Photovoltaic Effect
Photo = light; voltaic = produces voltage – Photovoltaic (PV) systems convert light directly into electricity (using semiconductors)
Solar Electricity system captures the sun’s energy using photovoltaic (Pv) cells. These cells convert the sunlight into electricity, which can be used to run household appliances.
Types of Solar PV Systems can be classified based on the end-use application of the technology. There are two main types of solar PV systems: On-grid (or grid-tied) and Off-grid (or stand alone) solar PV systems.
On Grid- Net Metering
PV systems are installed on buildings or mounted on the ground if land is not a constraint. A building has two parallel power supplies, one from the solar PV system and the other from the power grid. The combined power supply feeds all the loads connected to the main AC distribution boards
Solar PV supply to power grid supply varies, depending on the size of the solar PV system. Whenever the solar PV supply exceeds the building’s demand, excess electricity will be exported into the grid. When there is no sunlight to generate PV electricity at night, the power grid will supply all of the building’s demand. A grid-connected system can be an effective way to reduce your dependence on utility power, increase renewable energy production, and improve the environment.
Off-grid solar PV systems are applicable for areas without power grid. Currently, such solar PV systems are usually installed at isolated sites where the power grid is far away, such as rural areas or off-shore islands. But they may also be installed within the city in situations where it is inconvenient or too costly to tap electricity from the power grid.
Off Grid
An off-grid solar PV system needs deep cycle rechargeable batteries such as lead-acid, nickel-cadmium or lithium-ion batteries to store electricity for use under conditions where there is little or no output from the solar PV system, such as during the night.