Renew On Line (UK) number 71
|Extracts from NATTA's journal
Renew, Issue 171 Jan/Feb 2008
|Welcome Archives Bulletin|
5. Tidal Barrage reactions
The conditional support given by the Sustainable Development Commission to the Severn Tidal Barrage (see Renew 170) led to a lot of objections. Some were on basic environmental lines, but some also pointed to what they saw as better alternatives.
The RSPB said that its construction ‘will cause the emission of 10m tonnes of carbon. Greenhouse gas savings will be substantial in the long run, but those savings could be too late to avert the damage of climate change. It would be far better to spend the £15bn to £20bn the barrage will cost on measures that will cut emissions more quickly. The Severn estuary is an irreplaceable refuge for wildlife.’
The Wildfowl and Wetlands Trust (WWT), whose Slimbridge Wetland Centre is on the banks of the Severn, said: ‘WWT fully backs a shift toward low-carbon energy sources and recognises the potential benefits of harnessing the power of the massive movement of water in and out of the Severn Estuary each day. However the construction of a huge dam across the estuary could have a massive environmental impact on this delicate ecosystem and the wildlife that depends on it. There are alternative methods of harnessing that tidal power and WWT is calling for fair and balanced assessment of all the options and implications for the estuary’s international conservation importance so the best deal can be struck for people and wildlife.’
Friends of the Earth also came out noisily against (seebelow), and Plaid Cymru has also opposed it- something which caused some confusion since it’s Labour's coalition partner in the Welsh Assembly.
Jonathon Porritt, SDC chair, writing in the Guardian (3/10/07), was more sanguine, although he was aware that views were fiercely polarised. On one hand there were the engineers and enthusiasts, on the other eco-NGO’s and statutory bodies such as the Environment Agency, who argued that it would breach EU directives. Steering through these positions, he said the SDC took a ‘conditions-led’ approach and asked: ‘Is it feasible in engineering terms? We believe it is. Is it feasible in financial terms? We believe it is, though not without big strings attached. And can it be done in a way that is completely compatible with those EU directives? We believe it can, even though there will be significant environmental impacts.’
The SDC’s final condition was that ‘the government should not proceed with a Severn barrage proposal unless it accepts upfront that this is going to be publicly led as a project, and publicly owned as an asset. Crucially, this would also enable the use of the kind of very low discount rate that Sir Nicholas Stern recommended in his climate change report earlier in the year, which would in turn deliver not only a highly-competitive cost of electricity from the barrage, but enough financial resource to fund the compensation package, which needs to be built into the capital cost right from the start.’
But there was no hint on where the money should come from- some sort of PFI ?
Porritt said he saw tidal current turbines as ‘very different from tidal barrages, but equally significant in scale. We reckon another 5% of the total UK electricity demand could be met by tidal stream, though getting it into the grid from off the north coast of Scotland is going to be quite a challenge.’ But, on tidal lagoons he said ‘unfortunately, there is little evidence to indicate just how big a contribution lagoons might make and we have recommended that a pilot scheme should be undertaken’.
Emission savings? Only 0.92%
The SDC’s report says that, overall, tidal schemes might supply up to 10% of UK electricity, about 5% from barrages and 5% from tidal current turbines. That’s worth having. But, when looked at in detail, its analysis of the Severn barrage is not quite so positive at it seems at first glance. For example, it admits that, given the variable cyclic pattern of tides, its average ‘capacity value’ would only be ‘around 20-23%’ and it calculates that, assuming it displaces new gas fired CCGT which would otherwise produce 90tC/GWh, it would avoid the emission of 1.5 mtC p.a., which as a percentage reduction in carbon emissions is only 0.92% compared to 1990 levels. Not a lot for £15bn. The case for lagoons and tidal current turbines as better alternatives was made regularly during the SDC’s consultation exercises- we will review that process in Renew 172 and the full SDC report in Renew 173.
On economics, the SDC report says that at an 8% discount rate, the barrages ‘lie at the higher end in comparison to other low carbon technologies; at 15%, they are well above the costs of all other technologies except wave power, but using low discount rates of 2 or 3.5% a barrage becomes highly cost-competitive’. But surely the others would be even more so then?
The SDC report is at www.sd-commission.org.uk/pages/tidal.html.
FoE challenge SDC’s Severn Barrage proposals
Friends of the Earth said it was ‘alarmed at the pro-Severn Barrage recommendations published by the Sustainable Development Commission’. FoE expressed ‘disappointment that the Commission proposes a scheme that would be publicly funded. Due to its high generating cost of 9.2p per kWh the Barrage would be nearly three times the cost of large tidal lagoons.’
Instead FoE is calling for a comprehensive study of tidal lagoons and a smaller barrage on the Severn (Shoots barrage), and rejected the SDC’s recommendation that a feasibility study should be focused on the Severn Barrage- only looking at alternatives if the barrage failed key tests. FOE has identified six main reasons why tidal lagoons would be a better option than a Severn Barrage, as set out in a comprehensive report:
For FoE’s Barrage report summary, and the full FoE report, go to:www.foe.co.uk/cymru/english/news/severn_barrage_report.html
*We hear that a 4.6 sq mile tidal lagoon scheme is being considered in Canada in a 17 meter tidal range.
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