Nido de Águila Hydropower

LOCATION:  Cachapoal, Chile   |   OWNER:  Pacific Hydro Chile
McMillen Jacobs and Associates Logo
Print Image

The 98-megawatt Nido de Águila hydroelectric project will be located on the Cortaderal and Las Leñas rivers in the province of Cachapoal, Chile. Nido de Águila is a key Pacific Hydro Chile (PHC) project at the High Cachapoal river basin. The project will use the natural flow of the Cortaderal and Las Leñas rivers to generate renewable energy, mainly through the use of tunnels. Nido de Águila is expected to have an installed capacity of 172 megawatts, enough clean electricity to supply approximately 450,000 Chilean homes. This is the second project that PHC will develop and deliver in the Cachapoal Valley, building on the successful completion of the Chacayes hydro power plant.

Preliminary project plans feature two intakes connected by a power tunnel to an underground powerhouse, reducing potential environmental impacts and risks associated with a facility in a high area of the Andes Mountains. The underground powerhouse will be equipped with two turbines.

The proposed tunnel alignment comprises an approximately 11-kilometer-long (7 mi) headrace tunnel that passes under a maximum of 1,300 meters (4,265 ft) of rock cover. The key concern of the alignment is the potential for overstress along the nearly 4-kilometer (2.5 mi) central section of high cover, where granitic rock of variable strength is anticipated. Because the overstressing potential represented a high risk to the construction schedule, PHC retained McMillen Jacobs Associates to perform a project review to consider alternative layouts for the project and to help develop a cost-benefit comparison of viable alternatives.

This review included: 

  • Evaluation of granitic rock conditions
  • Evaluation of tunnel conditions
  • Constructability review of drill and blast and TBM construction options
  • Risk evaluation of tunnels
  • Cost and construction schedule assessment
  • Procurement strategy considerations for project advancement
  • Recommendations for geotech­nical investigations