EXHIBIT 23-A

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in Registration Statement Nos. 333-155747 on Form S-3 and 333-25261, 333-73041, 333-73075 and 333-136841 on Form S-8 of our report dated February 25, 2009 relating to the consolidated financial statements of Otter Tail Corporation and its subsidiaries (the “Company”) and management’s report on the effectiveness of internal control over financial reporting appearing in the 2008 Annual Report to Shareholders of the Company and incorporated by reference in this Annual Report on Form 10-K of the Company for the year ended December 31, 2008.

/s/ Deloitte & Touche LLP

Minneapolis, Minnesota
February 27, 2009