United States

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

[X] Annual Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

For the fiscal year ended:

December 31, 2015

[ ] Transition report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

For the transition period from _______________ to _______________

SECURITIES REGISTERED PURSUANT TO SECTION 12(b) OF THE ACT:

SECURITIES REGISTERED PURSUANT TO SECTION 12(g) OF THE ACT:

Indicate by checkmark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.

Indicate by checkmark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.

Indicate by check mark whether the registrants (1) have filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrants were required to file such reports) and (2) have been subject to such filing requirements for the past 90 days. Yes [X] No [ ]

Indicate by check mark whether the registrants have submitted electronically and posted on their corporate Web sites, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrants were required to submit and post such files): Yes [X] No [ ]

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrants' knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K. [  ]

Indicate by check mark if the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See definition of "large accelerated filer," "accelerated filer," and "smaller reporting company" in Rule 12b-2 of the Exchange Act:

Indicate by checkmark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).

The aggregate market value of the voting and nonvoting common equity held by nonaffiliates of each registrant as of June 30, 2015, was as follows:

The number of shares outstanding of each registrant's common stock as of February 1, 2016, were as follows:

DOCUMENTS INCORPORATED BY REFERENCE

Portions of MGE Energy, Inc.'s definitive proxy statement to be filed on or before March 28, 2016, relating to its annual meeting of shareholders, are incorporated by reference into Part III of this annual report on Form 10-K.

Madison Gas and Electric Company meets the conditions set forth in General Instruction (I)(1)(a) and (b) of Form 10-K and is therefore omitting (i.) the information otherwise required by Item 601 of Regulation S-K relating to a list of subsidiaries of the registrant as permitted by General Instruction (I)(2)(b), (ii.) the information otherwise required by Item 6 relating to Selected Financial Data as permitted by General Instruction (I)(2)(a), (iii.) the information otherwise required by Item 10 relating to Directors and Executive Officers as permitted by General Instruction (I)(2)(c), (iv.) the information otherwise required by Item 11 relating to executive compensation as permitted by General Instruction (I)(2)(c), (v.) the information otherwise required by Item 12 relating to Security Ownership of Certain Beneficial Owners and Management as permitted by General Instruction (I)(2)(c), and (vi.) the information otherwise required by Item 13 relating to Certain Relationships and Related Transactions as permitted by General Instruction (I)(2)(c).

Table of Contents

Filing Format

4

Forward-Looking Statements

4

Where to Find More Information

4

Definitions, Abbreviations, and Acronyms Used in the Text and Notes of this Report

5

PART I.

7

Item 1. Business.

7

Item 1A. Risk Factors.

14

Item 1B. Unresolved Staff Comments.

19

Item 2. Properties.

20

Item 3. Legal Proceedings.

22

Item 4. Mine Safety Disclosures.

22

PART II.

23

Item 5. Market for Registrants' Common Equity, Related Stockholder Matters, and Issuer Purchases of Equity Securities.

23

Item 6. Selected Financial Data.

26

Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations.

27

Item 7A. Quantitative and Qualitative Disclosures About Market Risk.

49

Item 8. Financial Statements and Supplementary Data.

52

Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure.

106

Item 9A. Controls and Procedures.

106

Item 9B. Other Information.

106

PART III.

107

Item 10. Directors, Executive Officers, and Corporate Governance.

107

Item 11. Executive Compensation.

107

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.

107

Item 13. Certain Relationships and Related Transactions, and Director Independence.

107

Item 14. Principal Accounting Fees and Services.

108

PART IV.

109

Item 15. Exhibits and Financial Statement Schedules.

109

Signatures - MGE Energy, Inc.

118

Signatures - Madison Gas and Electric Company

119

Filing Format

This combined Form 10-K is being filed separately by MGE Energy, Inc. (MGE Energy) and Madison Gas and Electric Company (MGE). MGE is a wholly owned subsidiary of MGE Energy and represents a majority of its assets, liabilities, revenues, expenses, and operations. Thus, all information contained in this report relates to, and is filed by, MGE Energy. Information that is specifically identified in this report as relating solely to MGE Energy, such as its financial statements and information relating to its nonregulated business, does not relate to, and is not filed by, MGE. MGE makes no representation as to that information. The terms "we" and "our," as used in this report, refer to MGE Energy and its consolidated subsidiaries, unless otherwise indicated.

Forward-Looking Statements

This report, and other documents filed by MGE Energy and MGE with the Securities and Exchange Commission (SEC) from time to time, contain forward-looking statements that reflect management's current assumptions and estimates regarding future performance and economic conditions—especially as they relate to economic conditions, future load growth, revenues, expenses, capital expenditures, financial resources, regulatory matters, and the scope and expense associated with future environmental regulation. These forward-looking statements are made pursuant to the provisions of the Private Securities Litigation Reform Act of 1995. Words such as "believe," "expect," "anticipate," "estimate," "could," "should," "intend," "will," and other similar words generally identify forward-looking statements. Both MGE Energy and MGE caution investors that these forward-looking statements are subject to known and unknown risks and uncertainties that may cause actual results to differ materially from those projected, expressed, or implied.

The factors that could cause actual results to differ materially from the forward-looking statements made by a registrant include (a) those factors discussed in Item 1A. Risk Factors, Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations, and Item 8. Financial Statements and Supplementary Data, Footnote 18. Commitments and Contingencies, and (b) other factors discussed herein and in other filings made by that registrant with the SEC.

Readers are cautioned not to place undue reliance on these forward-looking statements, which apply only as of the date of this report. MGE Energy and MGE undertake no obligation to release publicly any revision to these forward-looking statements to reflect events or circumstances after the date of this report, except as required by law.

Where to Find More Information

The public may read and copy any reports or other information that MGE Energy and MGE file with the SEC at the SEC's public reference room at 100 F Street, NE, Washington, D.C. 20549. The public may obtain information on the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0330. These documents also are available to the public from commercial document retrieval services, the website maintained by the SEC at sec.gov, MGE Energy's website at mgeenergy.com, and MGE's website at mge.com. Copies may be obtained from our websites free of charge. Information contained on MGE Energy's and MGE's websites shall not be deemed incorporated into, or to be a part of, this report.

Definitions, Abbreviations, and Acronyms Used in the Text and Notes of this Report

Abbreviations, acronyms, and definitions used in the text and notes of this report are defined below.

PART I.

Item 1. Business.

MGE Energy operates in the following business segments:

·

Regulated electric utility operations – generating, purchasing, and distributing electricity through MGE.

·

Regulated gas utility operations – purchasing and distributing natural gas through MGE.

·

Nonregulated energy operations – owning and leasing electric generating capacity that assists MGE through MGE Energy's wholly owned subsidiaries MGE Power Elm Road and MGE Power West Campus.

·

Transmission investments – representing our investment in American Transmission Company LLC, a company engaged in the business of providing electric transmission services primarily in Wisconsin.

·

All other – investing in companies and property that relate to the regulated operations and financing the regulated operations, through its wholly owned subsidiaries CWDC, MAGAEL, MGE State Energy Services, NGV Fueling Services, and Corporate functions.

MGE's utility operations represent a majority of the assets, liabilities, revenues, expenses, and operations of MGE Energy. MGE Energy's nonregulated energy operations currently include an undivided interest in two coal-fired generating units located in Oak Creek, Wisconsin, which we refer to as the Elm Road Units, and an undivided interest in a cogeneration facility located on the Madison campus of the University of Wisconsin, which we refer to as the West Campus Cogeneration Facility or WCCF.

As a public utility, MGE is subject to regulation by the PSCW and the FERC. The PSCW has authority to regulate most aspects of MGE's business including rates, accounts, issuance of securities, and plant siting. The PSCW also has authority over certain aspects of MGE Energy as a holding company of a public utility. FERC has jurisdiction, under the Federal Power Act, over certain accounting practices and certain other aspects of MGE's business.

MGE Energy's subsidiaries are also subject to regulation under local, state, and federal laws regarding air and water quality and solid waste disposal. See "Environmental" below.

MGE Energy was organized as a Wisconsin corporation in 2001. MGE was organized as a Wisconsin corporation in 1896. Their principal offices are located at 133 South Blair Street, Madison, Wisconsin 53788, and their telephone number is (608) 252-7000.

Electric Utility Operations

MGE distributes electricity in a service area covering a 316 square-mile area of Dane County, Wisconsin. The service area includes the city of Madison, Wisconsin. It owns or leases ownership interests in electric generation facilities located in Wisconsin and Iowa.

At December 31, 2015, MGE supplied electric service to approximately 146,000 customers, with approximately 90% located in the cities of Fitchburg, Madison, Middleton, and Monona and 10% in adjacent areas. Of the total number of customers, approximately 87% were residential and 13% were commercial or industrial. Electric retail revenues for 2015, 2014, and 2013 were comprised of the following:

Electric operations accounted for approximately 74.2%, 64.0%, and 69.0% of MGE's total 2015, 2014, and 2013 regulated revenues, respectively.

See Item 2. Properties, for a description of MGE's electric utility plant.

MGE is registered with North American Electric Reliability Corporation (NERC) and one regional entity, the Midwest Reliability Organization (MRO). The essential purposes of these entities are the development and implementation of regional and NERC reliability standards; and determining compliance with those standards, including enforcement mechanisms.

Transmission

American Transmission Company LLC (ATC) is owned by the utilities that contributed facilities or capital to it in accordance with Wisconsin law. ATC's purpose is to provide reliable, economic transmission service to all customers in a fair and equitable manner. ATC plans, constructs, operates, maintains, and expands transmission facilities that it owns to provide adequate and reliable transmission of power. ATC is regulated by FERC for all rate terms and conditions of service and is a transmission-owning member of the MISO.

Regional Transmission Organizations (RTO)

MISO

MGE is a nontransmission owning member of the MISO. MISO, a FERC approved RTO, is responsible for monitoring the electric transmission system that delivers power from generating plants to wholesale power transmitters. MISO's role is to ensure equal access to the transmission system and to maintain or improve electric system reliability in the Midwest.

MISO maintains a bid-based energy market. MGE offers substantially all of its generation on the MISO market and purchases much of its load requirement from the MISO market in accordance with the MISO Tariff. MGE participates in the ancillary services market operated by MISO. That market is an extension of the existing energy market in which MISO assumes the responsibility of maintaining sufficient generation reserves. In the ancillary services market, MISO provides the reserves for MGE's load, and MGE may offer to sell reserves from its generating units.

