It's the first question almost every plant head and finance director asks us, and it's a fair one: what will a solar plant actually cost? The honest answer is that there's no single sticker price, but there are believable ranges, and knowing them helps you sanity-check any quote that lands on your desk. So let's talk numbers, plainly.
Everything below is indicative. These are typical turnkey bands we see for commercial and industrial rooftop plants in Tamil Nadu and South India, reviewed September 2026: quoted before subsidies and GST, and inclusive of first-year O&M. These bands are the single reference we use for solar pricing across this site, so the figures here match those in our FAQ and worked examples. Your real number depends on your roof, your site and the components you choose, and prices in this industry move with module rates, the rupee and demand. Treat the figures as a starting point for a conversation, not a fixed quote.
Indicative turnkey cost by capacity
Here is roughly where turnkey pricing tends to sit across the four sizes people ask about most. Again, these are indicative bands, not quotes, and the per-watt figure is what really tells the story.
| Capacity | Indicative turnkey cost | Indicative ₹/W |
|---|---|---|
| 100 kWp | ₹45–50 lakh | ~₹45–50/W |
| 250 kWp | ₹1.05–1.15 crore | ~₹42–46/W |
| 500 kWp | ₹2.0–2.2 crore | ~₹40–44/W |
| 1 MWp | ₹3.8–4.2 crore | ~₹38–42/W |
Notice the pattern in that last column. A 100 kW plant lands around ₹45–50 per watt, while a 1 MW plant can come in closer to ₹38–42 per watt. That drop isn't a discount for being a bigger customer, it's real engineering economics, and we'll come back to why it happens.
Two plants of the same size, on two different roofs, can honestly carry two different price tags, and both can be fair.
What a turnkey price actually includes
When we say "turnkey," we mean the plant is designed, supplied, installed and handed over ready to generate, you're not left sourcing bits and pieces afterwards. A proper turnkey number generally covers:
- Tier-1 solar modules, the panels themselves, the single biggest line item.
- Inverters, string or central, sized to the array, that convert DC to usable AC.
- Mounting structure, the galvanised framework that holds panels at the right tilt and survives local wind.
- DC and AC cabling, the wiring from panels to inverters to your board.
- Protection equipment, DC and AC distribution boxes, breakers and surge protection.
- Earthing and lightning arrestors, the safety backbone that protects both plant and people.
- Installation and commissioning, labour, cranes, testing and switch-on.
- Net-metering liaison, the DISCOM paperwork and coordination to get you connected.
- First-year O&M, monitoring, cleaning guidance and support through the first year.
If a quote looks unusually cheap, it's worth asking which of these it quietly leaves out. A missing structural upgrade or a thin earthing scheme doesn't make solar cheaper, it just moves the cost, and the risk, onto you later.
What's included / what moves the price
- Always included in a real turnkey scope: Tier-1 modules, inverters, mounting, DC/AC cabling, protection, earthing and lightning arrestors, installation, net-metering liaison and first-year O&M.
- What pushes the number up: a weak or old roof needing structural strengthening, greater roof height, premium modules or inverters, long cable runs to an evacuation point, transformer or HT-side work, and tricky site access.
- What brings it down: a sound roof, larger contiguous area, a bigger plant that spreads fixed costs, and simple, close-by electrical evacuation.
What moves the number up or down
Two factories can ask for the same 250 kW plant and receive two genuinely different indicative prices. Here's what's usually behind that gap.
Roof type and height
A clean, strong metal roof at a sensible height is the easy case. An older RCC roof that needs waterproofing, or a tall structure that demands more scaffolding and safety, adds real cost. Sometimes the roof needs strengthening before a single panel goes up, that's money well spent, but it's money.
Module and inverter tier
All panels are not equal. Higher-efficiency modules and premium inverters cost more upfront but can generate more, last longer and behave better in the Tamil Nadu heat. The right choice depends on your roof area and how long you plan to hold the asset, it's a trade-off, not a rule.
Evacuation and transformer
Getting the power from your roof into your electrical system sounds trivial, but if the connection point is far away, or if transformer and HT-side work is involved, that's a meaningful part of the bill, especially on larger plants.
Site access
A site a crane can reach easily is cheaper to build than one where every panel is carried up by hand. Access, storage space and how much the plant can run without disturbing production all quietly shape the final figure.
Canopy versus rooftop
Rooftop is usually the most cost-effective home for a plant. Solar carports or ground-mounted canopies open up capacity when the roof runs out, but the extra steel and civil work make them cost more per watt than a straightforward rooftop install.
Why per-watt cost falls as you scale
Look back at the table and you'll see the ₹/W band shrink from around ₹45–50 at 100 kW to around ₹38–42 at 1 MW. This is the most reliable rule in solar pricing, and it comes down to fixed costs.
A design fee, a DISCOM application, the mobilisation of a crew, the safety setup, a lot of this barely changes whether you're building 100 kW or 1 MW. Spread across ten times the capacity, those fixed costs almost vanish on a per-watt basis. Bigger plants also buy modules and inverters in bigger lots and use labour more efficiently. It's the same reason a bulk order costs less per unit, the plant just gets more cost-efficient the larger it gets, right up until you run out of roof.
This is exactly why sizing matters, and why an honest feasibility study looks at your daytime load before it looks at your roof. There's little point paying for a 1 MW plant if you can only self-consume a fraction of it.
A quick word on subsidies and depreciation
You'll often hear that subsidies or accelerated depreciation change the maths. They can, but this is where we're most careful, because these benefits are entirely situation-specific. Commercial and industrial rooftop subsidies, tax treatment and accelerated depreciation depend on your business type, the prevailing central and state policy, and rules that change from year to year. Please treat any benefit as unconfirmed until it's verified against current policy for your specific case. We'd rather quote you a clean number without assumed subsidies than build a business case on a benefit that may not apply to you.
So, what should you do with these numbers?
Use them as a reality check. If a quote for a 500 kW plant lands far below ₹2 crore, ask what's missing. If it lands far above ₹2.2 crore, ask what's driving it, sometimes there's a genuine reason like a roof upgrade, and sometimes there isn't. The goal isn't to chase the cheapest figure; it's to understand what you're buying and why it costs what it does.
Every price on this page is indicative. The only way to get a number you can actually plan around is a site-specific assessment, your roof, your load, your evacuation point. You can start with our quick solar calculator for a first-cut estimate, or browse our case studies to see how real plants came together across different sites.