This model is getting highly popular in india and many opex.
Opex model solar rooftop.
The end consumer pays for the power generated under a long term power purchase agreement ppa.
This opex model is famous in many countries including us where half of rooftop solar pv installations are owned by opex developers.
It is successful model internationally and remains so in india also as the consumer has not to incur upfront capital costs.
In this model the consumer purchases the solar system by making 100 of the payment upfront or financing the system often through a bank.
Under the opex model a renewable energy service company resco invests builds and maintains a rooftop onsite solar plant.
B opex model pay per unit with power purchase agreement in opex model operation expenditure will be yours system instillation company will install the complete system at their own cost on your rooftop through a 10 25 year power purchase agreement ppa between you and installation company.