Renew On Line (UK) 69
|Extracts from NATTA's journal
Renew, Issue 169 Sept-Oct 2007
|Welcome Archives Bulletin|
3. UK Tidal Surges - and wave too
Marine Current Turbines is planning to install its 1.2 megawatt (MW) SeaGen tidal current turbine in Northern Ireland’s Strangford Lough marine nature reserve as soon as the Danish jack-up barge arrives - it was originally meant to start work at the end of August, but has been delayed on another project. It’s a commercial demonstration project with permission to operate in Strangford Lough for a period of up to 5 years. Then, according to Martin Wright, managing director of Marine Current Turbines, the aim is to “build on the success of SeaGen to develop a commercial tidal farm, of up to 10 MW in UK waters, within the next three years. With the right funding and regulatory framework, we believe we can realistically achieve up to 500 MW of tidal capacity by 2015 based on this new SeaGen technology.”
Future turbines will generally be rated at from 750 to 1500 kW depending on the local flow pattern and peak velocity, grouped in arrays much as with wind farms, in places with high currents.
The SeaGen consists of twin axial flow rotors, 15m to 20m in diameter, mounted on wing-like extensions on either side of a tubular steel monopile approximately three meters in diameter and set into a hole drilled into the seabed.
Installation is to be carried out by leading Danish contractor A2SEA A/S. Their jack-up barge will transport SeaGen from a shipyard in Belfast to Strangford Lough. It is expected that the drilling of a single pile into the seabed and the installation of the twin-turbine device would take 14 days, with commissioning and power generation to the local grid shortly afterwards.
An Environmental Impact Analyses by independent consultants recently confirmed that the technology does not offer any serious threat to fish or marine mammals. The rotors on SeaGen turn slowly at 10 to 20 rpm. A ship’s propellers, by comparison, typically run 10 times as fast. In addition, the risk of impact from SeaGen rotor blades is extremely small bearing in mind that virtually all marine creatures that choose to swim in areas with strong currents have excellent perceptive powers and agility, giving them the ability to successfully avoid collisions with static or slow-moving underwater obstructions.
SeaGen was developed on the basis of a SeaFlow prototype turbine installed by Marine Current Turbines off Lynmouth in Devon in 2003. The £8.5m Marine Current Turbine project received a £4.27m grant from the Governments Technology Programme for SeaGen. Marine Current Turbines has also now secured £7.5m of new investment from amongst others Triodos Bank
Several other Tidal current turbine projects are also moving ahead both in the UK and overseas (see our Technology section). For example, Scottish Power and Hammerfest Strøm have signed an agreement to further develop the Norwegians tidal turbine technology. They will form the tidal power company Hammerfest Strøm UK to work on a full-scale tidal energy turbine to be installed in the UK in 2009. Hammerfest Strøm, with its main partner Statoil, installed a prototype turbine in the Kval Sound near Hammerfest, northern Norway, in 2003. It was claimed to be the first in the world to supply power to the commercial power grid.
Meanwhile, with the European Marine Energy Centre’s tidal test facility in Orkney almost complete, its first client, Open Hydro, is about to connect to the grid. Many other tidal projects are lined up for test there- and at NaREC at Blyth in Northumberland. Wave projects are also being tested at both sites- and soon also at the Wave Hub in Cornwall (see p.9). However, money is still a problem especially for the newer projects. As noted later (p.9), so far no projects have managed to meet the criteria for funding from the governments £42m Marine Renewables Deployment Fund. Whereas with wind, the initial development phase could be on land, with wave and tidal projects, although some tests can be done with models in tanks, to really get going, shoreline wave apart, you have to go to sea with more or less full scale systems- so the entry cost for new ideas is high. Despite growing investor enthusiasm for renewables, wave and tidal power are still seen as long shots. Alex Illingworth, manager of the £67.5m Halifax Ethical fund, has noted that too few marine power technologies are being developed past the testing stage. But he claims that there was still scope for growth in the area and urged investors to keep watch. ‘We are now seeing environmental, political and, crucially, economic factors, coming together to create what I believe to be a genuine area of positive, long term growth for investors.’
