Cost calculator
DG cost per unit calculator: what every hour on diesel really costs.
Enter your DG set, the load it carries and the hours it ran this month. See what each DG unit costs, the extra over grid supply, and how much light loading adds.
Each DG unit costs about₹37.80₹29.80 more than a grid unit · ₹1,78,806 extra this month
- DG rating in kW at 0.8 power factor
- 200 kW
- DG loading
- 50%
- Diesel per hour
- 40.89 litres
- Units per litre
- 2.45
- Units from the DG this month
- 6,000 kWh
- Diesel this month
- 2,453 litres
- Diesel cost
- ₹2,20,806
- Servicing and upkeep
- ₹6,000
- Same units from the grid
- ₹48,000
- Extra cost over a year
- ₹21,45,672
- Per unit on a DG sized for this load 75% loaded
- ₹32.91
- CO₂ from the diesel
- 6,575 kg
A DG sized for this load would run 75% loaded and cost less per unit.
Illustrative defaults — replace them with your own. The fuel curve is a generic diesel generator estimate; your DG’s own fuel log gives the real figure. For the grid rate, use the energy rate plus duty and surcharges: demand charges stay the same whether the DG runs or not. DG purchase cost, operator wages and production lost at changeover are not included.
How the calculator works
- Cost per unit. Diesel cost plus servicing and upkeep for the month, divided by the units the DG generated.
- Units per litre from your log. Units generated ÷ litres filled over the same period. Use a month or more, so one fill does not skew it.
- Fuel curve estimate. Diesel per hour = 0.08145 × rated kW + 0.246 × load kW, with rated kW = kVA × 0.8. The first part burns whatever the load, which is why a lightly loaded DG costs more per unit.
- Extra over grid. DG units × (DG cost per unit − grid energy rate).
A DG burns a fixed amount of fuel just to keep turning. Spread over fewer units, each unit costs more. Long running below about 30% load can also leave unburnt fuel in the exhaust, known as wet stacking.
Ways plants cut DG cost
- Match the DG to the load. Run one set well loaded instead of two lightly loaded, or the smaller set when the load allows.
- Shed what can wait. Keep non-essential loads off while on DG, so the hours on diesel go to production.
- Let solar run with the DG. A DG controller keeps solar running during an outage, held below the load so the DG stays above its minimum.
- Watch units per litre every month. A falling figure points to an engine due for service, or fuel going missing.
DG cost in KONDUKTOR® EMS
- The DG’s meter is tagged as DG, with its rating, diesel price and fuel use per unit. The dashboard shows units generated and diesel cost for the month to date.
- DG load hour by hour, next to grid, solar and the plant load, so light loading shows up the day it happens.
- The solar planner compares a DG with a hybrid inverter and battery for outages, using the same fuel curve as this calculator.
Alerts when the DG runs below a set loading, and a monthly units-per-litre check against your fuel log, are set up for your plant as part of your project.
Common questions
How much diesel does a DG use per hour?+
It depends on its rating and the load it carries. A generic fuel curve puts a 250 kVA set carrying 100 kW at about 41 litres an hour, and the same set at full load at about 65 litres. Your DG’s own fuel log gives the real figure.
Is it cheaper to run the DG than to pay the peak-hour tariff?+
Almost never. Even with a peak-hour surcharge, a grid unit usually costs well under ₹15, while a well-loaded DG unit costs more than ₹25 at today’s diesel prices. A lightly loaded DG costs more still.
What loading should a DG run at?+
Around 60 to 80% of its rating is the usual range: units per litre are close to their best and there is headroom for motor starts. Long running below about 30% wastes fuel, and many DG makers advise against it.
See what your DG really costs, from its own meter.
Book a live demo and see DG units, loading and diesel cost next to grid and solar, on meters like yours.