One place to check all the frequently asked questions about RoofTop PV, Ground Mounted PV, Grid Connected Solar Rooftop Systems, Solar Parks.
Power generated from rooftop solar is much cheaper than power from diesel generators. Solar PV generates power at a cost of about Rs. 4.5-5/KWh while rough cost estimate of diesel generated power is about Rs. 16/KWh. Whether solar is more expensive than grid power depends on the current tariff of the consumer. In some cases, solar power is not cheaper than grid power, but in few other cases where consumers are paying a commercial tariff, solar power may be cheaper than grid power. This can be decided on a case-to-case basis.
Of course this is a relative question. It depends, in part, on how much electricity one uses and how efficient the appliances are that are being operated. That said, expect to generate excess electricity in the summer (when days are long) which can potentially offset the energy one uses from the grid in the winter. A combination of energy efficient appliances and light bulbs can help reduce homes energy bill by over two-thirds if planned properly and efficiently.
The area required by a rooftop PV plant is dependent on various factors like the extent of shade-free space available, duration for which sun is available and solar panel efficiency. A solar PV system typically requires 120-130 sq.ft (about 12 sq.m) of shade free roof area per kW of capacity at current crystalline panel efficiency levels.
The amount of electricity generated by a rooftop solar PV plant depends on the location, orientation of the roof, panel efficiency, and ambient temperature. As a rule of thumb, a 1 kWp plant will generate about 4 kWh (units) of electricity a day on average in a year.
To use the energy stored in the Battery Bank, we need a DC to AC Power Inverter. It changes the low voltage DC to 120 Volts AC for standard household appliances. There are 3 basic types. First is a Square Wave Inverter usually designed to plug into a car’s 12 Volt cigarette lighter outlet. These are cheap to buy but very poor quality. The next option is a Modified Sine Wave Inverter and is satisfactory for most applications. However, for a really clean power, a true Sine Wave Inverter is the best fit. A high quality Sine Wave Inverter often has a cleaner power footprint than any local utility company. That will be the best choice.
Solar photovoltaic panels require little maintenance – no need to wash or dust. It is, however, important to place panels where they will remain clear of shade and debris. Thus one will have to wipe them off if too much dust or leaves fall on them. Solar hot water collection arrays don’t need much attention either. It does help to improve the efficiency if periodically one can use a window wash brush, biodegradable soap, and water to clean the tubes/panels
The capacity of the rooftop solar plant required to power an average facility can be calculated keeping in mind the requirements, the constraints and the amount of sunlight available. Rooftop space is the most likely the major constraint that will limit the size of the solar plant. If the size of the plant is not sufficient to power the entire facility, one will have to choose between powering light loads, powering critical loads, and using a solar-diesel hybrid.
There are various solar policies that incentivise rooftop solar in India. Central government schemes include 80% accelerated depreciation, capital subsidy of 30% and more based on location, and Renewable Energy Certificates (RECs). Some states have further incentives under their own solar policies. Permissions primarily deal with ensuring the grid isn’t congested by receiving approval from local power distribution authorities.
Warranties Solar panels typically have 5-year manufacturer’s warranty with additional performance warranty of 90% of rated power output for first 10 years, and 80% of rated power output for the next 15 years. Other system components (inverters, mounting structures, batteries, junction boxes, etc.) typically have 1-year manufacturer’s warranty extendable to 5 years. Certifications Each component of the plant should conform to various IEC (international) or IS (Indian) standards. Panels should conform to IEC 61215/IS 14286 for design qualification and type approval, IEC 61730 for safety, and IEC 61701/IS 61701 for salt mist corrosion (for use in coastal areas).
Subsidy support from MNRE for Grid-connected Rooftop PV systems of sizes 100 kWp-500 kWp is routed through SECI.
Tenders are invited by SECI in phased manner for installation of rooftop Solar PV systems within 100-500 kWp range, in various cities/states in India. 15% subsidy is offered by SECI to the companies selected after their bid evaluation. The companies then pass on the subsidy support to the end-users. Rooftop owners/consumers can contact the selected companies for setting up rooftop PV systems on their premises.
SECI does not provide subsidy directly to the rooftop owner, but rather to the project developer. Housing societies may approach any of the developers selected through the competitive bidding process to avail the benefits of the programme.
