Interstate Gas Supply, Inc.
Retail Power Marketer electric utility · Ohio · #118 of 3,199 U.S. utilities by customers · EIA utility #58957
Interstate Gas Supply, Inc. is a retail power marketer electric utility serving 322,025 customers in Illinois, Maryland, Ohio, Pennsylvania. In 2025 it sold 10,627 gigawatt-hours of electricity for $880.33M in revenue, an average realized rate of 8.28¢ per kWh across all customer classes and 11.51¢ per kWh for residential customers. EIA records its activities as: retail marketing.
Customers, sales and rates by customer class (2025)
| Class | Customers | Sales (GWh) | Revenue | Avg realized rate | Share of sales |
|---|---|---|---|---|---|
| Residential | 268,015 | 2,398 | $275.89M | 11.51¢ | |
| Commercial | 54,010 | 8,229 | $604.44M | 7.35¢ | |
| Total | 322,025 | 10,627 | $880.33M | 8.28¢ |
Average realized rate = revenue divided by sales as reported on EIA Form 861. It blends fixed charges, demand charges and riders into one per-kWh figure; it is not the utility's tariff rate. Estimated residential bill assumes the average residential customer's actual 2025 usage (746 kWh/month).
Operations by state
| State | Customers | Sales (GWh) | Residential rate |
|---|---|---|---|
| Ohio | 208,337 | 6,467 | 10.73¢ |
| Pennsylvania | 83,533 | 2,560 | 12.95¢ |
| Illinois | 29,113 | 1,548 | 12.73¢ |
| Maryland | 1,042 | 53.0 | 12.30¢ |
Five-year trend
| Year | Customers | Sales (GWh) | Revenue | Residential rate |
|---|---|---|---|---|
| 2021 | 326,913 | 9,747 | $574.96M | 8.20¢ |
| 2022 | 307,017 | 9,282 | $675.76M | 10.98¢ |
| 2023 | 299,070 | 8,921 | $630.07M | 10.95¢ |
| 2024 | 292,738 | 9,309 | $650.68M | 10.25¢ |
| 2025 | 322,025 | 10,627 | $880.33M | 11.51¢ |
Energy supply (2025)
Net generation: — GWh
Wholesale power purchased: 10,627 GWh
Winter peak demand: — MW
Other large utilities in Ohio
- Adjustment 2025 - 4,559,641 customers, residential 13.93¢
- Dynegy Energy Services, LLC - 793,547 customers, residential 9.00¢
- NextEra Energy Services, LLC - 753,301 customers, residential 9.28¢
- AEP Energy - 618,459 customers, residential 8.66¢
- Ohio Power Co - 594,848 customers, residential 18.97¢
- Energy Harbor Corp. - 410,524 customers, residential 7.89¢
- Duke Energy Ohio Inc - 297,189 customers, residential 16.83¢
- Ohio Edison Co - 286,197 customers, residential 16.01¢
Source: U.S. Energy Information Administration, Form EIA-861 2025 (filed by the utility; figures as published). Utility #58957 in the EIA frame.