Duke Energy Florida 10-Q 2010 Q3 Quarterly report

Exhibit 32(f)

CERTIFICATION FURNISHED PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report on Form 10-Q of Florida Power Corporation (the “Company”) for the period ended September 30, 2010 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Mark F. Mulhern, Senior Vice President and Chief Financial Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

(1)           the Report fully complies with the requirements of Section 13(a) or 15(d), as applicable, of the Securities Exchange Act of 1934, as amended; and

(2)           the information contained in the Report fairly presents, in all material respects, the financial condition and result of operations of the Company.

/s/ Mark F. Mulhern

Mark F. Mulhern

Senior Vice President and

Chief Financial Officer

November 8, 2010

This certification is being furnished and shall not be deemed filed by the Company for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or incorporated by reference in any filing under the Securities Exchange Act of 1934, as amended, or the Securities Act of 1933, as amended.