The Challenge
A facility operated a 250 kVA generator with 1,500-liter fuel tank. Full facility load was 200 kW; at full load, the fuel tank supported 2.5 hours of operation. Grid outages longer than 2.5 hours would result in backup power failure before outage ended.
What Became Visible
Load analysis revealed that not all loads were equally critical. Production machinery required 160 kW. HVAC required 25 kW. Lighting/office/non-production required 15 kW. If a grid outage occurred, production could be maintained on 160 kW for the duration while HVAC and non-essential loads were shed temporarily. This reduced generator load from 200 kW to 160 kW, extending fuel duration from 2.5 hours to 3.1 hours — still short for extended outages.
What Changed
Two-tier load shedding strategy implemented: Tier 1 (critical loads: production + essential cooling) on generator at full priority. Tier 2 (non-critical: HVAC, office, non-essential equipment) shed automatically after 30 minutes on backup power. If outage extends >2 hours, Tier 2 remains off; essential systems only.
How it worked: The facility also implemented aggressive fuel conservation: production line speed reduced 15% during extended outages (extending run time by 15% while maintaining output). This combination extended fuel capacity for a 1,500-liter tank from 2.5 hours to 5.5 hours of essential operations.
Results
with load shedding + speed reduction
for 5.5+ hours
no manual intervention
without fuel resupply
Backup power duration is a function of both fuel capacity and load. Strategic load shedding doubles effective backup duration without adding fuel storage or larger generators.
Operational Reality
Most facilities discover they have insufficient backup duration only during extended grid outages. Load prioritization provides low-cost extended duration.