5. Marine Power - wave and tidal ups & downs

In association with the British Wind Energy Association, npower has produced the ‘npower juice Path to Power Report’, a route-map to utilising the full potential of the power of waves and tidal streams in the UK. The report says that marine renewable energy technologies could theoretically provide up to 8TWh p.a., or 2.1% of the UK’s electricity demand by 2020, enough it claims to power around 1.6 million homes, assuming a capacity factor of 30% and 3GW installed. 2.1% is less than the 3% suggested by the Carbon Trust, and even that seems rather low given the huge resource (see the Feature in Renew 163) and the recent flurry of innovative ideas (see our Technology section). But the npower report says that there are significant hurdles to harnessing this potential- identified as financing, grid access, and consenting.
£4.5m for Wave Hub

The DTI has allocated £4.5m from the Marine Renewables Deployment Fund for the Cornish wave hub- the ambitious, deep-sea electricity socket, that is to be sited in the waters 10 miles off the coast. If consented, the Wave Hub scheme that has been spearheaded by the South West of England Regional Development Agency (RDA), will act as a giant extension cable connecting up to four innovative wave energy devices to the national grid. The Government has pledged that if the green light is given to the project it will provide the South West RDA with almost a quarter of the estimated £20 million it will cost to get the Hub into the water and connected to the mainland via an underwater cable that will come ashore at Hayle, Cornwall.

Energy Minister Malcolm Wicks said: ‘As an island nation the UK has an invaluable resource in terms of marine energy and we are leading the world in developing the infrastructure to harness the power of the seas. We said in the Energy Review that we will be consulting later this year on how we can make the production of marine energy under the Renewables Obligation more valuable for developers but we have again underlined the Government’s ongoing commitment with the injection of up to £4.5m into the Wave Hub. The project has still to get through a robust consent process before getting into the water, and to finalise the device developers who will connect to it. But if successful, it will be a shining example of UK innovation that could provide three per cent of Cornwall’s electricity needs. That is up 20 MW of renewable and secure emission free energy powering 7,500 homes.’

Assuming the necessary consents are granted, Wave Hub could be in operation in 2008- the Government’s consultation with the stakeholders should lead to decision by the end of the year.

Surfers v Waves

The proposed £20m Wave Hub off the coast of Cornwall (see above) has come under fire from some surfers, who fear that plans for linking up to 20 wave energy devices to the Hub in a 3 mile stretch 10 miles out to sea off St Ives Bay could reduce wave heights. They say that the project, due to start fully in 2008, could affect the 20-mile coastline from St Ives to Newquay and could put at risk the surfing industry, worth an estimated £64m a year to the region. John Baxendale, a chartered physicist and engineer who runs a surf forecasting agency, told BBC News: ‘Surfers voting for this are like turkeys voting for Christmas’.

But environmental campaigners Surfers Against Sewage said there would only be an 11% reduction in surf height at most, according to an environmental impact assessment by consultants Halcrow. ‘It should not make a noticeable impact most of the time. We are satisfied that it is a good thing and we are backing it. You have to consider the long-term environmental gains and they outweigh any small impact on wave heights.’

After all, as they told Green Futures 59, sea rise could mean ‘goodbye to some of our surfing beaches’. Moreover researchers at the University of Exeter Cornwall Campus in Falmouth say that in practice the impacts are only likely to be about a 1.3% reduction in wave height with a realistic maximum of under 3%- they say 11% is the theoretical maximum.

FoE dig in on Severn Barrage…

Friends of the Earth Cymru have produce a critique of the Severn Barrage idea- given that the Welsh Assembly have recently been taking an interest in it. FoE present a strong environmental case against this project, which they say would seriously disrupt the local and regional estuarine environment, a view also taken by the Countryside Council for Wales, English Nature/Natural England and the Environment Agency in a recent joint statement.

FoE also argue that, given the cyclic nature of the tides, the 8.6GW barrage would be a very inflexible source of power- a huge pulse of energy every 12.5 hours, not well matched to demand, and backing it up would take away capacity needed to back up wind and other renewables. Moreover, although at some point energy storage facilities might be available, the barrage would not be a very cost-effective way of supplying power for it. They also claim that, given the long construction time and lengthy pay back time, its economics would be dubious. For example, it would probably have to rely on carbon credits, but it is hard to know what their value would be by the time it was built and in the years after that (since by then we should be producing much less carbon dioxide). Finally they argue that, if it was taken up, the £10-£15bn barrage project would crowd out funding for arguably much better renewable energy options, including tidal lagoons and tidal current turbines. Indeed they note that a Severn barrage would physically pre-empt the construction of the 60MW tidal lagoon proposed for Swansea bay.

No future for the Barrage?

These are certainly strong arguments, and the environmental ones have to be taken particularly seriously. Mind you, climate change will also damage the area, so the strategic argument as to which renewables we should be developing are perhaps equally important. Most of the rival technologies are likely to deployable much faster- even if some, like tidal current turbines, are still only under development.

It may of course be that barrages will be given a separate technology band in the revised RO, so they would not divert funding from rivals, and you would think that the value of carbon credits in the EU ETS or whatever follows it, as we try to reduce carbon emissions by 60% by 2050, will inevitably rise. And you would think that when and if we have a hydrogen economy, then the barrage could be a candidate for supplying it. But it is true that it’s very large and inflexible, while we are generally moving to smaller scale locally embedded and even domestic level technology.

On balance it looks like the barrage will end up being seen as something we might do later on, when we’ve developed all the other renewables. Oddly then it could end up being treated a bit like the way nuclear power was treated in the governments 2003 Energy Review- as an inflexible, invasive and expensive option, with some big environmental problems, that is to be kept open for later possible development.

… but Wales backs Tidal currents

A Welsh Affairs Select Committee report published in July on energy options called for the development of marine renewable energy, and £700,000 from the Welsh Assembly Government’s Objective 1 programme has been provided to Marine Current Turbines to investigate the potential for a commercial 10 MW tidal farm with 7 tidal turbines off Anglesey. Subject to planning consents and obtaining financial investment, MCT say it could be operational in 2009 and have the capacity to supply around 10-15% of domestic electricity demand on the island.