DG vs Solar Calculator
DG vs Solar Calculator — quick estimate
Diesel generation costs far more per unit than grid power, which is why displacing DG hours is usually the strongest solar case a factory has. Enter what your DG actually burns and see the cost per unit both ways.
Your diesel generator
Solar cannot replace a DG set — it displaces the daytime hours a DG runs to carry load, not its standby role. Set the displaceable share to match when your DG actually runs.
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Our engineers will read your DG log and load profile, work out exactly which hours solar can take over, and size the plant against them.
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Indicative estimates only, not a binding quotation. Actual DG efficiency varies with load factor and age; actual solar output varies by site, shading and season.
Questions engineers and CFOs ask
Can solar replace my diesel generator?
No, and any vendor who says otherwise is overselling. Solar generates only in daylight and only in proportion to irradiation, so it cannot hold your standby role during an outage at night or in monsoon. What it can do is displace the daytime hours your DG currently runs to carry load, which is usually where most of the diesel goes. Keep the DG for standby; use solar to stop burning diesel for routine daytime running.
Why is diesel generation so much more expensive than grid power?
A DG set typically delivers around 3 to 3.5 units per litre. At current diesel prices that puts fuel alone well above most C&I grid tariffs before you add maintenance, oil changes and overhauls. Because the fuel cost is the dominant term and it tracks the diesel price, DG cost per unit also rises with no cap.
What share of my DG output can solar realistically displace?
It depends entirely on when the DG runs. If it carries daytime process load during grid outages or load shedding, a large share can be displaceable — but only if the plant has a DG–solar controller that lets the inverters run alongside the DG; a plain grid-tied plant shuts down when the grid fails. If it only runs at night or as pure standby, very little is. The displaceable share is an input here rather than an assumption, because getting it wrong is the single biggest error in a DG-versus-solar case.
Does this include the cost of a battery?
No. The comparison here is solar against diesel for daytime running, with no storage. Adding batteries to cover evening or outage load changes the economics substantially and needs a separate design exercise around your actual load profile.
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