Rate Matters	9 Months Ended
Sep. 30, 2012
Rate Matters Disclosure [Abstract]
Rate Matters	10. Rate Matters - MGE Energy and MGE. a. Rate Proceedings. On March 23, 2012, MGE filed an application with the PSCW requesting a 5.8% increase to electric rates and a 2.6% increase to gas rates. The proposed electric increase will cover costs for new environmental equipment at Columbia, final construction costs for the Elm Road Units (including the prudence of construction costs incurred above a previously approved cap), transmission reliability enhancements, and purchased power costs. MGE has requested that these rates become effective January 1, 2013. 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. On January 12, 2011, the PSCW authorized MGE to increase 2011 rates for retail electric customers by 2.3% or $8.0 million and to increase gas rates by 1.0% or $1.9 million. The increase in retail electric rates is driven by costs for MGE's share of the Elm Road Units. Pursuant to the provisions of this rate order, the fuel rules bandwidth effective January 1, 2011, will be plus or minus 2%. See below for further description of fuel rules. Authorized return on common stock equity was set at 10.3% based on a 58.1% utility common equity. b. Fuel Rules. The PSCW approved new fuel rules that became effective January 1, 2011. The new 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. 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 September 30, 2012, MGE has deferred $5.9 million (for credit back to customers) of electric fuel-related savings that are outside the 98% range authorized by the PSCW in the most recent rate order.

Rate Matters

9 Months Ended

Sep. 30, 2012

10. Rate Matters - MGE Energy and MGE.

a. Rate Proceedings.

On March 23, 2012, MGE filed an application with the PSCW requesting a 5.8% increase to electric rates and a 2.6% increase to gas rates. The proposed electric increase will cover costs for new environmental equipment at Columbia, final construction costs for the Elm Road Units (including the prudence of construction costs incurred above a previously approved cap), transmission reliability enhancements, and purchased power costs. MGE has requested that these rates become effective January 1, 2013.

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.

On January 12, 2011, the PSCW authorized MGE to increase 2011 rates for retail electric customers by 2.3% or $8.0 million and to increase gas rates by 1.0% or $1.9 million. The increase in retail electric rates is driven by costs for MGE's share of the Elm Road Units. Pursuant to the provisions of this rate order, the fuel rules bandwidth effective January 1, 2011, will be plus or minus 2%. See below for further description of fuel rules. Authorized return on common stock equity was set at 10.3% based on a 58.1% utility common equity.

b. Fuel Rules.

The PSCW approved new fuel rules that became effective January 1, 2011. The new 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. 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 September 30, 2012, MGE has deferred $5.9 million (for credit back to customers) of electric fuel-related savings that are outside the 98% range authorized by the PSCW in the most recent rate order.