| Public Service Company of Oklahoma | American Electric Power | labor relations violation | 2004 | NLRB | $6,029,281 |
| Exelon Mystic LLC | Constellation Energy Corporation | environmental violation | 2004 | EPA | $6,000,000 |
| National Grid USA | National Grid | False Claims Act and related | 2021 | NY-AG | $6,000,000 |
| AES Alamitos, LLC and AES Redondo Beach, LLC | AES Corp. | energy market violation | 2023 | FERC | $6,000,000 |
| Hoosier Energy Rural Electric Cooperative Inc. | Hoosier Energy | environmental violation | 2010 | EPA | $5,950,000 |
| ABB Ltd | ABB Ltd. | Foreign Corrupt Practices Act | 2004 | SEC | $5,900,000 |
| Pacific Gas and Electric Company | PG&E Corp. | environmental violation | 2021 | CA-WAT | $5,900,000 |
| Minnesota Power | Allete | environmental violation | 2014 | EPA | $5,600,000 |
| Ormat Technologies Inc. et al. | Ormat Technologies | False Claims Act and related | 2016 | USAO | $5,500,000 |
| Pacific Gas And Electric Company | PG&E Corp. | wage and hour violation | 2018 | private lawsuit-federal | $5,500,000 |
| FirstEnergy Nuclear Operating Company | FirstEnergy | nuclear safety violation | 2005 | NRC | $5,450,000 |
| Pacific Gas & Electric Co. (PG&E) | PG&E Corp. | utility safety violation | 2016 | CA-PUC | $5,450,000 |
| National Grid | National Grid | environmental violation | 2023 | EPA | $5,380,000 |
| Duke Energy | Duke Energy | environmental violation | 2015 | EPA | $5,375,000 |
| Baltimore Gas & Electric | Exelon | employment discrimination | 2005 | private lawsuit-federal | $5,165,000 |
| CMS Energy Resources Management | CMS Energy | price-fixing or anti-competitive practices | 2017 | private lawsuit-federal | $5,125,000 |
| Entergy Arkansas LLC | Entergy | energy market violation | 2023 | FERC | $5,033,780 |
| Pacific Gas & Electric Co. (PG&E) | PG&E Corp. | utility safety violation | 2018 | CA-PUC | $5,005,000 |
| Dynegy Marketing & Trade (Dynegy) and West Coast Power LLC | Vistra Energy | price-fixing or anti-competitive practices | 2002 | CFTC | $5,000,000 |
| Narragansett Electric Co. | PPL Corp. | environmental violation | 2006 | MA-AG | $5,000,000 |
| Pacific Gas & Electric Co. (PG&E) | PG&E Corp. | utility safety violation | 2021 | CA-PUC | $5,000,000 |
| TXU Electric Delivery Company | Vistra Energy | consumer protection violation | 2007 | TX-PUC | $5,000,000 |
| Puget Sound Energy | Puget Sound Energy | environmental violation | 2008 | private lawsuit-state | $4,966,000 |
| Portland General Electric Co. | Portland General Electric | environmental violation | 2008 | private lawsuit-state | $4,966,000 |
| National Grid | National Grid | wage and hour violation | 2013 | NY-AG | $4,800,000 |
| Southern California Edison Co. | Edison International | utility administrative violation | 2007 | AZ-CC | $4,800,000 |
| Southern California Edison | Edison International | utility safety violation | 2022 | CA-PUC | $4,500,000 |
| Dynegy Inc. | Vistra Energy | price-fixing or anti-competitive practices | 2019 | private lawsuit-federal | $4,500,000 |
| Minnesota Power | Allete | utility service violation | 2022 | MN-PUC | $4,482,456 |
| Dominion Resources, Inc. | Dominion Energy | data submission deficiencies | 2006 | CFTC | $4,250,000 |
| PSEG Fossil LLC | Public Service Enterprise | environmental violation | 2006 | EPA | $4,250,000 |
| Wisconsin Electric Power Company | WEC Energy Group | wage and hour violation | 2019 | private lawsuit-federal | $4,236,231 |
| NSTAR | EverSource Energy | utility service violation | 2012 | MA-DPU | $4,075,000 |
| Allegheny Energy, Inc. | FirstEnergy | benefit plan administrator violation | 2007 | private lawsuit-federal | $4,000,000 |
| American Electric Power | American Electric Power | environmental violation | 2019 | MULTI-AG | $4,000,000 |
| Just Energy Group Inc. | Just Energy Group | consumer protection violation | 2015 | MA-AG | $4,000,000 |
| Southern California Gas Co. | Sempra Energy | environmental violation | 2016 | CA-LACDA | $4,000,000 |
