Key takeaway
As an illustrative planning band (not a quote or a surveyed price), a 100 kW commercial rooftop solar system costs ₹45–₹65 lakh all-in in India in 2026, or ₹45 to ₹65 per Wp including GST. With four savings streams, bill reduction, depreciation at 40% of written down value, REC income, and net export, the worked example below pays back in about 3.9 years; yours depends on tariff, ownership and tax.
What Does a 100 kW Commercial Solar System Cost in India?
The 100 kW rooftop segment is where solar investment transitions from a household decision to a corporate finance exercise. Factories, warehouses, cold storage units, hospitals, educational institutions, and commercial office buildings with monthly electricity bills above ₹2 lakh are the natural buyers here, and our guide to selling solar to factories covers who decides and what to collect before you quote.
In 2026, the all-in installed price for a 100 kW on-grid commercial system ranges from ₹45 lakh to ₹65 lakh, roughly ₹45 to ₹65 per watt peak (Wp). All prices in this guide are illustrative planning bands from our own view of the market, not quotes or survey data, so replace them with your supplier quotes. Larger systems usually get better rates in module purchasing, inverter sizing, and labour deployment.
The wide band reflects real differences in system design choices: string inverter bank versus central inverter, tier-1 ALMM-listed versus non-ALMM modules, simple RCC rooftop versus complex tin-sheet or asbestos-replacement structures, and whether the EPC firm is local or a national player with higher overhead. For the cost per watt benchmarks at other sizes, our comparison guides lay out the full picture.
Commercial and industrial (C&I) rooftop is a large segment of India's solar market, driven by grid tariffs, financing and corporate ESG pressure (we have not cited a growth figure). If your pipeline is moving past 100 kW, our guide to the 1 MW solar power plant cost in India covers how land, evacuation and capex shares change at megawatt scale.
Full Cost Breakdown for a 100 kW System
| Component | Specification | Est. Cost Range (₹) | % of Total |
|---|---|---|---|
| Solar modules (180–190 panels) | 530–580 Wp ALMM mono PERC/TOPCon | 22,00,000–32,00,000 | 50–54% |
| Inverter(s) | String bank (4–5 × 20 kW) or central 100 kW | 5,00,000–9,00,000 | 12–14% |
| Mounting structure | GI hot-dip galvanised, industrial-grade | 4,00,000–6,00,000 | 9–10% |
| BOS (cables, DCDB, ACDB, SPD) | Full BOS including earthing, LA, conduits | 2,50,000–4,00,000 | 6% |
| Monitoring system | Data logger, SCADA, remote monitoring | 50,000–1,50,000 | 1–2% |
| Civil + installation labour | Site prep, erection, testing, commissioning | 3,00,000–5,00,000 | 7–8% |
| DISCOM liaisoning + net meter | Net metering application, CEIG approval where your state requires it | 50,000–1,00,000 | 1–2% |
| GST at about 8.9% blended (arithmetic) | 5% on the 70% goods share (CBIC Notification 9/2025-IGST(Rate)); the 30% service share is under entry 38 of 11/2017-CT(Rate), 9% CGST or 18% IGST. The 8.9% is inter-State arithmetic only; confirm with your CA | 3,68,000–5,31,000 | ~8% |
| TOTAL ALL-IN (independent illustrative bands, so lines do not sum exactly) | ₹45,00,000–₹65,00,000 | 100% | |
Tip
At 100 kW scale, always request itemised module-level pricing from at least three vendors. Module costs can vary between suppliers for nominally the same specification. As an illustration, a ₹3 to ₹8 per Wp gap on about 1,04,500 Wp (190 panels of 550 Wp) is a ₹3.1 to ₹8.4 lakh swing purely on module pricing.
String Inverter Bank vs Central Inverter, Which Is Right for 100 kW?
