Board of Directors

As Senior Vice-President, Power and Storage, Mr. Hessen is accountable for all aspects of the company’s power generation and unregulated natural gas storage businesses including strategy, commercial, business development, projects and operations.

Before joining TC Energy in August 2020, Mr. Hessen was Senior Vice-President, Fuels, at Constellation, an Exelon Corporation, where he directed Constellation’s natural gas and LNG businesses as part of America’s third-largest trading deck. Previously, Mr. Hessen was Vice-President and Managing Director, Generation Development for Exelon Generation where he led the successful origination and development of more than $3 billion of new power assets, representing approximately three gigawatts of new wind, solar, combined cycle gas, peaking gas and stoarge power capacity. Prior to joining Exelon, he worked for Xcel Energy, serving in multiple leadership positions in nuclear operations/engineering, fossil-fueled generation, information systems, strategy and innovation programs.

Mr. Hessen served as a director for Longview Power, NetPower, and Annova LNG, and his civic leadership has included the boards of directors for the Balitmore Leadership School for Young Women, Young Women’s Leadership Charter School of Chicago, Saint Ignatius Loyola Academy in Baltimore, and president of the board of directors of The Rise School of Denver.

Mr. Hessen holds a Master of Business Administration in Finance from the University of San Francisco and a Bachelor of Science in Civil Engineering from Marquette University. Mr. Hessen has held professional engineering licences in seven American states.

Don MacKinnon began his career at Ontario Hydro in 1971 and is a lineman by trade. His union activism began more than 30 years ago and has included 11 years as the Power Workers’ Union’s (PWU) Vice-President before becoming the President of PWU in 2000. He retired from this position in 2017.

Don has a reputation as a skilled and innovative negotiator who uses mutual gains approaches to achieve settlements that address business needs while fully respecting the rights and values of employees.

He is recognized as an authority on Ontario’s electricity system and with previous appointments to the Ontario Ministry of Energy Electricity Transition Committee and the Ontario Government Electricity Conservation and Supply Task Force.

He is a member of the Order of Ontario and a recipient of The Canadian Forces Medallion for Distinguished Service, the Queen Elizabeth II Diamond Jubilee Medal and in 2015 was named as the Electricity Human Resources Canada Winner of the Award of Excellence for Leader of the Year.

Juliann Edwards is the Vice-President of Energy Origination & Development at TC Energy, and in 2023 will be formally appointed to the Board of Directors of Bruce Power. 

Prior to TC Energy she worked at EnergySolutions, an Energy Capital Partners portfolio company, where she was the Vice-President of Nuclear Decommissioning. Juliann has 15 years of nuclear and fossil industry experience in the acquisition of commercial nuclear facilities, engineering, procurement, and construction of energy related projects. Prior to joining the EnergySolutions she was the Director of Business Development for the CB&I Sales team where she led Combined Cycle Project Development in the PJM as well as managing all strategic accounts in the Power Division. Prior to CB&I, she served as the Manager of Marketing and Communications for Generation mPower – Charlotte, NC. She began her career at Edgen Murray Corporation where she assisted in the launching of Edgen Murray’s first nuclear power ASME program and managed the sales team for the nuclear segment.

Currently, Mrs. Edwards is an active Steering Committee member for Women in Nuclear, Board member for RSRT where she actively raises money and awareness for Rett Syndrome Research Trust with the intent of helping irradiate Rett Syndrome, a disorder her daughter Lily was diagnosed with in 2017.  

Mr. Warner is an Executive Consultant with WSC International, LLC, a consortium of leadership executives and senior managers with extensive experience in the nuclear power industry.

WSC International’s background and areas of expertise include major organizational redesign work, station recovery, plant management, operations, engineering, maintenance and work management/outage improvement. Mr. Warner joined WSC International in 2010 and has worked with Tokyo Electric Power Company, Bruce Power of Canada, Constellation Energy, American Electric Power, and the Salt River Project.

Prior to joining WSC International, Mr. Warner held executive leadership roles with PECO Energy, AmerGen, Exelon and FPL Energy over his 27-year career. Mr. Warner has held roles in regional and site operations, plant acquisitions and improving underperforming nuclear generation assets. Under his leadership, two of the facilities received the highest rating from the Institute of Nuclear Power Operations, whose mission is to promote excellence in the operation of commercial nuclear power plants.

Mr. Warner is a member of the Nuclear Safety Task Force for Tokyo Electric Power Company (TEPCO). The task force consists of international members who advise the Nuclear Safety Oversight Office for the company on the Nuclear Reform Plan to recover the Nuclear Programs following the Fukushima accident.

Mr. Warner serves on the Board for The Borland Center for Performing Arts, and is the Executive Director for Palm Beach Community Church.

Mr. Warner holds a Bachelor’s Degree in Engineering, Cum Laude from Villanova University, and a Senior Reactor Operator Certification from Peach Bottom Atomic Power Station. He completed the Advanced Management Program at the Fuqua School of Business and the INPO Senior Nuclear Plant Management Course.

Prior to his career in the Nuclear Power Industry, Mr. Warner served in the U.S. Marine Corps for eight years.

Michael W. Rencheck was appointed the President and Chief Executive Officer of Bruce Power starting Aug. 15, 2016.