| Pacific Gas & Electric | PG&E Corp. | environmental violation | 2020 | CA-MULTI | $4,000,000 |
| Southern California Edison Company | Edison International | utility service violation | 2017 | CA-PUC | $4,000,000 |
| Central Maine Power Company | Iberdrola | utility service violation | 2010 | ME-PUC | $4,000,000 |
| Petrogas West LLC | AltaGas | environmental violation | 2023 | WA-NCAA | $4,000,000 |
| FirstEnergy Corp. | FirstEnergy | energy market violation | 2022 | FERC | $3,860,000 |
| Arizona Public Service Company | Pinnacle West Capital | environmental violation | 2015 | EPA | $3,800,000 |
| Public Service Company of New Mexico | PNM Resources | environmental violation | 2015 | EPA | $3,800,000 |
| Tucson Electric Power | Fortis | environmental violation | 2015 | EPA | $3,800,000 |
| Consolidated Edison Company of New York, Inc. | Consolidated Edison | employment discrimination | 2015 | EEOC | $3,800,000 |
| Consolidated Edison Company of New York, Inc. | Consolidated Edison | employment discrimination | 2015 | NY-AG | (*)Penalty amounts marked by an asterisk are ones announced by more than one agency. Parent penalty totals are adjusted to avoid double-counting. $3,800,000 |
| Dominion Energy, Inc. | Dominion Energy | wage and hour violation | 2019 | private lawsuit-federal | $3,800,000 |
| Pacific Gas & Electric Company | PG&E Corp. | environmental violation | 2012 | CA-WAT | $3,600,000 |
| Southern California Edison | Edison International | environmental violation | 2015 | EPA | $3,500,000 |
| Berkshire Power Co. | Tenaska | environmental violation | 2016 | USAO | $3,500,000 |
| Duke Energy Corporation | Duke Energy | energy market violation | 2018 | FERC | $3,500,000 |
| Berkshire Power Co. | Tenaska | environmental violation | 2016 | MA-AG | (*)Penalty amounts marked by an asterisk are ones announced by more than one agency. Parent penalty totals are adjusted to avoid double-counting. $3,500,000 |
| Southern California Edison Company | Edison International | environmental violation | 2020 | CA-SBCDA | $3,500,000 |
| TAMPA ELECTRIC COMPANY - GANNON PLANT & BIG BEND PLANT | Emera | environmental violation | 2001 | EPA | (*)Penalty amounts marked by an asterisk are ones announced by more than one agency. Parent penalty totals are adjusted to avoid double-counting. $3,500,000 |
| NIPSCO | NiSource | environmental violation | 2011 | EPA | (*)Penalty amounts marked by an asterisk are ones announced by more than one agency. Parent penalty totals are adjusted to avoid double-counting. $3,500,000 |
| Duke Energy Trading and Marketing L.L.C. | Duke Energy | price-fixing or anti-competitive practices | 2009 | private lawsuit-federal | $3,466,667 |
| Reliant Energy Services Inc. | NRG Energy | price-fixing or anti-competitive practices | 2009 | private lawsuit-federal | $3,466,666 |
| AmerenUE | Ameren | environmental violation | 2005 | MO-AG | $3,400,000 |
| Southern California Gas Company | Sempra Energy | utility safety violation | 2019 | CA-PUC | $3,300,000 |
| Arizona Public Service Company | Pinnacle West Capital | price-fixing or anti-competitive practices | 2014 | FERC | $3,250,000 |
| POTOMAC ELECTRIC POWER COMPANY (PEPCO) | Exelon | environmental violation | 2017 | EPA | $3,205,429 |
| Wisconsin Electric Power Company | WEC Energy Group | environmental violation | 2014 | EPA | (*)Penalty amounts marked by an asterisk are ones announced by more than one agency. Parent penalty totals are adjusted to avoid double-counting. $3,200,000 |
| ProLiance Energy, LLC | CenterPoint Energy | energy market violation | 2009 | FERC | $3,195,959 |
| Berkshire Power Company LLC and Power Plant Management Services LLC | Tenaska | price-fixing or anti-competitive practices | 2016 | FERC | $3,042,563 |
| Duke Energy | Duke Energy | environmental violation | 2014 | EPA | $3,000,000 |
| Washakie Renewable Energy LLC | Washakie Renewable Energy | environmental violation | 2015 | EPA | $3,000,000 |
| Entergy Koch Trading, L.P. | Entergy | data submission deficiencies | 2004 | CFTC | $3,000,000 |
