Board of Directors

The IESO is governed by an independent board of directors that oversees its business and affairs. The IESO Board also approves the Market Rules, policies and guidelines that govern the IESO-administered markets. There are three committees of the board: Audit Committee, Human Resources and Governance Committee, and Markets Committee.

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William (Bill) Sheffield, Chair

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Currently Mr. Sheffield, in addition to chairing the IESO Board, serves on several private company/family business boards: including Atlantic Packaging Products Ltd., [Ontario, Quebec, & USA], Gorman Bros Lumber Ltd [BC]. He also consults with family enterprises, currently Leder Holdings [AB], & De Havilland Aircraft of Canada [BC].

Previous directorships include Hydro One, Burnbrae Farms, Velan Inc., Victorian Epicure, Houston Wire & Cable, Longview Aviation Capital, 4iiii Innovations, Canada Post Corporation, Ontario Power Generation, Corby Distilleries, Sappi Ltd, Pan Asia Paper, Royal Group Technologies, Family Enterprise Canada, and SHAD.

He was the Interim President & CEO of Hydro One from June 2022 to January 2023 and is the former Chief Executive Officer of Sappi Fine Papers, headquartered in UK and South Africa. Previously, he held senior roles with Abitibi-Consolidated, including time in Iroquois Falls, Ontario leading the paper mills, woodlands, and private hydro and distribution facilities located there. He began his career in the steel industry at Stelco Inc.

Bill Sheffield has a Bachelor of Science (Chemistry) from Carleton University and an MBA from McMaster University. He holds a professional director certification from the Institute of Corporate Directors (ICD.D) and a similar designation from the National Association of Corporate Directors in the USA. He has also completed the Family Enterprise Advisors Program at the University of British Columbia and holds the designation, FEA.


Fiona Blondin

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Fiona is the Vice President of Indigenous Strategy at Cormorant Utility Services. Fiona joined the executive team at Cormorant to develop and implement a long-term strategy to promote and ensure the inclusion of Indigenous communities across Cormorant’s business units. She is developing and leading Cormorant’s vision to be the best-in-class partner for Indigenous nation building & wealth creation in the high voltage power, natural resources, and infrastructure project development.

Fiona, a member of the Yellowknives Dene First Nation in Northwest Territories, is the proud mother of three children. Building from this strong cultural foundation and family, she has made an impact in her ability to connect with First Nations, Métis, and Inuit people in unique and effective ways; always tailoring her approach and strategies to the customs and needs of the people she represents.

Fiona serves as a member of the board of directors at VIA HFR, which will be one of the largest transportation electrification infrastructure projects in Canadian history with frequent, accessible, and sustainable rail service between Toronto, Peterborough, Ottawa, Montreal, Trois-Rivières and Quebec City.

With over 25 years of combined experience in power, mining, public sector, and private consulting for First Nation, Inuit and Métis communities, Fiona brings a wealth of experience and understanding knowing that the best path forward in projects involving Indigenous communities is truly understanding and supporting the unique goals and vision for respective Indigenous nations.

Simon Chapelle

Simon Chapelle

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Simon Chapelle, is a former municipal councillor for the City of Kingston (2018-2020) and continues to serve as a community representative on the Kingston and Area Taxi Commission. In addition to his community service, Mr. Chapelle is a corporate director of The Chapelle Group, a consulting firm focusing on telecommunications and rural economic development.

Prior to serving on council, Mr. Chapelle was a member of the Parole Board of Canada, where he implemented policy directives and made risk-based decisions regarding the conditional release of federal offenders.

Mr. Chapelle gained governance and electricity sector experience serving on the boards of Sudbury Hydro and Kingston Hydro.

He holds a B.Sc. in biology from Laurentian University and a master of public administration degree from Queen’s University. In addition to years of specialty sales and marketing experience, Mr. Chapelle has formal training in risk-based decision making and alternative dispute resolution and holds his ICD.D designation as an Independent Corporate Director.

