Solar system Net Energy Metering

"Net Energy Metering" allows electric meters to spin backward when customers produce more energy than their home or business is using at that moment. It also allows customers to essentially use the electric grid as a battery for free, storing excess energy they don't need now to offset their usage at other times when they draw power from the grid. Some customers have even produced more energy in a year than they use, and net metering provides for financial payments for that.

The down side is that when customers install solar and use Net Energy Metering they avoid paying their fare share of the electricity grid they use at night and of various programs that further a countries environmental and social policies. Remaining utility customers pay for the fixed costs of the electricity grid and other programs, driving the rates higher. Rates and charges for the utility company include charges to maintain the wires and equipment that make up the electricity grid. Other charges fund public sector programs, such as helping low-income families pay their energy costs, and also cover the costs of achieving a higher percentage collective renewables program. 33% would be nice for a goal in any country I would think.

The key to the solar PV rooftop market really taking off in India will be to reduce the risks for RESCO / IPP models. The customers often don't have the cash and companies able to provide an OPEX model don't have enough contractual security to scale it.
As long as solar is still a high cost / long-term investment, reducing the risk will be the crucial driver.

Look at e.g Germany: solar rooftop has become a no-brainer business proposition, with very low risks and an attractive FiT. As a result, banks provided up to 100% debt financing solutions. The market exploded.