Roof top PV system, view as a customer

May be we should look at it from a customer's point of view; because ultimately he is the one who shall give permission to install a rooftop PV on his house roof. Now if I am the lay man customer, I will look for two things (1) by installing a rooftop PV how much can I save on my monthly electricity bill, & (2) what are the upfront costs, that is, how much time will it take to break even, taking into account subsidies, favorable interest rates etc. If the calculations are positive and if there is someone who can explain me these calculations, then I shall go ahead. Now if that someone is a third party neutral body then I get even more convinced. If that someone is the utility itself, then I get skeptical, because isn't the utility in the business of selling electricity? So why does it wants me to generate electricity which would lead to reduced sales?

The platform is set for roof PV take off. The only thing needed is bringing down the cost which seems to be on cards in near future. Actually in a country like India...stand alone decentralized power generation and distribution is more required. Solar PV suits this parameter. I pay the utility in the State of Madhya Pradesh about Rs. 6.50/Kwh as tariff (tariff based on the consumption slab). Now if the cost of power generated from solar PV system (solar panel+ battery + inverter etc.) can come down to this level there should not be a problem. In Tamil Nadu the grid connected solar PV tariff (without battery etc). has already been offered at Rs. 5.93 / Kwh.