Systems
Off – grid PV system
There is also PV system that is fully independent to the electrical grid. This is the so called off-grid PV system, which requires the solar panels to produce enough electricity to cover 100% of the energy needs. Most homes, for example, have higher electricity demand in the evening or at night, so off-grid systems usually incorporate with either a battery (to store energy produced during the day) or backup source of energy (like a generator), or both. Off-grid systems are more complex and less flexible than on-grid ones so as well they are more expensive concerning constructing, service and maintenance.