EPA greenhouse gas reporting and emission rates

March 2023

The U.S. Environmental Protection Agency’s (EPA’s) mandatory national greenhouse gas (GHG) reporting program requires regulated natural gas utilities, and some of their largest customers, to report GHG emissions from their operations. The EPA website includes resources to understand the rule and an online tool to see if it applies to your company.

Electric utility energy mix and emission rates

This electric energy mix and emission rate information is provided for retail electric customers of Wisconsin Public Service Corporation (WPS), a regulated utility subsidiary of WEC Energy Group (WEC) operating in the state of Wisconsin. The emission rates are supplied for customers to estimate their environmental footprint from electric energy supplied by WPS, such as Scope 2 (indirect) greenhouse gas emissions.

Emission rates are calculated using total emissions and megawatt-hours from generation by owned and jointly-owned facilities, and from long-term purchased power arrangements. The CO2 equivalent emission rate includes all sources mentioned previously and net emissions from MISO purchases and sales. The emission rates apply to retail electric utility customers of WPS, except for customers of NatureWise®, WPS’s renewable energy program that is offered to all retail electric customers.

Emissions from electric generation facilities are calculated in accordance with the U.S. Environmental Protection Agency mandatory Greenhouse Gas Reporting Program regulations under 40 CFR Part 98. The energy resource mix represents net generation from WPS-owned facilities as well as generation acquired through long-term purchased power arrangements.

WEC and WPS reserve the right to use all or some of the environmental attributes associated with generation from renewable energy sources in future years to comply with renewable energy standards or other regulatory requirements, or to sell to third parties the environmental attributes such as renewable energy credits, offsets, allowances and the avoided emissions of greenhouse gases. All information is provided on a voluntary basis, could be subject to change, and has not received independent third party verification. Neither WEC nor WPS makes any assurances regarding the use of this information by external parties for marketing or other sustainability claims.

Wisconsin Public Service energy mix and emissions1

  2020 20212 20222,3
Emission rates: Owned energy + Purchased power arrangements (lbs/MWh)
Carbon dioxide (CO2) 1,256 1,319 1,201
Methane (CH4) 0.019 0.017 0.018
Nitrous oxide (N2O) 0.018 0.017 0.019
Carbon dioxide equivalent (CO2e)4 1,262 1,324 1,207
Sulfur dioxide (SO2) 0.17 0.19 0.16
Nitrogen oxides (NOx) 0.34 0.38 0.35
Energy resource mix: Owned energy + Purchased power arrangements
Energy from owned generation + purchased power arrangements (MWh) 10,869,076 11,392,440 11,163,015
Coal 44.5% 46.6% 41.0%
Natural gas 43.1% 39.6% 42.0%
Renewable energy 12.4% 13.8% 17.0%
Hydroelectric 8.8% 7.6% 8.5%
Biofuels   0.9% 0.5%
Wind 3.4% 3.6% 4.4%
Solar 0.2% 1.7% 3.6%
CO2-Equivalent (CO2e) Emission Rate4 (CO2e): Total net of CO2e / Customer Load (lbs CO2e/MWh)
Customer Load (MWh) 13,087,052 13,307,195 13,226,655
CO2-Equivalent Emission Rate (lbs CO2e/MWh) 1,2575 1,3706 1,2396

1 Table includes data for purchased power arrangements that were not included in previously available emissions data.

2 Rates and MWh for 2021-2022 are calculated using additional sources to be representative of energy resource mix.

3 Rates for 2022 are preliminary and subject to change after regulatory reporting.

4 Global warming potentials for calculating CO2-equivalents: CO2 = 1 ton; CH4 = 25 tons of CO2; N2O = 298 tons of CO2.

5 Regional average CO2 emissions in pounds per megawatt-hour, used to estimate CO2 from market energy purchases for CO2-equivalent emission rates, are provided by the Michigan Public Service Commission.

6 New methodology assigns emissions from contracted generating facilities and market purchases to the utility. Market purchases and sales use regional estimates from EIA CO2 rates by fuel type and MISO fuel mix data.

Information about the natural gas delivered by Wisconsin Public Service

If your company is required to report greenhouse gas emissions or chooses to analyze its carbon footprint, you may need information about natural gas delivered by Wisconsin Public Service. The EPA’s default emission factors for natural gas for CO2 and CH4 and N2O are appropriate to use for the natural gas we distribute along with WEC Energy Group’s leak rate of 0.55 kg/mmBTU. The amount of natural gas consumed can be found on your bill or in the My Account section of our website. As a service to customers, we provide the heating value of your natural gas below*.

Higher Heating Value (HHV) - (MMBtu/Mscf)
  2017 2018 2019 2020 2021 2022 2023
Jan 1.036 1.037 1.043 1.047 1.040 1.047 1.045
Feb 1.036 1.034 1.042 1.047 1.049 1.049 1.046
Mar 1.033 1.040 1.048 1.044 1.044 1.046 1.044
Apr 1.026 1.037 1.045 1.050 1.047 1.049 1.042
May 1.032 1.035 1.043 1.045 1.048 1.047 1.043
Jun 1.030 1.042 1.047 1.042 1.046 1.044  
Jul 1.028 1.043 1.047 1.042 1.042 1.046  
Aug 1.029 1.035 1.046 1.039 1.045 1.049  
Sep 1.032 1.037 1.047 1.044 1.051 1.050  
Oct 1.036 1.046 1.046 1.049 1.051 1.043  
Nov 1.041 1.044 1.044 1.043 1.048 1.045  
Dec 1.036 1.043 1.045 1.042 1.051 1.052  

STP: Standard Temperature - 60°F, Standard Pressure - 14.7 psia
Measurement Standard: GPA 2172-09

* The data on this page represent an average heating value for the system and may differ from data that meets state or local regulatory requirements and is used for billing purposes. Accordingly, it is data provided solely for informational purposes, and not for billing purposes. WPS makes no claim or representation that the data provided is accurate and makes no warranties express or implied, including but not limited to fitness for a particular purpose, including EPA compliance. No party should rely on such data, including, but not limited to, for billing purposes.

If you need or want more than consumption and heating value information, an independent natural gas analysis service provider can help.