Commercial solar MSME Tamil Nadu 2026 — 50 kW system ₹6L yearly savings breakdown

**TN MSME power cost reality:** commercial LT tariff (LT-CT) ₹8.20/unit + demand charge ₹75/kW. HT tariff (HT-IIA) ₹9.50/unit + ₹450/kVA. Typical 50 kVA MSME connection — monthly bill ₹80k-1.5L (5,000-15,000 units + demand). Annual power cost ₹10-18L — often 3rd biggest expense after rent + salaries.

**Why solar makes commercial sense NOW (2026):** (1) Tariff 6-12% hike April 2026 → offset value up. (2) Panel price stable ₹22-24/W (no wait-for-drop urgency). (3) 40% accelerated depreciation year 1 → effective capex 25-30% subsidized via IT saving. (4) 5-year workmanship + 25-year panel warranty. (5) Net metering unchanged (still 1:1). Combined economics — 3-4 year payback typical.

**50 kW system feasibility:** roof space needed ~350 sq m (unshaded, south-facing). Typical MSME shed roof 400-800 sq m easily supports. If roof insufficient, ground-mount OR carport structure OR two-part rooftop-and-carport. TN industrial estates (Guindy, Ambattur, Coimbatore Peelamedu, Karur Textile Park) mostly suitable.

**Generation math:** TN average 4.1 sun hours × 50 kW × 30 days × 0.85 system efficiency = 5,230 units/month. Yearly 62,760 units. Monsoon (Oct-Dec) 20% lower → summer (Feb-May) 15% higher — annual net stable.

**Consumption offset percentage:** typical MSME 12,000 units/month → 50 kW system offsets ~44%. For 100% offset need 100 kW+. But 100% offset uneconomical — annual net metering surplus lapses in TN. Sweet spot — 40-70% offset for MSMEs.

**Complete BOM (turnkey 50 kW commercial):** 91 × Waaree 570W TOPCon DCR panels ₹11.9L + Sungrow SG50CX 50 kW three-phase string inverter ₹3.2L + galvanized ground/rooftop mounting ₹2.8L + AJB (Array Junction Box) × 4 + AC/DC breaker panel ₹1.4L + wiring + cable trays ₹1.6L + earthing 6 pits + lightning arrestor ₹95k + net metering panel + monitoring SCADA ₹1.1L + install labour + civil ₹2.5L + commissioning + testing ₹95k + 5-year AMC year 1 ₹75k = ₹27.35L. Round to ₹28L delivered.

**Cost variations:** basic Mono PERC panels + Chinese inverter → ₹24-25L. Premium TOPCon + Sungrow + tracker option → ₹34-36L. Ground-mount 15-18% cost premium vs rooftop.

**Tax math — accelerated depreciation:** Income Tax Act Sec 32 — solar assets 40% AD year 1 + 15% straight-line remaining. ₹28L system → year 1 depreciation ₹11.2L. MSME in 30% tax bracket → ₹3.36L tax saving. Effective net investment ₹24.64L.

**GST + input credit:** 18% GST on solar installation. ₹28L invoice includes ~₹4.3L GST. Registered MSME can claim full input credit against output GST — effective capex ₹23.7L for GST-registered businesses.

**Financial return (Year 1):** electricity generation value 62,760 units × ₹9.50 avoided = ₹5.96L. Demand charge reduction (solar peak-time coincides with peak demand) ₹35k. Total year 1 savings ₹6.31L. Plus tax saving ₹3.36L one-time.

**Payback calculation:** effective net investment (post-tax + GST credit) ₹20.5L. Annual saving ₹6.3L (+ tariff hike compounding 6-8%/year). Simple payback 3.25 years. IRR 25-year 24.5%. NPV @ 12% discount ₹1.15 crore.

**Financing options:** Union Bank MSME priority sector loan — 8.5% interest, 10 year tenure. Canara Bank ₹10L cap residential doesn't apply — commercial ₹50L available. NBFC (Tata Capital) — 9.5-10.5% interest, 5-7 year tenure. Solar-EMI vendor financing (SVN partner) — down 25% + 24-month 0% EMI on balance.

**Net metering TN specifics:** monthly export-import netted, excess unit credit rolled next month. Annual settlement (April year-end) — final surplus credited at ₹3.15/unit (avg pool rate). Annual surplus lapses if not consumed. Design system to slightly under-generate rather than over-generate.

**TANGEDCO application timeline:** technical feasibility 15 days → sanction letter 10 days → net metering agreement + bidirectional meter install 20-25 days. Total 45-55 days parallel to installation. Total start-to-commissioning 90-110 days.

**Real SVN reference sites:** Annai Signs (Trichy) — 9.5 kW rooftop, ₹6.8L invested, ₹9.5k monthly savings, 5.9 year payback (residential-adjacent commercial). KR Fuels (Karur) — 6 kW zero-export system (petrol pump owners avoiding net metering complexity). Sabhari Metals (Perambalur) — 25 kW, ₹15.5L investment, ₹3.1L year 1 savings, 5 year payback.

**Sector-specific insights:** textile Karur — 8-hour looms + AC → daytime peak matches solar → high self-consumption ratio 90%+ → best payback (2.8-3.2 years). Cold storage Dindigul — 24×7 load → solar covers 40% only, but tariff avoidance still meaningful. Auto ancillary Coimbatore — heavy 3-shift, solar covers day-shift 60% → payback 3.5-4 years.

**Common commercial owner concerns:** (1) 'Roof leakage?' — SVN waterproofing 5-year warranty + rubber caps. (2) 'What if I sell factory?' — solar adds resale value + can be dismantled + reinstalled. (3) 'Warranty support after 5 years?' — AMC extendable to 25 years, ₹85k/year for 50 kW system. (4) 'What if tariff drops?' — TN historical CAGR 6-8%, drop scenario very unlikely.

**SVN commercial package deliverables:** feasibility + tariff analysis + design → procurement + install → net metering handling → monitoring dashboard + monthly report → 5-year AMC (extendable) → warranty coordination with manufacturers → 25-year performance guarantee support.