2024 Residual Mix Emissions Rates (2022 Data)

The information in this table can be used to calculate the greenhouse gas (GHG) emissions associated with untracked and unclaimed U.S.-based sources of electricity, based on location of consumption. The table provides the “Green-e® residual mix emissions rate,” an emissions rate that is adjusted to remove all Green-e® Energy certified sales for each Emissions & Generation Resource Integrated Database (eGRID) subregion[1]eGRID subregions are identified and defined by EPA and were developed as a compromise between NERC regions (which EPA felt were too big) and balancing authorities (which EPA felt were generally too … Continue reading (see eGrid subregion map).

Green-e® residual mix emissions rates are published each year using Green-e® Energy voluntary renewable energy market sales data collected during the annual Green-e® Energy verification audit from two calendar years prior and the most recent U.S. generation and emissions rate at the time of publication. It does not include any data that is not reported through the Green-e® Energy verification process. The residual mix emissions rate used should be based on the eGRID subregion in which the electricity is consumed. Individuals can figure out which eGRID subregion in which they are located by using the EPA’s Power Profiler tool.

Scope 2 Reporting

When calculating the emissions from unspecified purchased or acquired electricity (considered “Scope 2” emissions, as defined by the World Resources Institute [WRI]), where more-accurate information about the resources and emissions associated with electricity use is not available from the user’s state, region, or electricity supplier, residual mix emissions rates should be used. Regional residual mix emissions rates that factor out all specified electricity purchases are not yet available for all regions of the U.S. or published by a national data source. Until such time, Green-e® residual mixes are available, which factor out all Green-e® Energy certified sales of renewable energy. Users reporting their GHG data should cite the use of these residual mix rates in their accounting. Use of these numbers is compatible with WRI’s Greenhouse Gas Protocol Scope 2 Guidance,[2]Available at www.wri.org/research/ghg-protocol-scope-2-guidance. which defines residual mix in more detail. Green-e® Energy also offers the Green-e® Energy Summary of WRI Scope 2 Guidance, a guide for purchasers of Green-e® Energy certified renewable energy on how to calculate Scope 2 emissions.[3]The Green-e® Energy Summary of WRI Scope 2 Guidance is available at Green-e® Scope 2 Summary.

Residual Mix Rate Calculation Methodology

This table shows the residual mix calculation based on eGRID subregions. These rates were calculated using the data collected by Green-e® Energy during annual verification of 2022 certified sales and the 2022 emissions and generation data provided by eGRID in the U.S. for each eGRID subregion[4]U.S. EPA’s Emissions & Generation Resource Integrated Database (eGRID). eGRID2022 historical data (released 01/30/2024) can be found at https://www.epa.gov/egrid/historical-egrid-data..

The residual mix emissions rate is calculated by first subtracting all unique Green-e® Energy certified sales[5]Unique Green-e® Energy certified sales remove any MWh associated with a Green-e® Energy certified retail sale for which the supply was purchased via a Green-e® Energy certified wholesale … Continue reading (in megawatt-hours [MWh]) from the total generation within each subregion. The total CO2 emissions for each region are then divided by this new generation number for each subregion, resulting in an adjusted emissions rate (lb CO2/MWh) that accounts for use of renewable energy from a Green-e® Energy certified product.

For this calculation, each U.S.-generated MWh is assigned to a specific eGRID subregion, with generating facilities assigned to eGRID subregions using facility zip codes and Energy Information Agency data. Generation from facilities that cannot be readily assigned to eGRID subregions is excluded from these residual mix emissions rates.

2024 Green-e® Residual Mix Emission Rates (2022 Data)

 

eGrid Subregion CO2 Emissions (tons) Net Generation (MWh) Emission Rate (lb / MWh) Voluntary RE emissions (lbs) Voluntary RE (MWh) (12-month vintage) Adjusted System Mix (lbs / MWh) (12-month vintage) Difference (lbs / MWh) (12-month vintage) % Difference (12-month vintage)
AKGD 2,639,130 5,016,815 1,052.114 39387 1060.439144 8.325 0.79%
AKMS 415,782 1,677,313 495.772 495.7718273 0.000 0.00%
AZNM 66,106,424 170,369,549 776.036 194169 776.9211202 0.885 0.11%
CAMX 52,070,844 209,353,986 497.443 2323642 503.0262019 5.583 1.12%
ERCT 176,677,934 458,259,386 771.083 49237871.37 863.9053316 92.822 12.04%
FRCC 101,825,873 250,233,811 813.846 3295891 824.7082799 10.862 1.33%
HIMS 1,564,651 2,708,213 1,155.486 1155.486264 0.000 0.00%
HIOA 5,195,676 6,595,979 1,575.407 1575.407078 0.000 0.00%
MROE 16,915,395 22,864,489 1,479.621 1479.62149 0.000 0.00%
MROW 117,820,954 251,623,837 936.485 11373694.09 980.8190122 44.334 4.73%
NEWE 28,284,725 105,455,877 536.428 8524 536.4710355 0.043 0.01%
NWPP 87,316,362 290,045,161 602.088 8618734.23 620.5270966 18.439 3.06%
NYCW 14,483,027 32,721,381 885.233 885.2332491 0.000 0.00%
NYLI 6,500,715 10,828,139 1,200.708 1200.707677 0.000 0.00%
NYUP 11,967,722 87,177,697 274.559 4653 274.5739085 0.015 0.01%
PRMS 14,151,717 17,762,020 1,593.481 1593.480548 0.000 0.00%
RFCE 95,011,436 289,058,252 657.386 52766 657.5061046 0.120 0.02%
RFCM 57,053,918 93,807,524 1,216.404 1126265.19 1231.185651 14.782 1.22%
RFCW 267,775,418 535,522,392 1,000.053 1458977.55 1002.785105 2.732 0.27%
RMPA 37,754,232 67,125,368 1,124.887 1166143 1144.774865 19.888 1.77%
SPNO 37,416,972 78,559,613 952.575 11561105 1116.94941 164.374 17.26%
SPSO 75,559,656 155,729,281 970.398 20817512.6 1120.134395 149.736 15.43%
SRMV 73,314,707 183,054,493 801.015 777452 804.4316127 3.417 0.43%
SRMW 81,328,342 118,737,335 1,369.887 2435053 1398.568291 28.681 2.09%
SRSO 114,871,535 257,187,544 893.290 2227562.41 901.0946249 7.805 0.87%
SRTV 100,265,692 214,916,301 933.067 84691 933.4351824 0.368 0.04%
SRVC 100,845,600 323,748,776 622.987 3138318 629.084906 6.098 0.98%

References

References
↑1 eGRID subregions are identified and defined by EPA and were developed as a compromise between NERC regions (which EPA felt were too big) and balancing authorities (which EPA felt were generally too small). Using NERC regions and balancing authorities as a guide, the subregions were defined to limit the import and export of electricity in order to establish an aggregated area where the determined emission rates most accurately matched the generation and emissions from the plants within that subregion.
↑2 Available at www.wri.org/research/ghg-protocol-scope-2-guidance.
↑3 The Green-e® Energy Summary of WRI Scope 2 Guidance is available at Green-e® Scope 2 Summary.
↑4 U.S. EPA’s Emissions & Generation Resource Integrated Database (eGRID). eGRID2022 historical data (released 01/30/2024) can be found at https://www.epa.gov/egrid/historical-egrid-data.
↑5 Unique Green-e® Energy certified sales remove any MWh associated with a Green-e® Energy certified retail sale for which the supply was purchased via a Green-e® Energy certified wholesale transaction, since these two sales represent the same MWh of generation.