Comment of Sierra Club under CP13-552, et. al.

How to use eGRID for Carbon Footprinting Electricity Purchases in Greenhouse Gas Emission Inventories Art Diem, U.S. EPA/OAP/CAMD 1200 Pennsylvania Avenue NW 6204-J, Washington, DC 20460 202-343-9340, 202-343-2357 (fax), diem.art@epa.gov Cristina Quiroz, TranSystems|E.H. Pechan 5528-B Hempstead Way, Springfield, VA 22151 703-245-4069, 703-813-6729 (fax), caquirozpacheco@transystems.com July 2012 ABSTRACT There has been some confusion about which year of Emissions & Generation Resource Integrated Database (eGRID)s eGRID subregion GHG emissions factors to use for specified years of electricity data under different conditions. There is no one completely consistent method that will work in all cases since the plants whose emissions are aggregated in the eGRID subregions can change from year to year and the eGRID subregions can sometimes change considerably. The purpose of this paper is to provide some recommendations (and caveats) regarding which year(s) of eGRID subregion GHG emissions factors to use for estimating Scopes 2 and 3 GHG emissions from electricity use under various conditions. The paper also reviews other recommendations and rationale for decisions relating to the use of eGRID data to estimate indirect emissions from electricity, including, but not limited to which output emission rates to use, which aggregation level to use, how to find the applicable electric grid region, how to include line losses. Examples and key data sets from the newly released eGRID2012 year 2009 data, found at www.epa.gov/egrid, will be presented. INTRODUCTION The Emissions & Generation Resource Integrated Database (eGRID), published by the U.S. Environmental Protection Agency is a globally recognized source of emissions data for the electric power generated in the United States. eGRID uniquely links air emissions with electricity generation. The most recent eGRID data are available from the eGRID website, www.epa.gov/egrid. This paper highlights recommendations for the use of Emissions & Generation Resource Integrated Database (eGRID) output emission rates to estimate the indirect emissions from grid supplied electricity purchases for greenhouse gas (GHG) inventories, carbon footprint calculators, or avoided emissions calculations. eGRID contains emissions data related to grid connected power plants in the United States; therefore, indirect emissions from electricity use may be calculated whenever these data are available. The eGRID output emission rates, sometimes referred to as emission factors, are expressed in pounds (lb) per megawatt-hour (MWh) or lb per gigawatt-hour (GWh) and are particularly valuable for GHG emissions estimations. 1 eGRID eGRID includes operational data such as emissions, different ...