How to read your commercial electricity bill
Energy charge, demand charge, power factor, ToD — what each line on an Indian C&I electricity bill actually means, and which ones solar can touch.
- A commercial electricity bill in India has five parts that matter: energy charge, demand charge, power factor, time-of-day slabs, and fixed charges and duties.
- The energy charge (units consumed) is what rooftop solar addresses most directly.
- The demand charge bills your single highest sustained draw, not your consumption — solar affects it only partly, which is where battery storage comes in.
- Power factor is often the cheapest line to improve, and needs no generation at all.
- Four numbers tell an engineer most of what matters: tariff category, sanctioned demand, recorded maximum demand, and total units.
Most facility managers can tell you what their electricity bill totals. Far fewer can tell you what it's made of — and that's where the decisions live.
A commercial and industrial bill in Maharashtra is built from five components, and solar touches each one differently. Here they are, line by line.
1. Energy charge (the units)
This is what most people think of as "the bill": your consumption in kWh multiplied by a rate per unit. It's the part rooftop solar addresses most directly, because every unit your system generates and you consume on site is a unit you don't buy.
The nuance: solar only generates in daylight. If your load is concentrated at night, the arithmetic changes completely. This is why we ask for consumption patterns, not just totals.
2. Demand charge (maximum demand)
Separate from units consumed, you're billed on your maximum demand — effectively your highest sustained draw during the billing period, measured in kVA or kW. Push a big load on for fifteen minutes and you can pay for it all month.
Solar has only a limited effect here, because your peak may occur when the sun isn't cooperating. This is one of the clearest cases for battery storage, which can discharge into a peak deliberately.
3. Power factor incentive or penalty
Poor power factor means you're drawing more current than your useful work requires. Utilities penalise it and reward good correction. It's often the cheapest line on the bill to improve — sometimes just capacitor banks and maintenance, no generation required at all.
4. Time of Day (ToD) slabs
Many C&I connections are billed with time-of-day differentiation: different rates for different windows. Where ToD applies, when you consume matters as much as how much. Solar generation sits squarely in the daytime window — so the value of each solar unit depends on which slab it displaces.
5. Fixed charges, duty, and the rest
Fixed or demand-based charges, electricity duty, tax on sale, wheeling and other regulatory components make up the remainder. Most of these don't move with a solar installation, and any honest proposal will say so rather than quietly folding them into a savings claim.
Pull your last two bills. Find four numbers: your tariff category, your sanctioned or contract demand, your recorded maximum demand, and your total units. Those four tell an engineer most of what they need to know before ever visiting your site.
Why we ask for two bills, not one
One bill is a snapshot; two start to show a pattern — seasonality, shift changes, whether that demand spike was a one-off. If you have twelve months, better still. The more real data a proposal is built on, the fewer assumptions have to be invented.
Send yours and we'll tell you what we see: info@meridiancircle.in.
Bring your own numbers.
We'll read your bills and tell you what we see — including if the answer is 'not yet'.