How a rooftop solar system works
- Panels absorb sunlight — solar panels on your roof produce DC (direct current) electricity.
- The inverter converts it — DC becomes AC (alternating current), the type your appliances use.
- Your home uses it first — solar power reduces what you draw from the grid.
- Surplus goes to the grid — extra electricity is exported and credited to your bill through net metering.
- A bi-directional meter records both — it measures what you import and what you export.
Parts of the system
| Component | What it does | Approx. life |
|---|---|---|
| Solar panels (modules) | Convert sunlight to electricity. Rated in watts (Wp). | 25+ years |
| Inverter | Converts DC to AC. The “brain” of the system. | 8–12 years (usually replaced once) |
| Mounting structure | Holds panels at the right angle, withstands wind. | 25 years |
| Bi-directional (net) meter | Measures electricity imported and exported. | Provided/approved by your discom |
| Cables, earthing & safety devices | Safe wiring and lightning/surge protection. | 25 years |
Types of rooftop solar systems
| Type | How it works | Best for |
|---|---|---|
| On-grid (grid-tied) | Connected to the grid; extra power exported via net metering. No batteries. Cheapest and most popular. | Homes in cities/towns with reliable grid supply. Eligible for subsidy. |
| Off-grid | Works independently with batteries; no grid connection. | Remote areas with no or very poor grid supply. |
| Hybrid | Grid-connected plus battery backup. | Areas with frequent power cuts; costs more. |
Does solar suit my roof?
- You own the roof, or have permission from your housing society.
- Shadow-free area of roughly 100 sq ft per kW (a 3 kW system needs about 300 sq ft).
- RCC (concrete) roofs are ideal; tin/metal sheet roofs also work with the right structure.
- South-facing installation generates the most in Gujarat; east/west also works with a small loss.