SNP back Wave and Tidal
Scotlands new First Minister, SNP leader Alex Salmond, has made it clear that he will be backing marine renewables strongly, even if it meant going against the Westminster plan. On 31st May he commented in response to a question in the Scottish Parliament ‘Our support for the sector is already ahead of the rest of the United Kingdom. We will, with the industry, be considering the white paper proposals for marine energy. We will make our views known to the UK Government but, if necessary, we will continue to provide separate support schemes for Scotland, because... the support that we are providing in Scotland is substantially greater than that indicated by the energy white paper.’
Cornish Wave Hub
The world’s largest wave farm project planned off the north coast of Cornwall has been approved for £21.5m of funding. The investment, agreed by SW Regional Development Agency, means Wave Hub has the necessary £28m needed to build it, subject to final Government and EU approval
Wave Hub could be built as early as next summer if Ministers give it planning permission. It will provide a high voltage cable and undersea socket, 10 miles out to sea near Hayle and connected to the National Grid. Companies will be able to test their wave energy devices in a leased and consented area of sea on a scale never seen anywhere before.
Three wave energy companies are already working with the RDA to use Wave Hub- Ocean Power Technologies Ltd, Fred Olsen Ltd and WestWave, a consortium of E.On and Ocean Prospect Ltd, using the Pelamis technology of Ocean Power Delivery Ltd. The Australian Energetech OWC device has also now been selected as the fourth partner- the company is now known as Oceanlinx.
The DTI committed £4.5m & the RDA has already invested over £2m. About half the £21.5m now approved by the RDA is expected to come from the European Regional Development Fund through the Convergence Programme for Cornwall and the Isles of Scilly.
More at www.wavehub.co.uk
The new funding announcement coincided with the publication of an independent report into Wave Hub’s possible impact on surf conditions along some parts of Cornwall’s coastline.
Dr Kerry Black, a New Zealand based physical oceanographer, has concluded that the impact on wave height would be less than 5%- or less than five centimetres off a metre-high wave. This is in line with the RDA’s own findings and far less than the 11% feared previously by some surfers, and in line with studies by the UEC Falmouth (see Renew 164/165).
One very tentative example of an alternative to large invasive tidal barrages is the ‘tidal bridge’ idea being promoted by Bridge Across the Bay Ltd, who say that a 12-mile £700m bridge structure from Rampside to Heysham could be paid for out of revenue from electricity generated from tidal current turbines mounted on the bridge.. According to the North-West Evening Mail ‘By the end of this year the Bridge Across the Bay Ltd hopes to have appointed researchers to investigate the potential environmental and economic impact of the scheme. If all goes to plan, planning permission will be sought in 2010. Subject to approval, once the finance is in place, construction could begin around 2011, and the company estimates the bridge would be completed in 2015.’
Severn Barrage backed…
‘We must ensure that that can be done on a cost-effective basis and in a way that will provide the renewable energy that we want. So far we have not been able to find a satisfactory way of doing it, but we will continue to look at what we can do. In principle, of course we want it to happen, but it must be done in a way that is cost-effective’.
Tony Blair, Commons, June 13th
The Independent has claimed that there is strong backing in the Cabinet for the 8GW £15bn Severn Tidal Barrage. Peter Hain told them that tidal power was ‘a huge untapped energy resource’ and that ‘the Severn barrage is a project whose time has come’. David Miliband said: ‘generating 5% of the UK’s electricity from a reliable renewable source is a huge prize, so a tidal barrage across the Severn has to be worth very serious consideration. Other environmental impacts need to be weighed in the balance but we will not be protecting biodiversity unless we tackle climate change.’
