions faster. Curtailing energy use: These projects would include enhancing outreach and education efforts to encourage building occupants to curtail their energy use. Examples of energy curtailment outreach efforts include a June 2006 memo from GAO management requesting all employees to help conserve electricity, AOC’s “how-to guides” distributed to Members of Congress and their staff detailing cost-effective methods to save energy in the workplace, and GPO’s goal-sharing program, which is an incentive award program that encourages employees to reduce energy consumption and splits the cost savings realized from these efforts equally between the agency and its employees. According to GPO, fiscal year 2006 energy savings totaled $558,604, for an estimated award of $126.27 per employee. Energy curtailment activities generally involve a trade-off between convenience and productivity, and energy use. Purchasing energy-efficient computer equipment and appliances: Energy-efficient products have been identified through two federal programs—the Energy Star Program and FEMP. Energy Star-qualified and FEMP-designated products meet energy-efficiency guidelines set by EPA and DOE and, in general, represent the top 30 percent most energy efficient-products in their class of products. These products cover a wide range of categories, including appliances and office equipment. According to the Energy Star program, office products that have earned the Energy Star rating use about half as much electricity as standard equipment and generally cost the same as equipment that is not Energy Star-qualified. Under section 104 of the Energy Policy Act of 2005, agencies are required to purchase Energy Star-qualified and FEMP-designated products. Some of the agencies have reported adopting such practices to further reduce emissions. For example, officials from AOC and GAO reported that they currently have all Energy Star-qualified information technology equipment. Purchasing renewable electricity: Renewable-energy certificates (REC) represent the environmental, social, and other positive attributes of electricity generated by renewable resources. RECs can be purchased independent of the associated electricity from a wholesale supplier or bundled with the electricity from a utility company. It is usually less expensive to buy RECs from a wholesale supplier because a supplier generally has access to a wider array of resources than a utility company. In both cases, purchasing RECs helps the electricity generator invest more money in renewable energy, increasing the amount of renewable electricity and decreasing the amount of fossil fuel electricity entering the country’s power supply. For 8 months beginning in September 2003, AOC purchased RECs from its utility, Pepco Energy Services—equal to 51,296,000 kilowatt hours, or approximately 15 percent of its annual electricity use. In November 2006, AOC, GPO, and GAO participated in a GSA areawide electricity contract with Pepco Energy Services to purchase RECs equal to 3 percent of their energy consumption in order to meet the Energy Policy Act of 2005 federal purchase requirement. Other federal agencies, such as the Environmental Protection Agency, have chosen to purchase RECs equal to 100 percent of their energy use. Leasing and constructing energy-efficient facilities: Another way to reduce emissions is to consider the efficiency of potential building space when renewing or entering into a new lease as well as applying energy- efficiency measures in the design and construction of new federal facilities. Under the Energy Policy Act of 1992, executive branch agencies are required to fully consider energy efficiency when leasing and constructing facilities. AOC was also required to apply federal building energy standards adopted under the act to new buildings within its jurisdiction. AOC adopted a standard equivalent to a Silver rating of the Leadership in Energy and Environmental Design (LEED) Green Building Rating System in 2006 as a minimum standard for all new construction. The LEED Rating System, created and maintained by the U.S. Green Building Council, provides a benchmark for the design, construction, and operation of high-performance green buildings. Adjusting the fuel mix: The fuel mixture at the Capitol Power Plant could be adjusted to include renewable fuels, such as biomass. However, using renewable fuels would require extensive boiler retrofits and changes to emissions control technology. The agency could also adjust the fuel mixture to increase the use of natural gas since natural gas produces less carbon dioxide than any other fossil fuel. As discussed earlier, when AOC substituted natural gas for some coal in 2006 because of problems with its coal boilers, emissions from the power plant decreased. However, in 2006, the price of natural gas was more than five times higher than coal. Acquiring fuel-efficient vehicles: Approximately 296—92 percent—of legislative branch vehicles in fiscal year 2006 were trucks (approximately 73 percent of which are light duty trucks). Heavy duty trucks have an actual average fuel economy of 8.8 miles per gallon, light duty trucks have an actual average fuel economy of 16.2 miles per gallon, and cars have an actual average fuel economy of 22.4 miles per gallon. Hybrid-electric vehicles have even higher fuel economies because they combine an electric motor and