Rate Matters	3 Months Ended
Mar. 31, 2013
Rate Matters Disclosure [Abstract]
Rate Matters	10. Rate Matters - MGE Energy and MGE. a. Rate Proceedings. On April 15, 2013, MGE applied with the PSCW for authority to freeze electric and natural gas rates at 2013 levels for 2014. The application includes a request for categorizing 100% of the cost of the Columbia scrubber construction project as AFUDC. The plan includes a request for deferral of increases in ATC and MISO Schedule 26 fees. In addition, MGE is requesting that approximately $6.2 million pertaining to a fuel rule surplus credit be offset against MGE's increased costs. The fuel credit will accrue interest at MGE's weighted cost of capital during 2013, and the requested treatment of the credit will contribute to the overall rate freeze for 2014. On December 14, 2012, the PSCW authorized MGE to increase 2013 rates for retail electric customers by 3.8% or $14.9 million and to increase gas rates by 1.0% or $1.6 million. The change in retail electric rates was driven by costs for new environmental equipment at Columbia, final construction costs for the Elm Road Units, transmission reliability enhancements, and purchased power costs. The authorized return on common stock equity remains unchanged at 10.3%. On December 15, 2011, under a limited reopener of MGE's last rate order, the PSCW authorized MGE to increase 2012 rates for retail electric customers by 4.3% or $15.7 million and to increase gas rates by 0.3% or $0.6 million. The change in retail electric rates was driven by MGE's electric fuel and purchased power costs, increased transmission costs, an update to the Elm Road Units' costs, and an increase for energy efficiency programs. The PSCW also approved deferral of CSAPR costs. b. Fuel Rules. Fuel rules require the PSCW and Wisconsin utilities to defer electric fuel-related costs that fall outside a symmetrical cost tolerance band around the amount approved for a utility in its most recent base rate proceedings. Any over/under recovery of the actual costs is determined on an annual basis and will be adjusted in future billings to electric retail customers. The fuel rules bandwidth is currently set at plus or minus 2%. Under fuel rules, MGE would defer costs, less any excess revenues, if its actual electric fuel costs exceeded 102% of the electric fuel costs allowed in its latest rate order. Excess revenues are defined as revenues in the year in question that provide MGE with a greater return on common equity than authorized by the PSCW in MGE's latest rate order. Conversely, MGE is required to defer the benefit of lower costs if actual electric fuel costs were less than 98% of the electric fuel costs allowed in that order. As of March 31, 2013, MGE did not defer any electric fuel-related savings/costs that are outside the range authorized by the PSCW. c. Purchased Gas Adjustment Clause. MGE's natural gas rates are subject to a fuel adjustment clause designed to recover or refund the difference between the actual cost of purchased gas and the amount included in rates. Differences between the amounts billed to customers and the actual costs recoverable are deferred and recovered or refunded in future periods by means of prospective monthly adjustments to rates. At March 31, 2013, MGE had over collected $5.3 million, recorded in other current liabilities on the consolidated balance sheet. At December 31, 2012, MGE had under collected $0.1 million, recorded in other current assets on the consolidated balance sheet.

Rate Matters

3 Months Ended

Mar. 31, 2013

10. Rate Matters - MGE Energy and MGE.

a. Rate Proceedings.

On April 15, 2013, MGE applied with the PSCW for authority to freeze electric and natural gas rates at 2013 levels for 2014. The application includes a request for categorizing 100% of the cost of the Columbia scrubber construction project as AFUDC. The plan includes a request for deferral of increases in ATC and MISO Schedule 26 fees. In addition, MGE is requesting that approximately $6.2 million pertaining to a fuel rule surplus credit be offset against MGE's increased costs. The fuel credit will accrue interest at MGE's weighted cost of capital during 2013, and the requested treatment of the credit will contribute to the overall rate freeze for 2014.

On December 14, 2012, the PSCW authorized MGE to increase 2013 rates for retail electric customers by 3.8% or $14.9 million and to increase gas rates by 1.0% or $1.6 million. The change in retail electric rates was driven by costs for new environmental equipment at Columbia, final construction costs for the Elm Road Units, transmission reliability enhancements, and purchased power costs. The authorized return on common stock equity remains unchanged at 10.3%.

On December 15, 2011, under a limited reopener of MGE's last rate order, the PSCW authorized MGE to increase 2012 rates for retail electric customers by 4.3% or $15.7 million and to increase gas rates by 0.3% or $0.6 million. The change in retail electric rates was driven by MGE's electric fuel and purchased power costs, increased transmission costs, an update to the Elm Road Units' costs, and an increase for energy efficiency programs. The PSCW also approved deferral of CSAPR costs.

b. Fuel Rules.

Fuel rules require the PSCW and Wisconsin utilities to defer electric fuel-related costs that fall outside a symmetrical cost tolerance band around the amount approved for a utility in its most recent base rate proceedings. Any over/under recovery of the actual costs is determined on an annual basis and will be adjusted in future billings to electric retail customers. The fuel rules bandwidth is currently set at plus or minus 2%. Under fuel rules, MGE would defer costs, less any excess revenues, if its actual electric fuel costs exceeded 102% of the electric fuel costs allowed in its latest rate order. Excess revenues are defined as revenues in the year in question that provide MGE with a greater return on common equity than authorized by the PSCW in MGE's latest rate order. Conversely, MGE is required to defer the benefit of lower costs if actual electric fuel costs were less than 98% of the electric fuel costs allowed in that order. As of March 31, 2013, MGE did not defer any electric fuel-related savings/costs that are outside the range authorized by the PSCW.

c. Purchased Gas Adjustment Clause.

MGE's natural gas rates are subject to a fuel adjustment clause designed to recover or refund the difference between the actual cost of purchased gas and the amount included in rates. Differences between the amounts billed to customers and the actual costs recoverable are deferred and recovered or refunded in future periods by means of prospective monthly adjustments to rates. At March 31, 2013, MGE had over collected $5.3 million, recorded in other current liabilities on the consolidated balance sheet. At December 31, 2012, MGE had under collected $0.1 million, recorded in other current assets on the consolidated balance sheet.