The Challenge
A facility in Northern India used the same diesel supplier year-round, ordering summer-specification fuel (optimized for 15–40°C). During winter (5–12°C), the generator had cold-start issues and ran with 18% lower efficiency.
What Became Visible
Seasonal analysis revealed that fuel properties were wrong for the season. Summer specification fuel had a cloud point of 8°C — meaning it began to gel and plug filters below that temperature. Winter temperatures (5–10°C) were below cloud point, causing wax precipitation in fuel filters. The generator lost 18–20% power output in winter despite identical load.
What Changed
Seasonal fuel sourcing implemented. Winter months (November–February) use winter-specification fuel with cloud point <-5°C. Summer months (April–September) revert to summer-specification fuel.
How it worked: The facility contracted with suppliers to deliver winter fuel (with pour-point depressant additives) during cold months. Fuel heater was also installed to warm fuel slightly before injection, further improving cold-weather performance. Winter efficiency improved to summer levels.
Results
efficiency restored
in 12 months
minor vs efficiency gain
critical for grid outages
Diesel engine performance is highly temperature-sensitive. Using appropriate fuel for the season ensures consistent efficiency and reliability year-round.
Operational Reality
Facilities in cooler climates often lose 15–25% generator efficiency during winter without realizing it. Seasonal fuel switching restores performance to baseline.