In February 2021, MGE and the other co-owners of Columbia announced plans to retire that facility. The co-owners intend to retire Unit 1 and Unit 2 by June 2026. Final timing and retirement dates are subject to change depending on operational, regulatory, and other factors. Effects of environmental compliance discussed below will depend upon the final retirement dates approved and compliance requirement dates.

Water quality regulations promulgated by the EPA and WDNR in accordance with the Federal Water Pollution Control Act, commonly known as the Clean Water Act (CWA), impose restrictions on discharges of various pollutants into surface waters. The CWA also regulates surface water quality issues that affect aquatic life, such as water temperatures, chemical concentrations, intake structures, and wetlands filling into Waters of the U.S. (WOTUS), defined by EPA regulation. The CWA also includes discharge standards, which require the use of effluent-treatment processes equivalent to categorical "best practicable" or "best available" technologies. The CWA regulates discharges from "point sources," such as power plants, by establishing discharge limits via water discharge permits. MGE's power plants operate under Wisconsin Pollution Discharge Elimination System (WPDES) permits issued by the WDNR to ensure compliance with these discharge limits. Permits are subject to periodic renewal.

Effluent Limitations Guidelines and Standards for Steam Electric Power Generating Point Source Category

The EPA has promulgated water Effluent Limitations Guidelines (ELG) and standards for steam electric power plants which focus on the reduction of metals and other pollutants in wastewater from new and existing power plants.

In July 2021, the PSCW approved a Certificate of Authority (CA) application, filed by MGE and the other owners of Columbia. The CA application commits to close Columbia's wet pond system (as described in further detail in the CCR section below). By committing to close the wet pond system, Columbia will be in compliance with ELG requirements.

The Elm Road Units must satisfy the ELG rule's requirements no later than December 2023, as determined by the permitting authority. In December 2021, the PSCW approved a CA application for installation of additional wastewater treatment equipment to comply with the ELG rule. MGE's share of the costs to comply with the rule is estimated to be approximately $4 million. Construction began in March 2022 and is scheduled to be completed by the end of 2023.

Based on previous treatment of environmental compliance projects, management believes that any compliance costs will be recovered in future rates.

Section 316(b) of the Clean Water Act require cooling water intake structures at electric power plants meet best available technology (BTA) standards to reduce mortality from entrainment (drawing aquatic life into a plant's cooling system) and impingement (trapping aquatic life on screens). The EPA finalized its Section 316(b) rule for existing facilities in 2014. Section 316(b) requirements are implemented in Wisconsin through modifications to plants' WPDES permits, which govern plant wastewater discharges.

WCCF, Blount, and Columbia are considered existing plants under this rule. WCCF employs a system that meets the Section 316(b) rule. Blount's WPDES permit assumes that the plant meets BTA standards for the duration of the permit, which expires in 2023. Before the next permit renewal, MGE is required to complete an entrainment study and recommend a BTA along with alternative technologies considered. MGE completed the entrainment study in 2021 and submitted the results to the WDNR.

The WDNR will make the final BTA determination and include any BTA requirements in Blount's next permit renewal, which is expected to be completed and effective in 2023. Management believes that the BTA determination at Blount will not be material for MGE.

Intakes at the Columbia plant are subject to this rule. Columbia's operator received a permit in 2019 requiring studies of intake structures to be submitted to the WDNR by November 2023 to help determine BTA. BTA improvements may not be required given that Columbia is scheduled to retire both units by June 2026. MGE will continue to work with Columbia's operator to evaluate all regulatory requirements applicable to the planned retirements. Management believes that the Section 316(b) rule will not have a material effect on its existing plants and that any compliance costs will be recovered in future rates based on previous treatment of environmental compliance projects.

Federal and state air quality regulations impose restrictions on various emissions, including emissions of particulate matter (PM), sulfur dioxide (SO2), nitrogen oxides (NOx), and other pollutants, and require permits for operation of emission sources. These permits have been obtained by MGE and must be renewed periodically. Current EPA initiatives under the Clean Air Act, including the Cross-State Air Pollution Rule (CSAPR) and National Ambient Air Quality Standards (NAAQS), have the potential to result in additional operating and capital expenditure costs for MGE.

WCCF, the Elm Road Units, Blount, and Columbia could be impacted by GHG reduction guidelines and approval criteria established under the Clean Air Act for the control of GHG emissions from fossil fuel-fired electric generating units (EGUs). The EPA is undertaking a new rulemaking under section 111(d) of the Clean Air Act to establish emission guidelines and limit GHG emissions from existing fossil fuel-fired EGUs. The EPA is also conducting a comprehensive review of the New Source Performance Standards (NSPS) and may set new emission standards for GHG emissions from new, modified, and/or reconstructed fossil fuel-fired power plants. The EPA anticipates issuing a proposed rule in spring 2023 and promulgating a final rule by summer 2024. MGE will continue to evaluate greenhouse gas rule developments, including any new EPA actions towards rule development, and any further court decisions on the EPA's authority to regulate greenhouse gases.

