Solar, storage and hybrid plants for industry, with the switchboards built in our own works.
Free tool for plants that run on diesel backup
DG replacement calculator
Enter your DG set rating, monthly running hours and diesel price. You get your real cost per unit on diesel, the storage size that would carry most of those hours, an indicative capex and the payback in years. Runs in your browser; nothing is uploaded.
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Your numbers
Enter the DG rating and running hours to begin.
—what a unit on diesel costs you
—spent on DG per year
Unlock the detailed report
The headline numbers are free. The full breakdown, sizing and payback are emailed to you and unlocked here once you verify your work email.
- Full breakdown of every figure
- System size, capex and payback
- What to do next, flagged by our engineers
- A copy emailed to you, plus one-click request for the free feasibility study
One-time code to your email, nothing else. We do not share your details.
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How the calculator works
What a diesel unit really costs
A DG set at part load burns roughly 0.3 litres per unit generated. At ₹92 a litre that is ₹27 a unit in fuel alone, before lube, filters, service visits and the engine's own wear. Most plants land between ₹18 and ₹25 a unit once loading and maintenance are counted, against ₹7.5–8.5 from the grid.
How the battery is sized
The battery must carry your load for the outage length you choose. The calculator takes your DG load, multiplies by the outage hours, then allows for depth of discharge and conversion losses so the usable energy is what you need. The PCS is rated to the load. Both are rounded up to standard sizes.
What is counted as saving
- Units that move from diesel to stored grid power, valued at the difference between your diesel cost per unit and the grid tariff with charging losses.
- Maintenance hours avoided on the DG set.
- Not counted: demand-charge savings, solar charging, avoided production loss from trips, and the DG set's extended life. All of these improve the real case.
When DG replacement alone is not enough
Below about 20 hours a month the diesel saving is small, and the battery has to earn its keep on demand charges and ride-through instead. That is the normal industrial case, and it is why we size storage from the bill and the trip log together. Run the bill analyser for the other half of the picture.
Why is diesel power so expensive per unit?
A DG set at part load burns about 0.28 litres per unit. At ₹92 a litre that is ₹26 before lubricants, filters, service visits and wear, against ₹7.5 to 8.5 from the grid. Every hour on DG costs two to three times grid power.
Can a battery replace my DG set completely?
For short and medium outages, yes. For a long outage the DG still starts, so most plants keep it as the last line of defence and run it a fraction of the hours they did before. The calculator assumes the battery takes 85 per cent of DG hours.
What if my DG hours are low?
Below about 20 hours a month the diesel saving alone is small. The battery then has to earn its keep on demand charges and ride-through, which is the normal industrial case; use the demand charge calculator for that half of the picture.
