Rate Matters	3 Months Ended
Mar. 31, 2022
Regulated Operations [Abstract]
Rate Matters	9. Rate Matters - MGE Energy and MGE. a. Rate Proceedings. In April 2022, MGE filed with the PSCW a proposed electric limited 2023 rate case reopener. The limited reopener proposes a 4.38% increase for electric rates in 2023. The electric rate increase is driven by generation assets including our investments in Badger Hollow II (solar), Paris (solar and battery), Red Barn (wind), and West Riverside (natural gas). In addition, the reopener request includes a reduction in fuel costs, which MGE has partially offset with the recovery of deferred 2021 fuel costs. The reopener also revises the depreciation schedule for Columbia Unit 2 and shared equipment to 2029 to align with the depreciation schedule for Columbia Unit 1. PSCW approval of the 2023 limited reopener is pending. A final order is expected before the end of the year. In December 2021, the PSCW approved a settlement agreement for MGE's 2022 rate case. The settlement agreement provides for an 8.81% increase for electric rates and a 2.15% increase for gas rates in 2022. The electric and gas rate increases were driven by an increase in rate base including our investments in Badger Hollow I and a new customer information system. Also driving the requested electric increase were higher fuel and purchased power costs as well as the completion in 2021 of the one-time return of the electric excess deferred tax credit related to the 2017 Tax Act not restricted by IRS normalization rules. Included in the electric residential rate is a reduction in the customer charge. As part of the settlement agreement, for 2023, the PSCW approved a 0.96% increase in gas rates and to address a potential electric rate change through a limited rate case reopener. The return on common stock equity for 2022 and 2023 is 9.8% based on a capital structure consisting of 55.6% common equity. In December 2020, the PSCW approved a settlement agreement for MGE's 2021 rate case. The settlement agreement provided for a zero percent increase for electric rates and an approximately 4% increase for gas rates in 2021. The electric rate settlement included an increase in rate base but the associated rate increase was primarily offset by lower fuel and purchased power costs and a one-time $18.2 million return to customers of the portion of excess deferred taxes related to the 2017 Tax Act not restricted by IRS normalization rules. As part of the settlement, the fuel rules bandwidth was set at plus or minus 1% for 2021. When compared to the 2020 rate case, the settlement included lower forecasted electric sales for 2021 to reflect changes to customer usage during the COVID-19 pandemic. The gas rate increase covered infrastructure costs and technology improvements. The settlement agreement also included escrow accounting treatment for pension and other postretirement benefit costs, bad debt expense, and customer credit card fees. Escrow accounting treatment allows MGE to defer any difference between estimated costs in rates and actual costs incurred until a future rate filing. Any difference would be recorded as a regulatory asset or regulatory liability. The return on common stock equity for 2021 was 9.8% based on a capital structure of 55.8% common equity in 2021. Sierra Club and Vote Solar have filed petitions with the Dane County Circuit Court seeking review of the PSCW decision approving MGE's two most recent rate settlements (2021 and 2022/2023). The PSCW is named as the responding party; MGE is not named as a party. The petitions challenge the process the PSCW used to approve the portion of the settlements relating to electric rates and the electric customer fixed charge that does not vary with usage. The requested relief is unclear. The revenue requirement approved by the PSCW in the settlements have not been challenged. The PSCW is expected to vigorously defend its approval of the rate case settlements. MGE has intervened in the proceedings to further defend the PSCW's decision. b. Fuel Rules. Fuel rules require Wisconsin utilities to defer electric fuel-related costs that fall outside a symmetrical cost tolerance band around the amount approved for a utility in its annual fuel proceedings. Any over- or under-recovery of the actual costs is determined in the following year and is then reflected in future billings to electric retail customers. The fuel rules bandwidth is set at plus or minus 1%. Under fuel rules, MGE defers costs, less any excess revenues, if its actual electric fuel costs exceed 101% of the electric fuel costs allowed in its latest rate order. Excess revenues are defined as revenues in the year in question that provide MGE with a greater return on common equity than authorized by the PSCW in MGE's latest rate order. Conversely, MGE is required to defer the benefit of lower costs if actual electric fuel costs were less than 99% of the electric fuel costs allowed in that order. These costs are subject to the PSCW's annual review of fuel costs completed in the year following the deferral. The PSCW issued a final decision in the 2019 fuel rules proceedings regarding $1.5 million of deferred savings giving MGE the option either to use the $1.5 million as part of the settlement to MGE's 2021 rate case or to refund the balance to customers in October 2020. MGE elected to include the savings as part of the 2021 rate change settlement as described above, reducing electric retail rates as opposed to a one-time credit back to retail customers. There was no change to the refund in the fuel rules proceedings from the amount MGE deferred in the previous year. In September 2021, the PSCW issued a final decision in the 2020 fuel rules proceedings for MGE to refund $3.2 million of additional fuel savings realized during 2020 plus accrued interest to its retail electric customers over a one-month period in October 2021. There was no change to the refund in the fuel rules proceedings from the amount MGE deferred in the previous year. MGE has under recovered fuel costs in 2021. As of December 31, 2021, MGE had deferred $3.3 million of 2021 fuel costs. These costs will be subject to the PSCW's annual review of 2021 fuel costs, expected to be completed in 2022. MGE has proposed to include these costs as part of the 2023 electric limited reopener. As of March 31, 2022, MGE had no deferred 2022 fuel savings or costs.

