Rooftop solar energy system is a solar power system with electricity-generating photovoltaic (PV) modules mounted on the roof of a building. These systems use solar inverters, mounting systems, and other electrical components to convert sunlight into electricity for residential and commercial use, often with net metering to send excess power back to the grid for credit. Key benefits include reducing electricity bills, using available roof space, decreasing carbon emissions, and improving grid stability. 

How it Works

1. Energy Generation:

Photovoltaic (PV) panels convert sunlight into direct current (DC) electricity. 

2. Inversion:

A solar inverter converts the DC electricity into alternating current (AC) electricity, which is used by household appliances. 

3. Grid Connection:

The system is typically connected to the main electricity grid. 

4. Net Metering:

A bidirectional meter tracks the electricity consumed from the grid and the excess electricity sent back to the grid. 

5. Bill Reduction:

Any surplus solar energy generated but not used by the household is exported to the grid, leading to a reduction or credit on the electricity bill. 

Key Components

Photovoltaic (PV) Modules: The solar panels that generate electricity from sunlight. 

Mounting System: The structure that secures the solar panels to the roof. 

Solar Inverter: Converts DC electricity from the panels to AC electricity for use in the building. 

Net Metering System: Measures electricity flow both to and from the grid. 

Cables and Electrical Accessories: Components like disconnect switches, combiners, and grounding equipment. 

Benefits 

Cost Savings: Reduces or eliminates electricity bills by generating your own power.

Space Utilization: Uses existing roof space, eliminating the need for additional land.

Environmental Impact: Decreases reliance on fossil fuels, reducing carbon emissions.

Grid Support: Helps manage peak electricity demand and improves grid voltage stability.

Considerations

Roof Suitability: The direction, pitch, and shading of the roof affect solar production. 

System Sizing: The appropriate system size depends on factors like roof area and monthly electricity consumption. 

Regulations: Programs like the PM Surya Ghar Muft Bijli Yojana in India offer subsidies to encourage adoption. 

The scheme provides for a subsidy of 60% of the solar unit cost for systems up to 2kW capacity and 40 percent of additional system cost for systems between 2 to 3kW capacity. The subsidy has been capped at 3kW capacity.