The Corporation is authorized to issue an unlimited number of Common Shares. As of the date of this Information Circular and Proxy Statement, there were 115,229,497 Common Shares outstanding.

              At the Meeting, each Shareholder of record at the close of business on April 24, 2017, the record date established for the Notice of Meeting and for voting at the Meeting (the " Record Date "), will be entitled to one vote for each Common Share held on all matters proposed to come before the Meeting. At the close of business on the Record Date, there were 115,229,497 Common Shares outstanding and entitled to be voted at the Meeting.

              To the knowledge of the Board of Directors, there are no persons that beneficially own or exercise control or direction over Common Shares carrying approximately 10% or more of the votes attached to the issued and outstanding Common Shares. For more information, please see the section entitled "Security Ownership of Certain Beneficial Owners and Management" in this Information Circular and Proxy Statement.

CORPORATE GOVERNANCE AND COMMITTEES OF THE BOARD

              The Corporation is pleased to make the following disclosures regarding its corporate governance practices pursuant to National Policy 58-201—Corporate Governance Guidelines, National Instrument 58-101—Disclosure of Corporate Governance Practices, and Item 407 of Regulation S-K and other applicable rules of the U.S. Securities and Exchange Commission (the "SEC") and NYSE rules:

•

Directors are elected by Shareholders at the Corporation's annual general meeting, which is generally held in June of each year. Each Director holds office until the next annual meeting of the Shareholders or until his or her successor is elected or appointed. At the annual general and special meeting of Shareholders held on June 29, 2010, Shareholders approved, among other things, changes to the Corporation's Articles reducing the minimum Canadian residency requirement for Directors from 50% to 25%.



•

Under the Corporation's independence standards and under the NYSE corporate governance rules and National Policy 58-201—Corporate Governance Guidelines, a majority of the Board of Directors must qualify as "independent directors." At least annually, the Board of Directors is required to

7

Table of Contents

evaluate all relationships between the Corporation and each Director in light of relevant facts and circumstances for the purposes of determining whether a material relationship exists that might signal a potential conflict of interest or otherwise interfere with such Director's ability to satisfy his or her responsibilities as an independent Director. The Board of Directors has determined that each of Irving R. Gerstein, R. Foster Duncan, Kevin T. Howell, Holli C. Ladhani, Gilbert S. Palter, and Teresa M. Ressel (who will not stand for re-election at the Meeting), is currently an independent Director.

•

The non-independent member of the Board of Directors is James J. Moore, Jr. Mr. Moore is the President and Chief Executive Officer of the Corporation.



•

Two Directors also serve as directors on the boards of other reporting issuers (or the equivalent in other jurisdictions). Mr. Gerstein serves as a director on the boards of Medical Facilities Corporation and Student Transportation Inc., and Mr. Palter serves as a director on the board of RPX Corporation.



•

The independent members of the Board of Directors meet regularly without management present.



•

The Chair of the Board of Directors, Mr. Gerstein, is an independent Director. Mr. Gerstein's responsibilities include establishing, in consultation with the Chief Executive Officer of the Corporation, the Directors and appropriate members of management, the agendas for each meeting of the Board of Directors. The agenda for each committee meeting is established by the Chair of that committee in consultation with appropriate members of the committee and management.

              Each Director attended at least 75% of the aggregate of (i) the total number of meetings of the Board of Directors (held during the period for which he or she has been a Director) and (ii) the total number of meetings of all committees of the Board of Directors on which the Director served (during the periods that he or she served).

              The Corporation does not have a policy of requiring its Directors to attend the annual general meeting of Shareholders. The Chair of the Board of Directors is expected to attend and chair meetings of the Shareholders. All eight of the Directors then serving attended the annual meeting held on June 21, 2016.

              The Board of Directors meets as necessary, but no fewer than four times each year: three meetings to review quarterly results and one meeting prior to the issuance of the annual audited financial results of the Corporation. In addition, the Board of Directors generally meets annually in December to discuss the annual budget and in February to discuss the annual strategy and director education (and more frequently if required). The committees of the Board of Directors meet as required by their respective charters. During 2016, the Board of Directors met 15 times.