The EPA's NAAQS regulations have been developed to set ambient levels of six pollutants to protect sensitive human populations (primary NAAQS) and the environment (secondary NAAQS) from the negative effects of exposure to these pollutants at higher levels. The Clean Air Act requires that the EPA periodically review, and adjust as necessary, the NAAQS for these six air pollutants. The EPA's NAAQS review can result in a lowering of the allowed ambient levels of a pollutant, a change in how the pollutant is monitored, and/or a change in which sources of that pollutant are regulated. States implement any necessary monitoring and measurement changes and recommend areas for attainment (meets the ambient requirements) or nonattainment (does not meet these standards). The EPA makes final attainment and nonattainment determinations. States must come up with a State Implementation Plan (SIP) to get nonattainment areas into attainment and maintain air quality in attainment areas. A company with facilities located in a nonattainment area will be most affected. Its facilities in nonattainment areas may be subject to additional data submission and emission measurement requirements during permitting renewals, its facilities may need to meet new emission limitations set by the SIP (which could result in significant capital expenditures), and it may have additional expenses and/or difficulties expanding existing facilities or building new facilities. The process, which starts with determining acceptable primary and/or secondary NAAQS and ends with executing SIPs can take years. Since the NAAQS regulations have the potential to affect both existing and new facilities, MGE continuously monitors changes to these rules to evaluate whether changes could impact its operations. In addition, the EPA has adopted interstate transport rules, such as CSAPR, to address contributions to NAAQS nonattainment from upwind sources in neighboring states. In the following paragraphs we discuss specific NAAQS and transport rule developments that may affect MGE.

The Elm Road Units are located in Milwaukee County, Wisconsin, a nonattainment area. In October 2022, the EPA reclassified Milwaukee County from "marginal" to "moderate" nonattainment under the 2015 ozone NAAQS. The Wisconsin Department of Natural Resources (WDNR) must develop a SIP for the area, and this reclassification will result in more stringent SIP requirements for both constructing new development and modifying or expanding existing plants in the area. The deadline for moderate classified areas to meet attainment standards is August 2024. MGE will continue to monitor the WDNR's SIP development and the extent to which the requirements will impact the Elm Road Units. At this time, the operator of the Elm Road Units does not expect that the 2015 Ozone NAAQS will have a material effect on its existing plants based on final designations.

In January 2023, the EPA published a proposed rule to lower the average annual PM2.5 NAAQS from its current level. The EPA has also solicited comments on whether to lower the annual standard further than the proposed level, and whether or not to also lower the maximum 24-hour limit to be consistent with recommendations from its Clean Air Scientific Advisory Committee (CASAC). As the rule is currently proposed, the annual PM2.5 NAAQS and the 24-hour limit recommended by the CASAC is not expected to impact the counties where Columbia and the Elm Road Units are located. However, if the annual PM2.5 NAAQS is lowered further than the EPA's currently proposed value, the county where the Elm Road Units are located may be in nonattainment with the standard. A nonattainment designation would require the State of Wisconsin to develop a plan to get into attainment. However, we will not know the impact of this rule with any certainty until it is finalized, counties' attainment status is determined by the EPA, and the State of Wisconsin develops an attainment implementation plan. MGE will continue to follow the rule's developments.

The EPA's CSAPR and its progeny are a suite of interstate air pollution transport rules designed to reduce ozone and fine PM2.5 ambient air levels in areas that the EPA has determined as being significantly impacted by pollution from upwind states. This is accomplished in the CSAPR through a reduction in SO2 and NOx from qualifying fossil-fuel fired power plants in upwind "contributing" states. NOx and SO2 contribute to fine particulate pollution and NOx contributes to ozone formation in downwind areas. Reductions are achieved through a cap-and-trade system. Individual plants can meet their caps through reducing emissions and/or buying allowances on the market.

In April 2022, the EPA published a proposed Federal Implementation Plan (FIP) to address state obligations under the Clean Air Act "good neighbor" provisions for the 2015 Ozone NAAQS. This proposed rule impacts 26 states, including Wisconsin, and is designed to both revise the current NOx CSAPR ozone season cap-and-trade obligations for fossil-fuel generated power plants and add NOx limitations for certain industries in specified states. For Wisconsin, the proposed rule includes revisions to the current obligations for fossil-fuel power generation as well as the new limitations for certain industries.

If finalized, the proposed rule would be effective beginning with the 2023 ozone season and start with emissions budgets that can be achieved with what the EPA has defined as immediately available measures, including consistently operating emissions controls already installed at power plants. In 2026, additional obligations would go into effect, including potential daily emissions limits and technology upgrades to coal-fired power plants without existing emission controls. Wisconsin would need to submit a SIP to meet its obligations or accept the EPA's proposed FIP.

