| IDAHO POWER COMPANY | IDACORP | workplace safety or health violation | 2015 | OSHA | $11,000 |
| IES UTILITIES INC. | Alliant Energy | workplace safety or health violation | 2000 | OSHA | $8,750 |
| ILLINOIS - AMERICAN WATER COMPANY | American Water Works | workplace safety or health violation | 2013 | OSHA | $5,500 |
| ILLINOIS AMERICAN WATER CO | American Water Works | water pollution violation | 2016 | IL-ENV | $20,000 |
| Illinois American Water Company | American Water Works | labor relations violation | 2005 | NLRB | $19,000 |
| Illinois Power | Ameren | employment discrimination | 2002 | private lawsuit-federal | $559,000 |
| Illinois Power Co. and Dynergy Midwest Generation | Ameren | environmental violation | 2005 | IL-AG | (*)Penalty amounts marked by an asterisk are ones announced by more than one agency. Parent penalty totals are adjusted to avoid double-counting. $24,000,000 |
| Illinois Power Company | Ameren | labor relations violation | 2000 | NLRB | $20,000 |
| ILLINOIS POWER COMPANY | Ameren | air pollution violation | 2005 | EPA | $24,000,000 |
| ILLINOIS POWER COMPANY | Ameren | water pollution violation | 2000 | EPA | $25,000 |
| Illinois-American Water Co. | American Water Works | lead violation | 2006 | IL-AG | $9,200 |
| ILLINOIS-AMERICAN WATER CO. | American Water Works | workplace safety or health violation | 2003 | OSHA | $11,130 |
| ILLINOIS-AMERICAN WATER CO. | American Water Works | workplace safety or health violation | 2003 | OSHA | $8,750 |
| ILLINOIS-AMERICAN WATER CO. | American Water Works | workplace safety or health violation | 2006 | OSHA | $33,300 |
| Illinois-American Water Company | American Water Works | labor relations violation | 2008 | NLRB | $41,500 |
| Illinois-American Water Company | American Water Works | water pollution violation | 2006 | IL-ENV | $17,500 |
| ILLINOIS-AMERICAN WATER COMPANY | American Water Works | workplace safety or health violation | 2023 | OSHA | $17,859 |
| ILLINOIS-AMERICAN WATER COMPANY | American Water Works | environmental violation | 2002 | EPA | $8,424 |
| ILLUMINATING CO.; A FIRST ENERGY COMPANY | FirstEnergy | workplace safety or health violation | 2002 | OSHA | $70,000 |
| ILLUMINATING CO.; A FIRST ENERGY COMPANY | FirstEnergy | workplace safety or health violation | 2003 | OSHA | $8,500 |
| Indiana Gas Company Inc. dba CenterPoint Energy Indiana North | CenterPoint Energy | utility safety violation | 2023 | IN-URC | $227,000 |
| INDIANA GAS COMPANY, INC D/B/A VECTREN ENERGY DELIVERY OF INDIANA, INC. | CenterPoint Energy | labor relations violation | 2010 | NLRB | $14,000 |
| Indiana Gas Company, Inc. - Vectren | CenterPoint Energy | utility safety violation | 2021 | IN-URC | $50,000 |
| Indiana Gas Company, Inc. - Vectren | CenterPoint Energy | utility safety violation | 2021 | IN-URC | $894,000 |
| Indiana Gas Company, Inc. - Vectren | CenterPoint Energy | utility safety violation | 2020 | IN-URC | $584,000 |
| Indiana Gas Company, Inc. - Vectren | CenterPoint Energy | utility safety violation | 2013 | IN-URC | $75,000 |
| Indiana Gas Company, Inc. d/b/a CenterPoint Energy Indiana North | CenterPoint Energy | utility safety violation | 2021 | IN-URC | $150,000 |
| INDIANA MICHIGAN POWER CO DBA AMERICAN ELECTRIC POWER | American Electric Power | air pollution violation | 2016 | IN-ENV | $7,000 |
| INDIANA MICHIGAN POWER CO DBA AMERICAN ELECTRIC POWER | American Electric Power | air pollution violation | 2004 | IN-ENV | $20,000 |
| 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 Company, d.b.a. American Po | American Electric Power | environmental violation | 2005 | EPA | $80,769 |