In April 2022, MGE filed with the PSCW a proposed electric limited 2023 rate case reopener. The limited reopener proposes a 4.38% increase for electric rates in 2023. The electric rate increase is driven by generation assets including our investments in Badger Hollow II (solar), Paris (solar and battery), Red Barn (wind), and West Riverside (natural gas). In addition, the reopener request includes a reduction in fuel costs, which MGE has partially offset with the recovery of deferred 2021 fuel costs. The reopener also revises the depreciation schedule for Columbia Unit 2 and shared equipment to 2029 to align with the depreciation schedule for Columbia Unit 1. PSCW approval of the 2023 limited reopener is pending. A final order is expected before the end of the year.

In December 2021, the PSCW approved a settlement agreement for MGE's 2022 rate case. The settlement agreement provides for an 8.81% increase for electric rates and a 2.15% increase for gas rates in 2022. The electric and gas rate increases were driven by an increase in rate base including our investments in Badger Hollow I and a new customer information system. Also driving the requested electric increase were higher fuel and purchased power costs as well as the completion in 2021 of the one-time return of the electric excess deferred tax credit related to the 2017 Tax Act not restricted by IRS normalization rules. Included in the electric residential rate is a reduction in the customer charge. As part of the settlement agreement, for 2023, the PSCW approved a 0.96% increase in gas rates and to address a potential electric rate change through a limited rate case reopener. The return on common stock equity for 2022 and 2023 is 9.8% based on a capital structure consisting of 55.6% common equity.

In December 2020, the PSCW approved a settlement agreement for MGE's 2021 rate case. The settlement agreement provided for a zero percent increase for electric rates and an approximately 4% increase for gas rates in 2021. The electric rate settlement included an increase in rate base but the associated rate increase was primarily offset by lower fuel and purchased power costs and a one-time $18.2 million return to customers of the portion of excess deferred taxes related to the 2017 Tax Act not restricted by IRS normalization rules. As part of the settlement, the fuel rules bandwidth was set at plus or minus 1% for 2021. When compared to the 2020 rate case, the settlement included lower forecasted electric sales for 2021 to reflect changes to customer usage during the COVID-19 pandemic. The gas rate increase covered infrastructure costs and technology improvements. The settlement agreement also included escrow accounting treatment for pension and other postretirement benefit costs, bad debt expense, and customer credit card fees. Escrow accounting treatment allows MGE to defer any difference between estimated costs in rates and actual costs incurred until a future rate filing. Any difference would be recorded as a regulatory asset or regulatory liability. The return on common stock equity for 2021 was 9.8% based on a capital structure of 55.8% common equity in 2021.

Sierra Club and Vote Solar have filed petitions with the Dane County Circuit Court seeking review of the PSCW decision approving MGE's two most recent rate settlements (2021 and 2022/2023). The PSCW is named as the responding party; MGE is not named as a party. The petitions challenge the process the PSCW used to approve the portion of the settlements relating to electric rates and the electric customer fixed charge that does not vary with usage. The requested relief is unclear. The revenue requirement approved by the PSCW in the settlements have not been challenged. The PSCW is expected to vigorously defend its approval of the rate case settlements. MGE has intervened in the proceedings to further defend the PSCW's decision.

Fuel rules require Wisconsin utilities to defer electric fuel-related costs that fall outside a symmetrical cost tolerance band around the amount approved for a utility in its annual fuel proceedings. Any over- or under-recovery of the actual costs is determined in the following year and is then reflected in future billings to electric retail customers. The fuel rules bandwidth is set at plus or minus 1%. Under fuel rules, MGE defers costs, less any excess revenues, if its actual electric fuel costs exceed 101% of the electric fuel costs allowed in its latest rate order. Excess revenues are defined as revenues in the year in question that provide MGE with a greater return on common equity than authorized by the PSCW in MGE's latest rate order. Conversely, MGE is required to defer the benefit of lower costs if actual electric

fuel costs were less than 99% of the electric fuel costs allowed in that order. These costs are subject to the PSCW's annual review of fuel costs completed in the year following the deferral.

The PSCW issued a final decision in the 2019 fuel rules proceedings regarding $1.5 million of deferred savings giving MGE the option either to use the $1.5 million as part of the settlement to MGE's 2021 rate case or to refund the balance to customers in October 2020. MGE elected to include the savings as part of the 2021 rate change settlement as described above, reducing electric retail rates as opposed to a one-time credit back to retail customers. There was no change to the refund in the fuel rules proceedings from the amount MGE deferred in the previous year.

In September 2021, the PSCW issued a final decision in the 2020 fuel rules proceedings for MGE to refund $3.2 million of additional fuel savings realized during 2020 plus accrued interest to its retail electric customers over a one-month period in October 2021. There was no change to the refund in the fuel rules proceedings from the amount MGE deferred in the previous year.

MGE has under recovered fuel costs in 2021. As of December 31, 2021, MGE had deferred $3.3 million of 2021 fuel costs. These costs will be subject to the PSCW's annual review of 2021 fuel costs, expected to be completed in 2022. MGE has proposed to include these costs as part of the 2023 electric limited reopener.