In 2026, a typical Gujarat home with rooftop solar recovers its investment in roughly 3.5–5 years after the PM Surya Ghar subsidy, and a factory or commercial buyer typically in 3–5 years (sometimes under 3) thanks to high daytime self-consumption and 40% accelerated depreciation — after which the system delivers 20+ years of largely free power.
The single biggest driver of payback
It's the tariff you avoid: homes save roughly ₹5–6/unit and industry roughly ₹7–8/unit self-consumed, versus only ₹2.25/unit for surplus exported to the grid. So self-consumption — not export — makes payback fast. Payback is an honest estimate presented as a range, not a guarantee; it shifts with your consumption pattern, tariff slab, shading, system quality, and maintenance.
What payback and ROI mean (plain language)
- Payback period = the time it takes for your cumulative electricity-bill savings to equal the net cost of the system. Simple formula: Payback (years) = Net system cost (after subsidy) ÷ Annual savings. A more honest version subtracts running costs: Payback = (System cost − subsidy) ÷ (Annual savings − Annual maintenance).
- ROI (return on investment) = total lifetime savings relative to the money you put in, usually expressed as an annual percentage.
- IRR (internal rate of return) = the annualised return that makes all your future savings equal to today's investment — a clean way to compare a solar system against, say, a bank fixed deposit. Commercial CAPEX rooftop systems in India are commonly cited at 15–20%+ IRR over 25 years.
- Real-world payback is faster than simple math because each year's savings grow (tariff inflation rising grid rates make each year's savings larger — helps you), panel degradation (a small drag), and O&M plus one inverter replacement around year 10–15.
Cost per kW in Gujarat (2026, before subsidy)
- Residential small (1–3 kW): roughly ₹55,000–70,000/kW; smaller systems cost more per kW. A 3 kW system commonly runs ₹1.65–1.95 lakh all-in (~₹55,000–65,000/kW). Some quotes run higher; compare like-for-like.
- Larger residential / small commercial (5–10 kW): about ₹2.5–3.0 lakh for 5 kW and ₹4.75–5.5 lakh for 10 kW (~₹46,000–55,000/kW).
- Commercial/industrial (25–100 kW+): lower per kW, roughly ₹35,000–50,000/kW; a 100 kW plant is commonly around ₹40–50 lakh.
Note: the MNRE benchmark cost — not your actual quote — sets the residential subsidy. If your quote exceeds the benchmark, you still only get the benchmark-based subsidy.
Generation per kW in Gujarat
Gujarat is among India's best solar states (300+ sunny days). Realistic output is about 4–4.5 units/kW/day, or roughly 1,400–1,600 units/kW/year. This corresponds to a Capacity Utilisation Factor (CUF) of about 17–20% for fixed-tilt rooftop. As a real-world data point, one large Gujarat EPC reports an average CUF of 19.2% for fixed-tilt residential and 20.5% for fixed-tilt commercial (single-axis tracked reaches ~24.8%). Output depends on irradiance, orientation (south-facing, ~20–23° tilt is optimal in Gujarat), shading, temperature, and system losses (performance ratio ~75–85%). Dust is a real factor: disciplined cleaning can lift output by 1.5–2.5 CUF points.
The subsidy and incentives
- Residential (PM Surya Ghar): ₹30,000/kW for the first 2 kW, ₹18,000 for the 3rd kW, capped at ₹78,000 for 3 kW and above (a 5 kW or 10 kW system still gets only ₹78,000). Slabs unchanged since the February 2024 launch. The scheme is firmly active in 2026: as of May 30, 2026, 40 lakh households had been solarised with cumulative central financial assistance crossing ₹17,968 crore (per Union Minister Pralhad Joshi, reported by SolarQuarter), against a one-crore-homes target backed by a ₹75,021 crore allocation for FY2026–27. Subsidy is paid by DBT to the consumer's Aadhaar-linked account after DISCOM commissioning (typically within ~30 days). Equipment must be ALMM-listed; residential connections only.
- Commercial/industrial: does NOT get this subsidy. Instead they get 40% accelerated depreciation in year one (via a Written Down Value rule under Section 32 of the Income Tax Act — set at 40% by the Ministry of Finance effective April 1, 2017, down from the earlier 80%), plus a possible additional 20% bonus depreciation, and a concessional 5% GST.
