Backup Power
Backup power for continuity during grid outages
Battery energy storage systems (BESS) provide fast-response backup power, enabling facilities to maintain operations when the grid fails. Systems transition in milliseconds and support critical loads without reliance on fuel supply.
BESS can operate independently or alongside generators and renewables, forming a controlled backup system that reduces downtime and improves site resilience.
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Get backup system sizing
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Your selected solutionBackup Power
What operators gain
Backup power for essential operations
How battery backup power reaches your loads
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1During normal operation, the system remains charged and synchronized with the grid
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2On grid failure, the system transitions to backup mode via inverter control and switching logic
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3Critical loads are supplied based on predefined load prioritization or full-site support
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4If paired with a generator, the system bridges the startup delay and stabilizes load transitions
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5Once grid power returns, the system resynchronizes and restores normal operation
Typical configuration envelope
Backup power systems are engineered based on load profile, uptime requirements, and existing infrastructure.
| Parameter | Typical Range |
|---|---|
|
Capacity
|
100–2,000 kWh |
|
Power
|
50–500 kW |
|
Transfer Time
Application and switching dependent
|
15–50 ms |
|
Backup Duration
Load-dependent, scalable with additional energy capacity
|
1–4 hours |
Backup Power – Deployment Case Study
A regional hospital experienced frequent grid outages, with 30–60 second generator start delays during which critical monitoring equipment was exposed to power loss.
A 500 kWh / 250 kW BESS was deployed to bridge the gap between grid failure and generator start. The system was configured to support critical loads during transition and short-duration outages.
- No interruption to critical loads during outages
- Generator fuel consumption reduced by ~35%
- Improved reliability of backup power system
Plan your backup power requirements
Start with the loads that must stay on and the outage duration you need to cover. Then identify any motors, switching equipment, UPS units and generators that the battery must work alongside. These details determine both power output and usable energy.
Also consider how the battery will recharge after an outage. A backup power design should define its operating reserve, recharge window and sequence for restoring non-essential loads. Your site conditions and required transfer performance guide the final configuration.
Explore our commercial battery systems or discuss your backup power requirements. For background, see the U.S. Department of Energy’s energy storage research and resources.