This is the most consequential design decision for a 100 kW system. The two dominant configurations are a bank of four to five 20 kW string inverters, or a single 100 kW central inverter.
| Factor | String Inverter Bank (4–5 × 20 kW) | Central Inverter (1 × 100 kW) |
|---|---|---|
| Cost | ₹5,00,000–₹8,00,000 | ₹4,50,000–₹7,50,000 (slightly cheaper) |
| Partial failure impact | Only 20% capacity lost per inverter failure | 100% capacity loss on single failure |
| Shading tolerance | Higher, each string optimised independently | Lower, whole array on single MPPT |
| Installation complexity | Multiple wall-mount locations needed | Single large unit, needs dedicated room/cage |
| Efficiency | Check the datasheet; string models are often slightly higher | Check the datasheet |
| Certification | ALMM covers modules, not inverters, so check IEC test certificates and anti-islanding | Same: check certificates and anti-islanding |
| Recommended for | Rooftops with partial shading, uptime-critical facilities | Large uniform rooftops, lower budget |
For most commercial rooftop installations in India's Tier-1 and Tier-2 cities, where partial shading from water tanks, staircase structures, and neighbouring buildings is common, a string inverter bank is the preferred choice despite marginally higher cost. The uptime resilience is worth the premium when the facility depends on continuous operations.
See our detailed solar inverter price guide for brand-by-brand pricing at each capacity level.
Key Output and Savings Numbers
These are illustrative figures on the assumptions shown, not data from any survey or agency. Depreciation rate: Income-tax Rules, 2026, Appendix I.
The Commercial Solar ROI Stack, 4 Savings Streams
The most common mistake in 100 kW project proposals is presenting only the electricity bill saving. Commercial buyers who have seen multiple solar pitches expect a comprehensive financial picture. The Commercial Solar ROI Stack is a named framework that presents all four savings streams explicitly, making the financial case undeniable.
Stream 1, Electricity Bill Reduction (the obvious one) A 100 kW system generating 12,000 kWh/month at a blended commercial tariff of ₹8/unit saves ₹96,000/month or ₹11.5 lakh/year. This is the floor of the ROI case, not the ceiling.
Stream 2, Depreciation Tax Benefit Under section 33 of the Income-tax Act, 2025 (section 32 of the 1961 Act before 1 April 2026), solar power generating systems are depreciated at 40% of written down value, halved if the plant is used for less than 180 days in the tax year. For a ₹55 lakh system, a full first-year claim is ₹22 lakh. At an assumed 30% tax rate, the Year 1 tax saving is ₹6.6 lakh. Confirm the figures with the owner's CA.
Stream 3, Renewable Energy Certificate (REC) Income Solar generators injecting surplus power into the grid can earn RECs under the REC mechanism managed by POSOCO. At an assumed ₹1,000 per REC (1 REC = 1 MWh; check the current exchange price and whether your system is eligible), a 100 kW system generating 1,44,000 kWh/year and exporting 20% (28,800 kWh) could earn about ₹28,800 a year in REC income. This stream is small, so treat it as upside.
Stream 4, Net Metering Export Income Surplus generation exported to the grid via net metering is credited under your state's rule: net metering offsets units against the bill, and some states pay a notified rate for year-end surplus. At an assumed ₹2 per exported unit and a 15–20% export fraction (21,600 to 28,800 kWh), this adds about ₹43,000 to ₹58,000/year; the example below uses ₹45,000. Check your state's rule.
Total Year 1 return (₹55 lakh system example):
- Bill savings: ₹11,50,000
- Depreciation tax saving (Year 1 only): ₹6,60,000
- REC income: ₹32,000
- Export income: ₹45,000
- Total Year 1 benefit: ₹18,87,000
- Effective payback, counting the depreciation saving once: (₹55 lakh − ₹6.6 lakh) ÷ about ₹12.27 lakh a year of recurring benefit ≈ 3.9 years
Money
The depreciation benefit alone (about ₹6.6 lakh in Year 1 in the worked example, at an assumed 30% tax rate) can be what tips a commercial buyer from "considering" to "signing." Always present the full ROI Stack, not just bill savings, in every commercial proposal. See our ROI calculator for a working model.
