Tucson Electric Power Accepts Certain Tender Offers for Bonds

Business Editors/Energy Editors

TUCSON, Ariz.--(BUSINESS WIRE)--May 6, 2005--Tucson Electric Power Co. (TEP), a subsidiary of UniSource Energy Corp. (NYSE:UNS), invited the owners of several series of tax-exempt bonds listed in its invitations dated March 17, 2005 (the "invitations") to offer to sell their bonds to TEP for cash. With respect to each of the two series of bonds listed below, TEP announced on April 15, 2005, that it had established a purchase price of $101.50 per $100 in principal amount of bonds, offered to purchase all outstanding bonds of these series and extended the expiration date until 5 p.m. EDT on May 5, 2005. There have been tendered for purchase and TEP has accepted for purchase the principal amount of bonds listed below for each of the two series of bonds:

BONDS ACCEPTED FOR PURCHASE

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Pur- Pur- chase chase Price Price Principal (per (per Amount $100 $1,000 Inter- Accepted in prin- in prin- Name of est for cipal cipal Issuer Bonds Rate CUSIP Purchase amount) amount) ---------- --------- ------ --------- ------------- -------- --------

Indus- trial Indus- Develop- trial ment Develop- Author- ment 721774DF1 ity of Revenue the Bonds, County 1997 of Pima Series (Arizona) B 6.00% $146,415,000 $101.50 $1,015.00 ---------- --------- ------ --------- ------------- -------- ---------

Indus- trial Indus- Develop- trial ment Develop- Author- ment 721774DG9 ity of Revenue the Bonds, County 1997 of Pima Series (Arizona) C 6.00% $74,330,000 $101.50 $1,015.00 ---------- --------- ------ --------- ------------- -------- ---------

Total: $220,745,000

All bonds of a series listed above that were tendered pursuant to this offer have been accepted for purchase, subject to the terms and conditions of the invitations. The settlement date for the purchase of bonds of each of the series listed above is expected to be May 11, 2005, subject to change as provided in the invitations. An amount equal to accrued interest on the bonds to be purchased through the day before the settlement day will also be paid. Institutional investors with questions about the settlement should contact the dealer manager, Morgan Stanley. Individual investors and their brokers and account executives with questions about the settlement should contact the information and tender agent listed below:

Contact: Desiree Rose Bondholder Communications Group 30 Broad St., 46th floor New York, NY 10004 www.bondcom.com/tep e-mail: drose@bondcom.com Tel: 888-385-BOND (2663) Fax: 212-437-9827

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CONTACT: Tucson Electric Power Co., Tucson Joe Salkowski, 520-884-3625 (Media) Jo Smith, 520-884-3650 (Financial Analyst)

KEYWORD: ARIZONA INDUSTRY KEYWORD: UTILITIES SOURCE: Tucson Electric Power Co.

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