In a solar rooftop system, the solar panels are installed in the roof of any residential, institutional, social, Government, commercial, industrial buildings etc. .

In grid connected rooftop or small SPV system, the DC power generated from SPV panel is converted to AC power using Inverter and is fed to the grid either of 440/220 Volt three/ single phase line installed at residential, institution/commercial establishment. These systems generate power during the day time which is utilized by powering captive loads and feed excess power to the grid as long as grid is available. In case, where solar power is not sufficient due to cloud cover etc., the captive loads are served by drawing balance power from the grid.

Solar PV Modules/Solar Panels – The Solar PV modules/Solar Panels convert solar energy to electrical energy. They are available in different technologies such as Mono Crystalline, Poly Crystalline, thin film, CIGS, CdTe, HIT, etc. Poly Crystalline Solar PV panels are most common in use on roof tops.

Inverter – Inverter converts DC output of Solar PV panels into AC power.

Mounting structure – The mounting structure is the support structure that holds the Solar PV panels

Balance of System – These consist of cables, switchboards, junction boxes, meters, structures, earthing system ,circuit breaker, fuses etc.

The grid connected rooftop system can work on net metering basis wherein the beneficiary pays to the utility on net meter reading i.e. the difference between the import and the export energy, if the imported energy is more than the exported energy. If the exported energy is more than the imported energy the utility will pay to the beneficiary for the net energy exported. This concept is applicable to the solar applications registered before 25.03.2019. Thereafter, net feed-in method of billing is applicable.

Under net feed-in scheme for the applications registered on or after 25.03.2019, the surplus/excess energy generated that is unutilized and that flows to the grid at the end of the billing period will be calculated at a tariff fixed by the Hon’ble Commission and credited to the consumer’s account. The energy that is imported from the grid by the consumer will be calculated at the appropriate retail tariff and the monetary value of imported energy debited from the available credit on account of exported energy in the respective billing period. Any credit available in the account of the consumer after debiting value of imported energy will be carried over to the next billing period for adjustments against subsequent billing. If the amount to be debited is higher than the credit in a billing period, the consumer will have to pay the difference in charges..

The Benchmark costs for Grid Connected Rooftop Solar Power Plants for the Year 2019-20 communicated by MNRE is as under:-

Capacity                                                   Benchmark cost (Rs/Wp)

Above 1 kW and upto 10 kW                                  54
Above 10 kW and upto 100 kW                             48
Above 100 kW and upto 500 kW                           45

The Benchmark costs for Grid Connected Rooftop Solar Power Plants for the Year 2020-21 communicated by MNRE is as under:-

Capacity                                                   Benchmark cost (Rs/Wp)

Upto 1 kW                                                                  47
Above 1 kW and upto 2 kW                                     43
Above 2kW and upto 3 kW                                      42
Above 3 kW and upto 10 kW                                   41
Above 10 kW and upto 100 kW                              38
Above 100 kW and upto 500 kW                            36

Depending on the sanctioned demand of the existing service, load requirement of the beneficiary and availability of shadow free rooftop area, the beneficiary may decide the capacity upto 150 kW under LT service.

TEDA will finalise the list of empanelled vendors, float tenders and fix the project cost for the installation of Rooftop Solar domestic services throughout the State.

The consumer is having the option to choose the vendors among the list of empanelled vendors finalised by TEDA. TEDA will issue work order to the vendor. .

The concerned Executive Engineer/O&M will complete the feasibility analysis of distribution transformer capacity based on the verification by the Assistant Executive Engineer/O&M concerned. After receipt of feasibility report from Executive Engineer/O&M the same has to be informed to TEDA for issue of work order to the vendor to install the plant as per the technical standards..

On installation of the PV plants by the vendor, the vendor/consumer will send the readiness report to TANGEDCO. After completing the inspection by AEE/O&M for installations of capacity of 10 KW and by CEIG for installations of capacity of above 10 KW , on receipt of inspection report, bi-directional meter will be installed by TANGEDCO for providing grid connectivity.

On registering the applications in TANGEDCO's Unified Solar Rooftop Portal(USRP), the consumer has to choose the vendor from the empanelled vendor's list . After the issue of work order by TEDA, the vendor will install RTS. The consumer has to make payment to the vendor after deducting the eligible CFA amount. The vendor can claim the CFA from Tamil Nadu Energy Development Agency(TEDA), the implementing agency. TANGEDCO will release the CFA amount to TEDA for onward disbursement to the vendor.