Whether solar power can replace your diesel consumption entirely depends on a number of factors such as the nature and timing of the load, the extent of load shedding, the area of roof available, etc. Some of the factors that constrain the supply of rooftop solar power include
Solar Park is a concentrated zone of development of solar power generation projects. The parks are characterized by well-developed proper infrastructure where the risk & gestation period of the projects will be minimized.
Various infrastructure like transmission system, water, road connectivity and communication network etc. will be developed.
There will be 25 Solar Parks in various states, each with capacity 500 MW* or above, thereby targeting a cumulative capacity of around 20000 MW.
Smaller parks in Himalayan & Other hilly states where contiguous Land may be difficult to acquire in view of difficult terrain will also be considered.
All states & UTs are eligible.
States applying under the scheme will have to designate an agency for the development & Management of Solar Park, as per the modes envisaged below;
Private Organizations under Model-IV may opt to participate as Implementing Agency. Choice of implementing agency for development and O&M of Solar Park is left to the State government.
Solar Power Developers would have to arrange for their own buyer of power for Projects that are set up within the Solar Park, either by participating in some competitive bidding process, or through mutual negotiations or on nomination basis or for captive use or any other means.
Tariff shall be determined either through CERC/SERC Regulations or competitive bidding.
Following are the responsibilities of Implementing Agency
Include any other activity related to Solar Power Park, such as manufacturing Unit as per directions of MNRE & State Government
There are a number of Solar Power Developers in the market. You may engage their services. Around 5 acres of land is required for setting up a 1 MW SPV plant with crystalline Silicon technology. With Thin Film technology, land requirement is slightly higher.
Several tax/duty exemptions are available for solar plants depending on the respective state solar policies where the plants are located. You may contact the respective SNAs for more details.
In the year 2014-15, Central Electricity Regulatory Commission has given the benchmark capital cost for solar PV projects as around 700 lakhs/ MW. Actual cost would depend on site location, components selection, contractor hired etc.
There is no subsidy available for utility-scale SPV plants. Various states offer a bouquet of incentives (such as exemption from Open Access charges, feed-in tariffs, tax benefits, accelerated depreciation etc.) to solar power projects that are set up under their state schemes.
At the national level, solar PV plants are being set up through Jawaharlal Nehru National Solar Mission (Phase II). SECI is the nodal agency for Batch I of this Phase (750 MW). Under this programme, projects are being set up with Viability Gap Funding support from the Central Government. Project selection is through a competitive bidding process. Project selection under Batch I is over and no new projects would be accepted. However, another 2000 MW is going to be awarded soon by SECI. Developers willing to avail the Central Government support may participate in the open tendering process, as and when announced by SECI.
In a solar rooftop system, the solar panels are installed in 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.
Such rooftop system has battery as storage facility. The solar electricity is stored in the battery and can be utilized during night also when the sun is not available.
In grid connected rooftop or small SPV system, the DC power generated from SPV panel is converted to AC power using power conditioning unit and is fed to the grid either of 33 kV/11 kV three phase lines or of 440/220 Volt three/single phase line depending on the capacity of the system installed at institution/commercial establishment or residential complex and the regulatory framework specified for respective States. These systems generate power during the day time which is utilized fully 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 power from the grid.
The average cost of grid connected rooftop solar systems is about Rs. 80 per watt or Rs. 8.0crore per MWp capacity. Such rooftop systems can be installed at the roofs of residential and commercial complex, housing societies, community centers, government organizations, private institutions etc.
There is a provision of Central Financial Assistance of 15% of the total cost or Rs. 12 per watt or Rs. 1.20 crore per MWp under the Grid Connected Rooftop and Small Solar Plants Programme of the Ministry. This CFA has been reduced from 30% to 15%. There are provisions of concessional import duty/excise duty exemption, accelerated depreciation and tax holiday for setting up of grid connected rooftop power plants.
About 10sq.m area is required to set up 1 kWp grid connected rooftop solar system.
The grid connected rooftop system can work on net metering basis wherein the beneficiary pays to the utility on net meter reading basis only. Alternatively two meters can also be installed to major the export and import of power separately. The mechanism based on gross metering at mutually agreed tariff can also be adopted.
In feed-in-tariff the Government offers a tariff for purchase of the solar power generated from such plants.