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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 web site in February 2008.
November 20, 2009
- Passenger vehicles per year: Updated fuel economy and vehicle miles traveled figures to reflect 2007 data; previous figures were for 2005. Also adjusted the ratio of carbon dioxide emissions to total emissions based on 2007 data. Result is now slightly lower (5.23 metric tons CO2 equivalent per vehicle per year, compared with 5.46 previously).
- Gallons of gasoline consumed: Revised the methodology used to calculate emissions per gallon of gasoline; the new methodology yields a slightly different result (8.89*10-3 metric tons CO2/gallon compared with 8.81*10-3 metric tons CO2/gallon previously).
- Tanker trucks filled with gasoline: Corrected the result from 74.88 to 74.89 metric tons CO2/tanker truck.
- Home electricity use: Updated electricity use per home and the number of homes to reflect 2008 Residential Energy Consumption Survey (RECS) data. The changes result in a slightly higher level of annual CO2 emissions per home (7.70 metric tons based on 2008 RECS data versus 7.21 metric tons based on 2003 RECS data).
- Home energy use: Updated energy use per home and the number of homes to reflect 2008 Residential Energy Consumption Survey (RECS) data. The changes result in a higher level of annual CO2 emissions per home (11.21 metric tons based on 2008 RECS versus 10.99 metric tons based on 2003 RECS data).
- Number of tree seedlings grown for 10 years: Revised the caveats to the assumptions.
- Acres of pine or fir forests storing carbon for one year: Revised and updated the calculations; the new result is slightly higher than before (4.69 metric tons of CO2 per acre of pine or fir forests, compared with 4.4 previously).
- Acres of forest preserved from deforestation: Updated to reflect data from the 2009 U.S. Greenhouse Gas Inventory. The new result is lower than before (105.38 metric tons of CO2 per acre converted, compared with 143.37 previously).
- Propane cylinders used for home barbeques: Revised the calculation methodology to account for the fact that pure propane (rather than LPG) is used in propane tanks. The previous calculation mistakenly assumed that LPG is used in these tanks. The new result is higher than before (0.054 metric tons CO2/cylinder, compared with 0.024 previously)
- Tons of waste recycled instead of landfilled: Updated this calculation to reflect data from the 2009 version of WARM. The new result is slightly higher than before (2.97 metric tons CO2E per ton of waste recycled, compared with 2.90 previously).
- Coal-fired power plant emissions for one year: Changed the data source to eGRID from the Clean Air Markets Division. The new result is lower than before (3,850,479 metric tons CO2 per power plant, compared with 4,643,734 previously).
February 17, 2009
- 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) year 2005 U.S. annual non-baseload CO2 output emission rate updated from eGRID2007 Version 1.0 to eGRID2007 Version 1.1.
- Home Electricity Use: Updated the home electricity use calculation when converting units of avoided CO2 emissions into annual electricity use of number of homes: the eGRID U.S. annual CO2 output emissions rate was updated from eGRID2006 Version 2.1 (year 2004 data) to eGRID2007 Version 1.1 (year 2005 data).
- Home Energy Use: Updated the home energy use calculation when converting units of avoided CO2 emissions into annual energy use of number of homes: the eGRID U.S. annual CO2 output emissions rate was updated from eGRID2006 Version 2.1 (year 2004 data) to eGRID2007 Version 1.1 (year 2005 data).
December 8, 2008
- Electricity Use: Updated the electricity use calculation when converting reductions of kilowatt-hours into avoided units of carbon dioxide emissions: the eGRID non-baseload national average emissions rate was updated from eGRID2006 Version 2.1 (year 2004 data) to eGRID2007 Version 1.0 (year 2005 data).