MGE participates in the voluntary capacity auction, which provides an optional monthly forum for buyers and sellers of aggregate planning resource credits to interact. Load serving entities, such as MGE, may participate in the voluntary capacity auction potentially to obtain the necessary aggregate planning resource credits needed to meet their planning reserve margin requirement established by the PSCW. Generator owners may participate to sell any excess aggregate planning resource credits that are not needed by them.

PJM

MGE is a member of PJM. PJM, an RTO, is a neutral and independent party that coordinates and directs the operation of the transmission grid within its area of coverage, administers a competitive wholesale electricity market, and plans regional transmission expansion improvements to maintain grid reliability and relieve congestion.

Fuel supply and generation

MGE satisfies its customers' electric demand with internal generation and purchased power. During the years ended December 31, 2015, 2014, and 2013, MGE's electric energy delivery requirements were satisfied from the following fuel sources:

Sources used depend on market prices, generating unit availability, weather, and customer demand.

Generation Sources

MGE receives electric generation supply from coal-fired, gas-fired, and renewable energy sources. These sources include owned facilities as well as facilities leased from affiliates and accounted for under our nonregulated energy operations. See Item 2. Properties for more information regarding these generation sources, including location, capacity, ownership or lease arrangement, and fuel source. See "Nonregulated Energy Operations" below for more information regarding generating capacity leased to MGE by nonregulated subsidiaries.

Purchased power

MGE enters into short and long-term purchase power commitments with third parties to meet a portion of its anticipated electric energy supply needs. The following table identifies purchase power commitments at December 31, 2015, with unaffiliated parties for the next five years.

Gas Utility Operations

MGE transports and distributes natural gas in a service area covering 1,682 square miles in seven south-central Wisconsin counties. The service area includes the city of Madison, Wisconsin and surrounding areas.

At December 31, 2015, MGE supplied natural gas service to approximately 152,000 customers in the cities of Elroy, Fitchburg, Lodi, Madison, Middleton, Monona, Prairie du Chien, Verona, and Viroqua; 24 villages; and all or parts of 49 townships. Of the total number of customers, approximately 89% were residential and 11% were commercial or industrial. Gas revenues for 2015, 2014, and 2013 were comprised of the following:

Gas operations accounted for approximately 25.8%, 36.0%, and 31.0% of MGE's total 2015, 2014, and 2013 regulated revenues, respectively.

MGE can curtail gas deliveries to its interruptible customers. Approximately 3% of retail gas deliveries in 2015 and 17% in 2014 were to interruptible customers.

Gas supply

MGE has physical interconnections with ANR Pipeline Company (ANR) and Northern Natural Gas Company (NNG). MGE's primary service territory, which includes Madison and the surrounding area, receives deliveries at one NNG and four ANR gate stations. MGE also receives deliveries at NNG gate stations located in Elroy, Prairie du Chien, Viroqua, and Crawford County. Interconnections with two major pipelines provide competition in interstate pipeline service and a more reliable and economical gas supply mix, which includes gas from Canada and from the mid-continent and Gulf/offshore regions in the United States.

During the winter months, when customer demand is high, MGE is primarily concerned with meeting its obligation to firm customers. MGE meets customer demand by using firm supplies under contracts finalized before the heating season, supplies in storage (injected during the summer), and other firm supplies purchased during the winter period.

By contract, a total of 5,953,689 Dth of gas can be injected into ANR's storage fields in Michigan from April 1 through October 31. These gas supplies are then available for withdrawal during the subsequent heating season, November 1 through March 31. Using storage allows MGE to buy gas supplies during the summer season, when prices are normally lower, and withdraw these supplies during the winter season, when prices are typically higher. Storage also gives MGE more flexibility in meeting daily load fluctuations.

MGE's contracts for firm transportation service of gas include winter maximum daily quantities of:

·

162,150 Dth (including 106,078 Dth of storage withdrawals) on ANR.

·

65,108 Dth on NNG.

Nonregulated Energy Operations

MGE Energy, through its subsidiaries, has developed generation sources that assist MGE in meeting the electricity needs of its customers. These sources consist of the Elm Road Units and the WCCF, which are leased by MGE Power Elm Road and MGE Power West Campus, respectively, to MGE. See Item 2. Properties for a description of these facilities, their joint owners, and the related lease arrangements.

Transmission Investments

American Transmission Company owns and operates electric transmission facilities primarily in Wisconsin. MGE received an interest in ATC when it, like other Wisconsin electric utilities, contributed its electric transmission facilities to ATC as required by Wisconsin law. That interest is presently held by MGE Transco, which is jointly owned by MGE Energy and MGE. At December 31, 2015, MGE Transco held a 3.6% ownership interest in ATC.

In 2011, ATC and Duke Energy announced the creation of a joint venture, Duke-American Transmission Company, LLC, that seeks to build, own, and operate new electric transmission infrastructure in North America to address increasing demand for affordable, reliable transmission capacity.

Environmental

MGE Energy and MGE are subject to frequently changing local, state, and federal regulations concerning air quality, water quality, land use, threatened and endangered species, hazardous materials handling, and solid waste disposal. These regulations affect the manner in which they conduct their operations, the costs of those operations, as well as capital and operating expenditures. Regulatory initiatives, proposed rules, and court challenges to adopted rules, have the potential to have a material effect on our capital expenditures and operating costs. In addition to the regulations discussed below, MGE continues to track state and federal initiatives such as potential changes to regulations governing polychlorinated biphenyl (PCB), potential changes to air and water standards, and potential climate change legislation.

Water Quality

EPA's Finalization of its Effluent Limitations Guidelines Rule for Steam Electric Power Plants

In September 2015, the EPA released its final rule for Effluent Limitations Guidelines (ELG) for the Steam Electric Power Generating industry. The ELG rule lowers the existing permissible water discharge of metals and other pollutants in wastewater from new and existing steam electric generation plants. The rule mostly covers certain wastewater pollutants attributed to air pollution control and ash handling systems at coal-burning power plants with units greater than 50 megawatt (MW) generation capacity. We are currently evaluating the rule for its effects on our operation and expect that equipment upgrades may be necessary at our Elm Road Units and Columbia plants. The rule will go into effect in 2018 and will apply to Wisconsin-based power plants as they renew their WPDES permits.

MGE cannot estimate costs associated with this rule with any certainty until we complete our evaluation. Management believes compliance costs will be recovered in future rates based on previous treatment of environmental compliance projects.

EPA Cooling Water Intake Rules (Section 316(b))

Section 316(b) of the Clean Water Act (CWA) requires that the cooling water intake structures at electric power plants meet best available technology standards so that mortality from entrainment (drawing aquatic life into a plant's cooling system) and impingement (trapping aquatic life on screens) are reduced. The EPA finalized its 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. WDNR is currently developing rules to implement the EPA 316(b) rule.

Our WCCF, Blount, and Columbia plants are considered existing plants under this rule. Our WCCF facility already employs a system that meets the 316(b) rule. Our Blount plant has conducted studies showing that it will likely be in compliance with this rule when its WPDES permit is renewed in 2017. The operator of our Columbia plant plans to conduct an intake study to demonstrate compliance with the 316(b) rule and/or identify design criteria needed to meet the new rule requirements prior to Columbia's 2017 WPDES permit renewal. The exact requirements at Blount and

Columbia, however, will not be known until the WDNR finalizes its rule, approves the plant operators' approach, and those sites' WPDES permits are modified to account for this rule. Nonetheless, MGE expects that the 316(b) rule will not have material effects on its existing plants.

Energy Efficiency and Renewables

The Wisconsin Energy Efficiency and Renewables Act requires that, by 2015, 10% of the state's electricity be generated from renewable sources. As of December 31, 2015, MGE is in compliance with the 2015 requirement. The costs to comply with the Act and its accompanying regulations are being recovered in rates.

Air Quality

Air quality regulations promulgated by the EPA and Wisconsin Department of Natural Resources (WDNR) in accordance with the Federal Clean Air Act and the Clean Air Act Amendments of 1990 impose restrictions on emission of particulates, sulfur dioxide (SO₂), nitrogen oxides (NO_x), hazardous air pollutants and other pollutants, and require permits for operation of emission sources. These permits must be renewed periodically. Various newly enacted and/or proposed federal and state initiatives are expected to result in additional operating and capital expenditure costs for fossil-fueled electric generating units.

Mercury and Air Toxic Standards (MATS) Rule

In June 2015, the U.S. Supreme Court remanded the EPA's MATS rule to the D.C. Circuit Court. The Supreme Court's decision held that the EPA was required to consider the cost of compliance when deciding that it was "appropriate and necessary" to regulate mercury emissions from EGUs under Section 112 of the Clean Air Act. The remand was sent back to the D.C. Circuit Court. In December 2015, the D.C. Circuit Court ruled to keep the MATS rule in place while the EPA works to resolve the issues on remand. In November 2015, the EPA filed a proposed supplemental finding that the cost considerations of the rule do not alter the EPAs original determination that it is "appropriate and necessary" to regulate emissions of mercury from EGUs under Section 112 of the Clean Air Act. If the MATS rule is vacated or further delayed, the Wisconsin mercury rule, which has similar regulatory requirements as MATS, will remain in effect for utilities in Wisconsin. While the final version of the MATS rule remains uncertain, MGE has previously determined that current pollution controls on its Columbia and Elm Road Units would meet both MATS and the Wisconsin mercury rule. We do not expect any operational changes once the EPA's actions on remand are finalized.

Ozone NAAQS

In October 2015, the EPA revised the primary and secondary ozone NAAQS, lowering it to 70 ppb. The final standard will likely cause Milwaukee County, where our Elm Road Units are located, to be designated as nonattainment for ozone. The rule may also cause Columbia County (where our Columbia plant is located) and/or Dane County (where our WCCF and Blount plants are located) to be in nonattainment. Attainment and nonattainment designations are based on ozone data from 2014-2016 and thus are not known at this time. A nonattainment designation may have an effect on operations at our facilities, however, the NAAQS process involves many steps and any effect on our generation units will not be fully understood until the State of Wisconsin develops, receives approval for, and finalizes an implementation plan for any counties found to be in nonattainment. MGE will continue to monitor developments, attainment designations, and state and federal actions.

Sulfur Dioxide (SO₂) NAAQS

In March 2015, the EPA entered into a court-approved consent decree requiring 1-hour SO₂ attainment/nonattainment area designations to be completed in three phases extending out until 2020. In August 2015, the EPA published its data requirements rule that lays out expectations, designation process options, and timeframes for states and tribes to meet for the SO₂ NAAQS set in 2013. Under this new rule, states must submit their first designation proposals in July 2016 for those areas that contain large stationary sources of SO₂ (sources that emit over a threshold mass of SO₂, and/or over a threshold emissions rate). These proposals must identify one of the following options for demonstrating attainment with the 1-hour SO₂ NAAQS: modeling of SO₂ emissions; monitoring of SO₂ emissions; or limiting large stationary sources to 2,000 ton per year of SO₂ emissions by January 13, 2017. The EPA must make final designation determinations for these areas between 2017 and 2020 depending on the area.

