| Case Number | Case Title | Open Date | Closed Date |
| 00-0617-EL-COI | INVESTOR-OWNED ELECTRIC UTILITY COS | 04/03/2000 | |
| 01-0985-EL-COI | COMMISSION INVESTIGATION OF ELECTRIC POWER FOR SUMMER OF 2001 | 04/24/2001 | |
| 01-2708-EL-COI | COMMISSION'S INVESTIGATION OF LINE EXTENSIONS | 10/18/2001 | |
| 04-0486-EL-COI | IN THE MATTER OF THE COMMISSION INVESTIGATION OF THE FINANCIAL CONDITION OF THE DAYTON POWER AND LIGHT COMPANY | 04/06/2004 | |
| 73-0844-EL-COI | ELECTRIC COS IN OHIO | 12/03/1973 | 08/22/1974 |
| 74-0722-EL-COI | SUPPLY OF COAL | 10/28/1974 | 03/18/1976 |
| 75-0785-EL-COI | CLEVELAND ELECTRIC ILLUMINATING CO | 10/03/1975 | 12/15/1976 |
| 76-0857-EL-COI | TOLEDO EDISON COMPANY | 10/18/1976 | 05/11/1977 |
| 76-0858-EL-COI | OHIO POWER COMPANY | 10/18/1976 | 02/24/1982 |
| 76-0892-EL-COI | LONG RUN COST OF ELECTRICPLY | 10/27/1976 | 02/17/1982 |
| 76-1127-EL-COI | OHIO ELECTRIC LIGHT COS | 12/22/1976 | 01/03/1979 |
| 77-1139-EL-COI | EMERGENCY ELECTRICAL PROCEDURES | 09/07/1977 | 03/18/1981 |
| 80-0763-EL-COI | DAYTON POWER AND LIGHT COMPANY | 07/29/1980 | 08/19/1981 |
| 81-0619-EL-COI | ELECTRIC CO EMERGENCY PROCEDURES | 05/22/1981 | 06/17/1981 |
| 81-1096-EL-COI | CLEVELAND ELECTRIC ILLUMINATING CO | 09/15/1981 | 10/21/1981 |
| 81-1097-EL-COI | TOLEDO EDISON COMPANY | 09/15/1981 | 10/28/1981 |
| 83-0774-EL-COI | CLEVELAND ELECTRIC ILLUMINATING CO | 05/26/1983 | 10/05/1983 |
| 83-0848-EL-COI | CLEVELAND ELECTRIC ILLUMINATING CO | 06/16/1983 | 09/21/1983 |
| 83-1010-EL-COI | OHIO EDISON COMPANY | 08/01/1983 | 04/09/1985 |
| 83-1321-EL-COI | ZIMMER NUCLEAR POWER PLANT CONSTRN | 10/12/1983 | 01/28/1986 |
| 85-0521-EL-COI | PERRY NUCLEAR POWER STATION | 04/25/1985 | 01/12/1988 |
| 85-0522-EL-COI | GENERATING SYS OF ELECTRIC LIGHTPAN | 04/25/1985 | 11/24/1987 |
| 86-2033-EL-COI | OHIO EDISON COMPANY | 10/16/1986 | 10/28/1986 |
| 87-1183-EL-COI | FUNDING OF DECOMMISSIONING COSTS | 08/11/1987 | 04/19/1988 |
| 87-1777-EL-COI | BEAVER VALLEY NUCLEAR POWER STATION | 10/23/1987 | 03/07/1989 |
| 89-0498-EL-COI | CLEVE ELEC ILLUM/TOLEDO EDISON CO | 03/27/1989 | 06/03/1993 |
| 90-0723-EL-COI | DEMAND-SIDE MGMT PROFIT ELEC UTIL | 05/01/1990 | 10/01/1992 |
| 90-0724-EL-COI | ELEC TRANS ACCESS & PRIC ELEC UTIL | 05/01/1990 | 10/07/1999 |
| 90-0725-EL-COI | COMPETITIVE BIDDING FOR ACQUISITION | 05/01/1990 | 10/07/1999 |
| 91-2155-EL-COI | EMISSIONS ALLOW OHIO'S ELEC UTIL | 11/29/1991 | 08/24/1995 |
| 93-0898-EL-COI | ENERGY POLICY ACT OF 1992 | 06/01/1993 | 10/21/1993 |
| 94-1562-EL-COI | ENERGY POLICY ACT 1992 | 09/28/1994 | 10/20/1994 |
| 95-1139-EL-COI | CLEVELAND ELECTRIC ILLUMINATING | 12/11/1995 | 04/11/1996 |
| 95-1140-EL-COI | TOLEDO EDISON COMPANY | 12/11/1995 | 04/11/1996 |