You are correct its only one but its gone from zero in 2010 to about half of what hydro produces now, and the proportion from renewables has gone down quite considerably: https://en.wikipedia.org/wiki/Electricity_sector_in_Sri_Lank...

It is bizarre that you are citing a project that was planned in the 90s, broke ground in 2006 and ended in 2015 as a recent development.

I did not use the word recently, and what matters here are long term trends.