Almost all Costa Rica's electricity was produced by renewable energy in 2016. The Costa Rican Electricity Institute (ICE) said that around 98.1 per cent of the country's electricity came from green sources. These included large hydropower facilities, fed by a myriad of rivers and heavy seasonal rains, geothermal plants, wind turbines, solar panels and biomass plants. The country used carbon-free electricity for more than 250 days last year with a continuous 110-day stretch from 17 June until 6 October. Science and environment journalist Maria Gallucci described the tropical country as "a verdant gem amid a pile of black coal rocks". In comparison, less than 15 per cent of the US electricity supply for January to October 2016 was renewable. Coal and natural gas together made up nearly two-thirds of the US electricity generation over that period and nuclear power provided the remaining 19 per cent. ICE president Carlos Manuel Obregn said he expected renewable power generation to stay "stable" in Costa Rica in 2017. The country, which hosts more than five per cent of the world's species biodiversity despite a landmass that covers 0.03 per cent of the planet, has recently set up four new wind farms. Costa Rican clean development adviser Dr Monica Araya has said the extent of Costa Rica's renewable electricity generation is a "fantastic achievement".