Development for the purposes of a solar energy systems (i.e. a photovoltaic electricity generating system, solar hot water system or solar air heating system) may be considered exempt development if it meets the provisions of the State Environmental Planning Policy (Transport and Infrastructure) 2021, Part 2.3, Division 4.
If your development does not meet exempt requirements, planning approval is required through a Development Application (DA), which can be lodged through the NSW Planning Portal.