- Honest caveat: Several installer blogs claim a stacking Gujarat state top-up subsidy of ₹10,000–40,000 in 2026. This is uncertain — a major Gujarat EPC explicitly states that as of 2026, Gujarat does not offer an additional state cash subsidy on top of PM Surya Ghar for residential rooftop. Do not promise a state top-up; verify with the DISCOM/GEDA before quoting.
Tariffs that drive payback (2026 Gujarat)
GERC issued its FY2026–27 tariff orders on March 25, 2026, effective April 1, 2026, with no change in scheduled base tariff rates for the four state DISCOMs (UGVCL, DGVCL, MGVCL, PGVCL) and Torrent Power.
- Residential (RGP) energy slabs: Rs 3.05/unit (0–50), Rs 3.50 (51–100), Rs 4.15 (101–250), Rs 5.20 (above 250), plus small fixed charges (Rs 15–70/month by load), FPPPA and electricity duty. Effective cost on the upper slabs is roughly Rs 5–6+/unit — the value a home with a high bill saves per solar unit.
- LT commercial (Non-RGP): Rs 4.35/unit (load <10 kW), Rs 4.65/unit (>10 kW). LTMD (small industry, >40 kW load): Rs 4.60/unit + demand charges (Rs 90–265/kW/month).
- HT industrial (HTP-1, contract demand >100 kVA): energy charge Rs 4.00/unit (<500 kVA), Rs 4.20 (above 500 kVA), Rs 4.30 (above 2500 kVA), plus demand charges of Rs 150–475/kVA/month.
- FPPPA: GERC kept the base fuel & power purchase adjustment charge at Rs 2.45/unit for all state DISCOMs in the March 25, 2026 order (Rs 2.77 a year earlier; it can rise in high-fuel quarters).
- Effective all-in cost for C&I: once FPPPA (~Rs 2.45/unit), electricity duty (~15% on commercial/industrial), and demand-charge allocation are stacked onto the base energy charge, the realistic effective rate is broadly Rs 7–8/unit — well above residential. This is an analytical composite of base + statutory adders, not a single quoted figure, but it is the consensus across trade and bill-calculator sources.
Net metering / export rate 2026
Per GERC's Net Metering Regulations (Notification No. 02 of 2022), surplus exported power for self-owned rooftop / SURYA Gujarat consumers is compensated at Rs 2.25/unit for the first 5 years from commissioning, and thereafter for the remaining term of the project at 75% of the simple average of tariff discovered and contracted under competitive bidding by GUVNL for non-park-based solar projects. Residential net metering is allowed up to 10 kW/sanctioned load; systems 1 kW–1 MW are permitted under the broader framework. The open-access banking charge is fixed at Rs 1.50/unit. Why this matters for payback: self-consumption saving (Rs 5–8/unit) is far higher than the export earning (Rs 2.25/unit). So size the system to consume most of what it generates, not to over-export — over-sizing for export drags payback out.
What makes payback faster or slower
Faster payback:
- Higher electricity tariff (industry > commercial > residential) — high-tariff factories with high daytime self-consumption often pay back fastest.
- Higher self-consumption ratio (using your own solar vs exporting it cheaply).
- The PM Surya Ghar subsidy (residential) — knocks Rs 78,000 off net cost.
- Accelerated depreciation (commercial/industrial) — effectively reduces net system cost (by ~12% and pushes commercial payback from 4–5 years down to 3–3.5 years).
- Good irradiance, south orientation, low shading; lower cost per kW (bigger systems are cheaper per kW).
- Tariff inflation over time — grid rates have historically risen ~2–5%/year, widening your savings each year (a general trend, not a guarantee; Gujarat's base rates were flat in both FY2026 and FY2027).
Slower payback:
- Panel degradation ~0.4–0.5%/year (panels retain ~85–88% of rated output at year 25).
- O&M and cleaning — a small annual cost, but important in dusty Gujarat.
- One inverter replacement, typically around year 10–15.
- Over-sizing for cheap export; cheap, low-quality components that underperform (a poor install can cut generation 15–25%).
