PPA(Power Purchase Agreement) or RESCO model of Solar allows you to go solar without bearing the capital cost of the solar system. Under this model, the cost of installation and maintenance of the solar system is borne by a third party or a solar company. As a consumer, you just need to pay for your per unit consumption. The Levelized Cost of electricity in this case generally lies between 4-5 Rs/kWh which is subjective to the terms and conditions of the signed contract.
The RESCO/ PPA model of going solar is generally seen to be beneficial for consumers who have large power consumption such as an industry or large business set up. Since such businesses might have their funds employed in working capital, the RESCO/PPA model allows them to enjoy the benefits of solar without having to worry about the capital cost of solar. However, as the capital cost of the solar system here is paid off over the years, the levelized cost of solar energy in RESCO/PPA is higher than the CAPEX and DPA(Deferred Payment Agreement) model of going solar.
You can check an estimate of the solar tariff and the cumulative cash outflow that you would have to bear if you went solar under the RESCO/PPA model by running the MYSUN Solar Calculator.