Over the past 30+ years, Mike has served in a number of roles and most recently was the Deputy Chief Operating Officer for AREVA overseeing its extensive Global capital portfolio of nuclear and renewable projects. Prior to this, he served as President and CEO of AREVA Inc. in North America leading its diverse nuclear services business in Canada and the United States with a workforce of about 5,000 people.

Prior to joining AREVA, Mike was the Senior Vice-President and Chief Nuclear Officer at American Electric Power (AEP). AEP is a major investor-owned electric utility in the United States, delivering electricity to more than 5 million customers in 11 states with 38,000 MWs of generation assets.

After joining AEP in 1998 as Vice-President of Nuclear Engineering, Mike held various positions during his tenure, including Senior Vice-President of Engineering, Projects and Field Services; Senior Vice-President of Engineering, Technical and Environmental Services; and President of AEP ProServ, a wholly-owned engineering and field services subsidiary responsible for major power generation projects and outage management.

Before joining AEP, Mike worked for Florida Power Corporation serving as Director, Nuclear Engineering and Projects for Crystal River Nuclear Station. Earlier in his career, Mike worked at Public Service Electric & Gas Company Salem Nuclear Generating Station as Director of System Engineering and Duquesne Light Company’s Beaver Valley Power Station.

In 2014, Mike was recognized by the National Safety Council for his leadership demonstrating a personal commitment to worker safety and health as part of “CEO’s who get it.” He also has demonstrated a commitment to many organizations that make a difference in people’s lives including Habitat for Humanity and United Way. He is a Professional Engineer and certified senior reactor operator.

In his role as Chief Investment Officer, Ralph is responsible for the global strategy across all of OMERS investment activities.

Ralph, who has more than 25 years of investment industry experience, joined OMERS in 2013. He previously served as Global Head of OMERS Capital Markets, leading a world-class team responsible for public market investments representing nearly half of OMERS net investment assets. Before that, he spent more than eight years with OMERS Infrastructure, including six as Executive Vice President and Global Head of Infrastructure overseeing the growth and management of a portfolio of high-quality assets that now extends across five continents. Under Ralph’s leadership, OMERS capital markets and infrastructure portfolios became significantly broader across sectors and geographies.

Prior to joining OMERS, Ralph was a Managing Director and the Head of the European Energy & Power Team at Credit Suisse, where he spent seven years advising clients in M&A, IPO and structured finance transactions. Before that, he worked in the Energy team at Deutsche Bank in New York and London for almost 12 years.

Ralph holds a Law degree from Universidad de Buenos Aires, and investment strategy, leadership and business qualifications from The Whatron School, IMD Business School and Emory University Goizueta Business School.   

Mr. Limbacher and two partners formed Meridian Energy in 2017.  The firm offers advisory services, senior management, and consulting on special situations for exploration and production companies in the oil and gas industry.

Mr. Limbacher served as Interim President and Executive Vice-President of Strategy for Alta Mesa Resources from January 2019 through May 2020, while Meridian also led restructuring and divestiture efforts in April of 2020.

Prior to forming Meridian, Mr. Limbacher was Vice Chairman of the Board of Directors and President and Chief Executive Officer of Samson Resources, where he was tasked with the turnaround the highly leveraged business.

Mr. Limbacher also served as a member of the Board of Directors for TC Energy from 2018-2022.

Mr. Limbacher’s career in the oil and gas industry began in 1980 as a production engineer with Conoco and was a reservoir and completions engineer with Superior Oil from 1982-1985. He joined Burlington resources in 1985 as a reservoir engineering supervisor and worked his way up to Executive Vice President and Chief Operating Officer (2002-2006) and a Member of the Board of Directors (2004-2006).

Mr. Limbacher has a Bachelor of Science in Petroleum Engineering from Louisiana State University.

As Vice-President, Bruce Power, Mr. Black is accountable for all aspects of TC Energy’s Bruce Power asset.

Before joining TC Energy, Mr. Black was the Chief Engineer at a consulting firm supplying services to the Canadian nuclear electric sector.  Prior to this he was a long-time employee at Ontario Power Generation and the former Ontario Hydro where he held progressively more responsible positions in plant design, operations and major project delivery culminating as the Director of Station Engineering at the Pickering nuclear facility.

Mr. Black is a longtime supporter and active participant with the Canadian Standards Association in their development of nuclear standards.  He is currently vice-chair of the CSA Nuclear Strategic Steering Committee which oversees nuclear facility standard development in Canada.

Mr. Black holds a Bachelor of Engineering (Mechanical) from Carleton University and is a licensed professional engineer in the Province of Ontario

In his role as Managing Director at OMERS, Steven is responsible for originating and leading the pursuit of energy assets, primarily in North America.

He has deep expertise in the energy sector, and since joining OMERS  in November 2003 he has led numerous transactions and had asset management responsibilities at Oncor Electric Delivery Company, MCV, Vento II and Bruce Power.

Prior to joining OMERS, Steven served as Chief Operating Officer at Enwave Energy, where he was responsible for overall operations and major infrastructure projects. Before that he worked with an international consulting firm primarily on transportation and energy-related projects.

Steven is a board member of Oncor, Bruce Power Inc., and CIEL. He has a BA (Mechanical Engineering) and M.Eng (Mechanical Engineering) from the University of Toronto and is a Professional Engineer.


We stand in solidarity with Black, Indigenous and People of Colour communities across the world in the unquestionable proclamation that their lives matter.

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