              The Board of Directors has established four committees:

•

the Audit Committee;



•

the Compensation Committee;

8

Table of Contents

•

the Nominating and Corporate Governance Committee; and



•

the Operations and Commercial Oversight Committee.

              The chart below identifies the members and chair of each committee at the end of 2016 and the number of meetings held by each committee:

              Audit Committee.     The Audit Committee's primary purposes are to, among other things: (i) assist the Board of Directors in its oversight and supervision of the integrity of the accounting and financial reporting practices and procedures, the implementation and adequacy of the internal accounting controls and procedures and the compliance with legal and regulatory requirements in respect of financial disclosure; (ii) assess and monitor the strategic, operating, reporting and compliance risks of the business; and (iii) supervise the qualification, independence and performance of independent accountants of the Corporation.

              Compensation Committee.     The Compensation Committee's primary purposes include: (i) discharging the responsibilities of the Board of Directors relating to compensation of the Chief Executive Officer and other officers; (ii) evaluating the Corporation's compensation plans, policies and programs, taking into account factors it deems appropriate from time to time, including those that are of strategic significance to the Corporation, the degree of risk to the Corporation and its business those plans and policies may imply, and the results of non-binding Shareholder votes with respect to such matters; and (iii) reviewing and discussing with the Corporation's officers the Statement of Executive Compensation, including the Compensation Discussion and Analysis (" CD&A "), to be included in the Corporation's annual information circular and proxy statement and determining whether to recommend to the Board of Directors that the CD&A be included in the information circular and proxy statement. The Compensation Committee may form and delegate its authority to subcommittees consisting of one or more members of the Committee when appropriate. The Compensation Committee did not delegate any of its authority in 2016.

9

Table of Contents

              The Compensation Committee periodically utilizes the services of Pearl Meyer & Partners (" Pearl Meyer "), an independent compensation consultant, to assist it in reviewing its compensation program. The Compensation Committee reviewed and considered the information and advice provided by Pearl Meyer, among other factors, in making its executive compensation recommendations.

              In 2016, Pearl Meyer advised the Compensation Committee in regards to the short-term and long-term incentive awards and compensation market data for the Corporation's named executive officers. Pearl Meyer was directly engaged by the Compensation Committee and management had no role in engaging their consultation. Pearl Meyer did not provide any services to the Corporation other than those provided to the Compensation Committee.

              Nominating and Corporate Governance Committee.     The Nominating and Corporate Governance Committee's primary purposes are to, among other things: (i) screen and identify individuals who are qualified to become members of the Board of Directors; (ii) recommend to the Board, director nominees to be presented for Shareholder approval at the annual meetings of the Shareholders of the Corporation; (iii) recommend to the Board of Directors nominees to fill vacancies on the Board of Directors or as otherwise required outside of the annual meetings of Shareholders of the Corporation; (iv) select, or recommend to the Board of Directors, the Directors to comprise the committees of the Board of Directors; (v) implement a process for examining the size of the Board of Directors and to undertake, where appropriate, a program to establish a Board size which facilitates effective decision-making; (vi) establish procedures for the nomination of Directors and executive officers of the Corporation generally; (vii) establish and administer an annual assessment process relating to the performance of the Board of Directors as a whole, the committees of the Board of Directors and individual Directors; (viii) review with the Board of Directors from time to time the appropriate skills and characteristics required of Directors in the context of the current make-up of the Board of Directors, including issues of diversity, age, skills relating to the Corporation's businesses and professional background; (ix) recommend to the Board of Directors procedures for the conduct of Board meetings and the proper discharge of the Board of Directors' mandate as set out in the mandate of the Board of Directors; (x) monitor the relationship between the officers and the Board of Directors with a view to ensuring that the Board of Directors is able to function independently of officers; (xi) develop the Corporation's approach to governance, including the development of a set of governance principles and guidelines that are specifically applicable to the Corporation; (xii) perform a leadership role in shaping the Corporation's corporate governance practices and provide oversight with respect to its corporate governance conduct; and (xiii) perform such other functions as the Board of Directors may from time to time request.