battery pack with an internal combustion engine to improve efficiency. For example, the hybrid Toyota Camry is rated at 39 miles per gallon, while the rating for the gasoline-fueled standard model is 27 miles per gallon. There are currently no hybrid-electric vehicles in the legislative branch vehicle fleets. Hybrid electric vehicles are, on average, about $8,200 more expensive than the lowest-priced gasoline vehicle in fiscal year 2007. Acquiring alternative-fuel vehicles: Alternative-fuel vehicles include dedicated, flexible-fuel, or dual-fuel vehicles designed to operate on at least one alternative fuel, such as ethanol or biodiesel. The legislative branch vehicle fleets include 35 alternative-fuel vehicles and, in September 2006, AOC adopted a policy specifying that all newly acquired vehicles, with a few exceptions, are to be alternative-fuel vehicles. Although legislative branch entities are purchasing these vehicles, they generally fuel them with gasoline because the infrastructure for supplying alternative fuel in the Washington, D.C., metropolitan area is not conveniently located for legislative branch employees. LOC was the only entity that reported using ethanol to fuel its alternative-fuel vehicles to date, using 18 gallons in fiscal year 2006. LOC also reported using 8 cubic feet of compressed natural gas in fiscal years 2005 through 2006 to fuel its two gasoline/compressed natural gas light-duty vehicles. Alternative-fuel vehicles that run on ethanol or gasoline are, on average, $1,500 more expensive than the lowest-priced gasoline vehicle in fiscal year 2007 and get 20 percent to 30 percent fewer miles per gallon, but Congress is encouraging the use of these vehicles because burning ethanol in vehicles instead of gasoline reduces emissions by 18 percent to 29 percent per gallon. In response, AOC’s alternative fuel-vehicle policy states that the initial cost shall not be considered as a factor unless it exceeds the initial cost of a comparable conventionally fueled vehicle by at least 5 percent. However, despite the emissions reductions associated with burning ethanol in vehicles instead of gasoline, the net energy benefit of using ethanol is less clear cut when full life-cycle emissions are taken into account. If the emissions from the production of ethanol are included, ethanol can have higher emissions per gallon. It can also have higher emissions of VOCs per mile traveled, compared with gasoline. Purchasing offsets: Offsets are credits for emissions reductions outside an entity’s sphere of operations and can be purchased in the retail marketplace. Offset projects range from buying credits for carbon sequestration resulting from planting trees to funding energy-efficiency upgrades at a power plant in another city. The price of offsets ranges from $5 to $25 per ton, averaging about $10 per ton. While not specifically considered offsets, RECs also reduce emissions outside an entity’s sphere of operations. The renewable electricity associated with nationally- sourced RECs—those generated by sources in another part of the country—do not enter the customer’s electricity supply. In general, these RECs are less expensive than RECs generated from local sources. However, RECs generated from local sources support local projects, and the renewable energy enters the local electricity supply which increases the amount of renewable electricity received by the customer. The legislative branch agencies’ RECs contract did not exclude national RECs, but Pepco Energy Services won the contract with a proposal that included only RECs generated from local sources. Although the legislative branch is not required to inventory greenhouse gas emissions or develop an overall strategy to reduce emissions, individual legislative branch agencies have been taking some steps to minimize or reduce emissions. However, the legislative branch as a whole has not focused on reducing emissions. The base year, inventory, and trends presented in this report could serve as a starting point for a legislative branch initiative to follow the efforts of other U.S. government and private-sector entities to reduce emissions. Energy audits are a key step in identifying projects to reduce the largest sources of emissions from legislative branch operations. While all legislative branch agencies recognize the benefits of energy audits to reduce emissions, the agencies have varied in the extent to which they have used such audits. Consequently, each agency would benefit from a schedule to conduct audits regularly and a plan for implementing and financing the most cost-effective projects identified through the audits. The legislative branch could also evaluate other projects to reduce emissions, including curtailing energy use, acquiring fuel-efficient and alternative-fuel vehicles, and purchasing offsets, and combine these evaluations with information acquired from energy audits to develop an implementation plan for reducing emissions. Agencies that manage the operations of the legislative branch should establish a schedule for routinely conducting energy audits that provide sufficiently detailed information-—such as targeted or comprehensive audits-—to justify investing in projects. Furthermore, the agencies should implement selected projects as part of an overall plan to reduce emissions that considers cost-effectiveness, the extent to which the projects