Atlantic Power Corporation Announces Filings for Proposed Convertible Debenture and Common Share Offerings

BOSTON, MASSACHUSETTS--(Marketwire - Aug. 13, 2010) - Atlantic Power Corporation (TSX:ATP)(TSX:ATP.DB)(TSX:ATP.DB.A)(NYSE:AT) (the "Company") announced today that it has filed a preliminary prospectus in Canada and a registration statement on Form S-1 with the U.S. Securities and Exchange Commission (the "SEC") with respect to an offering of convertible unsecured subordinated debentures (the "Debentures") in Canada. The size and pricing of the Debenture offering and the final terms of the Debentures will be determined following clearance of the Canadian preliminary prospectus and U.S. registration statement by the applicable securities regulatory authorities. BMO Capital Markets is acting as sole bookrunner with respect to the offering of Debentures.

The Company also announced today that it has filed a registration statement on Form S-1 with the SEC with respect to a concurrent public offering of common shares (the "Common Shares"). The size and pricing of the Common Share offering will also be determined following clearance by the applicable securities regulatory authorities. UBS Investment Bank is acting as sole book-running manager for the offering of Common Shares.

Proceeds from these offerings will be used by the Company for (i) repayment of approximately US$20 million borrowed under its revolving credit facility in June 2010 to partially fund our previously-announced acquisition of a 27.6% equity interest in Idaho Wind Partners 1, LLC, and (ii) to fund a likely investment of up to US$75 million in the Piedmont Green Power biomass project in Barnesville, Georgia for substantially all of the equity interest in the project, which is currently in advanced discussions. Any remaining net proceeds will be used to fund additional growth opportunities and for general corporate purposes.

When available, copies of the prospectus related to the proposed offering of Debentures may be obtained from Investor Relations at BMO Capital Markets, Distribution Department, 1 First Canadian Place, B2 Level, Toronto, Ontario, M5X 1H3 (telephone: 416-363-6996 x224). When available, copies of the prospectus related to the proposed offering of Common Shares may be obtained from UBS Investment Bank, Attention: Prospectus Department, 299 Park Avenue, New York, NY 10171 or by telephone toll free at 888-827-7275.

No Canadian preliminary prospectus has yet become final for the purpose of a distribution of securities to the public. This press release does not constitute an offer to sell or the solicitation of an offer to buy, nor shall there be any sale or any acceptance of an offer to buy these securities in any province or territory of Canada prior to the time a receipt for the final prospectus or other authorization is obtained from the securities commission or similar authority in such province or territory of Canada and from the SEC.

The registration statements relating to these securities have been filed with the SEC but have not yet become effective. These securities may not be sold nor may offers to buy be accepted prior to the time the registration statements become effective.

About Atlantic Power

Atlantic Power Corporation is an independent power producer, with power projects located in major markets in the United States. Our current portfolio consists of interests in 12 operational power generation projects across eight states, one wind project under construction in Idaho, a 500 kilovolt 84-mile electric transmission line located in California, and six development projects in five states. Our power generation projects in operation have an aggregate gross electric generation capacity of approximately 1,823 megawatts (or "MW"), in which our ownership interest is approximately 808 MW. For more information, please visit the Company's website at www.atlanticpower.com.

Forward-Looking Statements

Certain statements in this news release may constitute "forward-looking statements", which reflect the expectations of the Company regarding its Debenture and Common Share offerings. These statements, which are based on certain assumptions and describe our future plans, strategies and expectations, can generally be identified by the use of the words "may," "will", "anticipate," "expect", "intend", "estimate", "anticipate", "plans" or "continue", or similar expressions that are predictions of or indicate future events or trends and which do not relate solely to present or historical matters. Specific forward looking statements contained in this press release include the statements with respect to the determination of final pricing terms and the terms of the offerings and the use of proceeds therefrom. These statements are subject to a number of risks and uncertainties and may depend on the Company's ability to complete the offerings on economically acceptable terms. There can be no assurance that the offerings will be completed or that the proceeds therefore will be used as expected.

Forward-looking statements reflect current expectations regarding future events and operating performance and speak only as of the date of this news release. Forward-looking statements involve significant risks and uncertainties, should not be read as guarantees of future performance or results, and will not necessarily be accurate indications of whether or not or the times at or by which such performance or results will be achieved. Please refer to the factors discussed under "Risk Factors" in the Company's Annual Information Form dated March 29, 2010 and the Company's registration statement on Form 10, as filed with the SEC, on July 21, 2010. Although the forward-looking statements contained in this news release are based upon what are believed to be reasonable assumptions, investors cannot be assured that actual results will be consistent with these forward-looking statements, and the differences may be material.

These forward-looking statements are made as of the date of this news release and, except as expressly required by applicable law, the Company assumes no obligation to update or revise them to reflect new events or circumstances.

FOR FURTHER INFORMATION PLEASE CONTACT:
        Atlantic Power Corporation
        Patrick Welch
        Chief Financial Officer
        (617) 977-2700
        info@atlanticpower.com
        www.atlanticpower.com

Source: Atlantic Power Corporation
Contact: Atlantic Power Corporation Patrick Welch Chief Financial Officer (617) 977-2700 info@atlanticpower.com www.atlanticpower.com