Renewables supplied about 98.1 percent of Costa Rica's electricity for the year, the Costa Rican Electricity Institute (ICE) said in mid-December. Fossil fuels provided the remaining 1.9 percent.

The country of 4.9 million people gets most of its electricity from large hydropower facilities, which are fed by multiple rivers and heavy seasonal rains.

Geothermal plants and wind turbines are also prominent sources of power, while biomass and solar power provide a tiny but growing share of electricity.

A few diesel-burning power plants round out the electricity mix, but Costa Rica has barely used them in the last two years.

The country enjoyed a 110-day stretch of carbon-free electricity from June 17 through Oct. 6, when the power company briefly turned on its fossil fuel plants. After that blip, Costa Rica resumed its run of consecutive, fossil fuel-free days, a spokesman for ICE told Mashable on Dec. 13.

In 2015, Costa Rica used 98.9 percent renewable energy, slightly more than 2016's expected total and for Costa Rica, the clean energy success story is likely to continue into 2017.

ICE's president Carlos Manuel Obregón said the power company expects renewable power generation to stay "stable" this year, thanks in part to the nation's four new wind farms and favorable hydro-meteorological conditions, which are projected near the nation's hydropower plants.