June 16, 2016 DEDHAM, Mass. - Atlantic Power Corporation Announces Substantial Issuer Bid /PRNewswire -- Atlantic Power Corporation (NYSE: AT) (TSX: ATP) ("Atlantic Power" or the "Company") announced today that its Board of Directors has approved a substantial issuer bid (the "Offer") pursuant to which the Company will offer to purchase for cancellation up to US$65 million aggregate principal amount of the Company's issued and outstanding 5.75% Series C Convertible Unsecured Subordinated Debentures maturing June 30, 2019 (the "Debentures").

The purchase price under the Offer is US$965 in cash per US$1,000 principal amount of Debentures. Holders of Debentures (each, a "Debentureholder") who tender and do not withdraw their Debentures under the Offer will receive a cash payment in respect of all accrued and unpaid interest on such debentures up to, but excluding, the date they are taken up by the Company pursuant to the Offer.

The Debentures are listed and posted for trading on the Toronto Stock Exchange (the "TSX") under the symbol "ATP.DB.U". On June 15, 2016, the last full trading day prior to the announcement by the Company of the approval of the Offer by its directors, the closing price per Debenture on the TSX was US$928. As of June 15, 2016, there was US$105.3 million principal amount of Debentures issued and outstanding.

Certain institutional Debentureholders have agreed, pursuant to lock-up agreements with the Company dated June 16, 2016, to tender an aggregate of approximately US$29.7 million principal amount of Debentures held by them to the Offer.

If the principal amount of the Debentures tendered and not withdrawn under the Offer exceeds in the aggregate US$65 million (or such larger principal amount as determined by the Company), such debentures to be purchased by the Company will be subject to pro-ration.

The Company will fund any purchases of Debentures pursuant to the Offer from available cash on hand. Management of the Company believes that repurchases of the Debentures will create value for the Company's shareholders by reducing the Company's cash interest payments, de-levering its balance sheet and improving its debt maturity profile.

The Offer is not conditional upon any minimum number of Debentures being deposited, but is subject to various other conditions as detailed in the formal offer to purchase, issuer bid circular and the related letter of transmittal, containing the terms and conditions of the Offer and instructions for depositing such debentures (the "Offer Documents"). The Offer Documents will be mailed to registered Debentureholders on June 17, 2016 and will be filed with the applicable securities regulators and available on SEDAR at www.sedar.com and on EDGAR at www.sec.gov.

Alexander Capital Group Inc. ("Alexander Capital") was engaged by the Company as the independent valuator to prepare a formal valuation of the Debentures in accordance with applicable Canadian securities laws (the "Valuation"). The Valuation contains Alexander Capital's opinion that, based on the scope of its review and subject to the assumptions, qualifications and limitations provided therein, as of June 15, 2016, the fair market value of the Debentures falls within the range of US$930 to US$970 per US$1,000 principal amount of Debentures. A copy of the Valuation will be attached to the Offer Documents.

The Offer will commence on June 17, 2016 and expire at 5:00 pm (Toronto time) on July 22, 2016 (the "Expiration Date"), unless extended, varied or withdrawn by the Company.