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Greenhouse Gas (GHG) Emissions Inventory
As part of its mission to protect human health and the environment, EPA considers the impact of its facilities and operations on the local community, as well as its effect on the planet. To better understand and manage its carbon footprint, the Agency has been working to quantify its annual GHG emissions and develop a comprehensive strategy for reducing them. Although federal mandates do not currently require specific quantitative GHG emission reductions, EPA is taking a proactive approach to demonstrate leadership in this area by developing a voluntary GHG emissions inventory and quarterly reporting system.
Developing the Inventory: A Phased Approach
Following the GHG Inventory Guidance developed by EPA's Climate Leaders Program, which EPA formally joined on May 26, 2009, the Agency chose to take a phased approach to developing its GHG emissions inventory. In the first phase, the Agency quantified the GHG emissions associated with energy consumption at the Agency’s 34 “reporting facilities”—facilities where the Agency controls building operations, pays utilities directly, and reports annual energy and water consumption data to the U.S. Department of Energy (DOE) in order to demonstrate compliance with federal energy and water reduction requirements.
EPA’s initial GHG emissions inventory quantified emissions for three of the six major GHGs—carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)—and accounted for the efforts that EPA has made to offset, or “adjust”, its emissions through green power and renewable energy certificate (REC) purchases. This quantification required EPA to calculate the following:
- Direct stationary emissions: EPA’s direct stationary sources of GHG emissions generally include the onsite combustion of natural gas, fuel oil, propane, and kerosene for heating and on-site power generation.
- Indirect stationary emissions: EPA’s indirect stationary GHG emissions result from purchased electricity, steam, chilled water, and high-temperature hot water.
- Inventory adjustment from renewable energy purchases: EPA has a long history of leading the federal government in the support of the renewable energy market. In FY 2008, EPA purchased 149,433,125 kWh of green power and RECs for its reporting facilities. This commitment to the development of clean energy generation has resulted in the avoidance of GHG emissions from the combustion of fossil fuel at conventional power plants. To quantify the environmental benefits of EPA’s renewable energy purchases, using the Climate Leaders-approved methodology EPA adjusted its GHG emissions inventory by netting out 84,800 metric tons of carbon dioxide equivalent (MTCO2e), equivalent to avoiding the combustion of more than 88 million pounds of coal.
60 to 70 Percent Reduction
Thanks to a combination of energy efficiency projects and extensive green power purchases, in FY 2008 EPA reduced the net GHG emissions of its most energy intensive facilities by nearly 70 percent compared to an FY 2003 baseline1.
In FY 2003, EPA’s baseline GHG emissions associated with energy consumption at its reporting facilities totaled 139,007 MTCO2e2. As a direct result of Agencywide energy efficiency improvements since FY 2003, these emissions in FY 2008 totaled 122,732 MTCO2e—a reduction of 16,275 MTCO2e (nearly 12 percent) from the Agency’s FY 2003 baseline.
Furthermore, the Agency’s purchases of green power and RECs enable EPA to adjust its GHG emissions from reporting facilities to 124,186 MTCO2e in FY 2003 and to 37,932 MTCO2e in FY 2008 . These data indicate that EPA has reduced net GHG emissions from its reporting facilities by 86,254 MTCO2e (69.5 percent) since FY 2003.
These preliminary emissions figures do not include mobile emissions from EPA’s fleet and tactical vehicles, fugitive hydrofluorocarbon (HFC)/perfluorocarbon (PFC) emissions from refrigeration and air conditioning equipment leakage, or sulfur hexafluoride (SF6) emissions from tracer gas fume hood testing. EPA expects emissions from these areas to collectively represent less than 10 percent of the Agency’s total GHG emissions. In addition, the first phase did not include emissions from EPA’s approximately 140 “non-reporting” facilities (for which EPA does not directly control utilities or formally report annual energy and water consumption to DOE), or emissions from EPA’s mobile sources.
Looking to the Future
In addition to developing the Agency’s internal GHG emissions inventory, in FY 2008 EPA also instituted a quarterly GHG reporting effort to prepare senior managers for future climate change mitigation efforts, help facility managers target areas for improvement, and inform critical management decisions throughout the Agency.
EPA is working to expand its GHG emissions inventory to account for and report the Agency’s emissions for its remaining office and warehouse facilities and all of its vehicles. Once the Agency’s comprehensive GHG emissions inventory is complete, EPA will have a new tool to help quantify its carbon footprint and evaluate potential GHG emissions reduction strategies.
1,3 EPA elected to use FY 2003 as the base year for its GHG emissions inventory to align with the base year against which annual energy reduction requirements are outlined in Executive Order 13423 and the Energy Independence and Security Act of 2007. EPA has not developed annual GHG emissions inventories for FY 2004 through FY 2006, indicated by the broken X-axis in the chart above.
2 EPA uses the Agency's Emissions and Generation Resource Integrated Database (eGRID) to calculate GHG emissions and inventory adjustments resulting from EPA's extensive green power purchases. Per Climate Leaders guidance, SFPB used eGRID v2.01 (year 2000 data) to calculate FY 2003 GHG emissions data and eGRID2007 v1.1 (year 2005 data) to calculate FY 2008 and FY 2009 GHG emissions data.