              In identifying, evaluating, and recommending suitable Director candidates, the Nominating and Corporate Governance Committee may take into account a number of factors, such as the appropriate skills and characteristics required of Directors in the context of the current make-up of the Board of Directors, including issues of diversity, skills relating to the Corporation's businesses and professional background and existing commitments to outside boards. Pursuant to its charter, the Nominating and Corporate Governance Committee, in considering the extent to which the membership of a candidate on the Board of Directors would promote diversity among the Directors, may take into account various factors and perspectives, including differences of viewpoint, professional experience, education, skill and other individual qualities and attributes as well as race, gender and national origin. It is the Corporation's practice to retain an outside recruiting firm to identify a wide range of candidates for review and consideration and to assist in the evaluation process. The Nominating and Corporate Governance Committee has not formally adopted any specific, minimum qualifications that

10

Table of Contents

must be met by each candidate for the Board of Directors, nor are there specific qualities or skills that are necessary for one or more of the members of the Board of Directors to possess. The Nominating and Corporate Governance Committee believes that candidates and nominees must reflect a Board of Directors that is comprised of Directors who have competencies, skills and personal qualities required of Board members in light of relevant factors, including: (1) the objective of adding value to the Corporation in light of the opportunities and risks facing the Corporation and the Corporation's proposed strategies; (2) the need to ensure that a majority of the Board of Directors is comprised of individuals who meet the independence requirements of the applicable securities legislation and stock exchanges or other guidelines, including the Corporation's categorical standards for Director independence; and (3) the policies of the Board of Directors with respect to board member tenure, retirement and succession and Board member commitments.

              It is the policy of the Nominating and Corporate Governance Committee to review and consider any director nominees who have been recommended by Shareholders in the same manner as described above. All Shareholder recommendations for director nominees must be submitted to the Corporate Secretary at Atlantic Power Corporation, 3 Allied Drive, Suite 220, Dedham, Massachusetts 02026 in accordance with the procedures of the Advance Notice Policy (discussed below).

              Operations and Commercial Oversight Committee.     The Operations and Commercial Oversight Committee's primary purposes include: (i) assisting the Board of Directors in discharging its responsibilities with respect to oversight of the Corporation's plant fleet operations, investment decisions in these plants, divestiture of plants, acquisition of additional assets and the capital required to support the plant fleet; (ii) examining the commercial aspects of the plants including power purchase agreements, re-contracting activity and the associated commercial relationships with customers, and (iii) assessing and monitoring the operating risks of the business.

Committee Charters and Corporate Governance Guidelines

              Each of the Audit Committee, the Compensation Committee, the Nominating and Corporate Governance Committee, and the Operations and Commercial Oversight Committee operates pursuant to its respective charter, a copy of which is available on the Corporation's website at www.atlanticpower.com under "ABOUT US—Leadership—Board Committees." A copy of the Corporate Governance Guidelines is available on the Corporation's website at www.atlanticpower.com under "ABOUT US—Corporate Governance Guidelines." Information contained on the Corporation's website or that can be accessed through the Corporation's website is not incorporated into and does not constitute a part of this Information Circular and Proxy Statement. The Corporation has included its website address only as an inactive textual reference and does not intend it to be an active link to its website.

Board Leadership Structure

              The Charter of the Board of Directors requires the Chair of the Board of Directors to be an independent director, as it was determined it would be beneficial to have an independent Chair whose sole responsibility is leading the Board of Directors, leaving the Chief Executive Officer's main focus on the Corporation's business goals and promoting both short-term and long-term growth. Currently, Mr. Gerstein serves as the Chair of the Board of Directors. The Chair

11

Table of Contents

is expected to attend and chair meetings of the Board of Directors and Shareholders. The Chair ensures that the Board of Directors carries out its responsibilities effectively and the Board of Directors understands the boundaries between Board of Directors and management responsibilities. The Chair is also responsible for providing direction with respect to the dates and frequency of Board of Directors meetings and related committee meetings. The Chair liaises with the Chief Executive Officer to prepare Board of Directors meeting agendas.

