The Italian firm has agreed to purchase a 27.3% stake in Pacific Hydro Chacayes S.A., the stand-alone company building the 111MW plant.

Financial terms of the deal were not disclosed. Astaldi will hold the stake via a new company it will establish along with investment partner Simest Societa Italiana per le Imprese all’Estero, which promotes Italian investment overseas.

Pacific Hydro is looking at development of a further three plants in the Cachapoal catchment, which Astaldi noted was of strategic interest.

The Chacayes plant will have 7km of tunnels and a powerhouse with a pair of 55.4MW turbines to generate approximately 57GWh of electricity per year.

In the third quarter of 2008, Astaldi was awarded an engineering, procurement and construction (EPC) contract worth US$282M to build the project.

The project developer holds perpetual water rights and 60% of the energy output is to be sold under long-term power purchase agreements (PPAs) when the plant becomes operational, scheduled for 2011.

The development budget is approximately US$450M, and the other three projects in the valley are values at more than US$1bn. Last year Astaldi entered into a development agreement with the Australian company to look at potential projects in the river basin, such as Nido de Aguila and Las Lenas.