Usually to install a stand alone rooftop off grid solar PV system no permits are needed. The off-grid solar PV systems can be installed for self-consumption in India without any permission or approval from any authority. You can cross check this with the solar policy of your state too as most of the regulations are mentioned there.
How ever, if you are going for On grid net-metering or gross-metering you would need to take permission from your DISCOM for grid connectivity and the CEIG (Chief electrical inspector to the government of your state).
The permission from the CEIG is generally needed in case the installed capacity is going to the more than the set threshold of the state. In most cases, this threshold is 10KW but varies from state to state.
If the rights of the rooftop are not vested with you then permission from the roof owner will be required.
In case of apartments, the rights usually lie with the RWA or the builder of the building. Hence permission would be needed for them.
In certain cases, a permit from the state building officer is also needed which varies from state to state.
For your reference, here are the main permits and approvals you require for rooftop and ground mounted solar power plants.
Permits for Rooftop Solar Power Plants
The permitting process for rooftop solar power plants depends on the state in which it is installed, the size of the power plant and the sector your building belongs to (residential, commercial or industrial).
Usually the permits required are two-fold:
Usually the electrical permits for rooftop solar power plants involve three stages: feasibility analysis, registration and connectivity.
The consumer will have to submit an application to the power distribution company (discom) along with an application fee.
The discom then decides whether to permit the connection for the applied capacity. Based on the recommended capacities from the discom, the customer will register for the solar power plant along with requisite documents and registration charges.
This can be usually done by filling out forms at the electricity board or doing them online.
This stage will also include the permits required for setting up the Net Metering facility, provided you are eligible for it.
Post the registration process, the connection agreement will be signed between the customer and the discom.
The connection agreement should clearly specify the financial arrangement for excess units exported to the grid in case of net metering and other specifics.
Post the installation of the solar power plant, the discom officials will test and evaluate the standard compliance of the rooftop plant before sanctioning the project.
In states where building permits are needed, the rooftop owner contacts the relevant state building officer.
The inspector will visit the site, review the plans and issue the building permit on-site. This is usually not applicable for residential customers.