Mary Anne Sullivan

Mary Anne Sullivan

Senior Counsel
Washington, D.C.

Email maryanne.sullivan@​

Phone +1 202 637 3695

Fax +1 202 637 5910

Practice groupGlobal Regulatory

"Vastly experienced energy attorney and 'well placed to advise clients on the major issues currently affecting the industry.'"

Chambers Global

Change is driving every part of the energy industry, and the solutions to today's problems require broad perspective and insight. Mary Anne Sullivan's deep experience and her sharp focus on regulatory trends enable her to provide advice that is both shaped by an understanding of the interrelationships across energy markets and adapted to the demands of the future.

Mary Anne's practice spans the energy spectrum. With her past government service as general counsel of the U.S. Department of Energy and her knowledge of the industry, she uses regulatory tools to advance her clients' interests. Whether in the development of new electric transmission for low carbon energy, LNG projects, new nuclear reactor technology, advanced biofuels, novel approaches to demand response, offshore wind development, electric vehicles or new efficiency standards, Mary Anne helps her clients navigate the challenges and find the benefits in the inexorable move to lower carbon energy options. She is at her best when helping her clients tackle their "one off" problems and succeed in their first-of-a-kind projects.

Mary Anne regularly writes and speaks on energy issues. Recognition by her peers includes invited speaker at the 2015 World Sustainability Conference in Abu Dhabi; speaker at the American Wind Energy 2018 Annual Conference, selection as a C3E Ambassador for the DOE/MIT Women in Clean Energy Initiative; and member of the Oak Ridge National Laboratory Technology Partnerships Advisory Board.

Awards and recognitions


Climate Change (Nationwide)
Chambers USA

2015-2017, 2019-2020

Energy Regulation: Conventional Power
Legal 500 US


Energy: Nuclear (Regulatory & Litigation) (Nationwide)
Chambers USA


Honorary Doctor of Laws
Fordham University


Energy: Nuclear (Regulatory & Litigation) (USA)
Chambers Global

2007, 2013

Energy and Natural Resources
Washington, D.C. Super Lawyers


Energy: Electricity (Regulatory & Litigation) (USA)
Chambers Global


Distinguished Environmental Advocate
ABA Section on Environment, Energy and Resources


Energy: Electricity (Regulatory & Litigation) (Nationwide)
Chambers USA

Education and admissions


B.A., Fordham University, summa cum laude

J.D., Yale Law School


Board of Directors, Energy Bar Association

Member, Department of Energy Contractor Attorneys Association

Member, Energy and Environment Section, District of Columbia Bar Association

Bar admissions and qualifications

District of Columbia

Court admissions

U.S. Court of Appeals, District of Columbia Circuit

U.S. Court of Appeals, Ninth Circuit

U.S. District Court, District of Colorado

U.S. Supreme Court

Related knowledge

Internet of Things

Representative experience

Assisted in obtaining federal loans, loan guarantees and grants totaling billions of dollars.

Advising a government entity on the restructuring of its electricity sector.

Representing the largest New England utility in the permitting of a cross-border electric transmission line.

Advising on the first small modular nuclear reactor project in the U.S.

Negotiated the first voluntary agreements to limit greenhouse gas emissions.

Advises on nuclear export control regulations.

Advises on nuclear waste disposal issues.

Represents manufacturers in energy efficiency standards compliance and enforcement matters.

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