Koskienergia Oy Contact information Koskienergia Oy is a hydropower company owned by three local energy companies, Etelä-Savon Energia Oy , Äänekosken Energia Oy and Kuoreveden Sähkö Oy . Koskienergia Oy owns and operates 30 hydropower plants across Finland. Hydropower plants produce carbon-free electricity, which is sold to end customers through owner companies. Koskienergia Oy and its partners take care of the operation and maintenance of hydropower plants.