States developing massive hydropower infrastructure are failing to take into account the loss of biodiversity, socioeconomic damage caused to nearby communities and environmental impact of such projects, warn researchers at Michigan State University.
In an article published in the Proceedings of the National Academy of the Sciences of the United States of America, the researchers argue that if the construction of large dams in developing countries is to continue, it must always be preceded by a painstaking assessment of the real cost, including the environmental and social impact.
“When a large dam is built, the result is a downstream loss of a great many fish species that are important to riverine populations. These communities will have to continue somehow making a living despite dwindling fish stocks for 15 or 20 years, for example, and the costs of these projects don’t take such economic and social losses into account,” says lead author and visiting professor at the University of Campinas (UNICAMP) Emilio Moran.
Read more: Study: large hydropower dams unsustainable
Developed countries in North America and Europe built thousands of dams between 1920 and 1970 but this process came to a halt because the best sites for hydropower generation had already been developed and environmental and social concerns made the associated costs unacceptable. Several of these developments have now reached the end of their working lives. According to the article, more dams are being removed than built in North America and Europe. In the US alone, 546 dams were dismantled between 2006 and 2014.
“The cost of removing a dam once its useful life is over is extremely high and should be taken into account when computing the total cost of a new hydro development,” Moran said. “If the cost of removal had to be included, many dams wouldn’t be built. It would be far more expensive to produce a kilowatt-hour of electricity via a hydro complex with a useful life of 30-50 years like those under construction in Brazil.”
Another major concern is that since an increasing number of these projects are designed to provide power to industrial sectors and national electricity grids, nearby populations which have to sacrifice the most for the construction of major dams end up reaping little, if any benefits.
“The people affected by these projects reap no benefits, such as access to electricity or a cheaper power supply. In the case of Belo Monte, the transmission line passes over the heads of the people affected and takes the electricity generated straight to the south and southeast, two of Brazil’s wealthiest regions,” Moran said.
An alternative to traditional dams recommended by the authors is submerged or in-stream turbine technology, also known as “zero head” because no height differential or damming is required. Moreover, it does not entail the displacement of local inhabitants or the other social costs of dams.
“Small turbines can also be installed near dams to supplement power generation and eliminate the need to build more dams.”