What is PV cell and how does it work?

Just what does the word "photovoltaic" mean, and how do photovoltaic systems generate electricity from sunlight? "Photo" means light, and "voltaic" means electricity, so putting the two together simply means electricity from light.

The individual photovoltaic cells that comprise PV modules are made up of silicon semiconductors. When sunlight strikes the cell, some of it gets absorbed into the silicon material. This solar energy frees electrons within the semiconductor. Electric fields within the PV cell force the electrons to flow in specific directions, which create a current. N-type silicon carries a negative charge and P-type silicon carries a positive charge. Metal contacts on the top and bottom of the PV cell allow the current to be drawn off for external use.

What is a solar electric or photovoltaic system?

The basic building block of PV technology is the "PV cell". PV cells are connected to form a PV "module" the smallest PV component sold commercially. Everlight Solar's modules range in power output from 10 watts to 300 watts. A PV system connected or tied to the utility grid has these components: One or more PV modules, which are connected to an inverter.The inverter, which converts the system's direct-current (DC) electricity to alternating current (AC). Batteries (optional) to provide energy storage or backup power in case of a power interruption or outage on the grid. AC electricity is compatible with the utility grid. It powers our lights, appliances, computers, and televisions.

Grid-connected photovoltaic system does not need batteries as energy storage because all energy is transferred to the public grid.

Electric utilities allow their distribution grid to be used like a battery through a process called "net metering." Net metering allows owners of small grid connected solar electric systems to direct surplus power back to the grid when their system is generating more power than they require, and draw from it when more is needed.