- Hydroelectric Technology
- List of Hydroelectric Power
Posted by Energetic
A list of ten proposed Severn Barrage Tidal Energy projects was published in July 2008. The feasibility study looked in further detail at the ten schemes and the consultation document published in January 2009 proposed that a short-list of 5 schemes should be the subject of more extensive research in phase two of the study. The 5 schemes are:
The Government response to consultation was published in July 2009. This confirmed detailed study in phase 2 would be carried out on the 5 schemes that were recommended in the consultation document. It also announced work to bring forward 3 further schemes that are currently in the very early stages of development.
The Severn Barrage plans would provide a predictable source of green energy during lifetime of the scheme, 5% of the UK's output from the 10-mile version. This could reduce the cost of meeting UK’s renewable energy targets, and help the UK to meet such targets, including those to tackle climate change. This is because of the few carbon emissions associated with the plan, because unlike conventional power generation, the Severn Barrage plans do not involve the combustion of fossil fuels. A consequence of this plan is that the carbon payback time—the time it takes for saved carbon emissions (those produced by generating the same amount of power in other ways) to outstrip those produced during construction— could be as little as four-and-a-half months, although likely to be around six.
It could continue to operate for around 120 years, compared with 30–40 years for nuclear power plants. An additional benefit would be to improve energy security.
However, although power supply is predictable, peaks in generation from the barrage do not necessarily coincide with peaks in demand. There are two major tidal cycles affecting power output:
Just under eight hours per day of generation time is expected.
Estimated costs for existing plans could be as low as £10bn and as high as £34bn. Recent studies have suggested that the smaller short-listed options could be privately financed, and so in effect the matter of cost and risk becomes a private one between the building consortium and their banks. Schemes of the scale of Cardiff-Weston are likely to require significant Government involvement. If the banks feel that a smaller project is viable and decide to lend the money at an acceptable cost of finance then the projects will go ahead (subject to planning and other approvals). None of this cost would directly fall on the tax-payer but any support mechanism for the tidal power would be likely to fall on consumers. There would though be secondary knock-on costs from the tidal power project that might be met by the tax-payer, such as modifying existing ports, provision of compensatory habitat and dealing with environmental change. However, these would be offset by the positive knock-on effects, such as flood protection - which would have otherwise also cost tax-payer money. Whether the parties actually decided to exchange money for these knock-on effects would be a matter for Government negotiation.
Any large-scale barrage would create leisure-friendly water conditions behind it. Flood protection would be provided by the barrage, covering the vulnerable Severn estuary from storm surges from the sea. New road and/or rail transport links could be built across a barrage if demand rises in the future, as outlined below. Any barrage could provide a boost to the local economy — construction industry in the short term, tourism and infrastructure in the long term.
However, shipping would have to navigate locks, and existing estuary industries, including fisheries, would be damaged and jobs lost. All industrial discharges into the River Severn (e.g. from Avonmouth) would have to be reassessed.