reduce emissions, and funding options. We provided a draft of this report to the Architect of the Capitol, the Government Printing Office, and GAO for review and comment. We received comments orally and via e-mail from officials designated to speak for their agencies. All of the agencies agreed with the report’s overall findings and recommendations and offered technical suggestions that we have incorporated, as appropriate. The Architect of the Capitol noted that, while AOC operates the facilities within the Capitol complex and would be responsible for energy audits of the building systems and implementing the projects that result from the energy audits, the agency has little influence over the energy use activities of the occupants of the facilities. We are sending copies of this report to the appropriate congressional committees, the Acting Architect of the Capitol, and the Acting Public Printer. We will also make copies available to others upon request. In addition, this report will be available at no cost on GAO’s Web site at http://www.gao.gov. If you or your staffs have any questions about this report, please contact me at (202) 512-6923 or dornt@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. Major contributors to this report are listed in appendix V. To conduct an inventory of the greenhouse gas emissions generated by legislative branch operations, we followed the Greenhouse Gas Protocol and additional guidance from the Environmental Protection Agency’s (EPA) Climate Leaders program. In accordance with the Greenhouse Gas Protocol, the scope of our work included direct emissions, such as the combustion of fossil fuels at the Capitol Power Plant, and indirect emissions from the consumption of purchased electricity, natural gas, steam, and chilled water. We excluded other indirect emissions that are optional under the Greenhouse Gas Protocol, such as those generated from business travel in private vehicles or commercial airplanes, employee commuting, or paper use. Our work covered the legislative branch’s leased and owned facilities and vehicles within the Washington, D.C., metropolitan area. We excluded indirect emissions from the U.S. Capitol Police for security reasons, as well as non-legislative branch facilities under AOC’s jurisdiction, such as the U.S. Supreme Court. We also excluded emissions from the Medicare Payment Advisory Commission and the Stennis Center for Public Service because of their small size and location within buildings outside of the legislative branch. To calculate emissions for the inventory of greenhouse gas emissions and identify emissions trends, we selected a base year, which is a reference year against which changes in emissions are measured over time. We selected the average annual emissions in fiscal years 1998 through 2001 as the base year because this is the time period set by the Chicago Climate Exchange, a voluntary greenhouse gas reduction program. We collected activity data from the Architect of the Capitol (AOC), GAO, Government Printing Office (GPO), Library of Congress, Congressional Budget Office, Senate Sergeant at Arms, House of Representatives Chief Administrative Officer, and General Services Administration (GSA) for each source of emissions, such as kilowatt hours of electricity, from fiscal years 1998 through 2006. In general, we multiplied the data by a corresponding emissions factor to determine emissions for each year. An emissions factor is a representative value that relates the quantity of a pollutant released to the atmosphere with an activity associated with the release of that pollutant. See table 2 for a list of emissions factors. We converted all greenhouse gas emissions to carbon dioxide equivalents by multiplying emissions for each greenhouse gas by its corresponding global warming potential. See table 3 for a list of the global warming potential of each greenhouse gas. The House of Representatives Chief Administrative Officer was unable to provide fuel use data from the House of Representatives’ 23 vehicles or volatile organic compounds (VOC) emissions data from its furniture shop that performs wood refinishing, painting, and upholstery. In addition, AOC was unable to provide data on leaks from their oil, diesel and propane tanks. Therefore, greenhouse gas emissions from these sources were not included in our calculations. In analyzing emissions trends from the base year to fiscal year 2006, we used data from the National Oceanic and Atmospheric Administration to compare changes in the local weather to changes in emissions to help explain emission trends. Some legislative branch entities verified the accuracy of their activity data and made corrections as they deemed appropriate. Some entities also made assumptions about their data. For example, AOC’s data were incomplete because there were periods of time for which AOC was not billed for energy use. AOC officials made the assumption that these facilities were under the control of a contractor/vendor during this period and bills were being paid for by these outside entities. We did not independently verify the accuracy of the data. In calculating the greenhouse gas emissions, we also had to make several assumptions in the absence of data. (See app. II for additional details on the calculations and assumptions.) Unless otherwise noted, we determined the data were sufficiently reliable for the purposes