Appendix A — Supplementary data

A.1 Emissions factors

Note for solid waste, the global warming potentials used to calculate CO2e are sourced AR4, not AR5, like the rest of our inventory. However, documentation for the EPA WARM tool (USEPA 2019), indicates that the differences in total CO2e emissions is negligible.

All EPA Emission Factor Hub values were pulled from an Excel workbook downloaded from the EPA website. Values were processed in epa_ghg_factor_hub.R.

Table A.1: Electricity emission factors. 2021 EPA GHG Emission Factor Hub, EPA eGRID2019, February 2021.
eGrid Subregion Grid Output GHG lb GHG per MWh
MROW (MRO West) Total output CO₂ 995.800
MROW (MRO West) Total output CH₄ 0.107
MROW (MRO West) Total output N₂O 0.015
Table A.2: Stationary combustion emission factors. 2021 EPA GHG Emission Factor Hub, Federal Register EPA; 40 CFR Part 98.
Fuel type GHG GHG Quantity Unit Value
Natural Gas
Natural Gas CO₂ Kilograms mmBtu 53.06000
Natural Gas CH₄ Grams mmBtu 1.00000
Natural Gas N₂O Grams mmBtu 0.10000
Natural Gas CO₂ Kilograms scf 0.05444
Natural Gas CH₄ Grams scf 0.00103
Natural Gas N₂O Grams scf 0.00010
Petroleum Products
Kerosene CO₂ Kilograms mmBtu 75.20000
Kerosene CH₄ Grams mmBtu 3.00000
Kerosene N₂O Grams mmBtu 0.60000
Propane CO₂ Kilograms mmBtu 62.87000
Propane CH₄ Grams mmBtu 3.00000
Propane N₂O Grams mmBtu 0.60000
Table A.3: Solid waste emission factors. 2021 EPA GHG Emission Factor Hub, EPA WARM version 15, November 2020.
Material Metric tons CO₂e per short ton material
Recycled
Mixed Recyclables 0.09
Mixed Organics NA
Mixed MSW NA
Landfilled
Mixed Recyclables 0.68
Mixed Organics 0.48
Mixed MSW 0.52
Combusted
Mixed Recyclables 0.11
Mixed Organics 0.05
Mixed MSW 0.43
Composted
Mixed Recyclables NA
Mixed Organics 0.17
Mixed MSW NA

Transportation emissions factors were processed in epa_moves.R. Read more about these emission factors in Section 7.3.

Table A.4: Transportation emissions factors. Source: EPA MOVES
GHG Grams per vehicle mile traveled
Passenger
CO₂ 353.4300
CO₂e 356.4390
CH₄ 0.0100
N₂O 0.0100
Medium
CO₂ 473.2400
CO₂e 476.2490
CH₄ 0.0100
N₂O 0.0100
Heavy
CO₂ 1212.3600
CO₂e 1223.9093
CH₄ 0.0206
N₂O 0.0402

A.2 Global Warming Potential (GWP)

The Global Warming Potential (GWP) was developed to allow comparisons of the global warming impacts of different gases. Specifically, it is a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period of time, relative to the emissions of 1 ton of carbon dioxide (CO2). The larger the GWP, the more that a given gas warms the Earth compared to CO2 over that time period (USEPA 2023).

Across all sectors, we used the GWP values established in the Intergovernmental Panel on Climate Change (IPCC) 6th Assessment Report (AR6), Table 7.SM.7 (IPCC 2023). We processed these values in global_warming_potential.R.

Table A.5: Global Warming Potential (GWP) values
Gas 100-year GWP value Source
CO₂ 1.0 IPCC AR5 (2014)
CH₄ 27.9 IPCC AR5 (2014)
N₂O 273.0 IPCC AR5 (2014)
CF₄ 7380.0 IPCC AR5 (2014)
HFC-152a1 164.0 IPCC AR5 (2014)
1 Hydrofluorocarbon-152a, Difluoroethane

A.3 Geographic data

Geographic data were processed in cprg_geography.R.

A.3.1 Counties

County data was pulled using {tigris}, an R package that downloads TIGER/Line shapefiles from the US Census Bureau (Walker 2023). 2021 geographies for Minnesota and Wisconsin were pulled, combined, and saved.

Table A.6: County geography metadata
Column Class Description
STATE character Full state name
STATEFP character State FIPS code
STATE_ABB character Abbreviated state name
COUNTYFP character County FIPS code
GEOID character County GEOID
NAME character County name
NAMELSAD character Full county name
geometry sfc_MULTIPOLYGON Simple feature geometry

Additionally, population estimates were obtained from the American Community Survey 5-Year estimates (2017-2021) using {tidycensus} (U.S. Census Bureau 2021).

Table A.7: County population metadata
Column Class Description
STATE character Full state name
STATEFP character State FIPS code
COUNTYFP character County FIPS code
GEOID character County GEOID
NAME character County name
NAMELSAD character Full county name
population numeric Total county population estimate
population_data_source character Population estimate data source

A.3.2 Cities

Minnesota cities, townships, and unorganized territories were imported from Minnesota Geospatial Commons (MnDOT 2023).

Wisconsin cities, towns, and villages were imported from Wisconsin’s Legislative Technology Services Bureau (Wisconsin Legislature 2023).

Data from both states was then combined and filtered to include only the workplan area counties.

Table A.8: City geography metadata
Column Class Description
CTU_NAME character City, township, unorganized territory, or village name
CTU_CLASS character City class (City, township, unorganized territory, or village)
COUNTY_NAM character County name
STATEFP character State FIPS code
STATE character Full state name
STATE_ABB character Abbreviated state name
GNIS_FEATU numeric Minnesota geographic identifier
geometry sfc_MULTIPOLYGON Simple feature geometry
GEOID character Wisconsin geographic identifier