Mary Anne Sullivan | Washington, D.C. | Hogan Lovells

Mary Anne Sullivan

Senior Counsel Global Regulatory

Sullivan Mary Anne

Mary Anne Sullivan
Sullivan Mary Anne
  • Overview
  • Experience
  • Credentials
  • Insights and events
quote mark

"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 and technology advances 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, carbon capture, new nuclear reactor technology, hydrogen, 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.

quote mark

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

Chambers Global

Representative experience

Assisted on dozens of projects involving federal loans, loan guarantees and financial assistance awards, across a broad array of energy technologies, totaling billions of dollars.

Advises clients on the structuring of and compliance with R&D agreements with national laboratories.

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 and nuclear waste disposal issues.

Represents manufacturers in energy efficiency standards compliance and enforcement matters.


  • B.A., Fordham University, summa cum laude
  • J.D., Yale Law School
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
  • Board of Directors, Energy Bar Association
  • Member, Department of Energy Contractor Attorneys Association
  • Member, Energy and Environment Section, District of Columbia Bar Association


Climate Change (Nationwide)

Chambers USA

Energy Regulation: Conventional Power

Legal 500 US

2015-2017, 2019-2020
Energy: Nuclear (Regulatory & Litigation) (Nationwide)

Chambers USA

Honorary Doctor of Laws

Fordham University

Energy: Nuclear (Regulatory & Litigation) (USA)

Chambers Global

Energy and Natural Resources

Washington, D.C. Super Lawyers

2007, 2013
Energy: Electricity (Regulatory & Litigation) (USA)

Chambers Global

Distinguished Environmental Advocate

ABA Section on Environment, Energy and Resources

Energy: Electricity (Regulatory & Litigation) (Nationwide)

Chambers USA