In March 2015, MGE's Columbia plant was identified in the Federal Register as meeting the criteria of a large stationary source of SO₂ (based on 2012 data). As such, the State of Wisconsin must submit an attainment/nonattainment area designation plan for Columbia County (the county in which the Columbia plant is located). Since the 2012 data was collected, Columbia has installed pollution control equipment that has lowered its total SO₂ emissions and its SO₂ emissions rate. We anticipate, based on recent SO₂ emissions modeling, that Columbia County will be recommended as an attainment area by the state. An attainment recommendation, however, has not yet been submitted by the State of Wisconsin to the EPA. Once the state submits its recommendation, the EPA will make final designations. While the

attainment designation seems likely for Columbia, a nonattainment designation may have an adverse effect on the operation of the Columbia plant. MGE will continue to monitor the developments with the Columbia County designation process. Management believes compliance costs will be recovered in future rates based on previous treatment of environmental compliance projects.

EPA's Cross-State Air Pollution Rule: Proposed Ozone Season Update based on 2008 Ozone NAAQS

In December 2015, the EPA published a proposed rule to amend the existing Cross-State Air Pollution Rule (CSAPR). The proposed rule is designed to incorporate 2008 Ozone NAAQS attainment levels (current CSAPR is based on 1997 Ozone NAAQS levels) in 23 states, including Wisconsin, by establishing a federal implementation plan (FIP) to identify and limit summertime NO_x levels, a precursor to ozone that contributes to ozone transport. The proposed rule also includes revisions to CSAPR that are designed to resolve issues remaining from the D.C. Circuit remand of CSAPR, including Wisconsin's inclusion in the NO_x ozone season portion of the rule.

The proposed rule's FIP goes into effect in 2017, which coincides with Phase II of the existing CSAPR. The rule as proposed would reduce ozone season NO_x emissions by about half as compared to Phase II numbers in the current rule. We are currently evaluating the rule for its impact to MGE and thus do not know with certainty the exact impact. Initial reviews, however, indicate that the proposed CSAPR update as written could have material effects on MGE. We will continue to monitor the rule developments and legal developments to help determine how this rule will ultimately affect MGE.

Clean Air Visibility Rule (CAVR)

Columbia may be subject to the best available retrofit technology (BART) regulations, a subsection of the EPA's Clean Air Visibility Rule (CAVR), which may require pollution control retrofits. Columbia's 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. In addition, the EPA has indicated that they intend to extend deadlines in this rule. At this time, however, the BART regulatory obligations, compliance strategies, and costs remain uncertain due to the continued legal uncertainty surrounding CSAPR.

Global Climate Change

MGE is a producer of GHG emissions, primarily from the fossil fuel generating facilities it uses to meet customers' energy needs, as well as from its natural gas pipeline system and fleet vehicles. Climate change and the regulatory response to it could significantly affect our operations in a number of ways, including increased operating costs and capital expenditures, restrictions on energy supply options, operational limits on our coal plants, permitting difficulties, and emission limits. MGE management would expect to seek and receive rate recovery of such compliance costs, if and when required. MGE continues to monitor proposed climate change legislation and regulation.

MGE has taken steps to address GHG emissions through voluntary actions. In 2005, MGE announced its Energy 2015 Plan, which committed to ensuring a balanced, economic energy supply with reduced environmental emissions. The Plan emphasized increased renewable energy, energy efficiency, and new cleaner generation – three strategies that reduced GHG emissions. Under MGE's Energy 2015 Plan and other actions, our CO₂ emissions declined from 2005 to 2015 by approximately 20% even though total system energy increased. In 2015, MGE announced its Energy 2030 framework and will continue to take steps to reduce CO₂ emissions. Subject to regulatory approvals and other conditions, MGE aims to increase renewable energy to 25% of retail electric sales by 2025 and to 30% by 2030. Under our Energy 2030 framework, we will also work to reduce CO₂ emissions by 40% from 2005 levels by 2030.  

Climate Change Legislation

Federal Legislative Actions on Climate Change

Several bills and/or actions related to GHG regulation, including those to limit, prevent or delay the EPA's regulation of GHGs under the current Clean Air Act, have been proposed in both the House and the Senate. It is not anticipated that Congress will enact broad GHG reduction legislation in 2016.

State and Regional Legislative Actions on Climate Change

It is not expected that the Wisconsin Legislature will enact broad GHG regulation in 2016. MGE continues to monitor legislative developments.

Greenhouse Gas Regulation

EPA's Greenhouse Gas (GHG) Reduction Guidelines under the Clean Air Act 111d Rule

In October 2015, the EPA published its Clean Power Plan rule, which became effective in December 2015, setting guidelines for states to use in developing plans to control GHG emissions from existing fossil fuel-fired EGUs and systems. In October 2015, the EPA also published a proposed federal implementation plan to be used as an example, or in the event that a state does not submit a plan under this rule. When fully implemented in 2030, the Clean Power Plan is projected to reduce GHG emissions from this sector by 32% below 2005 levels. States are given up to three years to submit a plan or be subject to a federal plan to meet the reduction goals, and states are expected to meet interim goals starting in 2022 and the final goal in 2030. Implementation of the rule is expected to have a direct impact on coal and natural gas fired generating units, including possible changes in dispatch and additional operating costs.

In October 2015, many states (including Wisconsin) and other litigants filed petitions with the U.S. Court of Appeals for the District of Columbia Circuit asking for a stay of the CPP rule, which would otherwise become effective on December 22, 2015, and seeking expedited review of the petitioners' challenges to the CPP's legality. The parties' request to stay the rule was denied by the D.C. Circuit on January 20, 2016, but the D.C. Circuit issued an expedited schedule for resolving the merits of the litigation including oral arguments that will be held in early June 2016. However, on January 26, 2016, several parties filed a request for a stay of the CPP with the U.S. Supreme Court; and on February 9, 2016, the U.S. Supreme Court granted that request. The CPP may not now be implemented until the courts ultimately resolve the underlying legality of the rule. Oral arguments are scheduled before the D.C. Circuit for June 2, 2016.

MGE is evaluating the CPP and related requirements. Given the pending legal proceedings and the need for a yet-to-be-developed state implementation plan or federal implementation plan, the nature and timing of any final requirements is subject to uncertainty. If the rule remains substantially in its present form, it is expected to have a material impact on MGE.

Solid Waste

EPA's Coal Combustion Residuals Rule

In December 2014, the EPA finalized its Disposal of Coal Combustion Residuals from Electric Utilities (CCR) rule. The rule became effective in October 2015. It provides that coal ash will be regulated as a solid waste, and defines what ash use activities would be considered generally exempt beneficial reuse of coal ash. The rule also regulates landfills, ash ponds, and other surface impoundments for coal combustion residuals by regulating their design, location, monitoring, and operation. Landfills and impoundments that cannot meet design criteria will need to formally close within defined timeframes.

The Columbia and Elm Road Units co-owners and plant operators are evaluating the final rule to determine what changes may be necessary at those facilities and the associated timeframes. We anticipate that some design and operational changes may need to be made at these facilities. Review of our Elm Road facility has indicated that the costs to comply with this rule are not expected to be significant. We are still evaluating the rule's full effects at Columbia. Columbia's operator has developed a preliminary implementation schedule for meeting the various deadlines spelled out in the rule. Management believes compliance costs will be recovered in future rates based on previous treatment of environmental compliance projects.

Columbia

Columbia is a coal-fired generating station operated by WPL in which WPL, WPSC, and MGE have ownership interests. In December 2009, the EPA sent a Notice of Violation (NOV) to MGE as one of the co-owners of Columbia. The NOV alleged that WPL and the Columbia co-owners failed to comply with appropriate pre-construction review and permitting requirements and, as a result, violated the Prevention of Significant Deterioration program requirements, Title V Operating Permit requirements of the CAA, and the Wisconsin SIP. In April 2013, the EPA filed a lawsuit against the co-owners of Columbia asserting similar allegations. In September 2010 and April 2013, the Sierra Club filed civil lawsuits against WPL alleging violations of the CAA at Columbia and other Wisconsin facilities operated by WPL. In June 2013, the court approved and entered a consent decree entered by the EPA, Sierra Club, and the co-owners of Columbia to resolve these claims, while admitting no liability. One of the requirements of the consent decree requires installation of an SCR system at Columbia Unit 2 by December 31, 2018. Installation of the SCR has been approved by the PSCW. MGE's share of the projected cost for the SCR system is approximately $19-29 million. See Footnote 18.c. of the Notes to Consolidated Financial Statements for additional information regarding this matter.

Employees

As of December 31, 2015, MGE had 708 employees. MGE employs 222 employees who are covered by a collective bargaining agreement with Local Union 2304 of the International Brotherhood of Electrical Workers and 93 employees who are covered by a collective bargaining agreement with Local Union No. 39 of the Office and Professional Employees International Union. Both of these collective bargaining agreements expire on April 30, 2018. There are also 5 employees covered by a collective bargaining agreement with Local Union No. 2006, Unit 6 of the United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial, and Service Workers International Union. This collective bargaining agreement expires on October 31, 2018.

Financial Information About Segments

See Footnote 21 of the Notes to the Consolidated Financial Statements for financial information relating to MGE Energy's and MGE's business segments.

Executive Officers of the Registrants

Note: Ages, years of service, and positions as of December 31, 2015.

(a)

Executive officer of MGE Energy and MGE.

(b)

Executive officer of MGE.

(c)

Retired as of December 31, 2015.

Item 1A. Risk Factors.

MGE Energy and its subsidiaries, including MGE, operate in a market environment that involves significant risks, many of which are beyond their control. The following risk factors may adversely affect their results of operations, cash flows and market price for their publicly traded securities. While MGE Energy and MGE believe they have identified and discussed below the key risk factors affecting their business, there may be additional risks and uncertainties that are not presently known or that are not currently believed to be significant that may adversely affect their performance or financial condition in the future.

Regulatory Risk

We are subject to extensive government regulation in our business, which affects our costs and responsiveness to changing events and circumstances.