of this report. To identify a strategy for reducing emissions, we reviewed documents from the World Resources Institute, and Congressional Research Service; and we interviewed officials and reviewed documents from AOC, GPO, and GAO to learn about energy audits and emissions reduction projects that the legislative branch has already implemented. We also interviewed officials from the National Renewable Energy Laboratory and DOE’s Federal Energy Management Program about energy audits, and types of emissions reduction projects and their cost-effectiveness; and officials from GSA about emissions reduction projects related to vehicles. In addition, we also interviewed Pepco Energy Services about its renewable energy contracts with the legislative branch agencies. We conducted our work from August 2006 through April 2007. To develop a greenhouse gas inventory in accordance with the Greenhouse Gas Protocol, we set an organizational boundary, operational boundary, and base year. This boundary defines the legislative branch and the criteria for reporting emissions. For the purpose of this report, the legislative branch includes the Architect of the Capitol (AOC), GAO, Government Printing Office (GPO), Library of Congress (LOC), Congressional Budget Office (CBO), and U.S. Botanic Garden. AOC has jurisdiction over the day-to-day operations of the Senate Office Buildings, House Office Buildings, U.S. Capitol and Grounds, LOC Buildings and Grounds, Capitol Power Plant, and U.S. Botanic Garden. We applied the Greenhouse Gas Protocol’s control approach based on the operational control criterion. Under this criteria, the legislative branch accounts for 100 percent of emissions from operations over which it has operational control—the full authority to introduce and implement operating policies. While the Greenhouse Gas Protocol states that geographic location is not relevant to establishing an organizational boundary, the scope of this study was limited to the Washington, D.C., metropolitan area because the majority of the legislative branch activity is located in this geographic area and data for activities outside this area were not readily available. This boundary identifies and categorizes the sources of emissions from legislative branch operations. The inventory includes emissions from the combustion of fossil fuels in the Capitol Power Plant and emergency generators, business travel in government-owned and leased vehicles, and heavy machinery; leaks in refrigeration equipment; the release of volatile organic compounds (VOC) in furniture and print shops; leaks from oil, diesel and propane tanks; and the consumption of purchased electricity, natural gas, steam, and chilled water. These emissions are placed in categories, or “scopes,” defined by the Scope 1 (direct emissions from sources that are controlled by the legislative branch): combustion of fossil fuel at the Capitol Power Plant; combustion of fossil fuels in emergency generators; business travel in government-owned and leased vehicles, as well as heavy machinery; leaks in refrigeration equipment; leaks from oil, diesel and propane tanks; and release of VOCs in furniture and print shops. Total Scope 1 emissions in fiscal year 2006: 106,045 metric tons of carbon dioxide equivalents. Scope 2 (indirect emissions from the consumption of purchased electricity, natural gas, steam, and chilled water by the legislative branch): use of electricity, use of natural gas, use of steam, and use of chilled water. Total Scope 2 emissions in fiscal year 2006: 209,946 metric tons of carbon dioxide equivalents. Scope 3—optional (all other indirect emissions such as paper use, contracted work, shipping/courier services, Member or employee travel and commuting, resource extraction, production and waste disposal, and transmission and distribution losses associated with the consumption of purchased electricity): none of these optional sources were included in the inventory. A base year is a reference year against which changes in emissions are measured over time. We selected the average annual amount emitted in fiscal years 1998 through 2001 for the base year because this is the time period set by the Chicago Climate Exchange, a voluntary greenhouse gas reduction program. The following section explains calculations and assumptions needed to prepare the data for the standard emissions equation (activity data x emissions factor = emissions) as well as additional information on specific sources. It is organized by relevant emissions sources and greenhouse gases. The first part includes those calculations and assumptions that apply to all legislative branch operations; the second part includes those that are specific to individual entities. The second part also contains tables that show the results of the emissions calculations by entity, source, and scope. Methane and nitrous oxide emissions from business travel in government-owned and -leased vehicles: We substituted the appropriate carbon dioxide emission factors for the methane and nitrous oxide emission factors. However, unlike carbon dioxide emission factors for vehicles, which are expressed in kilograms per gallon, these emission factors are expressed in grams per mile. Therefore, we used the formula: mileage = fuel use x fuel economy when the mileage was not provided. Except where noted, we obtained the average fuel economy figures from the