Alto Maipo Hydropower
Las Lajas HPP is one of the two plants comprising AES Gener's Alto Maipo Project. The plant has 480 meter head, two Pelton units of total 270 MW installed in an underground cavern of 37000 m3, design flow is 65 cubic meters per second.
The plant has its intake immediately downstream of the existing Alfalfal I HPP. The headrace comprises two km of concrete culvert, 9.5 km of unlined headrace tunnel 21-38 m2 and a vertical, steel lined pressure shaft, 150 m long, with diameter 3.7 m.
The tailrace tunnel is 13 km long, free surface flow, 38 m2. The tailrace from Alfalfal II HPP feeds directly into the headrace of Las Lajas.