MGE ENERGY INC

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

Transmission Investments

ATC 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, a wholly-owned subsidiary of MGE Energy. As of December 31, 2023, MGE Transco held a 3.6% ownership interest in ATC.

In 2016, ATC Holdco was formed by several of the members of ATC, including MGE Energy, to explore electric transmission development and investments outside of Wisconsin, which typically have long development and investment lead times before becoming operational. MGE Energy's ownership interest in ATC Holdco is held by MGEE Transco, a wholly-owned subsidiary. As of December 31, 2023, MGEE Transco held a 4.4% ownership interest in ATC Holdco.