Frequently Asked Questions for Grid Connected Rooftop Solar System
A Rooftop Solar System is a solar power energy generation system installed on the rooftop of consumer building premises, that generates electricity from sunlight using solar panels. The solar panels produce DC electricity which can be stored in batteries or converted to AC using an inverter used to power house hold appliance or feed in the grid. There are of three types Solar Rooftop Systems
- a) Rooftop Solar System with storage facility using battery,
- b) Grid Connected Rooftop Solar System.
- c) Hybrid Solar System
Grid Connected Rooftop System (GCRT) is a type of Rooftop Solar Systems that converts solar energy (DC) generated through solar panels to AC power and is connected with the grid using separate Meter Connection.
A GCRT systems generates power during sunshine hours and offsets part of the energy consumption from consumer electricity bills. A GCRT system may also feed excess power generated from solar plant to the grid. This excess power is later credited/offset to the consumers in subsequent electricity bills.
A 1 kW Grid Connected Rooftop Solar system generally requires 10 sq. metres of shadow-free roof area. Actual sizing, however, depends on local factors of solar radiation and weather conditions, efficiency of solar module, shape and orientation of the roof etc.
The amount of electricity generated by a rooftop solar plant depends on the location, orientation of the roof, panel efficiency, and ambient temperature. As thumbrule, an 1 kWp plant will generate about 4-5 kWh (units) of electricity a day, 120-150 units a month and 1200-1500 units annually.
A Grid Connected Solar Rooftop system can be installed on the roofs of consumer building premises.
- a) Generate your own electricity and enjoy electricity savings for lifetime
- b) Hassle-free ownership
- c) 40% Central subsidy
- d) To be part of clean energy transition in India
- e) Contribute to reduce Carbon Emission
- f) Sustainable energy generation
- a) Solar PV Modules/Solar Panels – The Solar PV modules/Solar Panels converts solar energy to electrical energy. They are available in different technologies such as crystalline, thin film, etc. Crystalline Solar PV panels are most commonly used in Rooftop Solar Systems.
- b) Inverter – Inverter converts DC output of Solar PV panels into AC power.
- c) Mounting structure – The mounting structure, is the support structure that holds the Solar PV panels.
- d) Balance of System – These consist of cables, switchboards, junction boxes, meters, structures, tracking system (if required), earthing system, circuit breaker, fuses etc.
- a) CAPEX Model – In this model, Consumer pays upfront amount for entire project cost and owns the system for lifetime. Responsibility of O&M for the system lifetime (25 years) is also with the rooftop owner. Developer is responsible for installing the system and initial 5 years comprehensive O&M.
- b) RESCO Model – In this model, a renewable service energy company develops, install, finance , operates and owns the Rooftop Solar Project and supplies the power generated from the project to the consumer on whose premises the project is set up on a pre decided tariff on monthly basis and excess generation may be exported to the grid through net metering.
Net Metering is a mechanism which allows domestic consumers who generates their own electricity through Rooftop Solar Plant can export their surplus energy through Bi-directional meters to the grid.
Under gross metering, all the electricity generated by the solar rooftop system is exported to the grid and energy required for consumption is imported from the grid. The consumers are paid a feed-in-tariff decided by the respective state nodal agencies for the electricity injected into the grid.
Warranties Solar panels typically have 10 years’ manufacturer’s warranty with additional performance warranty of 25 years. Other system components (inverters, mounting structures, batteries, junction boxes, etc.) typically have 1-5 years’ manufacturer’s warranty.
Dependent on electrical load requirement of the Consumer, electrical connected load, availability of shadow free rooftop area, maximum capacity allowed by respective State Regulatory Commission etc.
The programme will be implemented by DISCOMs and its local offices as the nodal points for Grid Connected Rooftop Solar programme scheme.
Implementing agency, i.e. DISCOMs will empanel Rooftop Solar Installer through transparent bidding. The details of Installer along with the installation cost shall he displayed on the online portal of DISCOMs and MNRE.
Interested Consumer can follow the below general guidelines and steps for installation of Grid Connected Rooftop Solar System.
Consumer can select the RTS Installer of the respective State Nodal Agency which were selected through transparent process empanelment against the MNRE’s sanctioned capacity.
In CAPEX mode, the agreement is signed between the consumer and the Rooftop Solar installer.
The selected installer after getting the work order will request for Feasibility analysis, the State Nodal Agency will do the feasibility study of the Rooftop Solar plants installed at the consumer rooftop as per the minimum technical standards specified by the Ministry under the scheme.
The selected Rooftop Installer will assist the consumer in submission of forms of respective DISCOMs for grid connectivity/net-metering connections etc. After submission of application form the DISCOM conducts feasibility study, charges application /net metering fees, conducts site visits, installs net-meter/ Bi-directional meter and provides grid connectivity/net metering after commissioning of the project.
The phase II of the programme has been approved by CCEA wherein central financial assistance has been restricted to domestic sector only up to maximum capacity of 10 kWp. The brief of new subsidy programme is as follows:
- a) 1-3 kW Rooftop – up to 40 % of the benchmark cost.
- b) Above 3 kW to 10 kW Rooftop – up to 20 % of the benchmark cost
After installation of Rooftop Solar plants the consumer shall inform the respective State Nodal Agency for inspection of the plants. Concerned State Nodal Agency after due inspection and satisfactory performance will disburse the applicable Subsidy to the beneficiary/ bidder depending on the condition that whether the full project cost has been made by consumer or project cost minus subsidy has been made by the consumer.
State Subsidy support is also available in a few states which varies according to the state policies.
Comprehensive maintenance for 05 years is guaranteed under CAPEX model and for the RESCO model, Operation and Maintenance are taken care of by the developer for 25 years of panel life.
The project commissioning timeline for the residential sector shall be fifteen months from the date of sanction from MNRE.
As these are net metered projects/ grid tied projects, with the failure of grid power, the rooftop system too shall stop operating.
An appreciable repair work may affect the generation for that period. But the overall functioning of the plant will remain unaffected.