Commercial Solar in India 2026: Cost, ROI & Tax Benefits for Businesses

What a commercial solar plant actually costs in 2026 — and how accelerated depreciation, GST credit and high C&I tariffs turn it into one of the fastest-paying investments on your balance sheet. By Solnce Energy.

For Indian businesses, electricity is rarely a small line item — and commercial and industrial (C&I) tariffs are among the highest in the country, often running well above what households pay. That single fact is why rooftop solar behaves very differently on a company balance sheet than on a home: every unit you generate offsets an expensive unit you would otherwise buy. Add 40% first-year accelerated depreciation and GST input credit, and the commercial solar plant cost is typically recovered in three to five years, followed by two decades of near-free power. This guide breaks down the real 2026 numbers.

Commercial Solar Plant Cost in India (2026)

Commercial systems are priced per kilowatt, and unit costs fall as system size rises. Note that costs have firmed up recently: ALMM enforcement and changes in Chinese export policy have pushed C&I project costs up by roughly 25% compared with the previous year, so 2026 quotes are higher than the numbers many businesses remember.

Expressed per kilowatt, that works out to roughly ₹40,000–₹55,000 per kW for atypical 100–500 kW rooftop plant, around ₹38,000–₹50,000 per kW at megawatt scale, and noticeably more per kW on smaller sub-100 kW systems, where fixed design and approval costs are spread over fewer kilowatts. Be aware that published per-kW figures vary considerably between suppliers depending on what is included — always compare quotes on a like-for-like, fully installed basis.

A useful rule of thumb for sizing the savings side: in most of India, 1 kW of well-installed solar generates roughly 1,400–1,500 units per year. So a 100 kW plant produces about 1.4–1.5 lakh units annually — at a commercial tariff of ₹7–9 per unit, that is roughly ₹10–13 lakh of avoided electricity cost every year.

What Drives the Cost

· Module choice: ALMM-listed, higher-efficiency or bifacial modules cost more but generate more per square foot — often worth it on constrained roofs.

· Inverter selection: string versus central inverters, and brand tier, meaningfully shift both price and long-term yield.

· Structure and site: standard rooftop, elevated/high-rise structures, shed retrofits or ground mount each carry different steel and civil costs.

· Scale: larger plants spread fixed costs (design, approvals, evacuation) across more kilowatts, lowering the per-kW price.

· Evacuation and approvals: transformer capacity, metering and DISCOM approvals add cost and time, particularly above 500 kW.

The Big Tax Lever: 40% Accelerated Depreciation

Accelerated depreciation (AD) is the single most powerful financial benefit available to Indian businesses installing solar. Under Section 32 of the Income Tax Act, 1961 (read with Appendix I of the Income Tax Rules), a solar power plant qualifies for a 40% first-year depreciation rate on the written-down value (WDV) method. This rate was reduced from the earlier 80% in 2017 and remains at 40% in 2026.

Crucially, AD applies to the plant as a whole — panels, inverters, batteries, mounting structures and balance-of-system components, when capitalised as a single solar asset. Only entities with business income can claim it: proprietorships, partnerships, LLPs, private and public limited companies, and trusts with business income.

The 180-Day Rule — Timing Matters

There is one condition that catches many businesses out. If the plant is "put to use" for less than 180 days in the year of acquisition, only half the rate is allowed in Year 1 — that is, 20% instead of 40%. In practice, a plant commissioned before 1 October captures the full 40%; one commissioned after that date captures only 20% in the first year, with the balance carried into subsequent years. If your financial case depends on the Year-1 deduction, commissioning date is a planning decision, not a detail.

GST and Input Tax Credit

Following the GST rationalisation effective 22 September 2025, solar modules and renewable energy devices moved to the concessional 5% GST slab. For turnkey EPC contracts, GST is generally applied under the works-contract composite-supply rule, where the concessional rate applies to roughly 70% of the contract value (the goods portion) and 18% to the remaining 30% (the service portion). Registered businesses can normally claim input tax credit on a commercial solar installation, which further reduces the effective net cost — a benefit unavailable to residential buyers.

ROI, Payback and IRR for Businesses

Because C&I tariffs are high and tax benefits are substantial, commercial solar economics are strong:

• Payback with AD and GST credit: typically 3–5 years; well-sited rooftop CAPEX projects often land at 3–4 years.

• Payback without tax benefits: around 5–7 years.

• Returns: C&I rooftop projects typically deliver 15–20% ROI, with internal rates of return commonly in the 18–22% range in 2026.

• Asset life: modules are generally warranted for 25 years, so a 4-year payback leaves roughly two decades of largely free generation.

A representative case: a 100 kW rooftop plant costing ₹40–45 lakh and saving about ₹10 lakh a year pays back in roughly 3.5–4.5 years — and that is before layering in the Year-1 depreciation benefit, which pulls the effective payback in further.

CAPEX vs OPEX (RESCO): Which Model Fits Your Business?

Businesses can either own the plant (CAPEX) or host a developer-owned plant and buy the power (OPEX, also called RESCO or PPA). The choice materially changes who captures the tax benefits.

The practical rule: if your business pays meaningful tax, owns its premises and plans to stay put, CAPEX almost always wins on lifetime value. If you cannot or prefer not to deploy capital — or you operate from leased property — OPEX delivers immediate savings, typically 30–50% below your DISCOM tariff, with no balance-sheet impact.

