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Haynes and Boone

Diana Liebmann

Diana Liebmann



  • Energy Regulatory
  • Energy, Power and Natural Resources
  • Power and Renewables
  • Project Finance and Development

WSG Practice Industries


Haynes and Boone
Texas, U.S.A.

Diana Liebmann's legal advocacy and regulatory experience have helped clients through multiple restructurings of the electric power markets in Texas, to create the rules for the evolving ERCOT market - the most vibrant and competitive market in the country. Diana understands the risks inherent in certain transactions under constantly changing market rules and dynamics. She has represented clients in analyzing and structuring power supply arrangements for both wholesale and retail sales, including assisting LNG facilities with structuring power transactions. Diana works on both utility-scale generation project development and with smaller projects including end use consumers on-site and back-up generation. She was instrumental in developing the current postage stamp transmission pricing mechanism in the Competitive Renewable Energy Zone proceedings to obtain access to markets for their generation in a $6 billion transmission build-out of the ERCOT market, in interconnecting on-site generation both with ERCOT and transmission and distribution utilities.

Diana's broad transactional experience and in-depth focus on the details of wholesale and retail power regulation and market structure give her the ability to effectively guide clients with respect to structuring transactions, compliance, and in the investment and deployment of capital in electricity markets.

Diana leads the firm's Power and Renewables practice, is a partner in the Capital Markets and Securities practice, manages the San Antonio office as its managing partner and is a leader in her community.

Diana is valued as a leading energy lawyer by Chambers USA, Chambers and Partners, and is described as a "utilities guru" with a "great understanding of the Public Utility Commission." She has become a go-to lawyer for regulatory matters relating to the Public Utility Commission of Texas, the Electric Reliability Council of Texas, the Southwest Power Pool, the Federal Energy Regulatory Commission and in various other state commission, regional entity and North American Electric Reliability Corporation proceedings.

Bar Admissions

Texas; 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; District of Columbia Court of Appeals;


  • J.D., University of Texas School of Law, 1996
  • B.A., Political Science, minor in Chemistry, Southwestern University, 1993
Areas of Practice

Energy Regulatory | Energy, Power and Natural Resources | Power and Renewables | Project Finance and Development

Professional Career

Significant Accomplishments

Structured financial hedges for project financing.

Transmission Cost of Service (TCOS) applications.

Development of power supply arrangements for a LNG facility including generation supply and regulatory requirement applicable to same and power supply negotiations between the facility third party suppliers, customers, and retail electric providers and qualified scheduling entities.

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.

Regulatory investigation and complaint proceedings before the Public Utility Commission of Texas and Texas Regional Entity.

Force Majeure Issues Impacting the Power Sector
Haynes and Boone, April 2020

The power sector has responded rapidly to the Coronavirus pandemic by following Emergency Operations Plans, some of which specifically include responses to epidemics. The reliability of the grids across the United States have been maintained and power providers are necessary to the continued functioning of the country...

Texas PUC Issues Three Orders in Response to COVID-19 to Assist Residential Ratepayers
Haynes and Boone, March 2020

The Public Utility Commission of Texas (PUCT or Commission) issued three orders on March 26, 2020, establishing a new COVID-19 Electricity Relief Program for residential customers and modifying certain regulatory requirements applicable to retail electric providers (REPs) and electric utilities, including transmission and distribution utilities (TDUs)...

WSG's members are independent firms and are not affiliated in the joint practice of professional services. Each member exercises its own individual judgments on all client matters.

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