A 1 kW rooftop system generally requires 10 sq. meters of shadow-free area. Actual sizing, however, depends on local factors of solar radiation and weather conditions, efficiency of solar module, shape of the roof etc.

• Cheaper and environment friendly electricity.
• Excess energy can be fed into the grid with tariff as determined by the State Electricity Regulatory Commissions .
• Electricity generation occurs at consumption center thus, saving transmission and distribution losses
• Lower payback period.
• 25 years guaranteed lifespan of the solar photovoltaic panels
• Highly modular
• 25 years guaranteed lifespan of the solar photovoltaic panels
• Subsidy is available from the Central Government for domestic category (residential) of LT consumers.
• Quick installation

Grid Connected RTS System cannot generate electricity during the night. In the absence of generation during night/monsoon, power supply will be fed from the grid.

Grid Connected Rooftop Solar (RTS) system can be installed within one or two months depending on the capacity of PV plant and also under the scope of the vendor.

The Grid Connected Rooftop Solar (RTS) system installed on a roof will generate an average of 4 to 5 units of electricity per kWh per day.

Not required.

All kind of loads, including inductive, capacitive and lighting load in category of LT services expect hut and agriculture can be connected with Rooftop Solar (RTS) system.

A Grid Connected Rooftop Solar (RTS) power plant has a lifespan of 25 years.

Under Phase-II Grid Connected Rooftop Solar Scheme(GCRTS) of Ministry of New and Renewable Energy(MNRE), the consumer can avail Central Financial Assistance(CFA) under Component A as follows:

Component A : Central Financial Assistance (CFA) to residential sector – 4GW:

• CFA at 40% for capacity upto 3 kWp
.
• CFA at 20% for capacity beyond 3 kWp and upto 10 kWp.
• CFA at 20% for Group Housing Societies (GHS)/Residential Welfare Associations (RWA) capacity upto 500 kWp (limited to 10 kWp per house and total upto 500 kWp).
• Domestic manufactured modules and Solar cells to be used.
• CFA shall be on benchmark cost of MNRE for the State/UT or lowest of the cost discovered in the tenders for that State/UT in that year, whichever is lower
• The CFA shall be permissible only if domestic manufactured Solar Panels (using domestic manufactured Solar cells) are used by the beneficiary.

Tamil Nadu Energy Development Agency(TEDA) is the implementing agency in Tamil Nadu for implementing the phase-II of Grid Connected Rooftop Solar Scheme(GCRTS).

The consumer has to make payment to the vendor after detecting the eligible CFA amount. The vendor can claim the CFA from Tamil Nadu Energy Development Agency(TDEA), the implementing agency. TANGEDCO will release the CFA amount to TEDA for onward disbursement to the vendor.

In any billing cycle if the energy imported by the consumer is more than the energy exported to the grid over and above his self consumption, then the import kwh and export kwh are adjusted and the bill will be raised for payment by the Consumer as per existing norms and the applicable service connections tariff. In any billing cycle, if the energy exported exceeds energy imported, the surplus of export Kwh over import Kwh shall be carried over to the next billing cycle for adjustment against the import Kwh of that billing cycle.

Energy settlement will be done on monthly basis. The electricity generated by the RTS will be utilised for the self consumption by the consumer. The excess unutilized energy flowing into the grid and recorded in the export register of the meter will be credited into the consumers account at a tariff fixed by the Regulatory Commission. The energy that is imported from grid by the consumer will be calculated at the appropriate retail tariff and the monitory value of imported energy debited from the available credit on account of exported energy in the respective billing period. Any credit available in the account of the consumer after debiting the value of imported energy will be carried out to the next billing period. If the amount to be debited is higher than the credit in a billing period, the consumer will have to pay the difference in charges. At the end of the settlement period monitory value of surplus generation, if any will be settled by TANGEDCO.

For installed PV systems of capacity above 10 KW, CEIG approval is compulsory.

Consumer has to comply with CEA standards and relevant safety standard as followed by CEIG.

Yes, some banks provide loans especially for Solar Rooftop Systems. .

Document for proof for the existing service in the name of the applicant for solar installation, any one of the valid ID issued by Government such as Aadhar card/Driving license/Voter’s ID/Passport for proof..

Time schedule as specified by the TNERC schedule and as per the norms in vogue will be followed..