Our business is subject to regulation at the State and Federal levels. We are subject to regulation as a holding company by the PSCW. MGE is regulated by the PSCW as to its rates, terms and conditions of service; various business practices

and transactions; financing; and transactions between it and its affiliates, including MGE Energy. MGE is also subject to regulation by the FERC, which regulates certain aspects of its business. The regulations adopted by the State and Federal agencies affect the manner in which we do business, our ability to undertake specified actions since pre-approval or authorization may be required, the costs of operations, and the level of rates charged to recover such costs. Our ability to attract capital is also dependent, in part, upon our ability to obtain a fair return from the PSCW.

We could be subject to higher costs and potential penalties resulting from mandatory reliability standards.

MGE must adhere to mandatory reliability standards for its electric distribution system established by NERC. These standards cover areas such as critical infrastructure protection, emergency preparedness, facility design, and transmission operations, among others. The critical infrastructure protection standards focus on physical and access security of cyber assets, as well as incident response and recovery planning. MGE could be subject to higher operating costs in order to maintain compliance with the mandatory reliability standards, and any noncompliance could result in sanctions including monetary penalties.

We face risk for the recovery of fuel and purchased power costs.

MGE has price risk exposure with respect to the price of natural gas, electricity, coal, emission credits, and oil. MGE burns natural gas in several of its peak electric generation facilities, and in many cases, the cost of purchased power is tied to the cost of natural gas. Under the electric fuel rules, MGE would defer electric fuel-related costs that fall outside a symmetrical cost tolerance band that is currently plus or minus 2% around the amount approved in its most recent rate order. Any over/under recovery of the actual costs is determined on an annual basis and will be adjusted in future billings to its electric retail customers. Under the electric fuel rules, MGE is required to defer the benefit of lower costs, if its actual fuel costs fall outside the lower end of the range, and would defer costs, less any excess revenues, if its actual fuel costs exceeded the upper end of the range. 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. MGE assumes the risks and benefits of variances that are within the cost tolerance band.

We are subject to changing environmental laws and regulations that may affect our costs and business plans.

Our subsidiaries are subject to environmental laws and regulations that affect the manner in which they conduct business, including capital expenditures, operating costs and potential liabilities. Changes and developments in these laws and regulations may alter or limit our business plans, make them more costly, or expose us to liabilities for past or current operations.

Numerous environmental laws and regulations govern many aspects of our present and future operations, including air emissions, water quality, wastewater discharges, solid waste, threatened and endangered species, and hazardous waste. These evolving regulations can introduce uncertainty with respect to capital expenditures and operational planning, and can introduce costly delays if previous decisions need to be revisited as a result of judicial mandate or regulatory change. These regulations generally require us to obtain and comply with a wide variety of environmental permits and approvals, and can result in increased capital, operating, and other costs and operating restrictions, particularly with regard to enforcement efforts focused on obligations under existing regulations with respect to power plant emissions and compliance costs associated with regulatory requirements. These effects can be seen not only with respect to new construction but could also require the installation of additional control equipment or other compliance measures such as altered operating conditions at existing facilities.

In addition, we may be a responsible party for environmental clean-up at current or future sites identified as containing hazardous materials or to which waste was sent that is subsequently determined to be hazardous. It is difficult to predict the costs potentially associated with a site clean-up due to the potential joint and several liability for all potentially responsible parties, the nature of the clean-up required, and the availability of recovery from other potentially responsible parties.

The following are significant proposed regulations that are expected to impact our operations:

The EPA's Cross-State Air Pollution Rule (CSAPR) is an interstate air pollution transport rule designed to reduce ozone and fine particulate (PM2.5) air levels in areas that the EPA has determined are being affected by pollution from neighboring and upwind states. In December 2015, the EPA published a proposed rule to amend the existing CSAPR. The proposed rule is designed to incorporate 2008 Ozone NAAQS attainment levels (current CSAPR is based on 1997 Ozone NAAQS levels) in 23 states, including Wisconsin, by establishing a federal implementation plan (FIP) to identify and limit summertime nitrogen oxide (NO_x) levels, a precursor to ozone that contributes to ozone transport. The rule as proposed would reduce ozone season NO_x emissions by about half as compared to existing Phase II numbers. We are

currently evaluating the rule for its impact to MGE and thus do not know with certainty the exact impact. Initial reviews, however, indicate that the proposed CSAPR update as written could have material effects on MGE.

In October 2015, the EPA published its Clean Power Plan rule, which became effective in December 2015, setting guidelines for states to use in developing plans to control GHG emissions from existing fossil fuel-fired EGUs and systems. When fully implemented in 2030, the Clean Power Plan is projected to reduce GHG emissions from this sector by 32% below 2005 levels. Implementation of the rule is expected to have a direct impact on coal and natural gas fired generating units, including possible changes in dispatch and additional operating costs. Given the pending legal proceedings and the need for a yet-to-be-developed state implementation plan or federal implementation plan, the nature and timing of any final requirements is subject to uncertainty. If the rule remains substantially in its present form, it is expected to have a material impact on MGE.

Operating Risk

We are affected by weather, which affects customer demand and can affect the operation of our facilities.

The demand for electricity and gas is affected by weather. Very warm and very cold temperatures, especially for prolonged periods, can dramatically increase the demand for electricity and gas for cooling and heating, respectively, as opposed to the softening effect of more moderate temperatures. Our electric revenues are sensitive to the summer cooling season and, to a lesser extent, the winter heating season. Similarly, very cold temperatures can dramatically increase the demand for gas for heating. A significant portion of our gas system demand is driven by heating. Extreme summer conditions or storms may stress electric transmission and distribution systems, resulting in increased maintenance costs and limiting the ability to meet peak customer demand.

We could be adversely affected by changes in the development, and utilization by our customers, of power generation and storage technology.

Developments in power generation and storage could affect our revenues and the timing of the recovery of our costs. Advancements in power generation technology, including commercial and residential solar generation installations and commercial micro turbine installations, are improving the cost-effectiveness of customer self-supply of electricity. Improvements in energy storage technology, including batteries and fuel cells, could also better position customers to meet their around-the-clock electricity requirements. Such developments could reduce customer purchases of electricity, but may not necessarily reduce our investment and operating requirements due to our obligation to serve customers, including those self-supply customers whose equipment has failed for any reason to provide the power they need. In addition, since a portion of our costs are recovered through charges based upon the volume of power delivered, reductions in electricity deliveries will affect the timing of our recovery of those costs and may require changes to our rate structures. Changes in power generation and storage technology could have significant effects on customer behaviors and their energy consumption. Customers could engage in individual conservation efforts by voluntarily reducing their consumption of electricity and pursuing alternative energy sources. Customer energy conservation could adversely affect our results of operations by reducing our revenues without necessarily changing our operating costs due to our obligation to serve.

We are affected by economic activity within our service area.

Higher levels of development and business activity generally increase the numbers of customers and their use of electricity and gas. Likewise, periods of recessionary economic conditions generally adversely affect our results of operations.

Our ability to obtain an adequate supply of coal could limit our ability to operate our coal-fired facilities.

The availability of coal and the means to transport coal could:

·

Affect our operating costs due to increased costs associated with lower levels of generation or the need for alternate supply or alternate transportation,

·

Limit our ability to generate electricity if we are unable to arrange adequate deliveries of coal, and

·

Result in potentially higher costs for replacement purchased power as well as potential lost market sales opportunities.

A significant portion of our electric generating capacity is dependent on coal. Increased oil exploration and production in the United States can increase the amount of oil being transported by railroad, which can affect the availability and scheduling of trains to transport coal. Demand for coal has also been impacted by prevailing prices for natural gas and may affect mine performance. Consequently, we are exposed to the risk that counterparties to these contracts will not be able to fulfill their obligations. Disruption in the delivery of fuel, including disruptions as a result of transportation delays, weather, labor relations, force majeure events, or environmental regulations affecting any of these fuel suppliers, could limit our ability to generate electricity at our facilities at the desired level. Should counterparties fail to perform, or other unplanned disruptions occur, we may be forced to replace the underlying commitment at higher prices, or we may be forced to reduce generation at our coal units and replace this lost generation through additional power purchases from third parties. These factors may also affect the terms under which any of our existing coal supply or transportation agreements are renewed or replaced upon the expiration of their current terms.

Our ability to manage our purchased power costs is influenced by a number of uncontrollable factors.

We are exposed to additional purchased power costs to the extent that our power needs cannot be fully covered by the supplies available from our existing facilities and contractual arrangements. Those needs, and our costs, could be affected by:

·

Increased demand due to, for example, abnormal weather, customer growth, or customer obligations,

·

The inability to transmit our contracted power from its generation source to our customers due to transmission line constraints, outages, or equipment failures,

·

Reductions in the availability of power from our owned or contracted generation sources due to equipment failures, shortages of fuel or environmental limitations on operations, and

·

Failure to perform on the part of any party from which we purchase capacity or energy, whether due to equipment failures or other causes.

An unexpected change in demand or the availability of generation or transmission facilities can expose us to increased costs of sourcing electricity in the short-term market where pricing may be more volatile.

The equipment and facilities in our operational system are subject to risks which may adversely affect our financial performance.

Weather conditions, accidents, and catastrophic events can result in damage or failures of equipment or facilities and disrupt or limit our ability to generate, transmit, transport, purchase, or distribute electricity and gas. Efforts to repair or replace equipment and facilities may take prolonged periods or may be unsuccessful, or we may be unable to make the necessary improvements to our operational system, causing service interruptions. The resulting interruption of services would result in lost revenues and additional costs. We are also exposed to the risk of accidents or other incidents that could result in damage to or destruction of our facilities or damage to persons or property. Such issues could adversely affect revenues or increase costs to repair and maintain our systems.

Acts of terrorism could materially and adversely impact our operations and financial condition.

Facilities for electric generation, transmission, and gas distribution are subject to the risk of being potential targets of terrorist threats and activities. A terrorist act at our facilities could result in a disruption of our ability to generate, transmit, transport, purchase, or distribute electricity or natural gas. A possible attack would have additional adverse effects, including environmental ramifications, increased security and insurance costs, as well as general economic volatility or uncertainty within our service territories. The inability to maintain operational continuity and any additional costs incurred for repairing our facilities could materially and adversely affect our financial condition and results of operations.

We rely on the performance of our information technology systems, the failure of which could have an adverse effect on our business and performance.

We operate in a highly engineered industry that requires the continued operation of sophisticated information technology systems and network infrastructure to manage our finances, to operate our control facilities, to provide electric and gas service to our customers, and to enable compliance with applicable regulatory requirements. Our computer-based systems are vulnerable to interruption or failure due to the age of certain systems, the introduction of viruses, malware, security breaches, fire, power loss, system malfunction, network outages and other events, which may

be beyond our control. System interruptions or failures, whether isolated or more widespread, could impact our ability to provide service to our customers, which could have a material adverse effect on our operations and financial performance.