Metering and Policy for C&I Systems

Under the Ministry of Power's consumer rules, net metering is mandated for rooftop systems up to 10 kW, with gross metering applying above that threshold — but states vary widely and many permit far higher net-metering limits for commercial consumers (Gujarat allows up to 1 MW, and Maharashtra up to 500 kW for certain categories). Larger consumers may also explore open access and captive structures. Note that the PM Surya Ghar subsidy is a residential scheme — commercial and industrial systems are not eligible for it. For businesses, the financial levers are accelerated depreciation, GST input credit, net metering or open access, and any applicable state-level incentives.

How to Evaluate a Commercial Solar Proposal

• Check the generation estimate — a credible proposal models your specific site, not a generic 1,500 units/kW.

• Confirm ALMM-listed modules and BIS-certified inverters, with written warranty terms.

• Ask for a post-tax financial model showing AD, GST ITC, payback and IRR — not just a headline price.

• Review structure design and wind loading, especially for elevated or shed-mounted systems.

• Clarify O&M scope: cleaning frequency, monitoring, response times and who bears inverter replacement.

• Plan the commissioning date around the 180-day rule to capture full first-year depreciation.

Frequently Asked Questions (FAQs)

1. How much does a commercial solar plant cost in India in 2026?

Indicatively, a 50 kW plant costs ₹27.5–40 lakh, a 100-kW plant ₹40–55 lakh, a 500-kW plant ₹2–2.75 crore, and a 1 MW plant ₹3.8–5 crore, fully installed. Final pricing depends on site, components and structure.

2. What is the cost per kW for commercial solar?

Roughly ₹40,000–₹55,000 per kW (about ₹40–₹55 per watt) for a typical 100–500 kW on-grid rooftop system, and around ₹38,000–₹50,000 per kW at megawatt scale. Smaller sub-100 kW systems cost more per kW because fixed costs are spread over fewer kilowatts.

3. What is the payback period for commercial solar in India?

Typically, 3–5 years when accelerated depreciation and GST input credit are claimed, and about 5–7 years without those tax benefits. Well-sited rooftop CAPEX projects often achieve 3–4 years.

4. What ROI or IRR can a business expect from solar?

C&I rooftop projects typically deliver a 15–20% ROI, with internal rates of return commonly ranging between 18% and 22% in 2026, across a 25-year asset life.

5. What is accelerated depreciation on solar?

It is a tax provision under Section 32 of the Income Tax Act that lets businesses claim 40% depreciation on a solar plant in the first year on the written-down value method, sharply reducing taxable income in Year 1.

6. How much tax can I actually save with accelerated depreciation?

On a ₹1 crore plant, the 40% Year-1 deduction is ₹40 lakh — worth roughly ₹10 lakh in tax saved at a 25% effective rate. On a ₹3.5 crore 1 MW plant, the deduction is ₹1.4 crore, worth about ₹42 lakh at 30%.

7. What is the 180-day (half-year) rule?

If the plant is put to use for fewer than 180 days in the year of acquisition, only half the rate — 20% instead of 40% — can be claimed in Year 1. Commissioning before 1 October secures the full 40%.

8. Who is eligible to claim accelerated depreciation?

Any entity with business income: proprietorships, partnerships, LLPs, private and public limited companies, and trusts with business income. Individuals installing residential solar cannot claim it.

9. Can businesses claim GST input tax credit on solar?

Registered businesses can generally claim input tax credit on a commercial solar installation, which lowers the effective net cost. Eligibility depends on your contract structure, so confirm with your tax advisor.

10. What is the GST rate on solar in 2026?

Following the September 2025 rationalisation, solar modules and renewable energy devices attract 5% GST. Turnkey EPC contracts are typically taxed under the works-contract rule, with the concessional rate on about 70% of value and 18% on the remaining 30%.

11. Is there a government subsidy for commercial solar?

No. The PM Surya Ghar Muft Bijli Yojana is a residential scheme and does not cover commercial or industrial systems. Businesses instead benefit from accelerated depreciation, GST input credit, net metering or open access, and any state-level incentives.

12. What is the difference between CAPEX and OPEX (RESCO) models?

Under CAPEX you fund and own the plant, claiming depreciation and GST credit. Under OPEX/RESCO a developer funds and owns it on your roof, and you simply buy the power under a long-term PPA at a fixed tariff.

13. Which model is better for my business?

CAPEX generally wins for tax-paying businesses on owned premises with a 5+ year horizon, because you keep the depreciation benefit and the asset. OPEX suits businesses that want zero upfront investment or operate from leased premises.

14. What PPA tariff should I expect under an OPEX model?

PPA tariffs in 2026 are typically around ₹4.50–5.00 per kWh, which usually sits 30–50% below prevailing commercial DISCOM tariffs, delivering savings from day one.

15. How much roof space does a commercial solar plant need?

Roughly 100 sq ft of shadow-free area per kW. A 100 kW plant therefore needs about 10,000 sq ft, and a 1 MW plant needs around 1 lakh sq ft or a suitable ground-mount site.

16. Does net metering apply to commercial systems?

It depends on your state. Central rules mandate net metering up to 10 kW and gross metering above that, but many states permit much higher net-metering limits for commercial consumers — up to 1 MW in Gujarat, for example. Always confirm with your DISCOM.

17. How long does a commercial solar plant last, and what maintenance does it need?

Modules are typically warranted for 25 years, while inverters usually need replacement after 8–12 years. Maintenance involves regular panel cleaning, monitoring and periodic electrical checks; most businesses budget roughly 1% of project cost annually for O&M.

18. How long does it take to install a commercial solar plant?

A typical 100 kW rooftop system takes around 4–8 weeks from order to commissioning, though DISCOM approvals, structural work and evacuation arrangements can extend timelines on larger projects.