The companies are paying approximately $67m for the stake in Norte Energia, which holds the concession for the Belo Monte dam project.
The stake will be acquired via a joint venture called Amazonia Energia Participacoes of which Cemig holds a 74.5% stake with Light holding the remaining 25.5% interest.
The Belo Monte hydroelectric dam, located on the Xingu River in the Brazilian state of Para, will have an installed capacity of about 11,233MW and is expected to commence power production in 2015.