Our operations and confidential information are subject to the risk of cyber-attacks.

Our operations rely on sophisticated information technology systems and networks. Cyber-attacks targeting our electronic control systems used at our generating facilities and for electric and gas distribution systems, could result in a full or partial disruption of our operations. Any disruption of these operations could result in a loss of service to customers and loss of revenue, as well as significant expense to repair system damage and remedy security breaches.

Our business requires the collection and retention of personally identifiable information of our customers, shareholders, and employees, who expect that we will adequately protect such information. A significant theft, loss, or fraudulent use of personally identifiable information may cause our business reputation to be adversely impacted and could lead to potentially large costs to notify and protect the impacted persons. The occurrence of such an event may cause us to become subject to legal claims, fines, or penalties, any of which could adversely impact our results of operations.

The safeguards we have may not always be effective due to the evolving nature of cyber-attacks. We cannot guarantee that such protections will be completely successful in the event of a cyber-attack. If the technology systems were to fail or be breached by a cyber-attack, and not be recovered in a timely fashion, we may be unable to fulfill critical business functions and confidential data could be compromised, adversely impacting our financial condition and results of operations.

Failure to attract and retain an appropriately qualified workforce could affect our operations.

Events such as an aging workforce and retirement of key employees without appropriate replacements may lead to operating challenges and increased costs. Some of the challenges include lack of resources, loss of knowledge, and length of time period associated with skill development. Failure to identify qualified replacement employees could result in decreased productivity and increased safety costs. If we are unable to attract and retain an appropriately qualified workforce, our operations could be negatively affected.

Financial Risk

We are exposed to commodity price risk relating to our purchases of natural gas, electricity, coal and oil.

We face commodity price risk exposure with respect to our purchases of natural gas, electricity, coal and oil, SO₂ allowances and risk through our use of derivatives, such as futures, forwards and swaps, to manage that commodity price risk. We could experience increased costs as a result of volatility in the market values of those commodities. We could also experience losses on our derivative contracts as a result of that market value volatility or if a counterparty fails to perform under a contract. In the absence of actively quoted market prices and pricing information from external sources, the valuation of these derivative contracts involves our exercise of judgment and use of estimates. As a result, changes in the underlying assumptions or use of alternative valuation methods could affect the reported fair value of these contracts.

We are exposed to interest rate risk.

We are exposed to interest rate risk on our variable rate financing. Borrowing levels under commercial paper arrangements vary from period to period depending upon capital investments and other factors. Such interest rate risk means that we are exposed to increased financing costs and associated cash payments as a result of changes in the short-term interest rates.

Interest rate movements and market performance affects our employee benefit plan costs.

Prevailing interest rates affect our assessment and determination of discount rates that are a key assumption in the determination of the costs and funding of our defined benefit pension plans and may impact the amount of expense and timing of contributions to those plans. The performance of the capital markets affects the values of the assets that are held in trust to satisfy the future obligations under our pension and postretirement benefit plans. We have significant obligations in these areas and hold significant assets in these trusts. A decline in the market value of those assets may increase our current and longer-term funding requirements for these obligations. Changes in the value of trust fund assets may affect the level of required contributions to these trusts to meet benefit obligations. Reduced benefit plan

assets could result in increased benefit costs in future years and may increase the amount and accelerate the timing of required future funding contributions.

We are exposed to credit risk primarily through our regulated energy business.

Credit risk is the loss that may result from counterparty nonperformance. We face credit risk primarily through MGE's regulated energy business. Failure of contractual counterparties to perform their obligations under purchase power agreements, commodity supply arrangements or other agreements may result in increased expenses for MGE as a result of being forced to cover the shortfall in the spot or short-term market, where prices may be more volatile.

As a holding company, we are dependent on upstream cash flows from our subsidiaries for the payment of dividends on our common stock.

As a holding company, we have no operations of our own, and our ability to pay dividends on our common stock is dependent on the earnings and cash flows of our operating subsidiaries and their ability to pay upstream dividends or to repay funds to us. Prior to funding us, our subsidiaries have financial obligations that must be satisfied, including among others, debt service and obligations to trade creditors, and are subject to contractual and regulatory restrictions on the payment of dividends.

Disruptions in the financial markets or changes to our credit ratings may affect our ability to finance at a reasonable cost and in accordance with our planned schedule.

The credit markets have experienced disruption and uncertainty in recent years. To the extent that such issues affect the ability or willingness of credit providers or investors to participate in the credit markets or particular types of investments, or affect their perception of the risk associated with particular types of investments, our cost of borrowing could be affected. We also rely on our strong credit ratings to access the credit markets. If our credit ratings are downgraded for any reason, borrowing costs could increase, potential investors could decrease, or we could be required to provide additional credit assurance, including cash collateral, to contract counterparties.

General economic conditions may affect our operating revenues and our counterparty risks.

Operational

MGE Energy's and MGE's operations are affected by local, national and worldwide economic conditions. The consequences of a prolonged period of reduced economic activity may include lower demand for energy, uncertainty regarding energy prices and the capital and commodity markets, and increased credit risk. A decline in energy consumption may adversely affect our revenues and future growth. Increased credit risk reflects the risk that our retail customers will not pay their bills in a timely manner or at all, which may lead to a reduction in liquidity and an eventual increase in bad debt expense.

Counterparty creditworthiness

Credit risk also includes the risk that trading counterparties that owe us money or product will breach their obligations. MGE's risk management policy is to limit transactions to a group of high quality counterparties. Should the counterparties to these arrangements fail to perform, we may be forced to enter into alternative arrangements. In that event, our financial results could be adversely affected and we could incur losses.

Item 1B. Unresolved Staff Comments.

MGE Energy and MGE

None.

Item 2. Properties.

Electric Generation

Net summer rated capacity in service at December 31, 2015, was as follows:

(1)

Net summer rated capacity is determined by annual testing and may vary from year to year due to, among other things, the operating and physical conditions of the units.

(2)

Baseload generation.

(3)

MGE's share. See "Columbia" below.

(4)

Facility is jointly owned. Based on the terms of the joint plant agreement between MGE and the UW, the UW has the ability to reduce net capability of these units by approximately 17 MW in the summer. The net summer rated capacity shown reflects this decrease. See "WCCF" below.

(5)

MGE's share. See "Elm Road" below.

(6)

Three facilities are owned by MGE and three facilities are leased.

(7)

These facilities are owned by MGE.

(8)

Nameplate capacity rating is 11 MW.

(9)

Nameplate capacity rating is 30 MW.

Columbia

MGE and two other utilities jointly own Columbia, a coal-fired generating facility consisting of two 512 MW units, which accounts for 31% of MGE's net summer rated capacity. Power from this facility is shared in proportion to each owner's ownership interest. MGE has a 22% ownership interest in Columbia. The other owners are WPL, which operates Columbia, and WPSC. The Columbia units burn low-sulfur coal obtained from the Powder River Basin coal fields located in Wyoming. The coal inventory supply for the Columbia units increased from approximately 48 days on December 31, 2014, to approximately 88 days on December 31, 2015. See "Executive Overview" under Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations, for a discussion of a possible reduction in MGE's future ownership share in Columbia.

Elm Road Units

MGE Power Elm Road and two other owners own undivided interests in the Elm Road Units, consisting of two 615 MW units, which account for 14% of MGE's net summer rated capacity. Power from these units is shared in proportion to each owner's ownership interest. MGE Power Elm Road owns an 8.33% ownership interest in the Elm

Road Units, and its interest in the Elm Road Units is leased to MGE. The other owners are Wisconsin Energy Corporation, which operates the Units, and WPPI Energy, Inc. The Elm Road Units burn bituminous coal obtained from northern West Virginia and southwestern Pennsylvania, and Powder River Basin coal from Wyoming. MGE's share of the coal inventory supply for the Elm Road Units decreased from approximately 53 days on December 31, 2014, to approximately 50 days on December 31, 2015.

MGE leases MGE Power Elm Road's ownership interest in the Elm Road Units pursuant to two separate facility leases. The financial terms of each facility lease include a capital structure of 55% equity and 45% long-term debt, return on equity of 12.7%, and a lease term of 30 years. At the end of the respective lease terms, MGE may, at its option, renew the facility lease for an additional term, purchase the leased ownership interest at fair market value, or allow the lease to end. The Unit 1 and Unit 2 leases commenced with the commercial operation of each respective unit.

WCCF

MGE Power West Campus and the UW jointly own undivided interests in a natural gas-fired cogeneration facility on the UW campus. The facility has the capacity to produce 20,000 tons of chilled water, 500,000 pounds per hour of steam, and approximately 150 MW of electricity. The UW owns 45% of the facility, which represents its interest in the chilled-water and steam assets. These assets are used to meet a part of the UW's need for air-conditioning and steam-heat capacity. MGE Power West Campus owns 55% of the facility, which represents its interest in the electric generating assets. These assets are used to provide electricity to MGE's customers. The UW's share of the plant and portion of the earnings from the WCCF are not reflected in the consolidated financial statements of MGE Energy or MGE. MGE Power West Campus' share of the cost of this project is reflected in property, plant, and equipment on MGE Energy's and MGE's consolidated balance sheets.

MGE leases the electric generating assets owned by MGE Power West Campus and is responsible for operating the entire facility. The financial terms of the facility lease include a capital structure of 53% equity and 47% long-term debt, return on equity of 12.1%, and a lease term of 30 years. At the end of the lease term in 2035, MGE may, at its option, renew the facility lease for an additional term, purchase the generating facility at fair market value, or allow the lease contract to end.

Electric and Gas Distribution Facilities

At December 31, 2015, MGE owned 880 miles of overhead electric distribution line and 1,210 miles of underground electric distribution cable, all of which are located in Wisconsin. These electric distribution facilities are connected by approximately 52 substations, installed with a capacity of 1,279,550 kVA. MGE's gas facilities include 2,690 miles of distribution mains, which are all owned by MGE.

A significant portion of MGE's electric and gas distribution facilities are located above or underneath highways, streets, other public places or property that others own. MGE believes that it has satisfactory rights to use those places or property in the form of permits, grants, easements, and licenses; however, it has not necessarily undertaken to examine the underlying title to the land upon which the rights rest.

