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eGRID FAQ
Quick Links
- eGRID2012 Version 1.0 - all files (ZIP) (34.2M)
- eGRID2012 eGRID Subregion GHG Output Emission Rates for Year 2009 (PDF) (1 pp., 311K)
- eGRID2012 year 2009 Summary Tables (PDF) (13 pp., 1.47M)
- eGRID2012 Technical Support Document for Year 2009 Data (PDF) (104 pp., 612K)
- Power Profiler eGRID Subregion and GHG Emissions Finder Tool (XLSX) (2.3M)
- Paper: The Value of eGRID and eGRIDweb to GHG Inventories (PDF) (13 pp., 296K)
You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.
- What is eGRID?
- Why eGRID?
- What information is contained in eGRID?
- Who uses eGRID?
- What is new in eGRID?
- What do the eGRID subregion and NERC region maps look like?
- Can I receive a shape file for the eGRID subregion or NERC region maps?
- What are the regional emission rates and resource mix?
- How can I find out when eGRID is updated?
- What other emissions data are available from EPA?
- Who Can I Contact For More Information?
What is eGRID?
The Emissions & Generation Resource Integrated Database (eGRID) is a comprehensive inventory of environmental attributes of electric power systems. The preeminent source of air emissions data for the electric power sector, eGRID is based on available plant-specific data for all U.S. electricity generating plants that provide power to the electric grid and report data to the U.S. government. eGRID integrates many different federal data sources on power plants and power companies, from three different federal agencies: EPA, the Energy Information Administration (EIA), the North American Electric Reliability Corporation (NERC), and the Federal Energy Regulatory Commission (FERC). Emissions data from EPA are carefully integrated with generation data from EIA to produce useful values like pounds per megawatt-hour (lb/MWh) of emissions, which allows direct comparison of the environmental attributes of electricity generation. eGRID also provides aggregated data by state, U.S. total, company, and by three different sets of electric grid boundaries.
Why eGRID?
Electricity generation is the dominant industrial source of air emissions in the United States today. Whenever you switch on an electrical appliance, chances are you are contributing to air pollution and greenhouse gas emissions. By documenting the environmental attributes of electric power generation, eGRID can help consumers to better understand the relationship between electricity and the environment.
In the United States, electricity is generated in many different ways, with a wide variation in environmental impacts. In many states, power companies are required to disclose the environmental attributes of their retail electricity products. Many consumers now have a choice regarding the source of their electricity, and some seek cleaner sources, such as wind and solar power. Data from eGRID underlies EPA’s Power Profiler application, which enables individual consumers to identify the environmental impacts of their own electricity usage. Power Profiler is updated with the eGRID2012 year 2009 data.
eGRID data can be used to support the following activities:
- Greenhouse gas registries and inventories,
- Carbon footprinting,
- Consumer information disclosure,
- Renewable portfolio standards,
- Development of emissions inventories and emission standards,
- Analysis of changing power markets, and
- Estimation of avoided emissions.
What information is contained in eGRID?
For every power plant in the United States, eGRID provides:
- A detailed emissions profile, covering nitrogen oxides (NOX), sulfur dioxide (SO2), carbon dioxide (CO2), methane (CH4) nitrous oxide (N2O), and mercury (Hg). (Hg emissions are not provided for year 2007 or 2009 data.) Emissions are reported in tons (pounds for CH4, N2O, and Hg), output emission rates in lb/MWh (pounds per gigawatt-hour for CH4, N2O, and Hg), and input emission rates in pounds per million British thermal units (lb/MMBtu) (pounds per billion Btu for CH4, N2O, and Hg),
- Generation resource mix, in megawatt-hours and percent, and
- Identification, ownership, corporate affiliation, and locational information.
eGRID also provides separate data files at the boiler and generator level.
Emissions and resource mix data from the plant level are aggregated by electric generating company, parent company (company level data is not provided for year 2009 data), state, U.S. total, and three types of power grid regions:
- NERC region, as designated by the North American Electric Reliability Corporation; plus Alaska and Hawaii,
- eGRID subregion (subregions of NERC regions), and
- Power control area (generally smaller regions of the power grid in which all power plants are centrally dispatched).
eGRID2012 currently contains data for years 2009, 2007, 2005, and 2004. Data for years 1996 through 2000 are in the archived eGRID2002. There are no other years of data compiled in eGRID.
