Rooftop Solar for Shops, Clinics and Small Businesses
Rooftop solar for shops, offices, clinics and small factories in India: size to daytime load, ToD banking, grid support charges, tax and payback.
Short answer: commercial power is expensive, so rooftop solar usually pays back fast for shops, clinics, offices and small factories, even without subsidy. The key is to size to daytime use, because many states now bank non-residential solar slot by slot under time-of-day (ToD) tariffs, and to account for state charges such as Maharashtra's grid support charge above 10 kW. Check net-metering eligibility for your category first.
Why businesses are a strong fit
- Commercial tariffs are higher than residential, so each saved unit is worth more.
- Most businesses use power in daylight, when solar produces.
- GST on solar modules and solar power devices fell from 12% to 5% from 22 September 2025, cutting system cost.
- Businesses may claim depreciation benefits (ask your CA about current rates).
Step 1: find your daytime share
Look at your bill and your hours:
| Business | Typical hours | Daytime share of use (rule of thumb) |
|---|---|---|
| Office, clinic, school | 9 am–6 pm | high |
| Shop, showroom | 10 am–9 pm | medium |
| One-shift workshop | 9 am–6 pm | high |
| Restaurant | noon–midnight | low to medium |
| Cold storage, 24×7 unit | round the clock | medium |
Sunlectric Studio uses 55–65% for shops and offices and 60–70% for one-shift factories as starting values. Replace them with the real share from a ToD bill when you have it.
Step 2: understand your state's banking rules
Under the Electricity (Rights of Consumers) Amendment Rules, 2023, ToD tariffs apply first to commercial and industrial consumers with maximum demand of 10 kW and above. Solar-hour rates are lower and peak rates higher than normal.
That matters because in several states, non-residential solar exports during solar hours can only offset solar-hour imports. Units exported at noon cannot cancel units used at 8 pm; the surplus is paid at the low surplus rate. Maharashtra applies slot-wise banking to non-residential consumers while residential consumers can use banked units at any hour.
Step 3: check state charges and eligibility
| State | What to check for commercial rooftop |
|---|---|
| Maharashtra | Grid support charge ₹1.96/unit (LT) on gross generation above 10 kW; kVAh billing above 20 kW; ToD solar-hour rebate |
| Uttar Pradesh | Commercial uses gross metering or net billing, not net metering |
| Gujarat | Large FPPAS (₹2.5–3/unit) makes savings bigger; draft DRES regulations pending |
| Karnataka | LT commercial energy rate (sources conflict); net metering under KERC DSPV rules |
| Telangana | Commercial and industrial net metering up to 80% of sanctioned load |
| Kerala | Grid support charge for new plants above 5 kW proposed from April 2027 |
Sunlectric tariff notes, Oct 2026. Check the current notification for your category.
Step 4: size and design
- Monthly units × daytime share = units solar can offset at full value.
- Divide by your city's yield (about 1,400–1,650 units per kW per year).
- Check roof or shed area, structure (tin sheds need purlin checks), and sanctioned load.
- Use a three-phase inverter above 10 kW; consider DC/AC ratio around 1.1–1.25.
Tin sheds and commercial roofs
Many small factories have trapezoidal metal roofs. Mini-rails fixed on the crests with EPDM seals avoid leaks. The rails must hit the purlins where the sheet is thin, and rusted sheets must be replaced first. Ask the installer for a structural check, especially in high-wind and coastal zones. See structure design and wind.
Money: what to expect
Commercial paybacks are often 3–5 years, but they swing with:
- the value of a saved unit (tariff + FAC + duty, minus any ToD solar-hour rebate),
- the share of solar that offsets same-slot use,
- grid support charges and kVAh billing,
- whether your state allows net metering for your category.
Our engineering review of a 50 kW Maharashtra commercial case moved its payback from an optimistic 1.5 years to about 3 years once the grid support charge, slot-wise banking, ToD rebate and kVAh billing were modelled. Ask your installer to show these items.
Practical tips
- Monitor daily generation and alarms; a tripped inverter in a shop can go unnoticed for weeks.
- Plan cleaning: commercial areas near roads get dusty fast.
- Fire safety: keep DC cables in conduit or tray, label isolators, and brief staff on shutdown.
- Insurance: tell your insurer about the system.
A quick sizing example (illustrative)
A small office uses 1,500 units a month and works 9 am to 6 pm. Assume 65% of its use falls in solar hours and a yield of 1,500 units per kW per year.
- Units solar can offset at full value: 1,500 × 0.65 ≈ 975 a month, or about 11,700 a year
- Size: 11,700 ÷ 1,500 ≈ 7.8 kW, so about 8 kW
- Anything beyond that is likely exported at the surplus rate if your state banks by ToD slot
If your state allows any-hour netting for your category, a larger system may be justified. Use real figures from a ToD bill wherever possible.
Before you sign
Ask for the generation estimate split into solar-hour and other units, the treatment of any grid support charge, and the monitoring access you will get.
Talk to Sunlectric
Run a shop, clinic or workshop? WhatsApp your bill to +91 89567 89307 (wa.me/918956789307) and our Solar Desk will estimate size and savings with your state's banking rules. We supply complete commercial kits, three-phase inverters, tin-shed structures and BOS from our Pune hub, and can introduce you to an installer.
Sources
- GST cut to 5% from 22 Sep 2025: Reslink
- ToD rules: Indian Infrastructure, 21 Jun 2023
- MERC grid support charge and banking: Saur Energy; pwrnxt
- UP commercial gross metering: Bridge to India
- Telangana 80% cap for C&I: Mercom
- Kerala grid support charge: Rayenna Energy
- Sunlectric Studio engineering review, Oct 2026 (50 kW MH case)
Questions people ask
Do commercial rooftop systems get the PM Surya Ghar subsidy?
No. PM Surya Ghar is for residential consumers and housing societies. Businesses can still benefit from accelerated depreciation (check with your CA), lower GST on solar devices since September 2025, and high commercial tariffs.
How should a shop size its solar system?
Size to daytime consumption, not total consumption, if your DISCOM banks solar units by ToD slot. A shop open 10 am to 9 pm uses part of its power after sunset, which solar can offset only if the state allows any-hour netting.
What is the grid support charge in Maharashtra?
MERC levies a grid support charge on gross solar generation for rooftop systems above 10 kW: ₹1.96 per unit for LT in FY 2026-27 (check current order). It reduces savings for larger commercial systems.
Is net metering available for commercial consumers everywhere?
No. Rules vary. UP, for example, allows net metering for domestic, agricultural and institutional consumers, while commercial consumers use gross metering. Check your state.