The solar rooftop system works on the principle of photoelectric effect in which sunlight falling on the solar panels is converted to electricity. The electricity so produced is in the form of Direct Current (DC). The DC charges the battery, which is connected with the solar rooftop system. The DC current can either be used directly to run DC appliances or can be converted into Alternating Current (AC) by using a solar inverter. The AC produced from the solar rooftop system can be used to run household appliances.

A solar rooftop system consists of the following:

• PV Panels
• Mounting Structure
• Battery Bank (in some cases)
• Inverter
• Junction Box
• Cables and other electrical accessories
• Charge Controller.

A solar rooftop system can be of two types:
(i) Solar Rooftop System with Storage facility: Such a rooftop system is battery operated. The solar electricity is stored in the battery and can be utilized when the sun is not available.

(ii) Grid Connected Solar Rooftop System: A grid connected rooftop solar system is connected to your local electricity distribution grid. Like the off-grid system, this too, is mounted on rooftop building complexes. This system converts the DC (direct-current) generated energy into AC (alternate current) energy to run your appliances. In case solar power is not sufficient due to cloud cover etc., energy can be drawn from the local grid². Excess power generated can also be fed back into the connected grid through the Net-Metering Provision.
Read more about the monetary benefits of the Net Metering provision in (11).

The Ministry of New & Renewable Energy provides a list of empanelled providers of solar rooftop system:
Some of the major solar rooftop system providers include (based on the accreditation provided by MNRE):
• Tata Power Solar Systems Ltd
• Godrej & Boyce Mfg Co Ltd
• Hero Solar Energy Pvt Ltd
• Thermax Limited
• Mahindra EPC Services Pvt Ltd
• Sun Edison Solar Power India Pvt Ltd
• Larsen & Toubro Ltd
• Bosch Limited
• Su-Kam Power Systems Ltd
• Juwi India Renewable Energies Pvt Ltd
• Gautam Solar Pvt Ltd
• Minda Industries Ltd
• Fourth Partner Energy Pvt Ltd
• Punam Energy Pvt Ltd
• Vikram Solar
• Luminous Power Technologies Pvt Ltd
• Asun Solar Power Pvt Ltd
• V-Guard Industries Ltd.
You can also visit: http://mnre.gov.in/schemes/decentralized-systems/solar-rooftop-grid-connected/ (channel partners section) to know more about organizations that can help you with your solar rooftop requirements. In addition, many of the state nodal agencies have also empanelled state-specific channel partners.

The size of a solar rooftop system depends on your daily energy consumption (which, in turn, is dependent on the types and number of appliances you use and the amount of time for which you run them) and availability of roof area. Rooftop solar systems from 1 kWp to 500 kWp or in combination can be set up on the roofs.³

About 10 m² of shade free area is required to set up 1kWp solar rooftop system. The area requirement for solar rooftop varies depending upon the capacity of the installation. The area must be free of any shade so as to allow maximum solar insolation on the rooftop system. It is advised to install the solar panel in south facing direction so that the panel absorbs maximum solar radiation and the system is more efficient.

The average cost of grid connected solar rooftop systems is about Rs. 80 per watt or Rs. 80,000 per kWp capacity⁴. The cost of a typical 1kWp off grid (with battery backup) solar rooftop system would be in the range of Rs 1.3 lakhs to 1.5 lakhs, depending on technology, user requirements, etc.⁵

The economic benefits of Rooftop Solar are due to its low maintenance and long-life. It’s a one-time investment. Some of the provisions and benefits available for installing a rooftop solar are:

For Industries and Commercial Organizations:
• Net Metering: Credited or paid for excess energy generated and fed into the grid.⁶
• Loan: The Reserve Bank of India has included renewable energy projects under Priority Sector Lending for which bank loans up to a limit of Rs. 15 crore to borrowers will be available for renewable energy projects including grid connected solar rooftop and ground mounted systems.
• Custom duty concessions
• Excise duty exemptions
• Accelerated Depreciation
• 10 years tax holiday

For Residences:
 Direct Capital Subsidy: takes care of the upfront cost for rooftop solar installation (for entire system as well as particular system parts).⁷
 Net Metering: Credited or paid for excess energy generated and fed into the grid.⁸
 Loan: Avail bank loan for rooftop solar as part of home loan/home improvement loan

For Educational Institutions
 Direct Capital Subsidy: takes care of the upfront cost for rooftop solar installation (for entire system as well as particular system parts).⁹
 Net Metering: Credited or paid for excess energy generated and fed into the grid.

Solar PV systems generally have very low maintenance and servicing requirements. However, some amount of maintenance is essential to ascertain system life and optimal power. Typical maintenance routine would include cleaning of the panels, inverter servicing, regular inspection of mounting structures and cable connections, etc.

In the grid connected rooftop system the Net Metering provision allows consumers to feed the excess power generated back into the grid. In other words, if the renewable energy-generating system generates more electricity than is consumed, the consumer may be credited or paid for the excess electricity contributed to the grid. Net metering customers are charged only for the net power that they consume from the electricity service provider that has accumulated over a specific period. Net metering is also a way to increase the energy in the power grid to keep up with increasing demand during peak power use.¹¹

The benefits of installing a solar rooftop system are numerous. Here are a few ways in which switching to solar energy will help both you and the planet:
• Green and clean alternative to conventional grid electricity. Reduces dependence on polluting and nature taxing fossil fuel-based power generation.
• Electricity that is generated can be utilized at source, hence savings in transmission and distribution losses.
• No requirement of additional land.
• Optimum utilization of space since the unused space at the rooftop is used for setting up the equipment.
• Saving of additional electricity cost.
• Requires less maintenance.
• The system has a life of 20-25 years.

