Rate Matters	3 Months Ended
Mar. 31, 2021
Regulated Operations [Abstract]
Rate Matters	Rate Matters - MGE Energy and MGE. a.Rate Proceedings. In May 2021, MGE filed an application with the PSCW requesting a 5.9% increase to electric rates and a 3.0% increase to gas rates for 2022. The proposed electric and gas rate increases are primarily 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 is the completion in 2020 of the one-time return of the electric excess deferred tax credit related to the 2017 Tax Act not restricted by IRS normalization rules. In its application, MGE is proposing to address potential 2023 rate changes through an electric limited rate case re-opener and a 1.65% increase in gas rates. The proposed return on common stock equity for 2022 is 9.8% based on a proposed capital structure consisting of 55.6% common equity in 2022. PSCW approval of the application is pending. A final order is expected before the end of the year. In December 2020, the PSCW approved a settlement agreement for MGE's 2021 rate case. The settlement agreement provides for a zero percent increase for electric rates and an approximately 4% increase for gas rates in 2021. The electric rate settlement includes an increase in rate base but the associated rate increase is primarily offset by lower fuel and purchase 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 is 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 covers infrastructure costs and technology improvements. The settlement agreement also includes 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 its next rate filing. Any difference would be recorded as a regulatory asset or regulatory liability. The return on common stock equity for 2021 is 9.8% based on a capital structure of 55.8% common equity in 2021. On January 27, 2021, Sierra Club and Vote Solar filed a petition with the Dane County Circuit Court seeking review of the PSCW decision approving the rate settlement in MGE's 2021 rate case. The PSCW is named as the responding party; MGE is not named as a party. The petition challenges the process the PSCW used to approve the portion of the settlement 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 settlement has not been challenged. The PSCW is expected to vigorously defend its approval of the rate case settlement. MGE has intervened in the proceedings to further defend the PSCW’s decision. In December 2018, the PSCW approved a settlement agreement between MGE and intervening parties in the then pending rate case. The settlement decreased electric rates by 2.24%, or $9.2 million, in 2019. The decrease in electric rates reflected the ongoing impacts of the 2017 Tax Act. Lower fuel costs and an increase in rate base from renewable generation assets further impacted the rate change. In 2020, electric rates decreased a further 0.84%, or $3.4 million, as approved by the PSCW in December 2019 in MGE's 2020 Fuel Cost Plan, which reflected lower fuel costs. The settlement agreement increased gas rates by 1.06%, or $1.7 million, in 2019 and 1.46%, or $2.4 million, in 2020. The gas increase covered infrastructure costs. It also reflected the impacts of the 2017 Tax Act. The return on common stock equity for 2019 and 2020 was 9.8% based on a capital structure consisting of 56.6% common equity in 2019 and 56.1% common equity in 2020. 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% in 2021. 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. In 2020 the fuel rules bandwidth was set at plus or minus 2%. 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. As of December 31, 2020, MGE had deferred $3.2 million of 2020 fuel-related savings. These costs will be subject to the PSCW's annual review of 2020 fuel costs, which is expected to be completed in 2021. In March 2021, as part of the 2020 fuel costs application filed with the PSCW, MGE seeks to return the 2020 fuel-related savings to customers in 2022 as part of the 2022 rate case. As of March 31, 2021, MGE had deferred $0.5 million of 2021 fuel savings. These costs will be subject to the PSCW's annual review of 2021 fuel costs, which is expected to be completed in 2022.

Rate Matters

3 Months Ended

Mar. 31, 2021

Rate Matters - MGE Energy and MGE.

a.Rate Proceedings.

In May 2021, MGE filed an application with the PSCW requesting a 5.9% increase to electric rates and a

3.0% increase to gas rates for 2022. The proposed electric and gas rate increases are primarily 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 is the completion in 2020 of the one-time return of the electric excess deferred tax credit related to the 2017 Tax Act not restricted by IRS normalization rules. In its application, MGE is proposing to address potential 2023 rate changes through an electric limited rate case re-opener and a 1.65% increase in gas rates. The proposed return on common stock equity for 2022 is 9.8% based on a proposed capital structure consisting of 55.6% common equity in 2022. PSCW approval of the application is pending. A final order is expected before the end of the year.

In December 2020, the PSCW approved a settlement agreement for MGE's 2021 rate case. The settlement agreement provides for a zero percent increase for electric rates and an approximately 4% increase for gas rates in 2021. The electric rate settlement includes an increase in rate base but the associated rate increase is primarily offset by lower fuel and purchase 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 is 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 covers infrastructure costs and technology improvements. The settlement agreement also includes 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 its next rate filing. Any difference would be recorded as a regulatory asset or regulatory liability. The return on common stock equity for 2021 is 9.8% based on a capital structure of 55.8% common equity in 2021.

On January 27, 2021, Sierra Club and Vote Solar filed a petition with the Dane County Circuit Court seeking review of the PSCW decision approving the rate settlement in MGE's 2021 rate case. The PSCW is named as the responding party; MGE is not named as a party. The petition challenges the process the PSCW used to approve the portion of the settlement 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 settlement has not been challenged. The PSCW is expected to vigorously defend its approval of the rate case settlement. MGE has intervened in the proceedings to further defend the PSCW’s decision.

In December 2018, the PSCW approved a settlement agreement between MGE and intervening parties in the then pending rate case. The settlement decreased electric rates by 2.24%, or $9.2 million, in 2019. The decrease in electric rates reflected the ongoing impacts of the 2017 Tax Act. Lower fuel costs and an increase in rate base from renewable generation assets further impacted the rate change. In 2020, electric rates decreased a further 0.84%, or $3.4 million, as approved by the PSCW in December 2019 in MGE's 2020 Fuel Cost Plan, which reflected lower fuel costs. The settlement agreement increased gas rates by 1.06%, or $1.7 million, in 2019 and 1.46%, or $2.4 million, in 2020. The gas increase covered infrastructure costs. It also reflected the impacts of the 2017 Tax Act. The return on common stock equity for 2019 and 2020 was 9.8% based on a capital structure consisting of 56.6% common equity in 2019 and 56.1% common equity in 2020.

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% in 2021. 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. In 2020 the fuel rules bandwidth was set at plus or minus 2%. 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.

As of December 31, 2020, MGE had deferred $3.2 million of 2020 fuel-related savings. These costs will be subject to the PSCW's annual review of 2020 fuel costs, which is expected to be completed in 2021. In March 2021, as part of the 2020 fuel costs application filed with the PSCW, MGE seeks to return the 2020 fuel-related savings to customers in 2022 as part of the 2022 rate case.

As of March 31, 2021, MGE had deferred $0.5 million of 2021 fuel savings. These costs will be subject to the PSCW's annual review of 2021 fuel costs, which is expected to be completed in 2022.