MGE expects the rule, if finalized as written, to impact our fossil-fueled generation assets. However, we will not know the impact of this rule with any certainty until it is finalized. We will continue to monitor rule developments.

Columbia is subject to the best available retrofit technology (BART) regulations, a subsection of CAVR, which may require pollution control retrofits. Columbia's existing pollution control upgrades, and the EPA's stance that compliance with the CSAPR equals compliance with BART, should mean that Columbia

will not need to do additional work to meet BART requirements. Wisconsin's 2021 SIP argues that Wisconsin will meet its current regional haze goals based on expected emissions reductions, which include Columbia unit retirements. Given that the Wisconsin SIP recognizes the Columbia unit retirements as part of its emission reduction plan, MGE does not anticipate further obligations with this rule at Columbia. MGE will continue to monitor legal developments and any future updates to this rule.

The CCR rule regulates as a solid waste coal ash from burning coal for the purpose of generating electricity and defines what ash use activities would be considered generally exempt beneficial reuse of coal ash. The CCR rule also regulates landfills, ash ponds, and other surface impoundments used for coal combustion residuals by regulating their design, location, monitoring, and operation. The CCR rule requires owners or operators of coal-fired power plants to stop transporting CCR and non-CCR wastewater to unlined surface impoundments. In addition, regulated entities must initiate impoundment closure as soon as feasible and in no event later than April 2021, unless the EPA grants an extension. A site-specific extension to initiate closure of the primary ash pond at Columbia by March 31, 2023, was requested. The EPA has not formally approved the extension.

In July 2021, the PSCW approved a CA application filed by MGE and the other owners of Columbia to install technology required to cease bottom ash transport water discharges rather than extend the longevity of the ash ponds. The coal combustion residuals system that will replace the unlined surface impoundment is undergoing final testing. Construction is expected to be completed by the end of the first quarter of 2023. MGE's share of the costs of the project is expected to be approximately $4 million.

Review of the Elm Road Units has indicated that the costs to comply with the CCR rule are not expected to be significant.

MGE is involved in various legal matters that are being defended and handled in the normal course of business. MGE maintains accruals for such costs that are probable of being incurred and subject to reasonable estimation. The accrued amount for these matters is not material to the financial statements. MGE does not expect the resolution of these matters to have a material adverse effect on its consolidated results of operations, financial condition, or cash flows.

Certain environmental groups have filed petitions against the PSCW regarding MGE's rate settlement and electric limited reopener. MGE has intervened in the petitions in cooperation with the PSCW. See Footnote 9.a. for more information regarding this matter.

MGE Energy and MGE have entered into various commodity supply, transportation, and storage contracts to meet their obligations to deliver electricity and natural gas to customers. Management expects to recover these costs in future customer rates.

As of December 31, 2022, the future minimum commitments related to these purchase contracts were as follows:


(In thousands)	2023		2024		2025		2026		2027		Thereafter
Coal(a)	$	23,886	$	17,104	$	7,782	$	2,868	$	—	$	—
Natural gas
Transportation and storage(b)		25,446		25,446		25,446		14,736		1,892		10,549
Supply(c)		30,778		—		—		—		—		—
Purchase power(d)		5,513		5,623		5,735		5,850		5,967		266
Renewable energy(e)		25,024		2,025		2,040		2,056		2,072		26,592
Other		6,105		2,224		350		359		108		689
	$	116,752	$	52,422	$	41,353	$	25,869	$	10,039	$	38,096

(a)

Total coal commitments for MGE's share of the Columbia and Elm Road Units, including transportation. Fuel procurement for MGE's jointly owned Columbia and Elm Road Units is handled by WPL and WEPCO, respectively, who are the operators of those facilities.

(b)

MGE's natural gas transportation and storage contracts require fixed monthly payments for firm supply pipeline transportation and storage capacity. The pricing components of the fixed monthly payments for the transportation and storage contracts are approved by FERC but may be subject to change.

(c)

These commitments include market-based pricing.

(d)

MGE has a purchase power agreement to help meet future electric supply requirements.

(e)

Operational commitments for solar and wind facilities.

MGE Energy holds investments in nonpublic venture capital funds. From time to time, these entities require additional capital infusions from their investors. MGE Energy has committed to contribute $8.0 million in capital for such infusions. The timing of these infusions is dependent on the needs of the investee and is therefore uncertain at this time.

In addition, MGE Energy has a three-year agreement with a venture debt fund expiring in December 2025. MGE Energy has committed to invest up to a total of $1.5 million into this fund. As of December 31, 2022, MGE Energy has $0.9 million remaining in commitments. The timing of infusions is dependent on the needs of the fund and is therefore uncertain at this time.

MGE has several other commitments related to various projects. Payments for these commitments are expected to be as follows:


(In thousands)	2023		2024		2025		2026		2027		Thereafter
Other commitments	$	333	$	333	$	333	$	333	$	333	$	2,332