Alto Maipo Hydropower Plant

Building one of Chile's largest underground hydropower schemes

The Alto Maipo Hydropower Development is located in the San José de Maipo region, south-east of Santiago de Chile. Under the leadership of STRABAG SpA Chile, almost 5,000 people from more than twenty nations contributed to the delivery of this large-scale infrastructure project.

The scheme comprised the design and construction of an extensive network of tunnels, caverns, hydraulic structures, civil works and earthworks. A total of 74 kilometres of tunnels were excavated using a combination of hard rock, double-shield and single-shield tunnel boring machines, demonstrating the project's exceptional technical complexity. 

Situated in a remote mountainous area at elevations ranging from approximately 820 to 2,500 metres above sea level, the works required sophisticated logistics and careful coordination. Environmental protection and the minimisation of construction impacts were key considerations throughout project delivery. 

Scope of Work

• Design and construction of underground hydropower infrastructure
• Excavation of 74 km of tunnels using TBM technologies
• Construction of underground caverns
• Construction of hydraulic structures, civil works and associated infrastructure
• Excavation and handling of more than 3 million m³ of material
• Execution of works in a high-altitude mountain environment with comprehensive environmental protection measures