| Liberty Utilities (EnergyNorth Natural Gas) Corp. d/b/a Liberty | Algonquin Power & Utilities | utility safety violation | 2018 | NH-PUC | $74,000 |
| Liberty Utilities (EnergyNorth Natural Gas) Corp. d/b/a Liberty | Algonquin Power & Utilities | utility safety violation | 2018 | NH-PUC | $15,000 |
| Liberty Utilities (EnergyNorth Natural Gas) Corp. d/b/a Liberty | Algonquin Power & Utilities | utility safety violation | 2018 | NH-PUC | $27,000 |
| Liberty Utilities | Algonquin Power & Utilities | utility safety violation | 2020 | MA-DPU | $50,000 |
| Liberty Utilities | Algonquin Power & Utilities | utility service violation | 2024 | NY-PSC | $39,000 |
| LG&E AND KU ENERGY LLC | PPL Corp. | environmental violation | 2013 | EPA | $23,010 |
| KUHLMAN ELECTRIC CORPORATION | ABB Ltd. | workplace safety or health violation | 2000 | OSHA | $6,375 |
| KUHLMAN ELECTRIC CORPORATION | ABB Ltd. | workplace safety or health violation | 2005 | OSHA | $17,075 |
| KUHLMAN ELECTRIC CORPORATION | ABB Ltd. | workplace safety or health violation | 2005 | OSHA | $5,000 |
| Keyspan Gas East Corporation dba National Grid | National Grid | environmental violation | 2020 | USAO | $49,577 |
| KEYSPAN ENERGY DELIVERY NEW ENGLAND | National Grid | environmental violation | 2006 | MA-ENV | $12,560 |
| KEYSPAN ENERGY DELIVERY NEW ENGLAND | National Grid | environmental violation | 2005 | MA-ENV | $15,000 |
| KEYSPAN ENERGY DELIVERY | National Grid | workplace safety or health violation | 2006 | OSHA | $6,000 |
| KEYSPAN ENERGY CORP. | National Grid | workplace safety or health violation | 2003 | OSHA | $5,000 |
| KEYSPAN ENERGY CORP. | National Grid | workplace safety or health violation | 2006 | OSHA | $5,400 |
| Keyspan Energy | National Grid | utility safety violation | 2006 | NH-PUC | $45,000 |
| Keyspan Energy | National Grid | utility safety violation | 2006 | NH-PUC | $6,000 |
| KeySpan Corporation | National Grid | price-fixing or anti-competitive practices | 2010 | DOJ_ANTITRUST | $12,000,000 |
| Kentucky-American Water Co. | American Water Works | consumer protection violation | 2010 | KY-PSC | $10,000 |
| Kentucky Utilities Company | PPL Corp. | air pollution violation | 2013 | EPA | $57,300,000 |
| KENTUCKY UTILITIES COMPANY | PPL Corp. | water pollution violation | 2017 | KY-ENV | $25,000 |
| KENTUCKY UTILITIES COMPANY | PPL Corp. | air pollution violation | 2009 | KY-ENV | $20,000 |
| KENTUCKY UTILITIES COMPANY | PPL Corp. | workplace safety or health violation | 2007 | OSHA | $6,300 |
| KENTUCKY UTILITIES COMPANY | PPL Corp. | environmental violation | 2005 | EPA | $1,728,569 |
| KENTUCKY UTILITIES COMPANY | PPL Corp. | environmental violation | 2009 | EPA | (*)Penalty amounts marked by an asterisk are ones announced by more than one agency. Parent penalty totals are adjusted to avoid double-counting. $1,400,000 |
| KENTUCKY UTILITIES COMPANY | PPL Corp. | environmental violation | 2013 | EPA | $300,000 |
| Kentucky Utilities | PPL Corp. | air pollution violation | 2009 | EPA | $136,400,000 |
| KENTUCKY POWER COMPANY - MITCHELL PLANT | American Electric Power | workplace safety or health violation | 2015 | OSHA | $5,000 |
| KENTUCKY AMERICAN WATER | American Water Works | water pollution violation | 2010 | KY-ENV | $10,000 |
| KANSAS GAS SERVICE, A DIVISION OF ONE GAS, INC. | ONE Gas Inc. | utility safety violation | 2020 | KS-CC | $24,000 |
| KANSAS GAS SERVICE, A DIVISION OF ONE GAS, INC. | ONE Gas Inc. | utility safety violation | 2019 | KS-CC | $14,000 |
| KANSAS GAS SERVICE, A DIVISION OF ONE GAS, INC. | ONE Gas Inc. | utility safety violation | 2019 | KS-CC | $5,500 |
| KANSAS GAS SERVICE, A DIVISION OF ONE GAS, INC. | ONE Gas Inc. | utility safety violation | 2019 | KS-CC | $5,500 |
