The three projects, all in the northern Atacama Desert, are part of Mainstream's plan to spend $2bn in Chile by 2020.
It is expected to begin building the already-licensed 180MW, $350m Sarco wind farm this year and start operation in the second half of 2017.
Mainstream also plans to invest $142m in the 70.5MW Pedernales PV project and $290m in the 245MW Escondido PV array.
