by Simon Tilleard
How environmentally and socially sustainable are big dam projects? Simon Tilleard takes on the issue of large-scale hydro in his recent letter to the New Scientist.
What does “renewable power” mean to you?
Chances are, you’ll think of solar, wind and hydropower. But when it comes to large-scale hydropower, just how ‘renewable’ is this power?
I recently read an article in the New Scientist Rise of renewables starts climate-change fightback – (6 July, page 6-7) which brought home to me once again how common it is to see ‘the next generation’ of large hydropower dams held up as examples of environmentally conscious and sustainable sources of power.
In the article, authors Marshall and Aldhous indicate that large hydropower dams can help to fight back on climate change and produce ‘green power’ whilst sustainably managing environmental resources. They go on to state that a few large dams have erroneously given the sector a bad reputation and that the World Bank’s recent decision to return to funding large dams is proof of improved procedures for management.
My experience as a water resources engineer working in South East Asia brings me a different perspective. It’s abundantly clear that it’s misleading to suggest that merely a few of the older dam projects were ill-conceived and unsustainable. In reality, the negative environmental and social impacts of large dams often outweigh their economic benefits.
The 2000 independent World Commission on Dams, the most comprehensive study on dam impacts, concluded that big, complex schemes cost far more but produce less energy than expected. Examples of environmental and social impacts from large hydropower are plentiful, devastating fish losses from the Pak Mun Dam in Thailand or mass displacement caused by the Narmada Valley […]