Residential solar rooftop system

In grid connected rooftop or small solar photovoltaic (SPV) system, the DC power generated from solar panel is converted to AC power using power conditioning unit/Inverter and is fed to the grid.

• Solar PV Modules/Solar Panels – The Solar PV modules/Solar Panels convert solar energy to DC (direct current) electrical energy. They are available in different technologies such as crystalline silicon, thin film silicon, CIGS, CdTe, HIT, etc. Crystalline Silicon Solar PV panels are most commonly used in solar rooftop system. Multiple panels are connected together to form arrays as per the desired capacity of the system.
• Inverter – Inverter converts variable DC output of Solar PV panels into AC power. Inverter also synchronizes with the grid so that generated power from the module can be injected into the grid.
• Module mounting structure – The module mounting structure, is the support structure that holds the Solar PV panels in place for full system life and is exposed to all weather conditions. These are normally fixed at particular angle and orientation in case of solar rooftop system. But these can also be of type that tracks the Sun, called as trackers.
• Bi-direction Meters – Meters are used to record the generation or consumption of electricity. Bi-direction (or Net-Meters) are used to keep track of the electricity that solar PV system injects to utility grid and the electricity that is drawn from the utility grid.
• Balance of System – These consist of cables, switchboards, junction boxes, earthing system, circuit breaker, fuses, lightning protection system, etc.

A 1 kW rooftop system generally requires 10 sq. meters of shadow-free area. However, actual area requirement may vary depending on the efficiency of solar module, and their placement etc.

Solar modules (and cells within) need uninterrupted sunlight to produce maximum electrical energy. With the shadow even on a part of the module, the generation reduces to a great extent thereby wasting installed system capacity. Also, prolonged

(regular, though intermittent) shadow on some cells or modules reduces their life substantially and these become useless much before their standard life of over 25 years.

Rooftop solar PV systems can be installed on any type of roof having sufficient load bearing capacity.

On a clear sunny day, 1 kWp solar power plant can generate 4 to 5.5 units in a day.

No, the daily energy generation from the RTS shall be dependent on the temperature and solar irradiance among other parameters and these may not be same every day.

• Plant Location
• Quality of equipment used
• No. of sunshine hours
• Workmanship
• PV module tilt angle and orientation
• Module Cleaning
• O&M activities etc.

No. On exposure to sunlight and outside environment, the solar module loses their generation capacity and this is called degradation.

Saving on electricity bill by the consumer.

• Utilization of available vacant roof space, no additional land required.
• Low gestation period.
• No additional requirement of transmission and distribution (T&D) lines.
• Reduces T&D losses as power consumption and generation are collocated.
• Improvement in the tail-end grid voltages and reduction of system congestion.
• Long term energy and ecological security by reduction in carbon emission.
• Better management of daytime peak loads by DISCOM/ utility.
• Meeting of the Renewable Purchase Obligations (RPOs) of obligated entities.