EXHIBIT 23.01

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in Registration Statement Nos. 333-148996, 333-104507, and 333-132148 of Xcel Energy Inc. on Form S-8 of our report dated June 27, 2008, appearing in this Annual Report on Form 11-K of the New Century Energies, Inc. Employee Investment Plan for Bargaining Unit Employees and Former Non-Bargaining Unit Employees and New Century Energies, Inc. Employees’ Savings and Stock Ownership Plan for Bargaining Unit Employees and Former Non-Bargaining Unit Employees for the year ended December 31, 2007.

/s/ DELOITTE & TOUCHE LLP

DELOITTE & TOUCHE LLP

Minneapolis, Minnesota

June 27, 2008