Sri Lanka, Dec. 20 -- Majority of those in the country who installed rooftop solar panels in their houses have fully recovered their capital cost within three years instead of the projected period of seven years to recover the cost, Energy Minister Kumara Jayakody revealed in Parliament yesterday (19). The Minister said that the cost of purchasing electricity via solar panels has greatly reduced. He said that batteries have been introduced newly for solar panels and the guarantee period for the batteries was 10 years in the market when the batteries were introduced but with technological changes and improvements with time, the guarantee period of batteries have been increased up to 15 years through later tenders which could further increa...