check out for projects done by Ktronics (PVT) LTD
https://www.facebook.com/KTronicsLanka. You can also visit those customers and see how there bill get reduces and the gains there getting.
Net metering 1KW will be roughly 120,000/= after premises checked out it can be lower or may be higher depends on roof type, roof to meter distance, premises distance from our office, etc.
Bill eke unit gana anuwa saha oyalage echonomy eka matha okkma wenswenawa. 5KW system ekak 450,000/= wage thama wenne, 10 year for inverters and panels. (part replacement warranty). 200 units nam bill eke thiyene 2KW system ekakin pulwan bill eka 0 koranna, roughly 2.5 lacks yayi. Extra units which you send to Grid you get 22/=