The Challenge
A facility with 50 kWp rooftop solar, grid connection, and 250 kVA backup generator used solar for daytime production and grid for evening peak. During monsoon, solar output dropped and grid peak charges surged.
What Became Visible
Energy source analysis revealed a suboptimal pattern: (1) Solar production was curtailed when grid was cheap (off-peak). (2) Diesel was never used to cover peak tariff hours because it was scheduled based on backup-failure assumptions, not economics. (3) During low-solar days, facility paid 100% of peak tariff charges without considering diesel as an alternative.
What Changed
Three-source energy management system implemented. Solar prioritized always. Grid used when tariff <₹12/kWh. Diesel activated when grid tariff >₹15/kWh AND load sustainable on DG.
How it worked: The system ranked energy sources by cost: (1) Solar (free). (2) Grid off-peak <₹5/kWh. (3) Grid standard ₹8/kWh. (4) Grid peak ₹18/kWh. (5) Diesel ₹16–17/kWh. Load was served from the cheapest available source in order. This reduced reliance on expensive peak-tariff grid hours and used diesel only during true peak periods.
Results
hours avoided or shifted
used on-site vs exported
12-month average
smart energy source selection
Three energy sources should be managed as an integrated system, not independently. Integrated management treats them as a portfolio: maximize low-cost sources, minimize high-cost sources.
Operational Reality
Facilities with solar, grid, and diesel typically save 10–25% on energy costs when sources are integrated versus operating them on separate schedules.