              Directors who qualify as "non-management" within the meaning of the NYSE rules meet on a regular basis in executive sessions without management participation and, at least once per year, an executive session is held with only independent directors present. The executive sessions are chaired by the Chair of the Board of Directors. In addition, the Audit Committee, Compensation Committee, Nominating and Corporate Governance Committee and Operations and Commercial Oversight Committee, all of which are comprised entirely of independent Directors, also perform oversight functions independent of management.

Board Mandate

              The mandate of the Board of Directors is included as Schedule "A" to this Information Circular and Proxy Statement.

Position Descriptions

              Position descriptions for the Chair of the Board of Directors, the Chair of the Audit Committee, the Chair of the Compensation Committee, the Chair of the Nominating and Corporate Governance Committee, the Chair of the Operations and Commercial Oversight Committee and the Chief Executive Officer of the Corporation have been developed by the Corporation as previously disclosed by the Corporation in its 2014 Information Circular and Proxy Statement.

Orientation and Continuing Education

              The Corporation, working with the Directors, will provide orientation opportunities for new Directors to familiarize them with the role of the Board of Directors, its committees, and its Directors, as well as the Corporation and its business. All new Directors will participate in an orientation program soon after the date on which a new Director first joins the Board of Directors. To date, the majority of directors have visited power projects of the Corporation to obtain an understanding of the operations of the Corporation. In addition to operational orientation, management has scheduled periodic presentations for the Board of Directors to ensure they are aware of major business trends and industry practices as and when required.

Ethical Business Conduct

              The Board of Directors has adopted a written code of business conduct and ethics for the Corporation (the " Corporate Code "), which sets out basic principles to guide all Directors, officers and employees of the Corporation and its subsidiaries, and a written code of business conduct and ethics for the Chief Executive Officer and senior financial officers (the " Officer Code " and, together with the Corporate Code, the " Codes "), which sets out basic principles to guide the Chief Executive Officer and the senior financial officers of the Corporation.

              The issues the Corporate Code addresses include, among other things, the following:

(a)

compliance with laws, rules and regulations;

12

Table of Contents

(b)

conflicts of interest;



(c)

confidentiality;



(d)

corporate opportunities;



(e)

protection and proper use of Atlantic Power Entity (as defined in the Corporate Code) assets;



(f)

competition and fair dealing;



(g)

gifts and entertainment; and



(h)

reporting of any illegal or unethical behavior.

              The issues the Officer Code addresses include, among other things, the following:

(i)

conflicts of interest;



(j)

full, fair, accurate, timely and understandable disclosure in reports and documents;



(k)

compliance with laws, rules and accounting standards;



(l)

reporting of violations of law or the Officer Code;



(m)

confidentiality;



(n)

sharing and maintenance of knowledge and skills; and



(o)

promotion of ethical behavior.

              To ensure the Directors exercise independent judgment in considering transactions, agreements or decisions in respect of which a Director or officer has declared a material personal interest (in accordance with relevant corporate law requirements), the Board of Directors follows a practice whereby any such individual must not cast a vote on any such matter.

              The senior officers of the Corporation and the Chair of the Audit Committee are responsible for monitoring compliance with the Corporate Code and the Officer Code, respectively, and are required to report to the Board of Directors or the Audit Committee, respectively, on any issues that have arisen under the applicable Code. Any waivers from the requirements in the Codes that are to be granted for the benefit of the Directors, managers or executive officers of the Corporation are to be granted by the Directors only (or a committee of the Board of Directors to whom that authority has been delegated) and will be promptly disclosed as required by law or stock exchange regulation.

              At least annually, the Board of Directors reviews the adequacy of the Codes.

              The Codes are available on the Corporation's website at www.atlanticpower.com under "ABOUT US—Codes of Conduct" and under the Corporation's profile on the System of Electronic Document Analysis and Retrieval (" SEDAR ") at www.sedar.com. Information contained on the Corporation's website or that can be accessed through the Corporation's website is not incorporated into and does not constitute a part of this Information Circular and Proxy Statement. The Corporation has included its website address only as an inactive textual reference and does not intend it to be an active link to its website.

