Acton-Boxborough Schools BESS
Middlesex County, Massachusetts · EIA plant ID 66966 · Operator: MSS Energy Holdings, LLC (d.b.a. Calibrant Energy)
Nameplate2MWSummer 2 MW
Generators1in service
Net generation-0GWh12 mo to Dec 2025
Capacity factor—not meaningful for storage
Heat rate—thermal plants only
First online2021
Monthly net generation
EIA-923, all units at the plant. Net of station use; storage can go negative.
FinalPreliminary
Capacity factor by year
Net MWh ÷ (summer MW × hours), primary-fuel units. Each year uses that year's EIA-860 ratings; the hollow dot is the latest 12 months.
No capacity factor available.
Heat rate by year
Electric fuel MMBtu × 1000 ÷ net MWh (Btu/kWh, HHV), fossil units only; CT + CA counted as one combined-cycle block.
Heat rate applies to fuel-burning (thermal) units only.
Annual data table
| Year | Net GWh | Capacity factor | Heat rate (Btu/kWh) |
|---|---|---|---|
| 2024 | -0.1 | — | — |
| 2025 | -0.1 | — | — |
Generators
EIA-860 (annual) with EIA-860M updates through Sep 2026. EIA-923 reports generation by plant, prime mover and fuel, not by unit, so unit-level output isn't shown.
| Gen ID | Technology | Prime mover | Nameplate MW | Summer MW | Online | Status | Planned retirement | OEM / model |
|---|---|---|---|---|---|---|---|---|
| ABRSD | Batteries | BA | 2.1 | 2.1 | May 2021 | Operating | — | coming soon |
Owner / operator
Operator: MSS Energy Holdings, LLC (d.b.a. Calibrant Energy). Ownership shares by in-service nameplate MW (EIA-860 Schedule 4; units not listed there are wholly owned by the operator).
| MSS Energy Holdings, LLC (d.b.a. Calibrant Energy) | 100.0% | 2 MW |
Nearby plants
Within 80 km.
| Acton Solar Landfill | 2 MW | 2.4 km |
| Kearsarge Concord II | 5 MW | 4.6 km |
| Maynard PV | 1 MW | 6 km |
| Stow PV | 2 MW | 6.2 km |
| GSPP Boxborough Littleton (MA) | 4 MW | 6.8 km |
| DG Webster LLC CSG | 1 MW | 8.6 km |