TransAlta Closes Cdn $275 Million Sale of Common Shares

CALGARY, ALBERTA--(Marketwire - Sept. 13, 2012) -

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TransAlta Corporation (TransAlta) (TSX:TA)(NYSE:TAC) announced today it has completed its public offering of 19,250,000 Common Shares at a price of $14.30 per Common Share. TransAlta has granted the underwriters an over-allotment option to purchase up to an additional 2,887,500 Common Shares at the same price, exercisable in whole or in part at any time for 30 days following today's closing of the offering. The over-allotment option will be used to cover over-allocations, if any, and for market stabilization purposes.

The offering, previously announced on September 4, 2012, resulted in gross proceeds to TransAlta of approximately Cdn $275 million. The net proceeds from the offering will be used to fund future growth capital expenditures, including to partially fund the previously announced acquisition of the Solomon power station if completed, repay short term indebtedness, and for general corporate purposes.

The Common Shares were offered through a syndicate of underwriters led by CIBC and RBC Capital Markets, and including Scotiabank, TD Securities Inc., BMO Capital Markets, National Bank Financial Inc., Bank of America Merrill Lynch, HSBC Securities (Canada) Inc., Canaccord Genuity Corp. and Desjardins Securities Inc., by way of a prospectus supplement to TransAlta's short form base shelf prospectus dated November 15, 2011.

About TransAlta Corporation

TransAlta is a power generation and wholesale marketing company focused on creating long-term shareholder value. TransAlta maintains a low-to-moderate risk profile by operating a highly contracted portfolio of assets in Canada, the United States and Australia. TransAlta's focus is to efficiently operate our geothermal, wind, hydro, natural gas and coal facilities in order to provide our customers with a reliable, low-cost source of power. For 100 years, TransAlta has been a responsible operator and a proud contributor to the communities where we work and live. TransAlta is recognized for its leadership on sustainability by the Dow Jones Sustainability North America Index, the FTSE4Good Index and the Jantzi Social Index. TransAlta is Canada's largest investor-owned renewable energy provider.

This news release may contain forward looking statements, including statements regarding the business and anticipated financial performance of TransAlta Corporation and the anticipated use of the proceeds of the offering. These statements are based on TransAlta Corporation's belief and assumptions based on information available at the time the assumption was made. These statements are subject to a number of risks and uncertainties that may cause actual results to differ materially from those contemplated by the forward-looking statements. Some of the factors that could cause such differences include, pricing in the market place, our inability to enter into long term contracts due to prevailing market conditions, legislative or regulatory developments, competition, global capital markets activity, changes in interest rates, currency exchange rates, inflation levels and general economic conditions in geographic areas where TransAlta Corporation operates.

Note: All financial figures are in Canadian dollars unless noted otherwise.