13

Table of Contents

              The Corporation's Whistleblower Policy is administered by the Chair of the Audit Committee. Any person may confidentially report complaints or concerns directly to the Chair of the Audit Committee. Confidentiality of complaints or concerns received by the Chair of the Audit Committee will be maintained to the fullest extent possible, consistent with the need to conduct an appropriate review.

Risk Oversight

              The Audit Committee receives and discusses a risk assessment update each quarter which is reviewed and discussed with management prior to the Audit Committee's recommendation to the Board of Directors to approve quarterly and annual financial disclosures. In addition, the Operations and Commercial Oversight Committee receives periodic operations reports about each of the Corporation's projects. The risk assessment update and operations reports are also made available to the Board of Directors in order to provide the opportunity for all Directors to inquire of management about any potential issues identified.

Assessments

              The charter of the Nominating and Corporate Governance Committee includes establishing and administering an annual assessment process relating to the performance of the Board of Directors as a whole, each committee of the Board of Directors and individual Directors, including the size and composition of the Board of Directors. The Audit, Compensation and Operations and Commercial Oversight Committees also administer annual assessments to analyze the performance and effectiveness of each of those committees.

Director Term Limits

              Each Director holds office until the next annual meeting of the Shareholders or until his or her successor is elected or appointed. The Board of Directors does not impose term limits on its Directors as it does not believe that arbitrary limits on the number of consecutive terms a Director may serve or on the Directors' ages are appropriate in light of the substantial benefits resulting from a sustained focus on the Corporation's business, strategy and industry over a significant period of time, without assuring increased independence. Accordingly, the Board's assessment of independence is of prime importance to ensure that retention of experience does not result in a failure to retain a sufficient number of independent Directors. The Board of Directors relies on thorough Director assessment procedures for evaluating its members (including their independence), and uses rigorous identification and selection processes for new directors, having regard to a variety of factors. In addition, to be identified as independent, a Director must be determined to be independent both in character and in judgment and free from any relationships or circumstances which are likely to affect, or could appear to affect, their judgment. Particular scrutiny is applied in assessing the continued independence of Directors having served more than nine years, with attention to ensuring that their tenure has not in any way eroded their independence and that their allegiance remains clearly with shareholders.

              Through these processes, the Board of Directors believes that it is well-positioned to address any problems or deficiencies that may arise as well as evaluate independence of Directors in an appropriate manner without having to adopt mandated term limits.

14

Table of Contents

Representation of Women on the Board and in Executive Officer Positions

              While the Corporation supports the principle of diversity in its leadership, of which gender is an important aspect, the Corporation has not formally adopted a policy or targets regarding the representation of women on the Board of Directors or in its senior management, as the Corporation does not believe that quotas or strict rules necessarily result in the identification or selection of the best candidates. Rather, the identification and selection process is made based on a variety of factors, such as differences of viewpoint, professional experience, education, skill and other individual qualities and attributes, including race, gender and national origin, as well as the requirements of the Board of Directors and senior management at the time. In addition, in identifying, evaluating and recommending suitable Director candidates, the Nominating and Corporate Governance Committee will take into account the criteria described under the section entitled "Corporate Governance Disclosure—Nominating and Corporate Governance Committee" of this Information Circular and Proxy Statement. Accordingly, in searches for new Directors and executive officers, the Corporation will consider the level of female representation and diversity on the Board of Directors and in its senior management and this will be one of several factors used in its search process.

              Following the Meeting and assuming all of the nominees for Director are elected as contemplated in this Information Circular and Proxy Statement, one of the six Directors on the Board of Directors will be a woman (representing approximately 17% of the Directors). As of the date hereof, none of the Corporation's three executive officers are women.