Worked example A — typical Gujarat home (3 kW)
| Item | Value |
|---|---|
| System cost before subsidy | ~Rs 1.80 lakh |
| Less PM Surya Ghar subsidy | − Rs 78,000 |
| Net cost | ~Rs 1.02–1.17 lakh (use ~Rs 1.05 lakh) |
| Annual generation | ~4.2 units/kW/day × 3 kW × 365 = ~4,200–4,800 units/year |
| Annual savings (effective ~Rs 5.5/unit, upper-slab self-consumption + a little export) | ≈ Rs 25,000–27,000/year |
| Simple payback | Rs 1.05 lakh ÷ Rs 25,000 ≈ 4 years (range 3.5–5) |
After ~year 4, the household keeps saving ~Rs 25,000+ a year — effectively free power for the remaining 20+ years.
Worked example B — typical Gujarat factory / commercial (100 kW)
| Item | Value |
|---|---|
| System cost | ~Rs 35–45 lakh (use ~Rs 40 lakh); no PM Surya Ghar subsidy |
| 40% accelerated depreciation, year 1 | shields ~Rs 16 lakh of taxable income → ~Rs 4 lakh year-1 tax saving (at 25% rate), effectively cutting net cost to ~Rs 36 lakh |
| Annual generation | ~4.2 units/kW/day × 100 kW × 365 = ~1.4–1.6 lakh units/year |
| Annual savings (effective industrial ~Rs 7.5/unit, high daytime self-consumption) | ≈ Rs 12 lakh/year |
| Simple payback | Rs 40 lakh ÷ Rs 11.5 lakh ≈ ~3.5 years, shortening toward ~3 years once depreciation is factored in |
The factory's faster payback comes from a higher avoided tariff (Rs 7–8/unit vs the home's Rs 5–6), high daytime self-consumption that matches solar generation hours, and the depreciation tax shield.
Typical payback ranges (ranges, not guarantees)
- Residential after PM Surya Ghar subsidy: ~3–5 years.
- Commercial/industrial: ~3–5 years, sometimes under 3 for high, high-daytime-use factories that also use depreciation.
- A broad all-segment Gujarat range is sometimes cited as 3–7 years depending on tariff and self-consumption.
- 25-year context: panels carry ~25-year performance warranties and realistically run 30+ years. So after a 3–5 year payback you get 20+ years of largely free electricity, and total lifetime savings can be several times the net investment (present cautiously as an estimate, since it depends on future tariffs).
Our recommendations
- Lead with ranges and the formula. State home ~3.5–5 years and factory ~3–5 years up front, then show the formula so the math is clear with your own bill. This builds trust and is honest.
- Right-size, don't over-size. Tell homeowners to size to roughly their own consumption (the unbeatable ~Rs 5–6/unit saving beats the ~Rs 2.25/unit export rate); maximise daytime self-consumption and avoid the cheap Rs 2.25/unit export rate.
- Protect the payback. Emphasise quality, ALMM-listed components, and 2–4 cleanings a year; tell readers to budget for one inverter swap (~year 10–15). Frame these as "payback protectors."
- For commercial buyers, lead with the IRR. Accelerated depreciation and commissioning timing (commissioning before year-end captures the full first-year depreciation), make the case better with these clients.
- Benchmarks that change the decision: if the RBI repo rate rises materially, lock tenure/rate expectations accordingly; if your roof exceeds ~250 kW potential, solicit RESCO bids; if you can commission a commercial system before the financial year-end, you capture the full first-year depreciation.
Want your real payback figure?
Send us your last few electricity bills and we'll calculate an honest payback estimate for your home or business — based on your actual tariff and usage, not a generic claim.
Estimate my paybackAll figures are 2026 estimates and ranges; actual results vary by site, consumption, tariff slab, shading and maintenance. Payback is an estimate, not a guarantee. The Rs 7–8/unit effective industrial rate is a composite (base energy charge + FPPPA + duty + demand charges), not a single official line item — accurate as a planning figure but worth labelling as "effective/all-in." Discounted payback (accounting for the fact that future rupees are worth less than today's) is modestly longer — a worked example uses an undiscounted 3–5 year range. The Gujarat state top-up subsidy is unconfirmed for 2026 — do not promise it; quote only the central Rs 78,000 unless the DISCOM/GEDA confirms otherwise.