The Marmelos Zero Power Plant is a decommissioned hydroelectric power plant on the Paraibuna River in Juiz de Fora, Minas Gerais, Brazil. Inaugurated in 1889, plant was the first major hydroelectric power plant constructed in South America, specifically for public use. It was purchased by CEMIG in 1980 and now serves as a museum. The Marmelos IA and II downstream are still in operation and are serviced by the original dam.