On Grid system is a system that uses solar energy as a source of electricity. It connects to the electrical system of the Electricity Generating Authority of Thailand (EGAT) or the Provincial Electricity Authority (PEA) or the Metropolitan Electricity Authority (MEA) to use as a backup power source. or sell the electricity back to the said agency. The On Grid system has the advantage of not having to use batteries to store energy. This saves costs and reduces energy loss.