Donna Byrne

Donna focuses her practice on representing electric power and natural gas market participants in proceedings before FERC and in the federal courts. Her representation in complex commercial disputes includes litigation in connection with the California energy crisis, issues related to Regional Transmission Organization withdrawal, issues related to federal pre-emption and the filed-rate doctrine, among other areas. Donna has represented clients seeking FERC approval for transactions covered by FPA section 203, has led matters involving FPA section 205 approvals, and has defended clients in complaint proceedings before FERC pursuant to FPA section 206.

In the energy regulatory space, Donna is recognized as a leading practitioner for companies and individuals regarding FERC enforcement investigations. She is experienced in conducting internal investigations, guiding clients through decisions about self-reporting potential regulatory violations, and all aspects of FERC enforcement investigations, including public show cause order proceedings and adjudication of alleged violations in federal district court. Donna has repeatedly succeeded in convincing FERC enforcement staff to close large-scale investigations based on a robust and comprehensive presentation of the relevant factual and legal issues. When FERC enforcement staff has not closed an investigation, Donna’s advocacy has resulted in favorable settlements for clients, either during the non-public phase of the investigation or later, in the public phase.

Donna has been recognized by Chambers USA as a leading practitioner in energy regulatory and litigation matters. Over the years, Chambers has reported that clients view Donna as “[a]n excellent, reliable lawyer” with “her finger on the pulse” of FERC matters, “an excellent critical thinker and a good strategist,” “very logical, detail-oriented and razor sharp in her arguments,” and a lawyer who is “meticulous, hard working and fights hard for her clients.”

FPA Section 203, 205, and 206 Matters

• Successful representation of Consumers Energy Company in an FPA Section 203 proceeding for the acquisition of New Covert Generating Company (FERC Docket No. EC22-110).
• Successful representation of AEP Generation Resources Inc. in an FPA Section 203 proceeding for the disposition of a generation facility (FERC Docket No. EC22-50).
• Successful representation of NextEra Energy, Inc. in an FPA Section 203 proceeding for the acquisition of Gulf Power Company from Southern Company (FERC Docket No. EC18-117).
• Successful representation of NextEra Energy, Inc. in an FPA Section 203 proceeding for the acquisition of generation facilities from Southern Company (FERC Docket No. EC18-119).
• Successfully defended Southwestern Public Service Company in several contested FPA Section 205 proceedings that challenged SPS’ right to self-fund transmission upgrades and collect return of and on costs of network upgrades to support transmission customer interconnection (FERC Docket Nos. ER22-2274, ER22-2379).
• Successful representation of Consumers Energy Company in a petition for a declaratory order proceeding (FERC Docket No. EL18-124).
• Successful representation of PJM Interconnection, LLC in a petition of declaratory relief proceeding involving federal pre-emption issues under PJM tariff (FERC Docket No. EL12-45).

Nonpublic FERC Enforcement Matters

• Successfully led the defense of a client facing a FERC enforcement matter related to capacity market accreditation in MISO; matter closed in 2023 with no sanctions.
• Successfully led the defense of a client facing a FERC enforcement investigation related to the client’s participation in the MISO Planning Resource Auction; matter closed in 2022 with no sanctions.
• Successfully led a utility client through a self-report of potential compliance matters related to the MISO capacity market; matter closed in 2021 with no sanctions.
• Advised a utility in a FERC/NERC investigation related to Winter Storm Uri.
• Successfully led defense of a client in a FERC enforcement investigation involving alleged tariff violations and market manipulation violations related to so-called “loop flow” transactions; matter closed with no sanctions.
• Successfully led the defense of clients in investigations focused on potential violations of PJM reactive power tariffs, resulting in closure with no sanctions.

Public FERC Enforcement Matters

• Represented a major utility in an investigation related to MISO’s demand response program (IN23-11); obtained favorable settlement.
• Represented a generation owner in an investigation related to MISO tariff compliance (IN23-5).
• Defended a large transmission-owning utility in a FERC enforcement investigation and order to show cause proceeding (FERC Docket No. IN20-6). The case, which involved an unprecedented civil penalty recommendation of $42 million for alleged violations of NERC reliability standards, was settled for a cash penalty of $1.9 million and $2.5 million in reliability enhancements.
• Represented an ISO-NE market participant in a FERC enforcement investigation and show order proceeding (FERC Docket No. IN18-7) alleging tariff violation and candor requirement violations; the matter resolved with an unprecedented FERC closure of the proceeding and no sanctions against the client.
• Represented PJM market participants in multiple venues, including FERC (FERC Docket No. IN15-3), federal district court, and Fourth Circuit Court of Appeals, on allegations of market manipulation.
• Represented a financial institution in a FERC show cause order proceeding (IN12-4) alleging market manipulation; matter resolved favorably for the client through settlement.

• Best Lawyers in America: Energy Law (2022-2026); Energy Regulatory Law (2023-2026)
• Chambers Global USA: Energy: Electricity (Regulatory & Litigation), Nationwide (2021-2025)
• Chambers USA: Energy: Electricity, Regulatory & Litigation, Nationwide (2020-2025)
• Legal 500 United States: “Leading Lawyer,” Energy Regulation: Electric Power (2025); Energy: Energy Litigation: Electric Power (2025)
• Thomson Reuters Stand-out Lawyer (2025) – independently rated lawyers
• U.S. District Court for the District of Columbia’s Daniel M. Gribbon Pro Bono Advocacy Award (2007)
• Florida Bar Association, Out-of-State Division Pro Bono Service Recognition Award (2007)