The numbers on a 50 kW factory roof
Let me walk the math the way I would on a whiteboard in your office. Every figure below is an estimate to show how the payback works — your real quote depends on your roof, your tariff and your load — but the method is exactly how we size the return.
Start with generation. Bhopal gives about 5.2 peak sun hours a day, and a plant runs a useful roughly 300 days a year once you allow for monsoon and cleaning downtime. So a 50 kW system makes about 50 × 5.2 × 300 = 78,000 units a year.
I value each unit at ₹7.50, deliberately conservative — commercial and industrial tariffs in MP actually run ₹8–9 a unit with duty. At ₹7.50, those 78,000 units are worth ₹5,85,000 a year off your bill, assuming you consume most of it in the daytime, which a factory or office does. Turnkey commercial solar lands around ₹40,000 per kW at this size, so 50 kW is roughly ₹20,00,000. Simple payback: about 3.4 years. After that the power is effectively free for the remaining 20-plus years.
Then the tax angle. Under accelerated depreciation you write off 40% of the asset value in year one: ₹8,00,000. At a 25% corporate rate that shields ₹2,00,000 of tax in the first year alone, pulling effective payback down to roughly 3.1 years. The remaining book value keeps depreciating in later years and GST input credit sits on top for a GST-registered firm — both left out to keep the number conservative.