RESCO Model vs Own-Install, A Direct Comparison
Not every commercial buyer wants to deploy capital. The RESCO (Renewable Energy Service Company) model offers solar without upfront investment, instead charging a per-unit tariff for solar power consumed.
| Factor | Own the 100 kW System | RESCO / PPA Model |
|---|---|---|
| Upfront capital | ₹45–₹65 lakh | ₹0 (or token security deposit) |
| Solar tariff paid | Nil (after payback, generation is free) | Set by negotiation for a multi-year PPA term; get written quotes |
| Depreciation | Claimable by asset owner | Claimable by RESCO, not consumer |
| O&M responsibility | Buyer (or AMC contract) | RESCO (built into PPA tariff) |
| Long-term savings | High, all generation value accrues to owner | Medium, PPA tariff escalates over time |
| Asset on balance sheet | Yes, increases fixed asset value | No, off balance sheet |
| Best for | Businesses with capital or access to cheap debt, 30%+ tax bracket | Capital-constrained, no tax liability, or leased premises |
Businesses with high taxable income often do better by owning the asset, because depreciation at 40% of written down value returns about 12% of system cost in Year 1 at a 30% tax rate (40% × 30%). The RESCO model is most compelling for businesses on leased premises where the landlord won't permit a capital installation, or for organisations with no current-year taxable income.
Group Captive Structure for Larger Consumers
The Group Captive model, enabled under the Electricity Act 2003, allows a group of consumers to jointly own a solar generation plant and consume the output as captive power. For 100 kW scale, this is less common, but it is a useful structure when multiple tenants or related businesses share a large commercial complex.
Under Group Captive:
- Captive users must hold at least 26% of the ownership of the plant, and consume at least 51% of the electricity generated on an annual basis, with each user's consumption proportionate to its ownership share (Electricity Rules, 2005, rule 3; read the current text before you rely on it)
- Some states exempt captive use from certain open access charges, so check your state's regulation
For most single-tenant commercial buildings, direct ownership or RESCO is simpler. But for multi-tenant IT parks, industrial estates, or business parks, the Group Captive option can unlock better per-unit economics. The MNRE guidelines and state electricity regulatory commissions (SERCs) govern the specific approval process.
DC:AC Ratio Optimisation for 100 kW
The DC:AC ratio (also called the Inverter Loading Ratio) is the ratio of installed solar panel capacity (DC kWp) to inverter output capacity (AC kW). Getting this right at 100 kW scale can add to annual generation without any additional module cost.
Financing Options, IREDA, ECB, and State Schemes
Capital cost is the primary barrier for commercial 100 kW adoption, which is why understanding the solar financing partners active in India matters as much as the technical design. In 2026, several financing options are available.
IREDA commercial solar loans: The Indian Renewable Energy Development Agency (IREDA) lends to renewable energy projects. We could not source current rates or tenures for 100 kW rooftop loans, so ask IREDA for a written quote and terms.
ECB (External Commercial Borrowing): For large corporates, ECB for green projects allows borrowing in foreign currency at lower interest rates. At 100 kW, the typical project value of ₹45–₹65 lakh may be too small for direct ECB, but large industrial groups with multiple sites can club projects.
State government support: Some states may offer capital subsidies or soft loans for commercial rooftop solar through their renewable energy development agencies. We have not verified any, so check with your state nodal agency.
NBFC and commercial bank loans: Banks and NBFCs offer solar project loans, with rates that depend on the borrower. Get quotes, then run the full ROI Stack at the quoted rate to demonstrate project viability.
Warning
Commercial installations are not eligible for PM Surya Ghar residential subsidy. Any vendor quoting subsidies for a commercial consumer is either misinformed or misrepresenting the scheme. Always verify eligibility on the MNRE portal before including subsidy figures in a commercial proposal.
Commissioning Timeline, an Illustrative Sequence
Large commercial projects have longer lead times than residential, and commissioning a large rooftop system follows a fairly predictable sequence. An illustrative planning sequence for a 100 kW system looks like this (our own planning view, not an official timeline; the DISCOM clock is the central rule that agreement, meter and commissioning are due within 15 days of your installation certificate):
Pros and Cons of a 100 kW Commercial System
PROS
- Better per-Wp pricing than small systems
- Depreciation at 40% of written down value gives a Year 1 tax saving (₹6.6 lakh in the worked example)
- Four independent savings streams maximise ROI
- 25-year asset life with rising electricity tariffs improves long-term returns
- Significant ESG and green credential value for corporates
- Loan financing can make it CapEx-light
CONS
- High absolute capital outlay (₹45–₹65 lakh)
- CEIG approval may be needed, depending on your state's threshold
- Requires roughly 1,000 to 1,200 sq m (about 11,000 to 13,000 sq ft) of usable, shadow-free roof area
- Structural roof load assessment is mandatory, adds cost
- No PM Surya Ghar residential subsidy applicable
- O&M and AMC commitments needed for 25-year asset life
How Quickest Solar CRM Helps You Win 100 kW Commercial Projects
For EPC teams and ops leads handling multiple large projects simultaneously, the administrative and proposal burden of commercial solar can be as complex as the technical work.
