Well, I've read A Christmas Carol too many times so... This is what I understand of the Swedish experience.
I'll assume all readers have no technical knowledge so apologise in advance if I'm over-explanatory. Here's the story as its been relayed to me....
Beginning around 40 years ago, the Swedish government established hydro schemes on four river systems. Two of these were suitable for low-head hydro only – i.e. the rivers have a low gradient, much like most of the rivers in our own systems that are attracting micro-hydro proposals. Of these two systems the government granted one to go ahead with mitigation measures and one entirely without ('mitigation' is where you off-set the likely environmental impact – for example by installing a fish pass). On the other two, both high-head systems, they did the same. High-head is where the water flows through a steep gradient – e.g. off a bloody great big hill – and the Swedes looked to benefit from huge snow melts from great lakes in the upper reaches of these systems. The high-head projects are still extant and can produce up to 70% of the country's electricity on demand, mitigation measures for these projects have been further developed and have been successful – the Swedish are now very hot-to-trot on their enviro-kudos. Conversely the low-head projects have been decommissioned due to the environmental damage they have caused, mitigation in place or not, coupled with their being completely financially unviable. The government has sensibly ceased all support for low-head hydro.
Present UK mitigation measures for
low-head hydro touted by the EA etc take successful working examples from the Swedish
high-head hydro experience which would not be replicable in the great majority of proposed UK sites as these will be based on low-head systems. An example is that of allowing a 'flushing spate' twice per year which cleans fish spawning gravels, and moves sediments trapped in the 'wrong' place by the scheme (weir, dam etc) to encourage invertebrate growth (aquatic invertebrates being the major food source for many species of fish including the Brown Trout). That's great if you've got huge lakes sitting above the scheme and can take advantage of their snow-melt but it simply doesn't cross-over to our wee rivers, save one or two in the highlands of Scotland. In the UK we simply can't generate the velocity of waters required for such action because of the shallow gradient of the rivers and even if we could it wouldn't be viable because we have very cunningly built huge swathes of houses on floodplains!
Thats it in a nutshell. I've been looking further at the complications of mitigation measures in the short film I've been making – for example, fish passes are brilliant, in theory...
If you're bored of the telly over the next few days and someone bought you Paxman's fishing anthology for the sixteenth time, here's some reading you might find useful:
Hydropower Fish Passage and
Fight the Hydropower! - The Angling Trust. Of course you might instead be out on the river enjoying it while it lasts.
Whatever you do
DO NOT UNDERESTIMATE the impact that these schemes will have on YOUR local river. Even if you're purely Stillwater, you've got to give a damn about this. Take up Richard's poll and say 'yes'.
All the very best
Ant
Re: The Fight against BAD HYDRO
Also, is this small scale hydro only commercially viable with subsidy, same as for PV and wind? ( i imagine so) - if so the way to kill it off is to kill off the subsidy (leaving only commercially viable, large scale, hydro as the way forward - which perhaps might be better, and also more sustainable long term as not dependent on continued subsidy)
Linear Mode
