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Revision History

This page describes the revisions and updates made to the Greenhouse Gas Equivalencies Calculator since it was originally posted on EPA's website in February 2008.

April 21, 2014

  • Sub region and national average non-baseload emissions rates: Updated the emission rates to reflect the eGRID Ninth edition with year 2010 data (Version 1.0).
  • Passenger vehicles per year: Updated the weighted average combined fuel economy of cars and light trucks, the average vehicle miles traveled, and the amount of carbon dioxide emitted per gallon of motor gasoline. The emissions factor for passenger vehicles was changed from 4.80 metric tons/vehicle/year to 4.75 metric tons/vehicle/year.
  • Miles driven by the average passenger vehicle: New equivalency added to calculator.
  • Gallons of gasoline consumed: Updated the emissions factor to be consistent with the value used by EPA and the Department of Transportation in national fuel economy standards. The previous emissions factor used by the calculator was 0.00892 metric tons/gallon of gasoline; the new value is 0.00887 metric tons/gallon of gasoline.
  • Barrels of oil consumed: Updated reference sources.
  • Propane cylinders used for home barbeques: Updated reference sources.
  • Pounds of coal burned: New equivalency added to calculator.
  • Railcars of coal burned: The heat content and carbon coefficient of coal were updated using the latest data from EPA and the Energy Information Administration. The previous emissions factor was 232.74 metric tons/railcar; the new factor is 186.5 metric tons/railcar.
  • Coal-fired power plant emissions for one year: This equivalency was updated using the most recent eGRID data. The previous emissions factor was 3,533,098 metric tons/year; the new factor is 3,808,651 metric tons/year.
  • Home electricity use: Updated the emissions factor for electricity based on the latest eGRID data, and updated the number of homes and the transmission losses factor based on data from the latest Annual Energy Outlook from the Energy Information Administration. The previous emissions factor was 7.268 metric tons/home; the new factor is 7.270 metric tons/home.
  • Number of wind turbines installed: New equivalency added to calculator.
  • Number of garbage trucks of waste recycled instead of landfilled: New equivalency added to calculator.

February 14, 2014

  • Home electricity use: Updated the data and sources for this calculation. The previous emissions factor used by the calculator was 6.68 metric tons CO2/home; the new value is 7.268 metric tons CO2/home.
  • Passenger vehicles per year: Updated the assumptions for average fuel economy and vehicle miles traveled in 2010 to account for revisions made in December 2012 to the Federal Highway Agency's published statistics. Note that the emissions factor (4.8 metric tons of CO2E per vehicle per year) is not affected by these updates.

November 7, 2012

  • Sub region and national average non-baseload emissions rates: Updated the emission rates to reflect the updated eGRID 2012 version 1.0.
  • Passenger vehicles per year: Updated assumptions for vehicle miles traveled and average fuel economy based on the most recent available sources.
  • Home electricity use: Updated the electricity emission factor to reflect the updated eGRID 2012 version 1.0.
  • Railcars of coal: The average heat content and emission factors for coal have been updated to the most recent figures available.
  • Coal-fired power plants: The number of coal-fired power plants and their CO2 emissions have been updated based on eGRID 2012.

November 1, 2011

  • Coal-fired power plant emissions for one year: Deleted the conversion to metric tons, which is not needed in the final equation and was inadvertently retained in the text from a previous version of the calculator. The result shown was correct and has not been changed.

May 20, 2011

  • Update included new NYUP sub region and national average non-baseload emissions rates to reflect new plant level data consistent with the eGRID2010_Version_1.1 release. Further information on eGRID.

April 12, 2011

  • Electricity use: Modified the electricity use emissions factor to an unrounded value so it more closely matches the value given for the U.S. annual non-baseload CO2 output emission rate in eGRID2010 Version 1.0.

February 28, 2011

  • Electricity use: Updated the electricity use calculation when converting reductions of kilowatt-hours into avoided units of carbon dioxide emissions: the Emissions & Generation Resource Integrated Database (eGRID) U.S. annual non-baseload CO2 output emission rate was updated from eGRID2007 Version 1.1 to eGRID2010 Version 1.0.
  • Passenger vehicles per year: Updated the amount of carbon dioxide emitted per gallon of motor gasoline burned from 8.89 to 8.92*10-3 metric tons to reflect latest U.S. EPA Greenhouse Gas Inventory data. This gives a result of 5.1 metric tons of carbon dioxide equivalent per vehicle per year, consistent with EPA figures provided in the 2011-2016 light-duty fuel economy standards analysis.
  • Gallons of gasoline consumed: Updated the amount of carbon dioxide emitted per gallon of motor gasoline burned from 8.89 to 8.92*10-3 metric tons to reflect latest U.S. EPA Greenhouse Gas Inventory data.
  • Barrels of oil consumed: Updated the heat content and carbon coefficient of crude oil to reflect latest U.S. EPA Greenhouse Gas Inventory data. The conversion factor used in the calculator is unaffected by these updates and remains the same.
  • Propane cylinders used for home barbecues: Changed the percentage of carbon in propane from 81.8% to 81.7% to reflect the latest U.S. EPA Greenhouse Gas Inventory. The conversion factor remains unchanged.
  • Railcars of coal burned: Updated the average heat content of coal and the average carbon coefficient of coal to reflect the latest U.S. EPA Greenhouse Gas Inventory. These updates change the conversion factor from 191.5 to 183.65 metric tons of carbon dioxide per railcar.
  • Coal-fired power plant emissions for one year: Updated the number of power plants using coal and their carbon dioxide emissions to reflect the latest eGRID data for 2007. These updates change the conversion factor from 3,850,479 to 4,023,304 metric tons of carbon dioxide per power plant.

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