| INDIANA MICHIGAN POWER COMPANY/AMERICAN ELECTRIC POWER COMPANY | American Electric Power | labor relations violation | 2005 | NLRB | $25,000 |
| INDIANAPOLIS P&L CO | AES Corp. | air pollution violation | 2000 | IN-ENV | $6,000 |
| INDIANAPOLIS P&L EAGLE VALLEY GENERATING STA | AES Corp. | air pollution violation | 2006 | IN-ENV | $8,750 |
| 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 Power & Light | AES Corp. | air pollution violation | 2020 | IN-AG | $600,000 |
| INDIANAPOLIS POWER & LIGHT CO - EAGLE VALLEY GENERATION STA | AES Corp. | environmental violation | 2008 | IN-ENV | $23,800 |
| Indianapolis Power & Light Compan | AES Corp. | energy market violation | 2014 | FERC | $333,500 |
| Indianapolis Power & Light Company | AES Corp. | air pollution violation | 2020 | EPA | $925,000 |
| 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 AND LIGHT COMPANY (AES INDIANA) | AES Corp. | air pollution violation | 2021 | EPA | $1,525,000 |
| Integrys Energy Services, Inc. | Exelon | energy market violation | 2008 | FERC | $994,506 |
| INTERSTATE POWER & LIGHT | Alliant Energy | air pollution 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 |
| Interstate Power & Light/Alliant Energy | Alliant Energy | environmental violation | 2015 | IA-ENV | $244,444 |
| Interstate Power and Light Company d/b/a Alliant E | Alliant Energy | water pollution violation | 2022 | EPA | $14,576 |
| Interstate Power and Light, a subsidiary of Alliant Energy | Alliant Energy | environmental violation | 2015 | EPA | $7,100,000 |
| INVENERGY | Invenergy | utility service violation | 2015 | TX-PUC | $109,000 |
| INVENERGY LLC | Invenergy | workplace safety or health violation | 2017 | OSHA | $18,108 |
| Jennings Technology Company, LLC | ABB Ltd. | hazardous waste violation | 2011 | CA-DTSC | $347,000 |
| Jersey Central Power & Light | FirstEnergy | wage and hour violation | 2011 | WHD | $182,640 |
| 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 | PCB violation | 2016 | EPA | $50,500 |
| JERSEY CENTRAL POWER AND LIGHT | FirstEnergy | utility safety violation | 2007 | NJ-BPU | $25,000 |
| Jersey Central Power and Light Company, A First Energy Company | FirstEnergy | labor relations violation | 2003 | NLRB | $495,000 |
| 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 |
| Just Energy Group Inc. | Just Energy Group | consumer protection violation | 2015 | MA-AG | $4,000,000 |
| 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 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 ENERGYTEXAS L.P. | Just Energy Group | consumer protection violation | 2019 | TX-PUC | $650,000 |
| 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 |
| KANSAS CITY POWER & LIGHT COMPANY | Evergy Inc. | workplace safety or health violation | 2002 | OSHA | $7,000 |
| KANSAS CITY POWER AND LIGHT | Evergy Inc. | air pollution violation | 2004 | EPA | $407,788 |
| KANSAS CITY POWER AND LIGHT | Evergy Inc. | air pollution violation | 2018 | EPA | $9,500 |
| KANSAS CITY POWER AND LIGHT CO. | Evergy Inc. | workplace safety or health violation | 2019 | OSHA | $13,260 |
| KANSAS CITY POWER AND LIGHT COMPANY | Evergy Inc. | hazardous waste violation | 2003 | EPA | $14,332 |
| 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 |
| KENTUCKY AMERICAN WATER | American Water Works | water pollution violation | 2010 | KY-ENV | $10,000 |
| KENTUCKY POWER COMPANY - MITCHELL PLANT | American Electric Power | workplace safety or health violation | 2015 | OSHA | $5,000 |