Communications with the Board of Directors

              Shareholders and other interested parties who wish to communicate with the Chair of the Board of Directors or independent Directors as a group, may do so by writing to them at Name(s) of Director(s)/Independent Directors of Atlantic Power Corporation, c/o Corporate Secretary, Atlantic Power Corporation, 3 Allied Drive, Suite 220, Dedham, Massachusetts 02026.

MATTER 1: ELECTION OF DIRECTORS

              The number of Directors to be elected at the Meeting is six. The persons named in the accompanying Form of Proxy will vote such proxy in accordance with the instructions contained therein. Unless contrary instructions are specified, if the accompanying Form of Proxy is executed and returned (and not revoked) prior to the Meeting, the Common Shares represented by the Form of Proxy will be voted for the election, as Directors, of the proposed nominees whose names are set out below. If a Director is unable to stand for election, the persons named in the enclosed Form of Proxy reserve the right to vote for another nominee at their discretion. Each nominee elected as a Director will hold office until the next annual meeting of the Shareholders or until his or her successor is elected or appointed.

Majority Voting Policy

              The Board of Directors has adopted a majority voting policy. Under this policy, a Director in an uncontested election who receives more votes withheld than cast in favour of his or her election will be required promptly to tender his or her resignation to the Chair of the Board of Directors following the applicable meeting of the Corporation's Shareholders. The resignation

15

Table of Contents

will be effective when accepted by the Board of Directors. The Nominating and Corporate Governance Committee of the Board of Directors will consider whether or not to accept the offer of resignation and will recommend to the Board of Directors whether or not to accept the resignation. A Director who tenders his or her resignation pursuant to the majority voting policy is not permitted to participate in any meeting of the Board of Directors and/or Nominating and Corporate Governance Committee at which his or her resignation is to be considered. With the exception of special circumstances that would warrant the continued service of the applicable Director on the Board of Directors, the Nominating and Corporate Governance Committee expects that resignations will be recommended for acceptance and accepted by the Board of Directors. Within 90 days following the applicable meeting of the Shareholders, the Board of Directors will make a decision on the Nominating and Corporate Governance Committee's recommendation. The Board of Directors will promptly announce its decision (including, if applicable, the reasons for not accepting any resignation) via press release in accordance with applicable securities laws, rules and regulations.

Advance Notice Policy

              The Corporation has adopted an advance notice policy (the " Advance Notice Policy "), which requires advance notice to the Corporation in circumstances where nominations of persons for election to the Board of Directors are made by Shareholders other than pursuant to: (i) a proposal made in accordance with the British Columbia Business Corporations Act (" BCBCA "); or (ii) a requisition of the Shareholders made in accordance with the BCBCA. Among other things, the Advance Notice Policy fixes a deadline by which Shareholders must submit director nominations to the corporate secretary of the Corporation prior to any annual or special meeting of Shareholders and sets forth the specific information that a Shareholder must include in such notice for an effective nomination to occur. Pursuant to the Advance Notice Policy, no person will be eligible for election as a director of the Corporation unless nominated in accordance with the provisions of the Advance Notice Policy.

              Pursuant to the Advance Notice Policy, in the case of an annual meeting of Shareholders, notice to the Corporation must be made not less than 30 nor more than 65 days prior to the date of the annual meeting; provided, however, that in the event that the annual meeting is to be held on a date that is less than 50 days after the date on which the first public announcement of the date of the annual meeting was made by the Corporation, notice may be made not later than the close of business on the 10th day following such public announcement. In the case of a special meeting of Shareholders (which is not also an annual meeting), notice to the Corporation must be made not later than the close of business on the 15th day following the day on which the first public announcement of the date of the special meeting was made.

Information Regarding Director Nominees

              Effective at this year's annual meeting, the number of directors will be reduced to six from seven, consistent with the Corporation's continuing focus on costs. The following table sets forth the names of, and certain information for, the individuals proposed to be nominated for election as Directors. The six nominees all currently serve on the Board of Directors. Teresa M. Ressel will not stand for reelection at the Meeting. Biographies for each nominee, which include

16

Table of Contents

a summary of each nominee's age, positions with the Corporation, principal occupation and employment within the five preceding years, are set out below.