The Severn Barrage
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My reason for visiting was not just see a Crewkerne business but also to try and understand a little more about how the UK's energy supply can be helped by hydro generation.
In particular we discussed the plans for the Severn barrage hydro electric generation plant. In a time when we are looking to rely less on fossil fuel driven energy supplies then a huge engineering feat such as this is of major importance. Predictable there is a strong environmental lobby who appear to be against this although studies have shown that many of the fears they have are in fact positive benefits to the scheme. Here is just a short list of the know advantages and disadvantages.
The cost is likely to be £15bn and there is the potential for the generation of 6% of the whole UK energy consumption – this is a significant project!
Benefits
- Predictable source of "green" energy during lifetime of barrage
- Unlike coal power stations then energy can be turned on and off in a much more predicable way and is therefore highly efficient
- Home-grown facility, independent of foreign uncertainties
- Flood protection for the vulnerable Severn estuary, including against global warming sea level rises
- Transport links for road and/or rail
- Better shipping and boating conditions behind the barrier
- Boost to local economy - construction industry in the short term, tourism and infrastructure in the long term
- Reduced turbidity (cloudiness) of water will improve the density and spread of invertebrate colonies in the estuary. This should lead to better carrying capacity for migratory fish and birds. (evidence needed to substantiate this statement as a barrage would lead to large losses of intertidal mudflats (bird feeding grounds) and a barrage could be a physical obstacle to migratory fish)
Disadvantages
- Existing ecosystems would be heavily altered, with new species moving in and perhaps dominating old species
- Some of the low-tide mud-flats would be lost, displacing some of the wading birds that make the estuary a protected area
- Lack of industry skill in the UK of a project of this size.
- Likely to stimulate silting in some areas and coastal erosion in others
- Enhance flood risk on the seaward side because only a proportion of the water that presently flows up stream will pass through the barrage leaving the remainder to rise up outside possibly raising levels by as much as a metre.
- Shipping would have to navigate locks
- Costs associated with navigating the locks would impact trade and commerce
- Severn bore weakened
- All industrial discharges into the River Severn (e.g. from Avonmouth) will have to be reassessed.
- Negative visual impact upon the landscape
- Huge amount of concrete (etc.) needed - quarrying of stone likely to impact on other areas.
- Cost of build would mean the buy back time would be considerable and the barrage may only have a finite life span due to silting up behind barrage negating the "green" element.
One of the most interesting of the positives is the potential for the barrage to stop the surges that have led to flooding along the Severn estuary.
The Government have commissioned another report which is due to report at the back end of 2009 and they will then take a decision.
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Harnessing the tides of the Severn Estuary need not be damaging to the environment as you suggest in your article. The 'Tidal Power Reef' could produce as much power as any of the alternatives and yet be environmentally benign which is why it is attracting interest from both wildlife groups and shipping interests. This is a totally Westcountry initiative, so I don't agree that we lack the engineering skills in this country.
'there is the potential for the generation of 6% of the whole UK energy consumption'
No, I think you will find that the estimate is 6% of UK electricty consumption, still considerable but much smaller than your figure.
Pity that you dont mention other tidal energy technologies that will be studied and that may well be both more cost-effective and less environmentally damaging eg tidal lagoons, tidal stream turbines and others. Environmentalists clearly dont oppose tidal energy but do want the smartest technologies available used within the best energy strategy.
A barrage is unlikely to meet the needs of the EU Habitats Directive due to massive estuary impacts, is opposed by the Environment Agency and by Natural England, and would have to pass tough tests according to the Sustainable Development Commission. Organisations like the Bristol Port Company are also very much against.
http://stopthebarrage.com/petition.html
Vowles,
My view is very simple - I think we ought to be trying to work towards any non-carbon scheme that we can. It is a fine cost/benefit analysis as to whether the potential environmental problems might outweigh the carbon ones. I do hope, however, that your Green Party campaign will not close your mind to other ways of achieving this - such as that outlined by Rupert in an earlier comment.
Super post. Hope to definitely come back again.