Surrounded by countries with significant hydrocarbon stores, Armenia's own fossil fuel reserves are limited to a small number of lignite or brown coal mines. Some oil reserves exist, but they are too deep to be economically viable. As a result, electricity generation depends on imported nuclear fuel (44%) for the country's Metsamor nuclear plant, due for decommissioning between 2017 and 2021, and natural gas (29%). Hydropower contributes around one third of the total power generation, with large hydro adding 24% and small hydro making up 3%.