This type of system is used to generate electricity for direct use or for sale to the Municipal Electric Authority (MEA) or the Provincial Electric Authority (PEA). Power generated from solar system is directly fed into the main distribution board (MDB) and is used within the home or business facility. Excess electricity is then fed into the grid. The excess electricity may be sold back to the electric authority under the net-metering program. Another form on-grid system is where the electricity generated is directly routed to the grid without being used at all. In this system, power from the solar system never enters your home and all power is sold to the electric authority.
An off-grid system is one in which the solar system is used to charge a battery bank that is large enough for the target load of your house or workplace. Power is then drawn from the battery into an inverter which converts direct current (DC) electricity into alternating current (AC). With a properly sized solar array and battery bank, it is possible to design the system to last 1, 2, 3 or even more days.