Yes. Central Financial Assistance (CFA) of 30% of the benchmark cost is provided for residential, institutional and social sectors for general category states and 70% of benchmark cost for special category states (North-Eastern states including Sikkim, Uttarakhand, Himachal Pradesh, J&K, Lakshadweep and Andaman & Nicobar Islands). No CFA is provided for commercial, industrial establishments in the private sector and government sector including PSUs.¹²

Yes. The Government is encouraging home loan/ home improvement loan seekers to install rooftop solar PV plants and include cost of system in their home loan proposals. A number of banks have been instructed to extend loans for Rooftop Solar plant under the home loan/home improvement loan.¹³

So far, 11 PSBs namely Bank of India, Syndicate Bank, State Bank of India, Dena Bank, Central Bank of India, Punjab National Bank, Allahabad Bank, Indian Bank, Indian Overseas Bank, State Bank of Bikaner & Jaipur and Bhartiya Mahila Bank have given instructions to their branches to extend loans for Grid Interactive Rooftop Solar PV Plants as home loan/ home improvement loan.¹⁴

The Reserve Bank of India has included renewable energy projects under Priority Sector Lending for which bank loans up to a limit of Rs. 15 crore to borrowers will be available for renewable energy projects including grid connected solar rooftop and ground mounted systems. For individual households, the loan limit is Rs. 10 lakh per borrower.¹⁵

List of state policies are available here: http://mnre.gov.in/file-manager/UserFiles/solar-rooftop-states-policy-tariff.htm

A grid-connected rooftop solar PV system generally has a payback period of 6-8 years, depending upon the system size and electricity tariff.¹⁶

For installing a rooftop solar you only need to connect to one of the rooftop solar providers listed in (5).

Yes. You can use the this solar calculator to determine the size of the system based on your budget and current energy consumption.

Making a switch to solar energy may turn out to be easy. Just adopt the following into your daily life to start your environment friendly life:
• Rooftop solar/Solar lighting: Use solar energy to power your house. Put an end to your reliance on the local grid for your energy needs.

There are also other ways in which you can start your solar journey
• Solar lanterns: Switch on to these pretty and climate friendly lanterns. You can charge them through the day to illuminate your nights. (Price: Rs 600-4500 approx.)
• Solar mobile chargers: Let the sun power your conversations too. Charge your phone with a solar charger. (Price: Rs 1500-3000 approx.)
• Solar fans: Use the sun to power your fan - solar fans are the eco-friendly choice! (Price: Rs 3000-10000 approx.)
• Solar study lamps: Studying under the sunlight has its benefits. But if that's not possible pull a late-nighter with these sun-powered lamps. (Price: Rs 1,000-3000 approx.)
• Solar laptop charger: Charge your portable electronics like MP3 players, mobile phones, digital cameras and laptops, while you’re on the go! (Price: Rs 7000-9000 approx.)
• Solar inverter: Slightly more expensive than conventional inverters at installation, these inverters can be fed into any electric grid and would exhibit the same outcomes but would greatly reduce environmental footprint. (Price: Rs 3500-10500 approx.)

Organizations can choose to go either partly or entirely solar. The more solar you go, the more grateful the Earth becomes. Use the following in your office space to make a difference:

• Rooftop solar/Solar lighting: Use solar energy to power your work area entirely. Put an end to your heavy reliance on the local grid for your energy needs. Go completely solar to set a really powerful example.

• Solar mobile chargers: Solar mobile chargers for your office common space would enhance the features of your office, while cutting down unnecessary electricity consumption from the grid.

• Solar thermal air conditioning systems: The solar thermal AC too can greatly reduce an organization's dependence on the local grid for drawing out energy. It can also reduce the country's dependence on coal and imported oil to produce vast amounts of energy.

• Solar water heating systems: A solar water heater consists of a collector to collect solar energy and an insulated storage tank to store hot water. This technology can be installed for meeting hot water requirements in hostels, guest houses and canteens.

RWAs as representatives of households in a locality can go solar by encouraging residents to adopt or by adopting the following solar powered systems:
• Rooftop solar/Solar lighting: Use solar energy to power houses in your area and light up the common areas and boundary walls. Be the first locality to go completely solar and independent.
• Solar water heating systems: A solar water heater consists of a collector to collect solar energy and an insulated storage tank to store hot water. This technology can be installed for meeting hot water requirements in houses and other buildings of your locality.
• Solar inverter: Slightly more expensive than conventional inverters at installation, these inverters can be fed into electric grid and would exhibit the same outcomes but would greatly reduce environmental footprint. Inform residents in your area about these climate friendly inverters. (Price: Rs 3500-10500 approx.)
You can even ask a solar energy provider to come to your area and exhibit solar powered equipments. Arrange a Solar Fair for your residents this year to help them power their lives on solar energy.

Schools and colleges are the best places to demonstrate that a solar powered life is a possibility. Adopt the following solar powered equipments to introduce your students to solar energy:
• Rooftop solar/Solar lighting: Use solar energy to power your school/college and light up common areas and boundary walls. Embed environment education into the very building of your school/college.
• Solar water heating system: A solar water heater consists of a collector to collect solar energy and an insulated storage tank to store hot water. This technology can be installed for meeting hot water requirements in your school or college.
• Solar study lamps: These may not be the cheapest study lamps around. But they will certainly make your library or common study room area more conducive an environment for studying. (Price: Rs 1,000-3000 approx.)