State-level Greenhouse Gas Emission Factors for Electricity Generation, Updated 2002
April 1, 2002
INTRODUCTION
Authorized by Title XVI, Section 1605(b) of the Energy Policy Act of 1992 (Public Law 102-486), the Voluntary Reporting of Greenhouse Gases Program provides the opportunity for corporations, government agencies, households, and voluntary organizations to report to Energy Information Administration (EIA) their emissions of greenhouse gases and their actions taken to reduce or avoid emissions or to sequester carbon.
To assist reporters in estimating emissions and emission reductions, EIA has made available in the instructions to Forms EIA-1605 and EIA-1605EZ emission coefficients for most commonly used fossil fuels and electricity. The emission coefficients for electricity originally presented these instructions were state-level coefficients developed by the Department of Energy’s Office of Policy for inclusion in the supporting documents to the Program’s guidelines. These coefficients were based on 1992 emissions and generation data. In 1999, updated coefficients were prepared based on the most recent data (1998) then available; however, the updated coefficients were not included in the instructions for the 1999 data year. Last year, these state-level factors were updated again, but based on a weighted average of three-years worth of data (1997, 1998, and 1999) rather than a single year. The adoption of this new three-year “rolling average” approach was intended to ameliorate the impact of transient anomalies (e.g., unusual weather) on the coefficients, while still enabling EIA to capture the impacts of long-term developments such as the deregulation of the utility industry.
The updated 1997-1999 coefficients from last year reflected only electric utilities; data for non-utility generators were purposely excluded from the computations performed to derive the coefficients. However, in a few states, the percentage of power produced by nonutility generators has become quite high, particularly where independent power producers have purchased plants previously owned by emissions or to sequester carbon. electric utilities. In 1999, nonutility generation exceeded 20 percent of the total amount of power generated in the following 10 states: Rhode Island (100 percent), Maine (90 percent), Massachusetts (89 percent), California (52 percent), Hawaii (37 percent), New York (33 percent), New Jersey (32 percent), Connecticut (27 percent), Louisiana (27 percent), and Alaska (22 percent). Therefore, EIA has included all generators, including utilities, nonutilities, and industrial cogenerators, in this year’s update of the state-level electricity emission factors.
This report documents the preparation of these updated state-level electricity coefficients for carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), which represent a three-year weighted average for 1998-2000.