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Marni Dicker

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Marni is currently the Executive Vice President of Infrastructure and Chief Legal Officer for the Canadian Premier League. In this role, she spearheads the development of infrastructure that is critical to the continued growth of the Canadian soccer ecosystem. She also oversees the league’s legal affairs and works closely with the League Commissioner on expansion efforts.

Previously, Marni was Executive Vice President and General Counsel at Live Work Learn Play Inc., where she led the organization’s corporate and organizational growth, major infrastructure projects and anchored deals on large scale real estate projects across Ontario. She was also the Chief Commercial Officer and General Counsel at Infrastructure Ontario where she was also responsible for the organization’s board governance as the Corporate Secretary.

Marni is currently Vice Chair of the Board of Directors for Tarion Corporation and is a member of the Board of Directors for Create TO, Technical Standards and Safety Authority and Muskoka Algonquin Healthcare. She is also a Distinguished Visiting Scholar at Toronto Metropolitan University, where she devotes her time to the Faculty of Law.

Marni holds a Bachelor of Business Administration from Western University, two law degrees from McGill University and the ICD.D designation from the Institute of Corporate Directors.

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Lesley Gallinger

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Under her leadership, the IESO oversees the safe and reliable operation of Ontario's bulk electricity system, ensuring affordable electricity is available when and where people need it.

As part of its mandate to plan and prepare for the future, the IESO works with sector partners to identify energy needs, develop supply options, drive innovation, and harness data and information for decision-making. The IESO also delivers energy efficiency and demand management programs that contribute to the cost-effectiveness and reliability of Ontario’s power system.

Throughout her career, Ms. Gallinger has focused on driving strategic change within complex organizations to deliver shareholder and stakeholder value. Prior to joining the IESO, she served as President and Chief Executive Officer of Elexicon Energy, a large municipally-owned electricity distributor in Ontario, which she led through a sizeable merger integration. She has also held senior roles in the electricity sector that include Chief Strategy and Financial Officer at the Electrical Safety Authority as well as VP, Corporate and Regulatory Affairs and Chief Financial Officer at Oakville Hydro.

Ms. Gallinger sits on several boards, including the Ontario Energy Network where she serves as Vice Chair, and the Nuclear Waste Management Organization. Prior to joining the IESO she also served on the boards of the Ontario Energy Association and the Electricity Distributors Association. She holds a Master of Business Administration from the Schulich School of Business at York University, is a Chartered Professional Accountant and a Certified Public Accountant (Illinois). She has also completed the Chartered Director and Audit Committee Certified program at the DeGroote School of Business, McMaster University.

Peter McMullen

Peter McMullen

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Peter McMullen was born in Sudbury and has lived there for most of his life. He has received his C.P.A. in Ontario and Illinois and is a member of the Ontario Bar.

Mr. McMullen has held positions at the colleges of Laurentian University, as well as owned and operated a number of small businesses in retail, technology and engineering. As a member of the Greater Sudbury Utilities Board of Directors, he was the District Director for the Northeastern District on the Electricity Distributors Association and MEARIE boards. He was elected and served as a member of Municipal Council for the Municipality of Killarney, Ontario.

Mr. McMullen currently operates a combined accounting and legal practice in Sudbury.

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Tom Mitchell

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Tom has over 40 years of nuclear energy leadership experience. He began his tenure as Chair of the World Association of Nuclear Operators (WANO) in March 2019. WANO’s mission is excellence in nuclear safety and reliability, and all companies that operate a commercial nuclear power plant worldwide are members of WANO. He formerly served on the Board of Directors of FirstEnergy Corporation, and also as Chair of the Board’s Nuclear Committee and as a member of its Governance Committee.

He is the retired President, CEO, and Director of Ontario Power Generation in Canada. In that role, and as Chief Nuclear Officer, Tom was directly responsible for the safe, reliable, and cost-effective operation of 10 CANDU-design nuclear units with 6600 MW of capacity. Prior to this Tom was the senior site vice president of the 4 CANDU unit Pickering B station.

