Additional Proxy Soliciting Materials (definitive) (defa14a)

[Email to MGE Energy Institutional Investors Sent on Tuesday, April 3, 2018.]

MGE Energy's annual shareholders meeting notice was recently sent to you. This year's ballot includes three shareholder proposals.

Attached is our Sustainability and Governance Fact Sheet to give you a brief overview of our initiatives, including environmental stewardship.

I would like to schedule a call with you to discuss the shareholder proposals described in the notice. Would you have time around the end of April for a brief phone conversation?

I will be following up with you in a week or so to see if you have any questions or concerns and certainly, if you would like to schedule a call earlier, please let me know.

Regards,

[Attached PDF: MGEE Sustainability and Governance Fact Sheet 2018]

Ken Frassetto

Director - Shareholder Services and Treasury Management

Madison Gas and Electric Co.

P.O. Box 1231

Madison, WI 53701-1231

Phone: 608-252-4723

Cell: 608-843-6166

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