Amendment No. 1 to Form 10-K
 
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 10-K/A
Amendment No. 1
(Mark One)
        [ X ] ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF
THE SECURITIES EXCHANGE ACT OF 1934
For the fiscal year ended December 31, 2006
OR
        [   ] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF
                      THE SECURITIES EXCHANGE ACT OF 1934
For the transition period from                to               .

Commission
File Number
Registrant; State of Incorporation;
Address; and Telephone Number
IRS Employer
Identification Number
     
1-13739
UNISOURCE ENERGY CORPORATION
(An Arizona Corporation)
One South Church Avenue, Suite 100
Tucson, AZ 85701
(520) 571-4000
86-0786732
     
1-5924
TUCSON ELECTRIC POWER COMPANY
(An Arizona Corporation)
One South Church Avenue, Suite 100
Tucson, AZ 85701
(520) 571-4000
86-0062700

Securities registered pursuant to Section 12(b) of the Act:
  
 
Registrant
 
Title of Each Class
Name of Each Exchange
on Which Registered
     
UniSource Energy Corporation
Common Stock, no par value, and
Preferred Share Purchase Rights
New York Stock Exchange

Securities registered pursuant to Section 12(g) of the Act:  None
 
Indicate by check mark if the registrant is a well known seasoned issuer, as defined in Rule 405 of the Securities Act.  
UniSource Energy Corporation       Yes    X          No _____
Tucson Electric Power Company    Yes ____       No __X__ 

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Securities Act. 
UniSource Energy Corporation     Yes ____       No __X__       
Tucson Electric Power Company        Yes    X         No _____ 

Indicate by check mark whether each registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes    X          No _____

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of each registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K. [ ]
 

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer or a non-accelerated filer. See definition of “accelerated filer” and “large accelerated filer” in Rule 12b-2 of the Exchange Act. (Check one):
 
UniSource Energy Corporation      Large Accelerated Filer    X       Accelerated Filer            Non-accelerated filer      
Tucson Electric Power Company   Large Accelerated Filer            Accelerated Filer            Non-accelerated filer   X  
 
Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).
UniSource Energy Corporation   Yes _____       No    X  
Tucson Electric Power Company  Yes  _____      No    X   

The aggregate market value of UniSource Energy Corporation voting Common Stock held by non-affiliates of the registrant was $1,055,512,081 based on the last reported sale price thereof on the consolidated tape on June 30, 2006.

At February 23, 2007, 35,256,170 shares of UniSource Energy Corporation Common Stock, no par value (the only class of Common Stock), were outstanding.

At February 23, 2007, 32,139,434 shares of Tucson Electric Power Company’s common stock, no par value, were outstanding, all of which were held by UniSource Energy Corporation.
 
Documents incorporated by reference: Specified portions of UniSource Energy Corporation’s Proxy Statement relating to the 2007 Annual Meeting of Shareholders are incorporated by reference into Part III.
 
 
 
Explanatory Note

This Amendment on Form 10-K/A constitutes Amendment No. 1 to the Annual Report on Form 10-K for the year ended December 31, 2006 of UniSource Energy Corporation (UniSource Energy) and Tucson Electric Power Company (TEP), which was originally filed with the Securities and Exchange Commission on February 28, 2007 (Initial Form 10-K).

This Amendment is being filed to amend UniSource Energy’s and TEP’s Initial Form 10-K to correct the date on UniSource Energy’s and TEP’s signature pages to the Initial Form 10-K, which was inadvertently mistyped. Exhibits 31(a), (b), (c) and (d) and Exhibit 32, which were filed with the Initial Form 10-K, also contained the same typographical errors. Such exhibits, with corrected dates, are filed herewith. This Form 10-K/A does not make any other changes to the Initial Form 10-K.

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PART IV

ITEM 15. – EXHIBITS AND FINANCIAL STATEMENT SCHEDULES
 
     
 Page
 (a)
1.     
Consolidated Financial Statements as of December 31, 2006 and 2005
and for Each of the Three Years in the Period Ended December 31, 2006
  
       
     UniSource Energy Corporation  
     Report of Independent Registered Public Accounting Firm
 81
     Consolidated Statements of Income
 84
     Consolidated Statements of Cash Flows
 85
     Consolidated Balance Sheets
 86
     Consolidated Statements of Capitalization
 87
     Consolidated Statements of Changes in Stockholders' Equity
 88
     Notes to Consolidated Financial Statements
 94
       
     Tucson Electric Power Company  
     Report of Independent Registered Public Accounting Firm
 83
     Consolidated Statements of Income
 89
     Consolidated Statements of Cash Flows
 90
     Consolidated Balance Sheets
 91
     Consolidated Statements of Capitalization
 92
     Consolidated Statements of changes in Stockholder's Equity
 93
     Notes to Consolidated Financial Statements
 94
       
  2.      Financial Statement Schedule  
     Schedule II  
          Valuation and Qualifying Accounts
 164
       
 
Reference to Items 15(a)(1) and (2) are made to the page numbers of the Initial Form 10-K.
       
