How CO2 Emissions are Calculated

Last Updated: Feb 06, 2015 02:10PM EST

How WegoWise calculates CO2 for:


CO2 emissions for a building can vary widely depending on where it's located due to geographic differences in the fuels used to generate electricity around the country.  For instance, two buildings with identical energy usage will have very different CO2 emissions if one is located in an area where hydro is the main source of electricity and the other is located where coal is the primary source.  To show accurate CO2 emissions that account for this, WegoWise uses eGRID emissions data.  eGRID breaks the country into 26 subregions with different CO2 emissions for each that are based off the mix of sources providing electricity.  WegoWise uses the zip code of your building to map it to the appropriate subregion and determine the CO2 emissions from your building's grid-purchased electricity.  For Canada, CO2 emissions are province-specific.  See below for the eGRID subregion map and a table of values for the US and Canada.


Electricity that is generated from PV panels and consumed on-site has zero CO2 emissions attributed to it.


WegoWise uses a national average for the CO2 emissions from natural gas, which is 11.71 lbs of CO2 per therm.  Source: EIA Carbon Dioxide Emissions Coefficients


WegoWise uses a national average for the CO2 emissions from oil, which is 22.4 lbs of CO2 per gallon. Source: EIA Carbon Dioxide Emissions Coefficients


WegoWise uses a national average for the CO2 emissions from propane, which is 12.7 lbs of CO2 per gallon. ​Source: EIA Carbon Dioxide Emissions Coefficients

eGRID subregion map

eGRID subregions 

Electricity CO2 Coefficients

Region Name Abbreviation CO2
ASCC Alaska Grid AKGD 0.00036837 lbs / btu
ASCC Miscellaneous AKMS 0.00013147 lbs / btu
WECC Southwest AZNM 0.00034514 lbs / btu
WECC California CAMX 0.00017902 lbs / btu
ERCOT All ERCT 0.00035703 lbs / btu
FRCC All FRCC 0.00035074 lbs / btu
HICC Miscellaneous HIMS 0.00038985 lbs / btu
HICC Oahu HIOA 0.00047534 lbs / btu
MRO East MROE 0.0004721 lbs / btu
MRO West MROW 0.00045028 lbs / btu
NPCC New England NEWE 0.00021163 lbs / btu
WECC Northwest NWPP 0.00024695 lbs / btu
NPCC NYC/Westchester NYCW 0.00018242 lbs / btu
NPCC Long Island NYLI 0.00039159 lbs / btu
NPCC Upstate NY NYUP 0.00015996 lbs / btu
RFC East RFCE 0.00029359 lbs / btu
RFC Michigan RFCM 0.00047754 lbs / btu
RFC West RFCW 0.00044064 lbs / btu
WECC Rockies RMPA 0.0005559 lbs / btu
SPP North SPNO 0.00052739 lbs / btu
SPP South SPSO 0.00046325 lbs / btu
SERC Mississippi Valley SRMV 0.00030182 lbs / btu
SERC Midwest SRMW 0.00053072 lbs / btu
SERC South SRSO 0.00039686 lbs / btu
SERC Tennessee Valley SRTV 0.00040715 lbs / btu
SERC Virginia/Carolina SRVC 0.00031467 lbs / btu
Source: eGRID 9th edition    
Province Name Abbreviation CO2
Alberta AB 0.00054882 lbs / btu
British Columbia BC 0.00002001 lbs / btu
Manitoba MB 0.00000361 lbs / btu
New Brunswick NB 0.00036739 lbs / btu
Newfoundland and Labrador NL 0.00001291 lbs / btu
Northwest Territories NT 0.00023696 lbs / btu
Nova Scotia NS 0.00049717 lbs / btu
Ontario ON 0.00006457 lbs / btu
Prince Edward Island PE 0.00001098 lbs / btu
Quebec QC 0.00000193 lbs / btu
Saskatchewan SK 0.00049071 lbs / btu
Yukon YT 0.00002583 lbs / btu
Source: The Climate Registry Default 2013 Emissions Factors