The average cost of a grid connected solar rooftop system is approx. Rs 50,000/KWp, upto 10KWp. For more than 10 KWp, it will be lower and if the size goes above 100 KWp it will be as low as rs 44,000/KWp.

Each KW requires about 10 Sq Mts. (100 Sq Ft) of shadow free space. So you can calculate, how much can you install.

Electricity Units produced by 1 kW Capacity of solar Panel is between 4-5 unit per day on an average.

Multiple benefits would be there like reduced electricity bill and other tax benefits

Payback time on investment made on Solar roof plant is between 4 to 5 year.
Annual return on investment made on On grid Roof top solar panel Plant is around 20%.

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 440/220 Volt three/single phase line or 33 kV/11 kV three phase lines depending on the capacity of the system installed at residential complex or institution/commercial establishment 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.

Yes, you will still receive the electricity bill. But it would be much lower because the electricity generated by solar Panel roof top plant will be deducted from your electricity bill.

The net metering based rooftop solar projects facilitates self-consumption of electricity generated by the rooftop project and allows for feeding the surplus energy into the network of the distribution licensee. In net metering the beneficiary pays to the utility on net meter reading basis only. Alternatively two meters can also be installed to measure the export and import of power separately. The mechanism based on gross metering at mutually agreed tariff can also be adopted.

Average maintenance cost is almost nil since the components used are having the MTBF (mean time between failure) of 23-25 years.

One can avail the benefit of 40% accelerated depreciation in the first year of installation itself (earlier it was 80%). This can help to significantly reduce your tax liability.