[GRAPHIC LOGO OMITTED]  UNISOURCE ENERGY
                        NEWS


FOR IMMEDIATE RELEASE                                          February 24, 2005
Media Contact: Joe Salkowski, (520) 884-3625                         Page 1 of 1
Financial Analyst Contact: Jo Smith, (520) 884-3650


                      UNISOURCE ENERGY ANNOUNCES PRICING OF
                 $125 MILLION CONVERTIBLE SENIOR NOTES OFFERING

TUCSON, ARIZ. - UniSource Energy Corporation (NYSE: UNS) announced today that it
has priced an offering of $125 million aggregate principal amount of 4.50%
Convertible Senior Notes due 2035 through a domestic offering to qualified
institutional buyers pursuant to Rule 144A under the Securities Act of 1933 (the
Act) and to persons in offshore transactions in reliance on Regulation S under
the Act. The sale of the notes to the initial purchasers is expected to close on
March 1, 2005.

Each $1,000 principal amount of notes will be convertible into 26.6667 shares of
UniSource Energy common stock at any time, representing a conversion price of
approximately $37.50 per share of UniSource Energy common stock, subject to
adjustment in certain circumstances.

Beginning on March 5, 2010, UniSource Energy will have the option to redeem the
notes, in whole or in part, for cash, at a price equal to 100% of the principal
amount plus accrued and unpaid interest. Holders of the notes will have the
ability to require UniSource Energy to repurchase the notes, in whole or in
part, for cash on March 1, 2015, 2020, 2025 and 2030, or if certain specified
fundamental changes involving UniSource Energy occur. The repurchase price will
be 100% of the principal amount of the notes plus accrued and unpaid interest.

UniSource Energy has also granted the initial purchasers a 13-day option to
purchase up to an additional $25 million aggregate principal amount of the
notes.

UniSource Energy intends to use the net proceeds from this offering to repay a
UniSource Energy debt obligation in the principal amount of $95 million plus
accrued interest to Tucson Electric Power Company (TEP), UniSource Energy's
principal subsidiary, and for other general corporate purposes. UniSource Energy
expects that TEP will use the proceeds it receives to redeem or repurchase
certain of TEP's existing indebtedness through transactions that may include
negotiated or market purchases, tender offers and redemptions. TEP has not
determined the series of debt to be repaid or repurchased.

This announcement is neither an offer to sell nor a solicitation of an offer to
buy any of these securities.

The securities have not been registered under the Act or any state securities
laws, and unless so registered, may not be offered or sold in the United States
except pursuant to an exemption from the registration requirements of the Act
and applicable state laws.