| Entergy Services, Inc. | Entergy | energy market violation | 2007 | FERC | $3,000,000 |
| Potomac Electric Power Company (PEPCO) | Exelon | environmental violation | 2002 | NOAA | $3,000,000 |
| Dynegy Inc. | Vistra Energy | accounting fraud or deficiencies | 2002 | SEC | $3,000,000 |
| Pacific Gas and Electric | PG&E Corp. | environmental violation | 2017 | USAO | $3,000,000 |
| Southern California Edison | Edison International | environmental violation | 2016 | CA-WAT | $3,000,000 |
| Southern California Edison | Edison International | environmental violation | 2009 | CA-SCAQMD | $3,000,000 |
| Peoples Gas Systems | Emera | utility safety violation | 2016 | FL-PSC | $3,000,000 |
| WESTAR ENERGY, INC | Evergy Inc. | environmental violation | 2010 | EPA | (*)Penalty amounts marked by an asterisk are ones announced by more than one agency. Parent penalty totals are adjusted to avoid double-counting. $3,000,000 |
| Washakie Renewable Energy, LLC | Washakie Renewable Energy | environmental violation | 2015 | EPA | (*)Penalty amounts marked by an asterisk are ones announced by more than one agency. Parent penalty totals are adjusted to avoid double-counting. $3,000,000 |
| New York State Electric and Gas Corporation | Iberdrola | utility safety violation | 2023 | NY-PSC | $2,750,000 |
| e Prime Inc. | Xcel Energy | price-fixing or anti-competitive practices | 2019 | private lawsuit-federal | $2,750,000 |
| CONSUMERS POWER CO | CMS Energy | environmental violation | 2014 | EPA | (*)Penalty amounts marked by an asterisk are ones announced by more than one agency. Parent penalty totals are adjusted to avoid double-counting. $2,750,000 |
| Constellation New Energy | Constellation Energy Corporation | utility service violation | 2023 | CA-PUC | $2,705,408 |
| Southern California Gas Company | Sempra Energy | consumer protection violation | 2023 | CA-PUC | $2,700,000 |
| SoCalGas | Sempra Energy | utility service violation | 2023 | CA-PUC | $2,700,000 |
| Washington Gas Energy Systems | AltaGas | fraud | 2014 | DOJ_ANTITRUST | $2,500,000 |
| Duke Energy | Duke Energy | price-fixing or anti-competitive practices | 2003 | FERC | $2,500,000 |
| Commonwealth Edison Company | Exelon | employment discrimination | 2000 | EEOC | $2,500,000 |
| NextEra Energy Resources | NextEra Energy | environmental violation | 2010 | CA-AG | $2,500,000 |
| GenOn Holdings, Inc. | NRG Energy | environmental violation | 2020 | DC-AG | $2,500,000 |
| Pacific Gas & Electric Co. (PG&E) | PG&E Corp. | utility safety violation | 2021 | CA-PUC | $2,500,000 |
| Rochester Gas & Electric Corporation | Iberdrola | utility safety violation | 2021 | NY-PSC | $2,500,000 |
| Xcel Energy Inc. | Xcel Energy | price-fixing or anti-competitive practices | 2021 | private lawsuit-federal | $2,500,000 |
| WISCONSIN POWER AND LIGHT COMPANY | Alliant Energy | environmental violation | 2013 | EPA | (*)Penalty amounts marked by an asterisk are ones announced by more than one agency. Parent penalty totals are adjusted to avoid double-counting. $2,450,000 |
| Constellation NewEnergy, Inc. | Constellation Energy Corporation | energy market violation | 2022 | FERC | $2,400,000 |
| Dynegy Inc. | Vistra Energy | price-fixing or anti-competitive practices | 2007 | private lawsuit-federal | $2,400,000 |
| Pacific Gas & Electric Co. (PG&E) | PG&E Corp. | utility safety violation | 2015 | CA-PUC | $2,300,000 |
| Northern Illinois Gas Co. | Southern Company | environmental violation | 2001 | IL-AG | $2,250,000 |
| Southern California Gas Company | Sempra Energy | utility safety violation | 2016 | CA-PUC | $2,250,000 |
| Dominion Oklahoma Texas Exploration & Production Inc. | Dominion Energy | False Claims Act and related | 2010 | DOJ_CIVIL | $2,219,974 |
| The United Illuminating Company | Iberdrola | utility service violation | 2021 | CT-PURA | $2,141,470 |
| Algonquin Power Windsor Locks LLC | Algonquin Power & Utilities | energy market violation | 2021 | FERC | $2,119,073 |
| Avista Energy | Avista | price-fixing or anti-competitive practices | 2001 | CFTC | $2,100,000 |