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Explore pipeline management for large commercial deals and see how field teams evaluate tools at best solar CRM software in India. The solar lead management guide covers handling multiple large commercial enquiries in parallel.
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Take the First Step Toward Your Best Commercial Project
The 100 kW commercial rooftop market rewards installers who show up with financial precision, not just technical competence. A buyer who gets a spreadsheet with four savings streams, a realistic commissioning timeline, a note on whether CEIG applies, and a year-one depreciation calculation is far more likely to sign than one who gets a one-page quote with just the panel count and price.
Build the full ROI Stack into every proposal. Present RESCO vs own-install honestly. Include the commissioning timeline. And get the proposal out within 48 hours of the site survey. That speed and thoroughness is what separates the EPC firms winning large commercial deals from those perpetually chasing them.
For related reading, see our 10 kW commercial guide, the solar cost per watt analysis, and the proposal pricing guide.
Frequently Asked Questions
Q1. What is the price of a 100 kW solar system in India in 2026? A 100 kW commercial rooftop solar system costs ₹45–₹65 lakh all-in, including modules, inverters, mounting, BOS, installation, and GST. The per-watt cost at this scale is about ₹45 to ₹65/Wp, as an illustrative planning band rather than a quote.
Q2. Is a 100 kW solar system eligible for PM Surya Ghar subsidy? No. PM Surya Ghar is a residential scheme only, capped at ₹78,000. Commercial and industrial installations are not eligible and should plan their ROI based on tariff savings, depreciation, and net metering income.
Q3. What is the depreciation benefit on a 100 kW solar system? The owner can claim depreciation at 40% of written down value (Income-tax Act, 2025, section 33; section 32 before 1 April 2026), halved if the plant is used for under 180 days in the year. For a ₹55 lakh system, a full first-year claim is ₹22 lakh. At an assumed 30% tax rate, the tax saving is ₹6.6 lakh in Year 1. Confirm with your CA.
Q4. How much electricity does a 100 kW solar system produce per month? Roughly 10,000–14,000 kWh/month as a planning range, depending on location, performance ratio, and irradiance. The worked example here assumes 12,000 kWh/month.
Q5. What is the payback period for a 100 kW commercial solar system? In the worked example, with bill savings, depreciation (counted once), REC income, and export income, payback is about 3.9 years. Yours depends on tariff, self-consumption, ownership and tax.
Q6. How long does it take to commission a 100 kW commercial solar system? There is no single official figure. The DISCOM must complete the agreement, meter and commissioning within 15 days of your installation certificate (Rights of Consumers Rules, 22 Feb 2024), and feasibility above 10 kW is due in 15 days. Whether CEIG (Chief Electrical Inspector) approval is needed depends on your state's notified threshold, for example above 56 kWp in Telangana.
Q7. String inverter bank or central inverter for 100 kW? For rooftops with partial shading or uptime-critical operations, a string inverter bank (4–5 × 20 kW) is recommended. Central inverters are slightly cheaper but all generation stops if the single unit fails.
Q8. What financing is available for a 100 kW commercial solar system? IREDA term loans, bank and NBFC solar project loans, and any state renewable energy agency support you can confirm are the main options. Rates and tenures depend on the borrower, so get written quotes.
Q9. Can I claim both net metering income and depreciation on the same system? Yes. Net metering and depreciation are independent benefits. Depreciation is an income tax provision; net metering is an electricity regulation. Both can be claimed simultaneously on a commercial installation.
Q10. What is the Group Captive model for 100 kW solar? A Group Captive allows multiple consumers to jointly own a solar plant and consume its output as captive power. It is more relevant for large industrial estates. Under rule 3 of the Electricity Rules, 2005 (check the current text), captive users must together hold at least 26% of the ownership and consume at least 51% of the annual generation.
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