Chile’s largest electric generators said August 9 they will reduce by a third the proposed inundation for their five-dam, 2,355-MW Aysen hydroelectric complex without compromising output.
Endesa Chile and Colbun S.A. made the announcement through their joint corporation, Centrales Hidroelectricas de Aysen S.A. (HidroAysen), which is to develop the complex in southern Chile’s Region X. Two power plants would be built on the Baker River and the remaining three on the Pascua River. (HNN 6/1/07)
The project has faced opposition from environmental and community groups who say it would spoil the natural areas in Chile’s mountainous and remote region of Patagonia.
HydroAysen said the reduction of 36.5 percent in the surface area of the reservoirs for the project “would maintain the generating capacity by maximizing the hydro resources available in the area, reducing the height of the dams, and building five power plants.”
The company indicated the reservoir reduction was possible because the complex now would use five smaller plants, rather than four larger ones originally proposed. It said the investment in the project, estimated at US$4 billion last year, would be pushed higher by the changes.
HidroAysen said the reservoir area would be reduced to 5,910 hectares (22 square miles), of which 1,900 is river surface area. The original inundated area was 9,000 hectares.
“This is the best solution we’ve been able to come up with,” HidroAysen Chief Executive Hernan Salazar said at the project presentation.
HidroAysen said the plants would deliver 18,430 gigawatt-hours annually to the central grid that serves Chile’s most populous region, satisfying 20 percent of the demand estimated for the end of the next decade.
Previous descriptions of Aysen proposed 680-MW Baker 1 and 360-MW Baker 2 plants on the Baker River and 450-MW Pascua 1 and 940-MW Pascua 2 plants on the Pascua River, plus a possible fifth, 70-MW, hydro plant.
In March, HydroAysen had said it planned to complete engineering in the first half of 2007, followed by environmental impact studies. At that time, it said it planned to issue a construction tender in June 2008 for the first plant, Baker 1, which would proceed to construction in December 2008.