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Solar vs Grid Cost Calculator

Project and compare grid inflation costs against solar plant installation and zero-energy running costs.

Live 2026 Data
Solar Cost/Unit ~₹1.80 - ₹2.20
Grid Cost/Unit ₹6.50 - ₹12.50
Grid Escalation ~5% Annual Rise
Breakeven Year Year 3 or Year 4

1. Enter Configuration Parameters

Frequently Asked Questions (FAQ)

How does grid inflation affect long-term power bills?

Grid tariff rates in India increase by an average of 4-6% annually due to rising coal import prices, logistics costs, and distribution system losses. Solar locks in a fixed capital cost.

What is the cash subsidy for rooftop solar under PM Surya Ghar Yojana?

The central government provides a direct subsidy of Rs. 30,000 per kW for the first 2 kW of solar capacity, and Rs. 18,000 for the 3rd kW. The maximum subsidy is capped at Rs. 78,000 for any residential installation of 3 kW or higher.

How much roof space is required to install a 3 kW solar system?

A 3 kW residential solar system requires approximately 250 to 300 square feet of shadow-free rooftop space. Each solar panel is roughly 20 square feet, and a 3 kW setup typically uses 6 to 8 high-efficiency monocrystalline panels.

How many units of electricity does a 1 kW solar panel generate daily?

In India, a 1 kW solar plant generates an average of 4 to 4.5 kWh (units) of electricity per day in standard sunny conditions. This translates to roughly 120 to 135 units per month, or 1,500 units annually per kW of installed capacity.

What is solar net-metering, and how does it work?

Net-metering uses a bidirectional meter to record both the power you import from the grid and the excess solar power you export to the grid. At the end of the billing cycle, your DISCOM bills you only for the net units consumed (Import minus Export).

What is the typical ROI payback period for residential solar in India?

With the PM Surya Ghar subsidy, the net out-of-pocket cost for a 3 kW solar system is roughly Rs. 70,000 to Rs. 90,000. Generating Rs. 30,000 worth of free power annually, the system pays for itself in 2.5 to 3 years, followed by 22+ years of free power.

Does a grid-tied solar system work during power outages?

No. Standard grid-tied solar systems automatically shut down during a power cut for safety reasons (anti-islanding) to protect utility workers repairing the lines. To run appliances during power outages, you need a hybrid solar system with battery backup.

About This Calculator

Target Audience: Property owners exploring solar ROI, panel sizing & government subsidy benefits

What Does This Calculator Do?

This tool compares the cumulative 10-year costs of relying solely on the grid vs investing in a rooftop solar plant (assuming grid tariffs rise by 5% annually).

How to Use It

  1. Current Monthly Bill: Input your current grid bill.
  2. Solar Size (kW): Enter solar capacity.
  3. Tariff Inflation: Select expected annual tariff hike percentage (standard is 5%).

The Logic Explained Simply

  • The Concept: Grid electricity prices rise every year due to fuel costs. Rooftop solar costs are almost 100% upfront, with free generation for 25 years. This comparison visualizes the crossover point.
  • The Formula:
  • Grid Cost (Year N) = Current Cost × (1 + Inflation)^N

Real-World Calculation Breakdown

  • Over 10 years, paying a ₹3,000 monthly bill with 5% inflation costs ₹4,53,000.
  • Installing a 3 kW solar system costs ~₹1,02,000 upfront (net of subsidy).
  • Solar saves you over ₹3.5 Lakhs over a decade.

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