Encumbrances

The principal plants and properties of MGE are subject to the lien of its Indenture of Mortgage and Deed of Trust dated as of January 1, 1946, as amended and supplemented, under which MGE's first mortgage bonds are issued. As of December 31, 2015, there were $1.2 million of first mortgage bonds outstanding. See Footnote 9 of the Notes to Consolidated Financial Statements for additional information regarding MGE's first mortgage bonds.

MGE Power Elm Road has collaterally assigned its right to lease payments from MGE for the Elm Road Units in order to secure the repayment of $65.3 million of senior secured notes issued by MGE Power Elm Road. See Footnote 9 of the Notes to Consolidated Financial Statements for additional information regarding these senior notes.

MGE Power West Campus has collaterally assigned its right to lease payments from MGE for the WCCF in order to secure the repayment of $46.7 million of senior secured notes issued by MGE Power West Campus. See Footnote 9 of the Notes to Consolidated Financial Statements for additional information regarding these senior notes.

Item 3. Legal Proceedings.

MGE Energy and MGE

MGE Energy and its subsidiaries, including MGE, from time to time are involved in various legal proceedings that are handled and defended in the ordinary course of business.

See "Environmental" under Item 1. Business and Footnote 18.c. of the Notes to Consolidated Financial Statements for a description of several environmental proceedings involving MGE. See Footnote 18.d. of the Notes to Consolidated Financial Statements for a description of other legal matters.

Item 4. Mine Safety Disclosures.

MGE Energy and MGE

Not applicable.

PART II.

Item 5. Market for Registrants' Common Equity, Related Stockholder Matters, and Issuer Purchases of Equity Securities.

Market for Common Equity

MGE Energy

MGE Energy common stock is traded on Nasdaq under the symbol MGEE. On February 1, 2016, there were approximately 38,308 shareholders of record. The following table shows high and low sale prices for the common stock on Nasdaq for each quarter over the past two years.

MGE

As of February 1, 2016, there were 17,347,894 outstanding shares of common stock, all of which were held by MGE Energy. There is no market for shares of common stock of MGE.

Dividends

MGE Energy

The following table sets forth MGE Energy's quarterly cash dividends per share declared during 2015 and 2014:

MGE

The following table sets forth MGE's quarterly cash dividends declared during 2015 and 2014:

See discussion below as well as "Liquidity and Capital Resources - Financing Activities" under Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations, for a description of restrictions applicable to dividend payments by MGE.

Dividend Restrictions

Dividend payments by MGE to MGE Energy are subject to restrictions arising under a PSCW rate order and, to a lesser degree, MGE's first mortgage bonds. The PSCW order restricts any dividends, above the PSCW authorized amount of $43 million, that MGE may pay MGE Energy if its common equity ratio, calculated in the manner used in the rate proceeding, is less than 55%. MGE's thirteen month rolling average common equity ratio at December 31, 2015, is 59.7%, as determined under the calculation used in the rate proceeding. MGE paid cash dividends of $30.0 million to MGE Energy in 2015. The rate proceeding calculation includes as indebtedness imputed amounts for MGE's

outstanding purchase power capacity payments and other PSCW adjustments, but does not include the indebtedness associated with MGE Power Elm Road and MGE Power West Campus, which are consolidated into MGE's financial statements but are not direct obligations of MGE.

MGE has covenanted with the holders of its first mortgage bonds not to declare or pay any dividend or make any other distribution on or purchase any shares of its common stock unless, after giving effect thereto, the aggregate amount of all such dividends and distributions and all amounts applied to such purchases, after December 31, 1945, shall not exceed the earned surplus (retained earnings) accumulated subsequent to December 31, 1945. As of December 31, 2015, approximately $353.0 million was available for the payment of dividends under this covenant.

Stock Split

On December 20, 2013, MGE Energy's Board of Directors declared a three-for-two stock split of MGE Energy's outstanding shares of common stock, effective in the form of a stock dividend. Shareholders of record at the close of business on January 24, 2014, received one additional share of MGE Energy common stock for every two shares of common stock owned on that date. The additional shares were distributed on February 7, 2014. Shareholders received cash in lieu of any fractional shares of common stock they otherwise would have received in connection with the dividend. All share and per share data provided in this report give effect to this stock split.

Issuer Purchases of Equity Securities

MGE Energy

*

Under the MGE Energy, Inc. Direct Stock Purchase and Dividend Reinvestment Plan (Stock Plan), common stock shares deliverable to plan participants may be either newly issued shares or shares purchased on the open market, as determined from time to time by MGE Energy. MGE Energy uses open market purchases to provide shares to meet obligations to participants in the Stock Plan. The shares are purchased on the open market through a securities broker-dealer and then are reissued under the Stock Plan as needed to meet share delivery requirements. The volume and timing of share repurchases in the open market depends upon the level of dividend reinvestment and optional share purchases being made from time to time by plan participants. As a result, there is no specified maximum number of shares to be repurchased and no specified termination date for the repurchases. All shares issued through the Stock Plan, whether newly issued or reissued following open market purchases, are issued and sold by MGE Energy pursuant to a registration statement that was filed with the SEC and is currently effective.

MGE

None.

Stock Performance Graph

The performance graph below illustrates a five-year comparison of cumulative total returns based on an initial investment of $1,000 in MGE Energy common stock, as compared with the Russell 2000 and the EEI Index for the period 2010 through 2015. The EEI Index reflects the consolidated performance of Edison Electric Institute investor-owned electric utilities.

Cumulative Five-Year Total Return Comparison

(assumes $1,000 invested on 12/31/2010 with dividends reinvested)

Value of Investment at December 31,

Item 6. Selected Financial Data.

MGE Energy, Inc.

(In thousands, except per share amounts)

Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations.

General

MGE Energy is an investor-owned public utility holding company operating through subsidiaries in five business segments:

·

Regulated electric utility operations, conducted through MGE,

·

Regulated gas utility operations, conducted through MGE,

·

Nonregulated energy operations, conducted through MGE Power and its subsidiaries,

·

Transmission investments, representing our equity investment in ATC, and

·

All other, which includes corporate operations and services.

Our principal subsidiary is MGE, which generates and distributes electric energy, distributes natural gas, and represents a majority portion of our assets, liabilities, revenues, and expenses. MGE generates and distributes electricity to approximately 146,000 customers in Dane County, Wisconsin, including the city of Madison, and purchases and distributes natural gas to approximately 152,000 customers in the Wisconsin counties of Columbia, Crawford, Dane, Iowa, Juneau, Monroe, and Vernon.

Our nonregulated energy operations own interests in electric generating capacity that is leased to MGE. The ownership/leasing structure was adopted under applicable state regulatory guidelines for MGE's participation in these generation facilities, consisting principally of a stable return on the equity investment in the new generation facilities over the term of the related leases. The nonregulated energy operations include an ownership interest in two coal-fired generating units in Oak Creek, Wisconsin and a partial ownership of a cogeneration project on the UW-Madison campus. A third party operates the units in Oak Creek, and MGE operates the cogeneration project. Due to the nature of MGE's participation in these facilities, the results of our nonregulated operations are also consolidated into MGE's consolidated financial position and results of operations under applicable accounting standards.

Executive Overview

Our primary focus today and for the foreseeable future is our core utility customers at MGE as well as creating long-term value for our shareholders. MGE continues to face the challenge of providing its customers with reliable power at competitive prices. MGE meets this challenge by investing in more efficient generation projects, including renewable energy sources. MGE will continue to focus on growing earnings while controlling operating and fuel costs. MGE maintains safe and efficient operations in addition to providing customer value. We believe it is critical to maintain a strong credit standing consistent with financial strength in MGE as well as the parent company in order to accomplish these goals.

We earn our revenue and generate cash from operations by providing electric and natural gas utility services, including electric power generation and electric power and gas distribution. The earnings and cash flows from the utility business are sensitive to various external factors, including:

·

Weather, and its impact on customer sales,

·

Economic conditions, including current business activity and employment and their impact on customer demand,

·

Regulation and regulatory issues, and their impact on the timing and recovery of costs,

·

Energy commodity prices, including natural gas prices,

·

Equity price risk pertaining to pension related assets,

·

Credit market conditions, including interest rates and our debt credit rating,

·

Environmental laws and regulations, including adopted and pending environmental rule changes,

and other factors listed in Item 1A. Risk Factors.

For the year ended December 31, 2015, MGE Energy's earnings were $71.3 million or $2.06 per share compared to $80.3 million or $2.32 per share for the same period in the prior year. MGE's earnings for the year ended December 31, 2015, were $45.4 million compared to $55.6 million for the same period in the prior year.

MGE Energy's net income was derived from our business segments as follows:

Our net income during 2015 compared to 2014 primarily reflects the effects of the following factors:

·

Electric net income decreased due to lower AFUDC and higher depreciation expense primarily related to the Columbia environmental project being placed in service in April (Unit 2) and July 2014 (Unit 1). In addition, there was a 0.3% decrease in electric retail sales in 2015 compared to the same period in the prior year.

·

Gas net income decreased due to a 27.0% decrease in gas retail sales reflecting lower customer demand compared to the demand resulting from the extremely cold weather experienced in 2014. Heating degree days (a measure for determining the impact of weather during the heating season) decreased by 18.9% compared to the prior year. The average temperature in January 2015 was 20.1 degrees compared to 11.5 degrees in the prior year.

·

Transmission investment income reflects our share of ATC's earnings. ATC's earnings for 2015 reflect a charge representing its estimate of its refund liability associated with the return on equity complaint filed with FERC. See "Other Matters" below for additional information concerning ATC.

·

The increase in all other income primarily results from a decrease in voluntary contributions.

Our net income during 2014 compared to 2013 primarily reflects the effects of the following factors:

·

Electric net income increased compared to the prior period primarily related to ongoing efforts to manage electric operating and maintenance expenditures.

·

Gas net income increased due to a 4.8% increase in gas retail sales reflecting higher customer demand due to a colder winter. The average temperatures in January and February 2014 were 11.5 degrees and 12.5 degrees, respectively, compared to 21.8 degrees and 21.3 degrees in the prior year. During 2014, heating degree days increased by 3.4% compared to the prior year. In addition, gas operating and maintenance expenditures decreased over the prior year.

·

In 2013, the PSCW approved recovery of the force majeure costs incurred during construction of the Elm Road Units. The higher non-regulated revenue in 2013 reflects the one-time adjustment for the carrying costs incurred in the prior periods on the force majeure costs.