The White Paper mentioned the potential of the Severn barrage, but did not devote much space to it, since tidal power is the subject of an inquiry by the Sustainable Development Commission. That should be out soon. It seems likely to be in favour of the Severn Barrage, which will raise hackles with most environmental groups, who as noted below, are opposed.
… but opposition grows
While there has been media speculation about the proposed 8.6 Gigawatt £15bn Severn Tidal Barrage being back the agenda, with Blair (see box) and organisations like the Institution of Civil Engineers in favour, most environmental groups are strongly opposed, arguing that there are better, less environmentally damaging options. Earlier this year, responding to indications from the Welsh Assembly that they would support the idea, WWF, RSPB and Friends of the Earth Cymru joined forces to point out that there were several technologies which could generate similar levels of power from the Severn with much less eco-impact.
Morgan Parry, Head of WWF Cymru commented; ‘We accept the urgent need for the Welsh Assembly Government to address climate change through developing marine renewables as a means of reducing carbon dioxide emissions but building the Severn Barrage is not the answer. The environmental damage caused by constructing a 10 mile concrete energy dinosaur will cause irreversible damage to Wales and England’s most important estuaries.’
Tim Stowe, Director of RSPB Cymru added ‘Risking irreplaceable wildlife sites for the sake of energy generation is not a sustainable option, and would contravene the Welsh Assembly Government’s duty to promote sustainable development. We believe that Welsh Assembly could achieve greater savings in carbon dioxide emissions by investing in small scale renewable projects in Wales.’
Julian Rosser, Director of Friends of the Earth Cymru, commented, ‘It is astonishing that, while Rhodri Morgan is happy for the Assembly Government’s policies on road transport and aviation to fuel climate change, he is proposing to wreck one of the most important wildlife sites in Europe in a bid to tackle the problem. A massive barrage with a road over the top of it is not the best way to generate electricity from the power of the Severn tides.’
Dr Mark Avery, Director of Conservation at the RSPB, wrote in the Independent that ‘The RSPB strongly supports the development of green energy, including the tidal power of the Severn’, but noted that ‘a Severn barrage is not the most useful nor is it the most economical way of harnessing the energy of the Severn’s tides. A tidal energy bridge may be, but so may tidal stream systems being tested in the UK. Tidal stream turbines would generate far more energy from the estuary, would be less intrusive and would do little environmental harm. A barrage would be only 23% efficient, even less efficient than the average on-shore wind farm. It would not produce large amounts of energy consistently and could cost far more than the present £15bn estimate after inflation and construction delays are taken into account.’
The Environment Agency, Countryside Council for Wales and English Nature (now Natural England) have also expressed concern over potential impacts on legally protected sites (see Renew 166). The Sustainable Development Commission should shortly publish its study of UK tidal energy options including the barrage. Signs are that they will back it: see www.sd-commission.org.uk/
* FoE says tidal lagoons are a better option- see Renew 166. Tidal Electric have produced a report claiming that lagoons have higher energy yield/impounded area than barrages.
Meanwhile, a smaller ‘Shoots’ barrage has been proposed by Parsons Brinkerhoff, just south of the Second Severn Crossing, which would be less invasive environmentally. It would generate 2.75 TWh/year, about a seventh of the proposed barrage. It would also presumably be quicker to build- the big barrage couldn’t be in place before 2020, making it more or less irrelevant to current climate plans. A bit like nuclear, you might say.
*The Cheltenham Science Festival in June was enlivened by a debate between speakers from WWF and the Severn Tidal Power Group consortium on the Severn Barrage. Points were about equal, on each side. But even more lively was the contrarian denial of climate politics by Claire Fox from the Institute of Ideas: it was all draconian greenie anti-progress manipulation aiming to make us comply with unnecessary constraints: science would solve the problem.
The useful special ‘renewables’ issue of the Scottish energy trade magazine Energy, linked to the All Energy event in Aberdeen is worth looking at not least for its coverage of marine energy - it is in clever electronic form at: http://mag.digitalpc.co.uk/activemagazine/enrm/ energy_ren-2007-05.asp
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