Federal Highway Administration’s 2004 Highway Statistics. For vehicles fueled with ethanol, we reduced the fuel economy by 30 percent because ethanol has approximately 30 percent less energy per gallon than gasoline. For vehicles fueled with compressed natural gas (CNG), we used an average fuel economy of 13 miles per gallon of gasoline equivalent as found at www.fueleconomy.gov. Since methane and nitrous oxide vehicle emission factors vary by model year and vehicle type, we categorized each entity’s vehicles by type (car, light truck, or heavy truck) and model year to the best of our ability. Since emission factors are available only through fiscal year 2002, we used the fiscal year 2002 figure for all vehicles from fiscal years 2002 through 2007. Similarly, if vehicles were older than the earliest available emissions factors, we used the earliest available factors. To estimate the mileage for each type of vehicle, we calculated the percentage of the vehicle type out of the total number of vehicles and then used that percentage of the total mileage. By equating the percentage of vehicle type with the percentage of mileage, we are assuming that all vehicles are driven equally. Emissions from the release of VOCs: We first calculated the carbon emissions using the formula: carbon emissions = VOC release x carbon content. We used the standard carbon content of VOCs, which is 56 percent of the VOC release, according to the U.S. Environmental Protection Agency (EPA). To convert carbon emissions to carbon dioxide emissions, we used the conversion factor 44/12 as laid out in EPA’s Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990- 2004. Emissions from the consumption of purchased steam: To convert steam consumption at the Ford House Office Building and GAO from pounds to BTUs, we used the heat content 1,003.342 BTUs/pound. To determine emissions, we calculated the activity data—that is, the fuel used by the General Services Administration (GSA) to generate every mmBTU of steam consumed. We used the formula: activity data [fuel input] = steam produced/boiler efficiency. We took boiler efficiency into account because some fuel input is lost in flue gases when fuel enters the boiler. Since we were unable to obtain the boiler efficiency for GSA’s boilers, we used the default efficiency value of 80 percent recommended by the EPA Climate Leaders program. Next, we divided the activity data into fuel type because the fuel input included both natural gas and oil. We calculated the emissions for each type of fuel and then added them to determine total emissions. Emissions from the consumption of purchased electricity and natural gas at leased facilities: Under the operational control approach set forth by the Greenhouse Gas Protocol, we defined operational control based on the agency occupying the space and, therefore, included the emissions from legislative branch capital leases and operating leases as Scope 2 emissions, even if this required estimating energy use based on an entity’s occupied square footage. Emissions from leased vehicles: Under operational controls set forth by the Greenhouse Gas Protocol, all leased vehicles are Scope 1 emissions. Therefore, there was no need to differentiate between government-owned and -leased vehicles. Adjustment for purchased renewable energy certificates (REC): We used the following formula to calculate emissions from renewable electricity: emissions = activity data for green electricity x emissions factor for power pool where renewable power is generated. We determined the power pool where the renewable power was generated using data provided to us by Pepco Energy Services. These emissions were subtracted from Scope 2 emissions to determine total net emissions. Emissions from business travel in government-owned and -leased vehicles: We needed to calculate activity data because CBO does not maintain fuel use data. The formula we used was: activity data = mileage/fuel economy. We used the average fuel economy figures provided by the Federal Highway Administration’s 2004 Highway Statistics. CBO first obtained a vehicle in the last 2 months of fiscal year 2004. Therefore, the activity data for that year are prorated. Emissions from business travel in government-owned and -leased vehicles: The vehicle activity data were available for fiscal years 2004 through 2006. Therefore, we assumed fuel use remained constant for fiscal years 1998 through 2004. Methane and nitrous oxide emissions from business travel in government-owned and -leased vehicles: We obtained 2006 model year and type data. We assumed the vehicle type data remained constant from fiscal years 1998 through 2006. We also assumed that the model year was 1 year earlier than the year for which we were calculating emissions, unless the model year provided in the fiscal year 2006 data was earlier. In such cases, we kept the earlier year. To convert cubic feet of compressed natural gas to gallons of gasoline equivalent, we used the conversion factor 121.5 cubic feet/gallon of gasoline equivalent found at www.fueleconomy.gov. Emissions from the consumption of purchased electricity and natural gas at leased facilities: LOC has operating leases for two facilities—Landover warehouse and National Library for the Blind and Physically Handicapped. GSA provided us with activity data for both leases. To convert cubic feet of natural gas to BTUs, we