During 2015, the following events occurred:

2015 Rate Filing: In December 2014, the PSCW authorized MGE to increase 2015 rates for retail electric customers by 3.8% and to decrease rates for gas customers by 2.0%. The increase in retail electric rates cover costs associated with the construction of emission-reduction equipment at Columbia, improvements and reliability of the state's electric transmission system, fuel and purchased power related to coal delivery costs, partially offset by lower cost as a result of market conditions for pension and post-retirement benefit costs.

The PSCW approved a change in the electric and gas rate design as part of the December 2014 rate order. The rate design better aligns the related fixed costs of providing gas and electric services. For example, the change lowers the gas distribution variable rate (excluding purchased gas) by approximately two-thirds and increases the fixed customer charge. Thus, gas earnings will be less sensitive to weather as a result of the change in rate design. Also, gas earnings will be more evenly spread throughout the year rather than being predominantly recognized in the winter months.

ATC Return on Equity: Several parties have filed a complaint with the FERC seeking to reduce the base return on equity (ROE) used by MISO transmission owners, including ATC. MISO's base ROE is 12.38% and ATC's base ROE is 12.2%. In December 2015, an administrative law judge issued an initial decision authorizing transmission owners to collect a base ROE of 10.32%. The initial decision will be reviewed by FERC and it is anticipated FERC will issue an

order on this issue by October 2016. In February 2015, a second complaint was filed with the FERC requesting a reduction in the base ROE used by MISO transmission owners, including ATC, to 8.67%, with a refund effective date retroactive to the filing date of the complaint. An initial decision from the administrative law judge is expected by June 30, 2016. In January 2015, FERC accepted the transmission owner's request for a 50 basis-point incentive ROE adder for participating in MISO. The adder became effective January 6, 2015, subject to refund, and FERC accepted the transmission owner's request to defer collection of the adder pending the outcome of the first ROE complaint proceeding. Our share of ATC's earnings for 2015 and 2014 reflects a pre-tax charge of $2.4 million and $0.7 million, respectively, recorded by ATC for this matter representing its estimate of its refund liability for the period of November 2013 through December 2015. Any change to ATC's ROE could result in lower equity earnings and distributions from ATC in the future. We derived approximately 6.4% and 6.7% of our net income for the years ended December 31, 2015 and 2014, respectively, from our investment in ATC. See "Other Matters" below for additional information concerning ATC.

During 2016, several items may affect us, including:

2016 Rate Case Filing: In July 2015, the PSCW approved MGE's request to extend the current accounting treatment for transmission related costs through 2016, conditioned upon MGE not filing a base rate case for 2016. This accounting treatment will allow MGE to reflect any differential between transmission costs reflected in rates and actual costs incurred in its next rate case filing.

2016 Annual Fuel Proceeding: In August 2015, the PSCW approved a $0.00256/kWh fuel credit to begin on September 1, 2015, and continue throughout 2016. The fuel credit established a mechanism to return fuel savings to electric customers as a bill credit. MGE returned $2.6 million of electric fuel-related savings in customer bill credits during the period from September 1, 2015, through December 31, 2015. As of December 31, 2015, MGE has deferred $9.5 million of 2015 electric fuel-related savings that are outside the range authorized by the PSCW. These costs are subject to PSCW's annual review, expected to be completed in 2016.

In January 2016, the PSCW lowered MGE's 2016 fuel rules monitored costs by $14.8 million as a result of continued lower projected fuel costs in 2016. The PSCW will address the return of the 2016 fuel savings to customers as an update to the fuel credit or through another approved mechanism. The return of the fuel savings to customers for 2016 will be addressed during the PSCW's annual review during 2016 of 2015 fuel costs. MGE will defer these fuel savings until a determination is made by the PSCW.

Loss of Industrial Customer: In November 2015, a large industrial customer announced its intention to relocate its operations out of state and to close its manufacturing facilities within our service territory. That closure is expected to occur in early 2017. This customer contributed approximately $3.8 million of pre-tax earnings for the year ended December 31, 2015. While we expect that our rate request for 2017, which would be filed during 2016, will be structured to address the effects of the closure, there could be some impact on our electric revenues during 2016 if the customer's operations are curtailed as a result of the impending closure.

Environmental Initiatives: There are proposed legislation, rules, and initiatives involving matters related to air emissions, water effluent, hazardous materials, and greenhouse gases, all of which affect generation plant capital expenditures and operating costs as well as future operational planning. Such legislation and rulemaking could significantly affect the costs of owning and operating fossil-fueled generating plants, such as Columbia and the Elm Road Units, from which we derive approximately 44% of our electric generating capacity. We would expect to seek and receive recovery of any such costs in rates; however, it is difficult to estimate the amount of such costs due to the uncertainty as to the timing and form of the legislation and rules, and the scope and time of the recovery of costs in rates, which may lag the incurrence of those costs.

EPA's Clean Power Plan: On August 3, 2015, the EPA finalized its Clean Power Plan rule setting guidelines for states to use in developing plans to control GHG emissions from existing fossil fuel-fired EGUs and systems. Implementation of the rule is expected to have a direct impact on coal-based generating units, including possible changes in dispatch and additional operating costs. MGE is currently evaluating the rule and its requirements. Although the implementation of the rule is presently stayed as a result of a February 9, 2016, U.S. Supreme Court ruling, compliance with the rule's requirements, including the yet-to-be-developed state implementation plan, could have a material impact on MGE if the rule is upheld and becomes effective.

Pension and Other Postretirement Benefit Costs: Costs for pension and other postretirement benefits are affected by actual investment returns on the assets held for those benefits and by the discount rate, which is sensitive to interest rates, used to calculate those benefits. Interest rates and investment returns have experienced volatility since the end of the year which could affect the value of the pension and postretirement benefit obligations. The changes in the discount

rates and value of plan assets are not expected to have an impact on the income statements for 2016. However, these changes may affect benefit costs in future years. MGE expects changes in the cost for employee benefit plans will be factored into future rate actions.

Future Generation: MGE is negotiating an agreement in 2016 with Alliant Energy that would allow MGE to reduce its coal ownership in Columbia and give MGE potential investment ability in efficient new natural gas generation. In the proposed agreement with Alliant Energy, MGE may acquire up to a 50 MW share of the capacity of Alliant Energy's proposed Riverside Energy Center project. Alliant Energy's Riverside project, which calls for an approximately 700 MW expansion of its existing natural gas generation facility, is currently under review by the PSCW. A final decision is expected this spring. If approved, project completion is expected by early 2020. Also as part of the proposed agreement, MGE may forgo certain capital expenditures at Columbia, which Alliant Energy then will pay for in exchange for a proportional increase in its ownership share of the plant. The arrangement excludes capital expenditures related to the recently approved project to install additional environmental controls on Unit 2 at Columbia. MGE currently owns 22% of Columbia.

General Economic Conditions: Economic conditions both inside and outside our service area are expected to continue to affect the level of demand for our utility services and may affect the collection of our accounts receivable and the creditworthiness of counterparties with whom we do business. We have in place lines of credit aggregating $150 million for MGE Energy (including MGE) and $100 million for MGE to address our liquidity needs. As of December 31, 2015, there were no borrowings outstanding under MGE Energy's or MGE's lines of credit.

The following discussion is based on the business segments as discussed in Footnote 21 of the Notes to Consolidated Financial Statements.

Results of Operations

Year Ended December 31, 2015, Versus the Year Ended December 31, 2014

Electric Utility Operations - MGE Energy and MGE

Electric sales and revenues

The following table compares MGE's electric revenues and electric kWh sales by customer class for each of the periods indicated:

Electric operating revenues increased $17.7 million or 4.5% for the year ended December 31, 2015, due to the following:

·

Rate changes. Rates charged to retail customers for the year ended December 31, 2015, were $14.4 million or 3.6% higher than those charged during the same period in the prior year.

In December 2014, the PSCW authorized MGE to increase 2015 rates for retail electric customers by $15.4 million or 3.8%. See "2015 Rate Filing" under "Executive Overview" for more information.

·

Fuel Credit. During the years ended December 31, 2015 and 2014, customers received a fuel credit on their bill related to the fuel savings of $2.6 million and $6.5 million, respectively, which increased electric revenues when compared to the same period in the prior year.

·

Adjustments to Revenue. The adjustments to revenues amount includes the elimination of carrying costs for the Elm Road Units and the WCCF that were collected in electric rates, which are recognized as nonregulated energy operating revenues in our Nonregulated Energy Operations segment.

·

Volume. During the year ended December 31, 2015, there was a 0.3% decrease in total retail sales volumes compared to the same period in the prior year primarily driven by lower use per residential customer.

·

Sales to the market. Sales to the market represent wholesale sales made to third parties who are not ultimate users of the electricity. These sales may include spot market transactions on the markets operated by MISO. These sales may also include bilateral sales to other utilities or power marketers. Generating units are dispatched by MISO based on cost considerations as well as reliability of the system. Sales to the market typically occur when MGE has more generation and purchases online than are needed for its own system demand. The excess electricity is then sold to others in the market. For the year ended December 31, 2015, market volumes increased compared to the same period in the prior year, reflecting increased opportunities for sales. In addition, market settlement resulted in lower revenue per kWh for the year ended December 31, 2015, reflecting lower market prices.

Electric fuel and purchased power

Electric fuel and purchased power costs reflect an increase in internal generation volumes partially offset by a decrease in the volume of purchased power when compared to the prior period. Adjustments related to the regulatory recovery for fuel costs, known as fuel rules, increased purchased power expense. These items are explained below.

Fuel for electric generation

The expense for fuel for internal electric generation increased $11.0 million during the year ended December 31, 2015, compared to the same period in the prior year, due to the following:

This increase in expense reflects a 13.6% increase in per-unit cost of internal electric generation primarily at Columbia and a 10.7% increase in internal generated volume delivered to the system.

Purchased power

Purchased power expense increased $8.0 million during the year ended December 31, 2015, compared to the same period in the prior year, due to the following:

The decrease in expense (before fuel rules adjustments) reflects a 3.8% decrease in the per-unit cost of purchased power and a 12.8% decrease in the volume of power purchased from third parties primarily as a result of increased internal generation.

Under fuel rules, MGE is required to defer electric fuel-related costs that fall outside a 2% cost tolerance band around the amount used in the most recent rate proceeding. Any fuel rules adjustments are reflected in purchased power expense. Any over/under recovery of the deferred costs is determined on an annual basis and adjusted in future billings to customers. During the year ended December 31, 2015, MGE deferred $11.6 million in fuel related cost savings to be returned to customers. In addition, MGE returned $2.6 million of electric fuel-related savings on customer bills during the year ended December 31, 2015. During the year ended December 31, 2014, as part of its rate freeze, MGE amortized $6.3 million of the 2012 fuel rule credits, which reduced purchased power expense for that period. In addition, MGE returned $6.5 million on customer bills in October 2014 related to the 2013 fuel rules credit.

