A micro-scale hydropower project in Vietnam. Photo: Wikipedia.
Large scale hydropower rightly riles environmentalists and often social justice activists as well. In comparison small scale hydro, which doesn't require the large dams or even dams at all, has been touted as a good clean power source. Conservation Magazine, however, throws some cold water on that enthusiasm, highlighting some new analysis of the eco-impact of small-scale hydropower.Conservation sums up the work of Tasneem Abbasi and S.A. Abbasi in Renewable and Sustainable Energy Review:
"By all reasoned assessments, the environmental problems caused by small hydro look small in comparison to large hydro," they concede. But after walking through a series of scenarios, they argue those advantages fade when large and small projects are compared by "the scale of impact per kilowatt of power generated. Once this is done, it emerges that the problems that would be caused due to widespread use of SHS would be no less numerous, and no less serious, per kilowatt generated, than those from centralized hydropower." Problems such as siltation and eutrophication, for example, are likely to be common at "mini" and "micro" projects because they tend to create small, shallow pools. And the emissions of methane and other greenhouse gases from such muddy lagoons could rival emissions from rice paddies, they add.
All Energy Production Has Environmental Impact
Consider our current levels of energy use, which are only projected to increase it's worth remembering, there isn't a way of generating electricity that doesn't have significant environmental impacts at some point in the production chain.
The problems with fossil fuels throughout that are well documented. Nuclear power has that pesky problem of waste disposal and mining impacts, two name but two. Mass biofuel production under most production scenarios that extend beyond the local level are industrial agriculture with a twist. Producing solar panels has similar problems to the entire electronics industry, even if when you focus on the electricity production only it's carbon-free--and that doesn't even talk about potential habitat disruption of commercial-scale solar power plants, either photovoltaic or solar thermal. Wind power, geothermal, tidal, all have their own issues as well.
Which is all to say this sort of research is good in that it allows us to better assess which renewable energy sources we should be developing, based on local need and local conditions.