Small Hydroelectric Dams Not So Green

2008-08-19 02:53 AM

Geo Energy Network
Chaguanas, TX
Posts: 39

Eco Panas – August 04, 2008

The combined impacts of numerous small hydroelectric dams in one river basin can be at least as harmful as one large dam, warn experts, eco-activists and indigenous groups, who face a flood of new projects along the rivers of the western Brazilian state of Mato Grosso. Hydraulic energy from small dams "is very interesting for its low environmental costs, but everything has its limits," says André Villas-Boas in reference to their proliferation along the tributaries of the Xingú River, in the Amazon.

At least six small dams are concentrated on the rivers in northeast Mato Grosso, points out Villas-Boas, coordinator of the Xingú Program of the non-governmental Socio-Environmental Institute (ISA). Two have already been built and a third has been given the green light by the energy and environmental authorities for the Culuene River alone, the main tributary of the Xingú. Such projects should not be authorized without an integral assessment of the river basin in its environmental and social aspects, for a planned exploitation of the water resource as a whole, and limiting the number of hydroelectric dams, according to Villas-Boas, noting that more than half the area of the Xingú is indigenous land.

The dams are located around the Indigenous Park of the Xingú, a symbol of Brazil's indigenous policy that is home to some 5,000 people of 14 different ethnic groups. Often included among "clean" sources of energy, small hydroelectric dams have become an attractive business for the "soft legislation" under fiscal and financial control and incentives, without duly considering that "they alter biological dynamics" in a serious way if there are many in one watershed, says Villas-Boas. As a result, there are 240 small hydroelectric dams planned in Brazil, according to data from the National Electric Energy Agency (ANEEL). The 81 dams already under construction will produce 1,342 megawatts, or 17.29 percent of electricity from combined sources.

Because of their presumed limited ecological impact, environmental permits for small hydroelectric dams are granted by state, not federal, agencies. The state bodies are more vulnerable to local economic pressures, but they heed the national Brazilian Institute of Environment when the projects affect Indians, says Valle. In the cases of northern Mato Grosso, it is a matter of survival of native peoples, who rely on fish for their food, he adds. That is the main argument against the dams in the legal cases that are still pending. The counter-argument of the construction companies and state authorities is that the indigenous groups do not suffer direct impacts, given that their lands are dozens of kilometers away from the dams.

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