In order to keep up with the rapidly changing U.S. power industry, eGRID data reflect the industry structure, including company mergers, and grid reconfigurations that exist close to the time of publication. For example, 1999 and 2000 data reflect the industry structure through December 31, 2002; 2004 data reflect the industry structure through October 1, 2006; 2005 data reflect the industry structure through December 31, 2007; and 2007 data reflect the industry structure through December 31, 2010. Year 2009 data has not been reconfigured to reflect changes in operator names or changes in ownership information.
eGRID2012 contains year 2009 power interchange data and grid gross loss factors for the three continental interconnections and Alaska, and Hawaii. Net imports-exports by state are provided for years 2007, 2005 and 2004. The archived edition, eGRID2002, includes data on net imports-exports by state and power interchange between grid regions for years 1996 through 2000.
Who uses eGRID?
eGRID data support a wide variety of users globally through a wide variety of uses. eGRID is valuable to those in the Federal Government, state and local governments, non-governmental organizations, academia, and provides constructive direction to companies who are generally seeking environmental information from the electric power sector in the United States. eGRID is most often used for the estimation of indirect emissions from electricity purchases, in GHG inventories, for carbon footprinting, and for estimating avoided emissions from programs and projects that would reduce the consumption for grid supplied electricity. eGRID data is cited by emission inventory and registry protocols, by various emission calculation tools and applications, by many academic papers, by many consultants, and is used for many research applications and efforts.
Within EPA, eGRID data are used in the following applications and programs: Power Profiler, Climate Leaders, Portfolio Manager, WasteWise Office Carbon Footprint Tool, the Green Power Equivalency Calculator, the Household Greenhouse Gas Emissions Calculator, and the Greenhouse Gas Equivalencies Calculator.
When the EPA announced the winners of its Apps for the Environment challenge on November 8, 2011, and the two top winning apps — Light Bulb Finder 
and Hootroot use eGRID data for a mobile app and/or a web app, as did several other entries. Another of the winning entries, Joulebug uses eGRID data.
In 2010, Executive Order 13514 was issued, requiring Federal agencies to “measure, report, and reduce their greenhouse gas emissions from direct and indirect activities.” The Federal GHG Accounting and Reporting Guidance accompanied this order and recommended using eGRID non-baseload emission rates to estimate the Scope 2 emission reductions from renewable energy.
Fueleconomy.gov, a partnership between EPA and DOE, uses eGRID data to estimate the total GHG emissions from electric and plug-in hybrid vehicles in its Greenhouse Gas Emissions for Electric and Plug-in Hybrid Electric Vehicles calculator.
eGRID is also used by other Federal Government agencies such as Oak Ridge National Laboratory (ORNL) for their Combined Heat and Power Calculator, the National Energy Technology Laboratory (NETL) for their sponsored Distributed National Carbon Sequestration Database and Geographic Information System (NATCARB), and the National Renewable Energy Laboratory (NREL) for their micropower distributed generation optimization model named HOMER.
One of the most popular recent uses of eGRID is to determine the indirect GHG emissions from electricity purchases and avoided GHG emissions from projects and programs that reduce the demand for grid supplied electricity. For example, The Climate Registry, the California Climate Action Registry, and the Greenhouse Gas Protocol Initiative cite eGRID for use in estimating Scope 2 GHG emissions from electricity purchases in the United States. Most carbon footprint calculators that are applicable to the United States use eGRID data.
States and local governments rely on eGRID data for electricity labeling (environmental disclosure programs), emissions inventories, and registries as well as for efforts to analyze air emissions from the electric power sector. Several states have published state specific emissions information from eGRID or have used eGRID to inform policy decisions.
RECS Tracking Systems, such as ISO-New England’s Generation Information System (GIS) and PJM Interconnection’s Generation Attribute Tracking System (GATS), utilize eGRID data.
eGRID is used by many nongovernmental organizations’ (NGOs) tools and analysis.
What is new in eGRID?
The newest edition, eGRID2012, contains several new fields of information and several methodological improvements. Please see the Technical Support Document (PDF) (104 pp., 612K) for more details.
eGRID2012 with year 2009 data includes the following data file changes:
- The separate eGRID Excel workbooks presented in previous editions of eGRID are now combined into a single Excel workbook (with ten tabs).
- The derivation and data sources for the EIA-based state level grid gross loss have been replaced by the FERC- and EIA-based grid gross loss, beginning with year 2009. Consequently, the state import-export files have not been developed for year 2009. A new methodology for estimating grid gross losses has been employed using EIA utility sales data, FERC-714 power control area/balancing authority generation, and FERC-714 interchange data that are summed to the grid level.
