I live in Chennai and consume around 1100 kWh per bimonthly cycle. Below is the TNPDCL tariff structure for reference:
With 1100 units consumed, my bill totals ₹8,025 per cycle.
I’ll be getting a 3 kW plant based on my consumption. On average, a 1 kW plant would generate 4-5 kWh /day. You can either generate 3/4th of the requirement and pay the difference. Or you can have a surplus of units, which will be carried over to the next billing cycle. Very few states allow an annual cash payout for net excess credits. Most carry over to next year.
Now, let’s break down the cost of setting up a 3 kW plant.
With the govt. subsidy, PM Surya Ghar scheme, I’ll be getting ₹78,000 back, bringing the net investment amount to ₹1,32,000.
Now let’s compute the new bill. The 3kW will generate at least 4 x 3 = 12 kWh /day, or 720 units /bimonthly cycle. So now, I’ll only pay for 400 units instead of 1100.
With an annual savings of ~₹40k, the system will pay for itself in approximately 3 years, after which all savings become pure profit. Since solar panels have a lifespan of ~25 years, this translates to decades of reduced electricity costs. During peak summer, the system can generate up to 16 kWh/day, naturally balancing out higher seasonal electricity consumption.
In conclusion, a solar rooftop system is a one-time investment that significantly cuts electricity costs, offers government subsidies, and pays for itself within 3 years, leading to huge long-term savings.
