Manufacturing Plant – part 3
Most plant managers know their monthly diesel bill. Very few have ever calculated the annual number — and when they do, it’s almost always a shock. This guide shows you the exact calculation for facilities of 100–2000 kW, what’s driving the cost higher than it needs to be, and how plants across India are cutting it by 60–80% with a single capital decision.
The Number Most Plant Managers Have Never Calculated
Here is a question. When was the last time you added up your total annual diesel spend — not just last month’s bill, but the full 12-month cost including fuel, maintenance, and DG depreciation?
For most plant managers, the answer is never. The monthly bill comes in, gets paid, and life moves on. But when you calculate the annual number — and factor in what diesel actually costs per unit of electricity generated — the figure is almost always larger than expected.
₹18–24/kWh
That’s the true cost of diesel-generated electricity in India in 2025 — including fuel, maintenance, oil changes, and DG depreciation. Grid electricity in most Indian states costs ₹7–9/kWh. Your DG is generating power at 2.5 to 3× the grid rate — every single hour it runs.
The problem is not that plant managers are unaware of diesel costs. The problem is that the true cost per kilowatt-hour is almost never calculated. The diesel bill is paid. The maintenance bill is paid separately. The DG’s depreciation is an accounting entry somewhere. When you combine these three — the number changes the conversation entirely.
The fuel bill alone was ₹1.71Cr. Total true cost with maintenance and depreciation: ₹2.03 Crore per year — on diesel that could be reduced by 70%.
Why DG Running Costs Are So Much Higher Than the Grid — The Real Maths
Here is a question. When was the last time you added up your total annual diesel spend — not just last month’s bill, but the full 12-month cost including fuel, maintenance, and DG depreciation?
For most plant managers, the answer is never. The monthly bill comes in, gets paid, and life moves on. But when you calculate the annual number — and factor in what diesel actually costs per unit of electricity generated — the figure is almost always larger than expected.
"We knew diesel was expensive. But when our accounts team finally did the full calculation - fuel, AMC, and depreciation. The number was ₹1.9 crore a year. That's when we took BESS seriously."
The Three Drivers of High DG Cost And Which One Is Killing Your Bill
Not all DG cost is the same. Understanding which driver is biggest for your facility tells you exactly how much a BESS investment can save — and in which way. There are three main causes:
- Long Running Hours (The Most Common)
- Demand Charges (The Hidden One)
- Poor Solar Integration (The Missed Opportunity)
| Cost Component | Grid Electricity | Diesel Generator |
|---|---|---|
| Fuel/Energy cost | ₹8.5/kWh | ₹18.5/kWh (fuel only) |
| Maintenance cost | Zero (grid side) | ₹3–5/kWh (oils, AMC) |
| Reliability | Dependent on grid | Good but delayed start |
| Emission | Low (improving) | High (CO₂, NOx, noise) |
| True cost per kWh | ₹8.5 | ₹21–24 |
Frequently Asked Questions
How long does a BESS installation take from order to commissioning?
Does BESS replace the diesel generator entirely
What happens to the BESS after 10–12 years? Does it need replacement?
