Diana Liebmann


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Education and Clerkships

J.D., University of Texas at Austin School of Law, 1996

B.A., Political Science, Minor in Chemistry, Southwestern University, 1993

Bar Admissions


District of Columbia

Court Admissions

U.S. District Court for the Western District of Texas

U.S. District Court for the Southern District of Texas

U.S. Court of Appeals for the Fifth Circuit


Diana Liebmann is a Partner in the Energy and Power Practice Group of Haynes and Boone, LLP. She represents clients in regulatory matters before and relating to the Public Utility Commission of Texas, the Electric Reliability Council of Texas, and the Southwest Power Pool and in various state commission proceedings. Diana represents clients in corporate and transactional matters including project development of both renewable and conventional generation, in drafting and negotiating power purchase agreements for both long-term and short-term sales including the sale of renewable energy credits and advising clients with regard to regulatory benefits and impediments to transactions. She also assists clients in litigation associated with conduct in the electric markets including litigation over power deals and litigation of market rules, protocols, and administrative investigations leading up to and including notices of violations. Diana has worked on regulatory matters, in rulemakings and contested cases, and completed transactional matters including:

  • Proceedings to establish rules for Competitive Renewable Energy Zones including related rulemakings and contested cases;
  • Proceedings to implement wholesale and retail restructuring at the State Office of Administration Hearings, the Public Utility Commission of Texas, at the Federal Energy Regulatory Commission and with the Electric Reliability Council of Texas;
  • Rulemakings regarding transmission access and pricing;
  • Competitive matters and confidentiality issues involving Open Records and Open Meetings laws;
  • Wholesale and retail power purchase and sale agreements, retail electric provider agreements, qualified scheduling entity agreements, qualified facility agreements, contracts with third parties regarding professional services, and power plant construction agreements; including EPC agreements, and power plant project finance documents;
  • Proceedings at ERCOT and the PUCT regarding ERCOT governance, congestion management, ancillary services, settlement, transmission and distribution losses, reliability must run, resource adequacy and market monitoring;
  • Litigation involving the application of the antitrust laws to the ERCOT market;
  • Sale of electric power facilities and generating assets; and
  • Regulatory investigation and complaint proceedings before the Public Utility Commission of Texas and Texas Regional Entity.


Best Lawyers

Best Lawyers in America 2015

Best Lawyers in America®, an annual referral guide listing outstanding lawyers throughout the U.S., has once again recognized Haynes and Boone, LLP lawyers. This year, 56 of the firm's practices were listed in the guide.

Published by Woodward/White, Inc. in August 2014

News and Publications

Professional and Community Activities

  • Member, Energy & Sustainability Committee, Greater San Antonio Chamber of Commerce (Chairman 2011-2013) 
  • Advisory Board Member, University of Texas Kay Bailey Hutchison Center for Energy, Law and Business 
  • Advisory Board Member, Greater San Antonio Chamber of Commerce 
  • Member, San Antonio Bar Association Natural Resources Section (President 2006-2009) 
  • Member, Oil, Gas & Energy Resources Section of the State Bar of Texas (Council Member 2009-2012) 
  • Member, Gulf Coast Power Association 
  • Director, Arc of San Antonio, Inc. (President 2004)


Chambers USA 2015

Chambers USA Recognizes 51 Haynes and Boone Lawyers

Fifty-one Haynes and Boone, LLP lawyers are recognized in the 2015 edition of the highly regarded Chambers USA directory of top lawyers and law firms.

Published by Chambers & Partners in May 2015

Professional Recognition

  • Selected for inclusion in Who's Who in Energy by the San Antonio Business Journal, American City Business Journals, 2012-2014 
  • Recognized by San Antonio Scene in 2015's Best San Antonio Lawyers for Energy & Oil & Gas, 2015 Scene Monthly LLC
  • Recognized by Chambers USA as one of the leading practitioners in Texas for energy, Chambers & Partner, 2011-2015
  • Named a Rising Star by Law360 as one of the top 10 energy lawyers under 40 to watch, Portfolio Media, Inc., 2010 
  • Named one of The Best Lawyers in America - Energy Law, Woodward/White, Inc., 2006-2015 
  • Named a Texas Super Lawyer Rising Star in Utility Law, Thomson Reuters, 2004-2008
  • Named a Texas Super Lawyer, Thomson Reuters, 2013-2014 
  • Listed as one of 2015's Best S.A. Lawyers in Energy & Oil & Gas (15 or more years), San Antonio Scene Magazine, Scene Monthly, LLC
  • Selected by the San Antonio Business Journal as one of its 40 Under 40 Rising Stars, American City Business Journals, 2008

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