Electric utilities in Guam
Every electric utility serving Guam in EIA data year 2025, with ownership type, grid operator, balancing authority, customers and the counties each one serves.
Retail electric utilities in Guam
Sorted by customers. See Guam on the map, and the state regulator, Guam Public Utilities Commission.
| Utility | EIA ID | Type | ISO or region | Balancing authority | Customers | Counties served |
|---|---|---|---|---|---|---|
| Guam Power Authority | 40428 | State authority | Island grid (no ISO) | — | 51,372 | 1 Guam |
Retail power marketers and other entities in Guam
Competitive suppliers, wholesale marketers, transmission-only companies and behind-the-meter providers that report to EIA for Guam. They have no county service territory of their own.
| Entity | EIA ID | Type | ISO or region | Customers |
|---|---|---|---|---|
| Sunnova | 59579 | Behind-the-meter provider | Island grid (no ISO) | 1,085 |
About this data
Which utilities exist comes from the U.S. Energy Information Administration’s Form EIA-861 and EIA-861S, data year 2025 (final release, October 7, 2026), read directly from eia.gov. County service territories, balancing authority codes and customer counts come from EIA-861 for 2018, the latest year compiled at county level for this directory; utilities that started reporting after 2018 carry their 2025 values. County boundaries are U.S. Census cartographic boundaries (us-atlas 3.0, Albers USA projection).
Customer counts are per utility within Guam. A county’s grid operator is the one serving most of its customers, estimated by spreading each utility’s customers evenly over its counties. Download every state in one file from the U.S. Electric Utility Directory.
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