La Confluencia

completed

The project consists of the development, construction (approximately 3 years), and operation of a 158 MW run-of-river hydro power plant to be located on the Tinguiririca, Portillo and Azufre Rivers in the VI Region of Chile. The project area is located in the foothills of the Andes Mountains, approximately 75 km southeast of the city of San Fernando. La Confluencia is upstream of the La Higuera Project (IFC#21315); the two projects are designed to operate in cascade, and both projects can operate independently in the event of closure of either plant. The project sponsors for the Tinguiririca Joint Venture are Pacific Hydro Pty Ltd., through its 100% subsidiary, Pacific Hydro Chile S.A., and Statkraft Norfund Power Invest AS, through its 100% subsidiary SN Power Holding Chile Pte. Limited.The project combines water from the Tinguiririca and the Portillo Rivers and their tributaries. The Portillo branch consists of a low diversion weir, open canals and an 11 km tunnel. The Portillo branch tunnel also collects waters of Azufre, Los Humos and Riquelme Rivers. The Tinguiririca branch consists of a low diversion weir, an off-river regulation pondage of 1.2 million m3 live storage, and a 9.3 km long tunnel. The Tinguiririca branch tunnel also collects waters from El Ciruelo and La Gloria streams. The Tinguiririca and Portillo branch tunnels terminate at a concrete lined vertical shaft dropping to the above ground La Confluencia powerhouse via a concrete and steel lined high pressure tunnel. This water will then be discharged directly into the conveyance system for La Higuera for additional power generation. An 18 km transmission line will connect the project to the Tinguiririca Substation at La Higuera.Several assets of the two projects will be shared, and governed by a Shared Services Agreement: - Back-up Plant:The project will utilize La Higuera’s 60 MW Colmito gas/diesel back-up plant (Colmito), which is currently being constructed in V Region under an Engineering, Procurement, and Construction (EPC) contract. It is expected to be completed in 2008.- La Higuera Transmission Line:The project will utilize the 38 km transmission line that will connect the La Higuera project to the grid. The transmission line is being developed for, and will be owned by, the La Higuera project.- Roads:The project will utilize existing private and public roads used for La Higuera project’s construction to access the site. In addition, permanent and temporary construction roads will be created specifically for the works within the site boundaries.- Tinguiririca Substation:The project will connect to and use the substation currently being built for La Higuera.- Pondage:La Confluencia will own an off-river regulation pondage of 1.2 million m3 live storage, to be shared with the La Higuera project.- La Higuera headworks and regulation pondage:The project will discharge flow from the project powerhouse into the La Higuera headworks (re-regulation pondage and pressure culvert).The project is expected to sell about 50-55% of its energy production under a power sales agreement with Chilectra, the largest distribution company in Chile. The balance of the project’s energy will be sold in the spot market. Being a run-of-river hydropower plant, the project will generate power at a very low cost and will be among the first power plants in the system to be dispatched. As the project’s water inflows are primarily determined by snow melting, La Confluencia’s hydrology is uniquely different from that of the system’s rain-fed hydropower projects. During the dry season, La Confluencia will be supplied by snow melting, and during the wet season from rainfall. Hence, it is expected that La Confluencia will be available to dispatch at full load during the dry season, when the hydrology in the system is below average and the cost of generation tends to be higher.