Public Service Co Of Oklahoma S-3 Shelf registration

EXHIBIT 23.(a)

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in this Registration Statement on Form S-3 of our reports dated February 27, 2006 relating to the financial statements (and with respect to the report on those financial statements, expressed an unqualified opinion and included an explanatory paragraph concerning the adoption of new accounting pronouncements in 2003 and 2004) and financial statement schedule of Public Service Company of Oklahoma appearing in and incorporated by reference in the Annual Report on Form 10-K of Public Service Company of Oklahoma for the year ended December 31, 2005 and to the reference to us under the heading “Experts” in the Prospectus, which is part of this Registration Statement.

/s/ Deloitte & Touche LLP

Columbus, Ohio

April 26, 2006