On September 7, 2016 Science alert reported that “Costa Rica ran on 100 percent renewable energy for 76 straight days between June and August this year.
According to the article, “(t)his is the second time in two years that the Central American country has run for more than two months straight on renewables alone, and it brings the 2016 total to 150 days and counting.”
Costa Rica has a mix of hydro, geothermal, wind and solar energy sources; hydropower was the predominant source in August 2016.
You may read the article on the Science Alert internet site.