While at OPG, Tom oversaw the successful completion of several new hydroelectric projects including the Niagara Tunnel and the Upper and Lower Mattagami Projects, the conversion of Atikokan and Thunder Bay stations to use biomass as fuel, the Ontario transition from coal-fired power generation, and a major business transformation of the company’s size and cost structure.

Prior to his OPG experience, Tom had roles of increasing responsibility at Philadelphia Electric Company’s (now Exelon) Peach Bottom Atomic Power Station in Pennsylvania USA culminating in his appointment as Site Vice President.

Tom was Vice President of International Programs and Assistance at the US Institute of Nuclear Power Operations and served as Deputy Director of the WANO Atlanta Centre. While at OPG, Tom was a member of the Atlanta Centre Governing Board and its Chair from 2012 to 2015.

Tom has served on the Board of the US Electric Power Research Institute and was a member of the Leadership and Compensation Committee. He also has served on the Board of the US Nuclear Energy Institute and was Chair of the WANO Post-Fukushima Commission.

Tom has an undergraduate degree in nuclear engineering from Cornell University, a master degree in mechanical engineering from George Washington University, and an honorary doctorate degree from University of Ontario Institute of Technology. Tom has also completed the Corporate Director program at Rotman School of Management.


Fiona Oliver-Glasford

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Fiona is currently the Chief Operating Officer for ClearBlue Markets which supports client participation in compliance and voluntary carbon markets with advisory and market analysis services.

Fiona has specialized at the intersection of energy and climate for more than 20 years. She has held numerous roles within the energy efficiency and demand management sectors, including positions at Canadian Energy Efficiency Alliance, Clean Air Foundation, Summerhill Group, Union Gas and Enbridge.

At Enbridge, Fiona led the Energy Transition portfolio, including governance, strategy development, implementation of the cap-and-trade portfolio and transition to the federal carbon pricing program.

After leaving Enbridge, Fiona spent some time at Sasol Energy South Africa, as the Vice President of Low Carbon Energy Solutions.

Fiona has served as a member of the Board of Directors for several organizations including the Clean Energy Transition Fund, Energy Storage Canada and the Canadian Biogas Association.

Fiona holds a Bachelor of Arts in Business from Western University and a Master of Business Administration Degree from the Schulich School of Business at York University.

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Robert Wong

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Robert Wong was the Chair of the Broader Public Sector (BPS) Cyber Security Expert Panel, that reported to the Minister of Public and Business Service Delivery for the Province of Ontario, providing advice and recommendations to strengthen the digital resilience and enhance the cyber security posture of BPS partners.

He is also the Principal of Hesketh Sloane Advisory, an executive consulting and advisory services provider specializing in the areas of corporate governance, strategy, enterprise risk management, information technology, cyber security, operations, and performance management.

Robert was the former Executive Vice-President, Chief Information Officer at Toronto Hydro-Electric System Limited. He had held the senior IT role since 2010 and was responsible for the overall delivery of information technology services for the organization, including operational technology, cyber security, and telecommunications. He had also held the role of Chief Risk Officer, having developed and implemented Toronto Hydro’s Enterprise Risk Management system, and had responsibility for strategic planning, corporate governance, performance measurement, and business continuity. Having been with the organization for over 32 years, he has extensive industry experience in the electrical distribution operations areas of the business and working with the company’s board of directors.

Robert had also served as a member of the Board of Directors, Finance and Audit, and Research Committees of Canadian Cyber Threat Exchange (CCTX).

A professional engineer with a Bachelor of Applied Science Degree in Electrical Engineering from the University of Toronto, Robert also holds a Master of Business Administration Degree from the Schulich School of Business at York University, and the Chartered Director (C.Dir.) designation from The Directors College (a collaboration between McMaster University and The Conference Board of Canada).