Construction on four of the facilities is expected to begin following financial close scheduled during 2015 while the other facility, the Negrete wind farm has been in service since early 2014.
The facilities include 44MW Alena wind farm in the Bio Bio region, 26MW San Manuel wind farm in the Bio Bio region, 150MW Sarco wind farm located in the Atacama region and 90MW Aurora wind farm in the Los Lagos region.
The 15-year PPAs will supply renewable energy to 26 Chilean distribution companies across the country and will power approximately 440,000 households annually.
Mainstream and Actis have launched a joint venture company, Aela EnergÃa, in 2013 to develop 600MW of wind and solar projects in Chile by 2016.
Aela EnergÃa is 40% owned by Mainstream and 60% by Actis. Mainstream will be responsible for construction and operation of the power facilities on behalf of the joint venture.
Aela Energia CEO Sergio del Campo said: "This award of contracts with Electricity Distributors allows us to realise five wind projects in the Central Interconnected System, thereby achieving an installed capacity of 343 megawatts and a total annual production of 1,140 gigawatt hours.
"This commitment of Aela Energia is undoubtedly an important contribution to meeting the demand and price competitiveness of energy for the benefit of households in our country."
