Photovoltaic (PV) cells have seen popular use for decades in household electronics such as calculators, battery chargers and emergency radios. PV generation is easily expandable. Single cells produce a small amount of DC voltage at their terminals and can be connected in series and parallel until their total combined output reaches the required capacity.

Shanggui Trade have been working on photovoltaic industry.

With modern technology, PV generation has become so efficient it is often the most cost-effective option for utility-scale production.

In a utility scale system, PV cells numbering in the millions are methodically stacked into groups connected in both series and parallel. These ordered panels are referred to as strings. Together their combined output of DC voltage and current can be used to produce a significant amount of power.