Roof Top Solar - frequently asked questions

In a solar rooftop system, the solar panels are installed on the roof of any residential, commercial, institutional and industrial buildings.
This can be of two types
(i) Solar Rooftop System with storage facility using battery, and
(ii) Grid Connected Solar Rooftop System.

A Photovoltaic system is a power system which converts light to electricity using one or several Solar panels/modules. A PV system consists of a number of solar panel/modules that produce DC electricity in presence of sunlight, an inverter which converts DC energy to AC energy for either direct consumption, storage in battery banks or feeding into the electricity grid.

The grid connected rooftop system can work on net metering basis wherein the beneficiary pays to the utility on net meter reading basis only.

A Grid-tied inverter converts direct current (DC) into an alternating current (AC) suitable for injecting into the electricity grid. The operating range of a grid-tied inverter is typically 120 Volts RMS at 60 Hz or 240 Volts RMS at 50 Hz, based on grid requirements.

Bi-directional meters or Netmeters are electricity meters that measure and display both the amount of consumed power and the power fed to the grid. These are used in the calculation of payoffs or compensation to the consumer based on power generated from the rooftop system

Typically, rooftop systems with capacity of 1 kW peak generate anywhere in the range of 4-5 units a day, which is about 120-150 units a month and 1200-1500 units annually (units in kilowatt-hour).

Any person, entity or organization owning/possessing a vacant shadow-free rooftop area and registered as a metered consumer under the purview of DISCOMs is eligible for getting SPV system installation.

As per the DERC guidelines, maximum solar plant capacity should be the Sanctioned Load of the connection. If a consumer wants to install plant beyond this capacity, he/she needs to pay the additional SLD charges as per DERC Guidelines.

About 10 sq.m or 120 sq. ft. area is required to set up 1 kWp grid connected rooftop solar system.

The electricity consumption in any time block (e.g., peak hours, off-peak hours, etc.) shall be first compensated with the electricity generation in the similar time blocks in the same billing cycle. For the purpose of carrying forward of surplus or setting off of energy credits, the energy units shall be moderated as per the relevant rebate/surcharge percentage of ToD Tariff.