| KANSAS GAS SERVICE, A DIVISION OF ONE GAS, INC. | ONE Gas Inc. | utility safety violation | 2018 | KS-CC | $8,500 |
| KANSAS GAS SERVICE, A DIVISION OF ONE GAS, INC. | ONE Gas Inc. | utility safety violation | 2018 | KS-CC | $5,000 |
| KANSAS GAS SERVICE, A DIVISION OF ONE GAS, INC. | ONE Gas Inc. | utility safety violation | 2018 | KS-CC | $5,000 |
| KANSAS GAS SERVICE, A DIVISION OF ONE GAS, INC. | ONE Gas Inc. | utility safety violation | 2016 | KS-CC | $6,000 |
| KANSAS GAS SERVICE, A DIVISION OF ONE GAS, INC. | ONE Gas Inc. | utility safety violation | 2016 | KS-CC | $8,500 |
| KANSAS GAS SERVICE, A DIVISION OF ONE GAS, INC. | ONE Gas Inc. | utility safety violation | 2015 | KS-CC | $7,500 |
| KANSAS CITY POWER AND LIGHT COMPANY | Evergy Inc. | environmental violation | 2003 | EPA | $14,332 |
| KANSAS CITY POWER AND LIGHT CO. | Evergy Inc. | workplace safety or health violation | 2019 | OSHA | $13,260 |
| KANSAS CITY POWER AND LIGHT | Evergy Inc. | environmental violation | 2004 | EPA | $407,788 |
| KANSAS CITY POWER AND LIGHT | Evergy Inc. | environmental violation | 2018 | EPA | $9,500 |
| KANSAS CITY POWER & LIGHT COMPANY | Evergy Inc. | workplace safety or health violation | 2002 | OSHA | $7,000 |
| Kansas City Power & Light Co. | Evergy Inc. | labor relations violation | 2005 | NLRB | $52,000 |
| KANSAS CITY POWER & LIGHT CO. | Evergy Inc. | workplace safety or health violation | 2001 | OSHA | $16,800 |
| JUST ENERGYTEXAS L.P. | Just Energy Group | consumer protection violation | 2019 | TX-PUC | $650,000 |
| Just Energy Texas, LP | Just Energy Group | consumer protection violation | 2014 | TX-PUC | $164,000 |
| Just Energy Texas, LP | Just Energy Group | consumer protection violation | 2010 | TX-PUC | $17,250 |
| Just Energy Solutions, Inc. | Just Energy Group | utility service violation | 2020 | CA-PUC | $132,388 |
| Just Energy Solutions, Inc. | Just Energy Group | utility service violation | 2020 | CA-PUC | $35,864 |
| Just Energy Solutions, Inc. | Just Energy Group | utility service violation | 2020 | CA-PUC | $5,261 |
| Just Energy Solutions, Inc. | Just Energy Group | utility service violation | 2019 | CA-PUC | $362,304 |
| Just Energy Solutions, Inc. | Just Energy Group | utility service violation | 2019 | CA-PUC | $46,587 |
| Just Energy Solutions, Inc. | Just Energy Group | utility service violation | 2019 | CA-PUC | $39,927 |
| Just Energy Solutions, Inc. | Just Energy Group | utility service violation | 2019 | CA-PUC | $33,000 |
| Just Energy Solutions, Inc. | Just Energy Group | utility service violation | 2019 | CA-PUC | $22,444 |
| Just Energy Solutions, Inc. | Just Energy Group | utility service violation | 2019 | CA-PUC | $19,980 |
| Just Energy Solutions, Inc. | Just Energy Group | utility service violation | 2019 | CA-PUC | $11,988 |
| Just Energy Solutions, Inc. | Just Energy Group | utility service violation | 2019 | CA-PUC | $5,994 |
| Just Energy Solutions, Inc. | Just Energy Group | utility service violation | 2019 | CA-PUC | $5,000 |
| Just Energy Solutions, Inc. | Just Energy Group | utility service violation | 2018 | CA-PUC | $33,300 |
| Just Energy Solutions, Inc. | Just Energy Group | utility service violation | 2018 | CA-PUC | $10,000 |
| Just Energy Solutions, Inc. | Just Energy Group | utility service violation | 2018 | CA-PUC | $5,328 |
| Just Energy Group Inc. | Just Energy Group | consumer protection violation | 2015 | MA-AG | $4,000,000 |
| JUST ENERGY | Just Energy Group | wage and hour violation | 2014 | IL-DOL | $5,624 |
| Just Energy | Just Energy Group | consumer protection violation | 2010 | IL-ICC | $90,000 |
| Just Energy | Just Energy Group | consumer protection violation | 2010 | OH-PUC | $111,000 |