used the heat content 1,011.5691 BTUs/cubic feet. The Army Corps of Engineers leases space within GAO’s building. The Architect of the Capitol leases space within the Government Printing Office’s building. Capitol complex operations under the Architect of the Capitol’s (AOC) jurisdiction accounted for 88 percent of legislative branch greenhouse gas emissions in fiscal year 2006 (see fig. 3). The Government Printing Office (GPO) and GAO accounted for 7 percent and 4 percent of emissions, respectively. Capitol complex operations not under AOC’s jurisdiction, such as Senate Sergeant at Arms’ vehicles and release of volatile organic compounds and the Library of Congress’ two leased facilities, made up the remaining 1 percent of emissions. Overall, emissions from Capitol complex operations under AOC’s jurisdiction increased by 8 percent from the base year to fiscal year 2006. There were two decreases in emissions during this time period— a 7 percent decrease from fiscal year 2003 to fiscal year 2004 and a 1 percent decrease from fiscal year 2005 to fiscal year 2006 (see fig. 4). The emissions generated by GPO decreased by 18 percent from the base year (the average of fiscal years 1998 through 2001) through fiscal year 2003 and then continued to decrease through fiscal year 2006, for an overall decrease of 28 percent (see fig. 5). The emissions generated by GAO increased 9 percent through 2004 and then decreased 8 percent through fiscal year 2006, for an overall increase of 0.2 percent (see fig. 6). In addition to the contact named above, key contributors to this report were Sara Vermillion (Assistant Director), Elizabeth R. Eisenstadt, Michael Hix, Bert Japikse, Heather Krause, Sara Ann Moessbauer, Joshua Ormond, Frank Rusco, and Stephanie Sand.

Summary: Because of concerns about changes in Earth's climate due to greenhouse gas emissions and the potential economic and environmental consequences of these changes, GAO (1) inventoried greenhouse gas emissions generated by legislative branch operations in fiscal year 2006, as well as identified trends in emissions starting from a base year of the average annual amount emitted in fiscal years 1998 through 2001, and (2) identified a strategy for reducing emissions. To perform this work, GAO followed the Greenhouse Gas Protocol and additional guidance from the Environmental Protection Agency, using data provided by officials responsible for legislative branch operations and the General Services Administration. Legislative branch operations generated about 316,000 metric tons of greenhouse gas emissions (expressed in carbon dioxide equivalents) in fiscal year 2006. The amount of greenhouse gas emissions generated by legislative branch operations is equal to the emissions produced by about 57,455 cars and represents an increase of about 4 percent from the average annual quantity emitted in fiscal years 1998 through 2001. The largest source of these emissions (63 percent) was the consumption of electricity purchased from an external provider that relies primarily on fossil fuel combustion to generate the electricity. The second-largest source of emissions (32 percent) was the combustion of fossil fuels in the Capitol Power Plant to produce steam for the majority of the legislative branch buildings. The remaining 5 percent of emissions came from other sources that each generated 1 percent or less of emissions, such as natural gas and chilled water purchased from outside sources and business travel in government-owned and -leased vehicles. While emissions in 2006 increased 4 percent over the base year levels, emissions in the intervening years varied depending on factors such as fluctuations in weather, the fuel mix used at the Capitol Power Plant, and the quantity of renewable energy used by legislative branch operations. A strategy for reducing emissions includes conducting energy audits to identify and evaluate energy efficiency and renewable energy projects, as well as evaluating other emissions-reduction projects that may fall outside the scope of energy audits. Such a strategy would also involve developing an implementation plan that considers cost-effectiveness, the extent to which the projects reduce emissions, and funding options. Energy audits are a key step because the projects identified through the audits would address the largest sources of emissions--purchased electricity and fossil fuel combustion in the Capitol Power Plant--and would include information on cost-effectiveness and the potential for reducing emissions. Agencies could finance these projects through direct appropriations or contracts with utility or energy service companies. Since fiscal year 1998, the Architect of the Capitol, GAO, and the Government Printing Office have commissioned 11 energy audits of some of their facilities, but the audits have generally not been comprehensive and the agencies have varied in the extent to which they have implemented the projects identified through the audits. Another part of a strategy would involve evaluating the cost-effectiveness, emissions reduction, and funding options of projects that may fall outside the scope of energy audits--such as acquiring fuel-efficient vehicles--on a case-by-case basis. The energy audits and evaluations of other projects would provide information for legislative branch agencies to develop plans for implementing projects to reduce emissions.