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5,016 kWh

Commercial energy storage systemFortress Power

Fortress Power FP-Mega-Cxxxx-O

5,016 kWh · 2,058 kW · Lithium Ion

UL 9540CEC listed · Aug 21, 2026

Nameplate energy5,016 kWh
Continuous power2,058 kW
ChemistryLithium Ion

Overview

CEC Energy Storage System List

FP-Mega-Cxxxx-O: 5,016 kWh nameplate energy; 2,058 kW continuous; lithium ion.

Capacity & power

CEC Energy Storage System List

Nameplate energy (CEC)5,016 kWh
Rated power (CEC)2,508 kW
Max continuous discharge (CEC)2,058 kW
Full-power discharge timeabout 2.4 h at full power
ChemistryLithium Ion

Safety listings

CEC Energy Storage System List

UL 9540 (energy storage system)Certified by CSA Group
Certificate date & editionMay 6, 2026 · Ed. 3 : 2025

UL 9540 certifies the whole storage system; UL 9540A is the fire-propagation test that fire codes ask for indoors and near walls.

California grid & code compliance

CEC Energy Storage System List

UL 1741 SB (IEEE 1547-2018)No
UL 1741 SA (Rule 21)No
CSIP (IEEE 2030.5)No
JA12 declaration (Title 24)No

Questions & answers

How much energy does the Fortress Power FP-Mega-Cxxxx-O store?

5,016 kWh nameplate, per the California Energy Commission list.

Is the FP-Mega-Cxxxx-O UL 9540 certified?

Yes — the CEC list shows UL 9540 certification (certified by csa group).

Sources

California Energy Commission — Energy Storage System List, data as of Oct 7, 2026. Manufacturer-reported values confirmed by CEC against certificates.