| Just Energy | Just Energy Group | utility service violation | 2022 | TX-PUC | $60,000 |
| Jersey Central Power and Light Company, A First Energy Company | FirstEnergy | labor relations violation | 2003 | NLRB | $495,000 |
| JERSEY CENTRAL POWER AND LIGHT | FirstEnergy | utility safety violation | 2007 | NJ-BPU | $25,000 |
| JERSEY CENTRAL POWER & LIGHT COMPANY | FirstEnergy | workplace safety or health violation | 2009 | OSHA | $5,000 |
| JERSEY CENTRAL POWER & LIGHT COMPANY | FirstEnergy | workplace safety or health violation | 2012 | OSHA | $21,000 |
| Jersey Central Power & Light Company | FirstEnergy | environmental violation | 2016 | EPA | $50,500 |
| Jersey Central Power & Light | FirstEnergy | wage and hour violation | 2011 | WHD | $182,640 |
| Jennings Technology Company, LLC | ABB Ltd. | hazardous waste violation | 2011 | CA-DTSC | $347,000 |
| INVENERGY LLC | Invenergy | workplace safety or health violation | 2017 | OSHA | $18,108 |
| INVENERGY | Invenergy | utility service violation | 2015 | TX-PUC | $109,000 |
| Interstate Power and Light, a subsidiary of Alliant Energy | Alliant Energy | environmental violation | 2015 | EPA | $7,100,000 |
| Interstate Power and Light Company d/b/a Alliant E | Alliant Energy | environmental violation | 2022 | EPA | $14,576 |
| Interstate Power & Light/Alliant Energy | Alliant Energy | environmental violation | 2015 | IA-ENV | $244,444 |
| INTERSTATE POWER & LIGHT | Alliant 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. $1,100,000 |
| Integrys Energy Services, Inc. | Exelon | energy market violation | 2008 | FERC | $994,506 |
| INDIANAPOLIS POWER AND LIGHT COMPANY (AES INDIANA) | AES Corp. | environmental violation | 2021 | EPA | $1,525,000 |
| Indianapolis Power & Light Company | AES Corp. | air pollution violation | 2020 | EPA | $925,000 |
| Indianapolis Power & Light Company | AES Corp. | hazardous waste violation | 2024 | IN-ENV | $5,600 |
| INDIANAPOLIS POWER & LIGHT COMPANY | AES Corp. | workplace safety or health violation | 2012 | OSHA | $165,300 |
| INDIANAPOLIS POWER & LIGHT COMPANY | AES Corp. | workplace safety or health violation | 2013 | OSHA | $18,000 |
| Indianapolis Power & Light Compan | AES Corp. | energy market violation | 2014 | FERC | $333,500 |
| INDIANAPOLIS POWER & LIGHT CO - EAGLE VALLEY GENERATION STA | AES Corp. | environmental violation | 2008 | IN-ENV | $23,800 |
| Indianapolis Power & Light | AES Corp. | air pollution violation | 2020 | IN-AG | $600,000 |
| INDIANAPOLIS P&L PETERSBURG GENERATING STATION | AES Corp. | air pollution violation | 2008 | IN-ENV | $11,000 |
| INDIANAPOLIS P&L PETERSBURG GENERATING STATION | AES Corp. | hazardous waste violation | 2000 | IN-ENV | $7,750 |
| INDIANAPOLIS P&L EAGLE VALLEY GENERATING STA | AES Corp. | air pollution violation | 2006 | IN-ENV | $8,750 |
| INDIANAPOLIS P&L CO | AES Corp. | air pollution violation | 2000 | IN-ENV | $6,000 |
| INDIANA MICHIGAN POWER COMPANY/AMERICAN ELECTRIC POWER COMPANY | American Electric Power | labor relations violation | 2005 | NLRB | $25,000 |
| Indiana Michigan Power Company, d.b.a. American Po | American Electric Power | environmental violation | 2005 | EPA | $80,769 |
| Indiana Michigan Power Company | American Electric Power | nuclear safety violation | 2005 | NRC | $60,000 |
| INDIANA MICHIGAN POWER COMPANY | American Electric Power | workplace safety or health violation | 2001 | OSHA | $9,000 |
| INDIANA MICHIGAN POWER COMPANY | American Electric Power | workplace safety or health violation | 2019 | OSHA | $5,000 |
| INDIANA MICHIGAN POWER CO DBA AMERICAN ELECTRIC POWER | American Electric Power | air pollution violation | 2016 | IN-ENV | $7,000 |