Electric operating and maintenance expenses

Electric operating and maintenance expenses increased $4.0 million during the year ended December 31, 2015, compared to the same period in 2014. The following changes contributed to the net change:

For the year ended December 31, 2015, increased transmission costs are primarily related to an increase in transmission reliability enhancements. In addition, increased administrative and general costs are primarily due to increased pension and other postretirement benefits costs predominantly driven by a reduction in the discount rate, which has the effect of increasing the related costs. Decreased customer account costs are primarily related to lower uncollectible accounts receivable.

Electric depreciation expense

Electric depreciation expense increased $3.0 million for the year ended December 31, 2015, compared to the same period in the prior year. This increase is primarily related to the completion of the Columbia environmental project. The systems and equipment for Unit 2 and Unit 1 were placed into service in April 2014 and July 2014, respectively.

Other Electric Income

Other electric income decreased $2.4 million, primarily due to AFUDC equity related to the completion of the Columbia environmental project. Unit 2 and Unit 1 were placed into service in April and July 2014, respectively.

Gas Utility Operations - MGE Energy and MGE

Gas deliveries and revenues

The following table compares MGE's gas revenues and gas therms delivered by customer class during each of the periods indicated:

Gas revenues decreased $78.0 million or 35.2% for the year ended December 31, 2015. These changes are related to the following factors:

·

Volume. For the year ended December 31, 2015, retail gas deliveries decreased 27.0% compared to the same period in the prior year, as a result of extremely cold weather experienced in the first quarter of 2014. The decrease was also attributable to a large commercial customer's decision to purchase gas from a third party supplier and to use MGE's facilities for the transport of that gas. While the shift affects revenues, the impact to gas income of this shift is not material as we do not earn margin on the natural gas commodity cost billed to customers.

·

Rate/PGA changes. In December 2014, the PSCW approved changes to customer rates and rate design for gas service. Rates were reduced by 2.0%, effective January 1, 2015. Gas rate design consists of a fixed monthly customer charge and a variable charge tied to actual usage, in addition to the separate charge for natural gas commodity costs that is recovered through the PGA. The change shifted more of the rate recovery to the monthly charge, reflecting the related fixed costs of providing gas services, and reduced the variable usage-based charge. Thus, gas net income was more evenly distributed during the year and less sensitive to weather.

MGE recovers the cost of natural gas in its gas segment through the purchased gas adjustment clause (PGA). Under the PGA, MGE is able to pass through to its gas customers the cost of gas. Changes in PGA recoveries affect revenues but do not impact net income.

The average retail rate per therm for the year ended December 31, 2015, decreased 12.8% compared to the same period in 2014, reflecting a $28.7 million decrease in natural gas commodity costs (PGA) offset by an $8.2 million increase (comprised of a decrease in variable rate costs offset by an increase in fixed rate charges) related to rate design changes. As noted previously, as a result of the rate design changes, revenues in the first and fourth quarters, when usage is higher, were lower than in past years; and revenues in the second and third quarters, when usage is lower, were higher than in past years.

·

Transportation and other effects. During the year ended December 31, 2015, transportation and other effects increased $1.3 million primarily attributable to a large commercial customer's decision to purchase gas from a third party supplier and to use MGE's facilities for the transport of that gas. The impact to gas income of this shift is not material.

Cost of gas sold

For the year ended December 31, 2015, cost of gas sold decreased by $67.5 million, compared to the same period in the prior year. The volume of gas purchased decreased 26.8%, which resulted in $38.5 million of decreased expense. The cost per therm of natural gas decreased 27.6%, which resulted in $29.0 million of decreased expense.

Gas operating and maintenance expenses

Gas operating and maintenance expenses decreased $1.2 million for the year ended December 31, 2015, compared to the same period in 2014. The following changes contributed to the net change.

For the year ended December 31, 2015, decreased customer service costs are due to lower Focus on Energy payments, Wisconsin's statewide energy efficiency and renewable resource program to promote energy efficiency on customer's premises. Decreased customer accounts costs are due to lower uncollectible accounts receivable. Increased administrative and general costs are primarily due to increased pension and other postretirement benefit costs predominantly driven by a reduction in the discount rate.

Nonregulated Energy Operations - MGE Energy and MGE

For the years ended December 31, 2015 and 2014, net income at the nonregulated energy operations segment was $20.1 million and $19.3 million, respectively. The nonregulated energy operations are conducted through MGE Energy's subsidiaries: MGE Power Elm Road (the Elm Road Units) and MGE Power West Campus (WCCF), which have been formed to own and lease electric generating capacity to assist MGE.

Transmission Investment Operations - MGE Energy and MGE

Transmission investment other income

For the years ended December 31, 2015 and 2014, other income at the transmission investment segment was $7.7 million and $9.2 million, respectively. The transmission investment segment holds our interest in ATC, and its income reflects our equity in the earnings of ATC. See Footnote 4.b. of the Notes to Consolidated Financial Statements and Other Matters below for additional information concerning ATC and summarized financial information regarding ATC.

All Other Operations - MGE Energy and MGE

Other income

The increase in all other income primarily results from a decrease in voluntary contributions.

Consolidated Income Taxes - MGE Energy and MGE

Both MGE Energy's and MGE's effective income tax rate for the years ended December 31, 2015 and 2014, was 36.7% and 37.5%, respectively. The decrease in the effective tax rate is due in part to a higher estimated domestic manufacturing deduction, offset by lower AFUDC equity earnings in 2015.

Noncontrolling Interest, Net of Tax - MGE

The noncontrolling interest, net of tax, reflects the accounting required for MGE Energy's interest in MGE Power Elm Road (the Elm Road Units) and MGE Power West Campus (WCCF). MGE Energy owns 100% of MGE Power Elm Road and MGE Power West Campus; however, due to the contractual agreements for these projects with MGE, the entities are considered VIEs with respect to MGE and their results are consolidated with those of MGE, the primary beneficiary of the VIEs. Also included in noncontrolling interest, net of tax, is MGE Energy's interest in MGE Transco, which holds our investment in ATC. The following table shows MGE Energy's noncontrolling interest, net of tax, reflected on MGE's consolidated statements of income:

(a)

In mid-2016, MGE is no longer expected to be the majority owner of MGE Transco. The change will have no effect on MGE Energy's consolidated financial statements; however, MGE Energy's proportionate share of the equity and net income of MGE Transco will be deconsolidated from MGE's financial statements. See further discussion in Footnote 8 of the Consolidated Financial Statements.

Results of Operations

Year Ended December 31, 2014, Versus the Year Ended December 31, 2013

Electric Utility Operations - MGE Energy and MGE

Electric sales and revenues

The following table compares MGE's electric revenues and electric kWh sales by customer class for each of the periods indicated:

Electric operating revenues decreased $9.1 million or 2.3% for the year ended December 31, 2014, due to the following:

In July 2013, the PSCW authorized MGE to freeze 2014 rates at 2013 levels for retail electric customers.

·

Fuel Credit. During the year ended December 31, 2014, customers received a fuel credit on their bill related to the 2013 fuel savings of $6.5 million, which decreased electric revenues when compared to the same period in the prior year.

·

Other. During the year ended December 31, 2014, other items affecting electric operating revenues decreased $2.2 million primarily attributable to a decrease in demand charges, lower monthly on-peak sales, and a shift in commercial customer rate classes.

·

Volume. During the year ended December 31, 2014, there was a 0.5% decrease in total retail sales volumes compared to the same period in the prior year driven by cooler than normal weather.

·

Sales to the market. Sales to the market represent wholesale sales made to third parties who are not ultimate users of the electricity. These sales may include spot market transactions on the markets operated by MISO and PJM. These sales may also include bilateral sales to other utilities or power marketers. Generating units are dispatched by MISO based on cost considerations as well as reliability of the system. Sales to the market typically occur when MGE has more generation and purchases online than are needed for its own system demand. The excess electricity is then sold to others in the market. For the year ended December 31, 2014, market volumes increased compared to the same period in the prior year, reflecting increased opportunities for sales. In addition, market settlement resulted in higher revenue per kWh for the year ended December 31, 2014, reflecting higher market prices.

Electric fuel and purchased power

Electric fuel and purchased power costs reflect a decrease in internal generation volumes partially offset by an increase in the volume of purchased power when compared to the prior period. Adjustments related to the regulatory recovery for fuel costs, known as fuel rules, moderated the effects of that increased volume. These items are explained below.

Fuel for electric generation

The expense for fuel for internal electric generation decreased $3.2 million during the year ended December 31, 2014, compared to the same period in the prior year, due to the following:

This decrease in expense reflects a 13.7% decrease in internal generated volume delivered to the system primarily as a result of reduced generation at Columbia to reduce coal use in order to maintain inventory levels, partially offset by a 7.7% increase in per-unit cost of internal electric generation.

Purchased power

Purchased power expense decreased $7.6 million during the year ended December 31, 2014, compared to the same period in the prior year, due to the following:

The decrease in expense reflects a 5.9% decrease in the per-unit cost of purchased power and a 23.4% increase in the volume of power purchased from third parties primarily as a result of the reduced generation at Columbia.

Under fuel rules, MGE is required to defer electric fuel-related costs that fall outside a 2% cost tolerance band around the amount used in the most recent rate proceeding. Any fuel rules adjustments are reflected in purchased power expense. Any over/under recovery of the deferred costs is determined on an annual basis and adjusted in future billings to customers. During the year ended December 31, 2014, as part of its rate freeze, MGE was allowed to amortize $6.3 million of the 2012 fuel rule credit as a reduction of purchased power costs. In addition, MGE returned $6.5 million on customer bills in October 2014 related to the 2013 fuel rules credit.

Electric operating and maintenance expenses

Electric operating and maintenance expenses decreased $8.1 million during the year ended December 31, 2014, compared to the same period in 2013. The following changes contributed to the net change:

For the year ended December 31, 2014, decreased administrative and general costs are primarily due to decreased pension and other postretirement benefits costs predominantly driven by an increase in the discount rate, which has the effect of reducing the related costs.

Electric depreciation expense

Electric depreciation expense increased $1.2 million for the year ended December 31, 2014, compared to the same period in the prior year. This increase was a result of Columbia assets going in to service in April and July 2014.

Gas Utility Operations - MGE Energy and MGE

Gas deliveries and revenues

The following table compares MGE's gas revenues and gas therms delivered by customer class during each of the periods indicated: