Monday, 12 October 2015

Hydropower - how environmentally friendly is it ?

A Dam in the USA blocks the upstream and downstream movement of fish. Here, sturgeon congregate at the base of a dam that is preventing them from swimming upstream to spawn (Photo by USFWS)

Many green campaigners would have us believe that hydro power is easy on the environment but just how environmentally friendly is it ?

Amy Kober has written a thought provoking article on it :
If hydropower is not done right, it can be destructive for rivers and the fish and wildlife that depend on them. It damages natural habitat and prevents fish from reaching spawning grounds. It can dry up entire stretches of river. It’s the only renewable energy source that drives species toward extinction.

One could argue that wind turbines and solar panels could drive certain bird species towards extinction. There are environmental drawbacks with most renewable technologies just like there are with most conventional generation technologies i.e. there are no easy lunches. 

In Ireland, our main hydro plant is Ardnacrusha operated by ESB. According to Dr William O'Connor, just 500 salmon passed through the fish pass there in 2013. I fully agree with him when he states that :

It is a national disgrace that salmon escapement through the Shannon dams has fallen so low, when measured by successes on other European Rivers with many more problems than the River Shannon has (i.e. Rhine, Thames, and Seine). There should and can be salmon in the upper Shannon.
Personally, I would not mind paying the PSO Levy if it went to compensate ESB for curtailing generation during times of peak upstream Salmon migration. Sadly, the PSO is going to less efficient and reliable sources, while salmon numbers in the Shannon continue to dwindle.


  1. There is a growing media tendency these days to bash hydropower without looking at details. The ecological impact of hydropower varies hugely between projects. The question should rightly be "How environmentally friendly is [this particular] hydropower scheme?" And where there's an issue, the next question should be "What can be done to make it more environmentally friendly ?" For example, there are plenty of low-head schemes now opening up our rivers with state-of-the-art fish passes which would otherwise not be paid for. And all new schemes can only run if they are consented under latest guidance informed by national and EU environmental objectives.

    1. Well I'm glad to hear that modern hydro schemes are more environmentally friendly although forgive me if I'm slightly skeptical of any claims made by operators.

      I think my solution for Ardnacrusha is a reasonable one. One could also argue that for 80MW, is this power plant really required at all nowadays considering we now have waste to energy plants in the order of 60MW ?