Commercial Solar: real costs, real payback

Most "commercial solar" quotes doing the rounds in India are either suspiciously cheap or padded with line items you don't need. Here's a transparent breakdown for a real-world 30 kWp rooftop system on an Indian SME site - the size most shops, clinics, small offices, showrooms and workshops actually end up at.

Why 30 kWp is the typical sweet spot

Almost every state DISCOM keeps a non-domestic LT commercial category (LT-3 / LT Cat 3A / LT-II depending on the state) that a 30 kWp plant fits comfortably inside. That means:

• You stay on the LT tariff (no HT conversion, no CT/PT metering)
• Net metering goes through the standard LT 1Φ/3Φ bi-directional meter
• Sanctioned load of 25-50 kW typically supports a 30 kWp plant without breaching the system size ≤ sanctioned load rule that nearly every state's net-metering regulation carries

Above 50 kWp things change in most states - electrical inspectorate (CEIG/CEI) certification, structural drawings to the DISCOM, longer review cycles. 30 kWp keeps you on the fast path.

Installed cost: Rs 18-21 lakh, line by line

For Tier-1 hardware, properly installed, anywhere in urban India in 2026:

Line item	Cost (₹)
Mono PERC / TOPCon panels (54 × 555 Wp)	6,40,000 – 7,20,000
String inverter (25–30 kW, Tier-1)	2,40,000 – 3,00,000
Galvanised mounting structure	1,20,000 – 1,50,000
DC + AC cabling, MC4, conduits	80,000 – 1,10,000
ACDB / DCDB, SPDs, isolators, earthing, LA	70,000 – 90,000
Net-metering compatible meter + DISCOM fees	35,000 – 50,000
Civil work, transport, installation labour	1,80,000 – 2,40,000
Liaisoning, drawings, commissioning	60,000 – 80,000
Monitoring (Wi-Fi/4G data logger)	25,000 – 40,000
GST and contingency	2,50,000 – 3,20,000
All-in	₹18,00,000 – ₹21,00,000

That's roughly ₹60,000-₹70,000 per kWp all-in. Anything materially below ₹50,000/kWp usually means swapped BoS, downrated panels, or a no-show inverter brand.

What the system actually generates

Specific yield across most of India runs 1,400-1,650 kWh per kWp per year - the higher end in Gujarat, Rajasthan, Telangana, Karnataka and Maharashtra, the lower end in the eastern and north-eastern states. Taking a mid-band site at ~1,550:

• Annual generation: ~45,000-47,000 units
• Monthly average: ~3,800 units

The savings math

Commercial LT tariffs in 2026, with fixed and energy charges combined, land around ₹8.5-₹11/unit in most states for SMEs in the relevant slab. Using ₹10/unit:

• Energy displaced: ~46,000 units × ₹10/unit = ₹4.6 lakh/year
• Net of ₹15,000-₹20,000/year in cleaning + minor AMC
• Net annual benefit: ~₹4.4 lakh

Payback

• System cost: ₹19.5 lakh (midpoint)
• Net annual benefit: ₹4.4 lakh
• Simple payback: 4.5 years
• With accelerated depreciation (40% in year 1, on the depreciable cost): payback effectively compresses to 3.5-4 years for profitable businesses
• Without AD: 5-6 years, and still 19-20 years of near-free power after

What we won't compromise on at this size

• ALMM List-I panels with BIS certification
• Tier-1 inverter with a service centre in or near your city
• Hot-dip galvanised structures (not painted MS - it rusts inside 4 years)
• Original Stäubli MC4 connectors
• Remote monitoring from day one

If your quote doesn't itemise these, you're not comparing apples to apples.