  3. Exhibits   
      
  Reference is made to the Exhibit Index commencing on page 8 of this Form 10-K/A.  
 
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SIGNATURES

Pursuant to the requirements of Section 13 and 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

 UNISOURCE ENERGY CORPORATION


Date: February 28, 2007                                            By: /s/ Kevin P. Larson                   
Kevin P. Larson
Senior Vice President and Principal
Financial Officer


Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.


Date: February 28, 2007                                            /s/       James S. Pignatelli*                 
James S. Pignatelli
Chairman of the Board, President and
Principal Executive Officer


Date: February 28, 2007                                            /s/       Kevin P. Larson                   
Kevin P. Larson
Principal Financial Officer


Date: February 28, 2007                                            /s/       Karen G. Kissinger*                 
Karen G. Kissinger
Principal Accounting Officer


Date: February 28, 2007                                            /s/       Lawrence J. Aldrich*                 
Lawrence J. Aldrich
Director


Date: February 28, 2007                                            /s/       Barbara Baumann*                  
Barbara Baumann
Director


Date: February 28, 2007                                            /s/       Larry W. Bickle*                   
Larry W. Bickle
Director


Date: February 28, 2007                                            /s/       Elizabeth T. Bilby*                  
Elizabeth T. Bilby
Director


Date: February 28, 2007                                            /s/       Harold W. Burlingame*               
Harold W. Burlingame
Director
 
 
Date: February 28, 2007                                            /s/       John L. Carter*                    
                                                                                          John L. Carter
                                                                                          Director

4
 
Date: February 28, 2007                                            /s/       Robert A. Elliott*                   
Robert A. Elliott
Director


Date: February 28, 2007                                            /s/       Daniel W.L. Fessler*                 
Daniel W.L. Fessler


Date: February 28, 2007                                            /s/       Kenneth Handy*                   
Kenneth Handy
Director


Date: February 28, 2007                                           /s/        Warren Y. Jobe*                   
Warren Y. Jobe
Director


Date: February 28, 2007                                            /s/       Joaquin Ruiz*                     
Joaquin Ruiz
Director


Date: February 28, 2007                                           By:  /s/ Kevin P. Larson                   
Kevin P. Larson
As attorney-in-fact for each
of the persons indicated
 
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SIGNATURES

Pursuant to the requirements of Section 13 and 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

TUCSON ELECTRIC POWER COMPANY


Date: February 28, 2007                                           By: /s/  Kevin P. Larson                     
Kevin P. Larson
Senior Vice President and Principal
Financial Officer


Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.


Date: February 28, 2007                                            /s/       James S. Pignatelli*                   
James S. Pignatelli
Chairman of the Board, President and
Principal Executive Officer


Date: February 28, 2007                                            /s/       Kevin P. Larson                      
Kevin P. Larson
Principal Financial Officer


Date: February 28, 2007                                            /s/       Karen G. Kissinger*                   
Karen G. Kissinger
Principal Accounting Officer


Date: February 28, 2007                                            /s/       Lawrence J. Aldrich*                   
Lawrence J. Aldrich
Director


Date: February 28, 2007                                            /s/       Barbara Baumann*                    
Barbara Baumann
Director


Date: February 28, 2007                                            /s/       Larry W. Bickle*                      
Larry W. Bickle
Director


Date: February 28, 2007                                            /s/       Elizabeth T. Bilby*                     
Elizabeth T. Bilby
Director


Date: February 28, 2007                                            /s/       Harold W. Burlingame*                   
Harold W. Burlingame
Director
 

Date: February 28, 2007                                            /s/       John L. Carter*                       
John L. Carter
                                                                                          Director
6
 
Date: February 28, 2007                                            /s/       Robert A. Elliott*                      
Robert A. Elliott
Director


Date: February 28, 2007                                            /s/       Daniel W.L. Fessler*                   
Daniel W.L. Fessler


Date: February 28, 2007                                            /s/       Kenneth Handy*                      
Kenneth Handy
Director


Date: February 28, 2007                                            /s/       Warren Y. Jobe*                     
Warren Y. Jobe
Director


Date: February 28, 2007                                            /s/       Joaquin Ruiz*                       
Joaquin Ruiz
Director


Date: February 28, 2007                                           By: /s/  Kevin P. Larson                      
Kevin P. Larson
As attorney-in-fact for each
of the persons indicated
 
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EXHIBIT INDEX


31(a)
--
 
31(b)
--

31(c)
--

31(d)
--

**32
--
 
 
** Pursuant to Item 601(b)(32)(ii) of Regulation S-K, this certificate is not being “filed” for purposes of Section 18 of the Exchange Act of 1934, as amended.
 
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