- Because of budgetary issues, year 2009 data are trimmed by eliminating the updated operator, owners, nufront, and parent companies to a specified year 2012 date. The operators and owners (and plant name) displayed in the eGRID plant file for year 2009 are as reported in the 2009 EIA-860. There are no associated operator parent companies in the plant file and there are no aggregation files for EGC operator-based, EGC owner-based, parent company operator-based, or parent company owner-based data in the final eGRID workbook.
eGRID2012 includes several new data elements:
- In the boiler file, EPA/CAMD unit-level program codes replaced the NOx Budget Program flag;
- In the plant file, plant associated ISO/RTO territory is added.
- In the eGRID subregion file, annual CO2 equivalent non-baseload output emission rates are added; and
Methodological changes in eGRID2012 data include the following:
- EIA-923 unit/boiler level data included.
- A few updated GHG emission factors (EF).
- Updated latitude-longitude coordinates.
- Ozone season net generation from EPA/CAMD is derived differently from year 2007’s.
- For partial combustion plants (i.e., includes both combustion and non-combustion generators), fuel-type output emissions rates are determined by dividing the total plant emissions by the combustion net generation (rather by the total plant net generation, as done for year 2007 data and earlier),
eGRID2012 includes modification to the biogas/biomass plant adjustment flag due to additional unit level data being available. See the Technical Support Document for more details.
One update to the year 2007 plant file is made with the release of eGRID2012. This update corrects the plant longitude for those plants whose longitude is -99.xx (they had inadvertently been replaced by ‘N/A’ in the previous edition).
For more information about the year 2009 data, see the eGRID2012 Technical Support Document. For methodology from previous years, see the previous Technical Support Documents.
The eGRIDweb application does not yet have the most recent year of eGRID data, but still has years 2004 and 2005 data. A link to this application is available on the eGRID Archive page.
Because there are some methodological changes in different editions of eGRID from year to year, please use caution when comparing data from different years.
What do the eGRID subregion and NERC region maps look like?
eGRID Subregion Representational Map.
This is a representational map; many of the boundaries shown on this map are approximate because they are based on companies, not on strictly geographical boundaries.
NERC Region Representational Map.
This is a representational map; many of the boundaries shown on this map are approximate because they are based on companies, not on strictly geographical boundaries.
Can I receive a shape file for the eGRID subregion or NERC region maps?
EPA cannot release a shape file for the eGRID subregions or the NERC regions because these maps are representational. Many of the boundaries shown on these maps are approximate and are not based on strictly geographical boundaries. The NERC regions and eGRID subregions are based on groups of power control areas (a.k.a. balancing authorities). Some boundaries shown on the maps are approximations of overlapping power control areas. Also, plants assigned to a particular eGRID subregion may not be connected by transmission lines to a particular power control area and may also be located far away from the utility service territories that the power control area serves. For example, the Intermountain Power Project plant’s power control area is the Los Angeles Department of Water and Power, yet, this plant is located in Utah.
What are the regional emission rates and resource mix?
Summary information for data years 2009, 2007, 2005 and 2004 by state, eGRID subregion, NERC region, and the U.S. can be found in the following documents:
- eGRID2012 year 2009 Summary Tables (PDF) (13 pp., 1.47M)
- eGRID2010 year 2007 Summary Tables (PDF) (13 pp., 2.6M)
- eGRID2007 year 2005 Summary Tables (PDF) (12 pp., 511 K)
- eGRID2006 year 2004 Summary Tables (PDF) (9 pp., 3M)
How can I find out when eGRID is updated?
If you are interested in receiving an alert once updated versions of eGRID are issued, please enter your email address and comment like "Please inform me when an updated eGRID is available" in the feedback field of the eGRID feedback form.
What other emissions data are available from EPA?
Other EPA emissions data sources provide data on emissions associated with electricity generation. Air Trends Reports are EPA's "report card" on the status of air quality and air pollutant emissions. Reports are published annually, about ten months after year-end. U.S. Greenhouse Gas Inventory Reports include inventories of U.S. greenhouse gas emissions and sinks. In addition, Clean Air Markets Division Progress Reports includes emissions data for power plants in the Acid Rain Program or the NOX Budget Trading Program. Also, see the National Emissions Inventories for the U.S.
Who Can I Contact For More Information?
For questions about eGRID, contact Art Diem at 202-343-9340, or provide us your feedback on eGRID.