Atlantic Power Preferred Equity Ltd. — AGM Information 2020

May 4, 2020

Please be advised that the attached Meeting Notice is being refiled to remove the sample text that was included on the version filed on April 29, 2020 and to include additional information under the “PLEASE NOTE” section on page 2. No other changes have been made to this document.

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IMPORTANT ANNUAL MEETING INFORMATION

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Vote by Internet

• Go to www.investorvote.com/ATP

• Or scan the QR code with your smartphone

• Follow the steps outlined on the secure website

Atlantic Power Corporation Meeting Notice

Important Notice Regarding the Availability of Proxy Materials for the Atlantic Power Corporation Annual and Special Meeting of Shareowners to be Held on June 17, 2020

Under Securities and Exchange Commission rules, you are receiving this notice that the proxy materials for Atlantic Power Corporation’s annual meeting of shareowners are available on the Internet. Follow the instructions below to view the materials and vote online or request a copy. The items to be voted on and location of the annual meeting are on the reverse side. Your vote is important!

This communication is not a form of voting and presents only an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting. The proxy circular, form of proxy and 2019 annual report to shareowners are available at:

https://materials.proxyvote.com/04878Q

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Easy Online Access — A Convenient Way to View Proxy Materials and Vote

When you go online to view materials, you can also vote your shares. Step 1: Go to www.investorvote.com/ATP

Step 2: Click on the icon on the right to view current meeting materials.

Step 3: Return to the investorvote.com window and follow the instructions on the screen to log in. Step 4: Make your selection as instructed on each screen to select delivery preferences and vote.

When you go online, you can also help the environment by consenting to receive electronic delivery of future materials.

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Obtaining a Copy of the Proxy Materials – If you want to receive a copy of these documents, you must request one. There is no charge to you for requesting a copy. Please make your request for a copy as instructed on the reverse side on or before June 5, 2020 to facilitate timely delivery.

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Atlantic Power Corporation Meeting Notice

Atlantic Power Corporation’s Annual and Special Meeting of Shareowners will be held on June 17, 2020 virtually at https://web.lumiagm.com/279797129 at 10:00 a.m. Eastern Daylight Time.

Proposals to be voted on at the meeting are listed below along with the Board of Directors’ recommendations.

The Board of Directors recommends a vote FOR the following proposals:

1. Election of Directors.

   • Nominees:

     • R. Foster Duncan

     • Kevin T. Howell Danielle S. Mottor

     • Gilbert S. Palter

     • James J. Moore, Jr.

2. The approval, by non-binding advisory vote, of named executive officer compensation as described in the Circular.

3. The appointment of KPMG LLP as the auditors of the Corporation and the authorization of the Corporation’s Board of Directors to fix such auditors’ remuneration.

4. The approval of an ordinary resolution of the Shareholders, the full text of which is set forth in Schedule “B” to the Circular, authorizing the Corporation to amend its sixth amended and restated long-term incentive plan (the “LTIP”) to increase the number of Common Shares of the Corporation issuable under the LTIP, as more particularly described in the Circular.

PLEASE NOTE –YOU CANNOT VOTE BY RETURNING THIS NOTICE. To vote your shares you must vote online or request a paper copy of the proxy materials to receive a proxy card. To join and vote at the Meeting, go to https://web.lumiagm.com/279797129 with your 15-digit control number or user name and the password atlpow2020.

Note: Shareholders who wish to appoint a third party proxy holder to represent them at the online Meeting must submit their proxy or voting instruction form (if applicable) prior to registering the proxy holder. YOU MUST go to https://www.computershare.com/AtlanticPower prior to the Meeting and provide Computershare with the name and email address of the person you are appointing. Computershare will use this information ONLY to provide the appointee with a user name to gain entry to the online meeting. If the appointee’s information is not provided to Computershare prior to the Meeting, the appointee will need to login as a guest and will not be able to vote the shares during the Meeting.

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Here’s how to order a copy of the proxy materials and select a future delivery preference:

Paper copies: Current paper delivery requests can be submitted via telephone or email options below.

Email copies: Current email delivery requests must be submitted via the Internet following the instructions below. If you request an email copy of current materials you will receive an email with a link to the materials.

PLEASE NOTE: You must use the number in the shaded bar on the reverse side when requesting a set of proxy materials.

• g Internet – Go to www.investorvote.com/ATP. Follow the instructions to log in and order a copy of the current meeting materials and submit your preference for email or paper delivery of future meeting materials.

• g Telephone – Call us free of charge at 1-866-962-0498 to order a paper copy of the materials by mail for the current meeting.

• g Email – Send an email to info@atlanticpower.com with “Proxy Materials Atlantic Power Corporation” in the subject line. Include in the message your full name and address and state in the email that you want a paper copy of current meeting materials.

  • To facilitate timely delivery, all requests for a paper copy of the proxy materials must be received by June 5, 2020.

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