The tide is turning (and so are the turbines)

Committee Room 20 is about as far as you can go along the corridors of the House of Commons without actually ending up on the roof, so I was slightly surprised to see just how many people, including a large number of Parliamentarians, made the trek to discuss wave and tidal power at the PRASEG meeting on Tuesday. I guess though that the great turn out serves as a weathervane for the justified and renewed interest in the technologies that is currently under way after lots of disappointment that promising early prototype work has not really scaled up as had been hoped.

Well no more long periods of disappointment on this front, apparently. Or at least not as far as tidal energy is concerned. Remarkably, the front runner for full scale deployment doesn’t rely on anything new and untested; as Mark Shorrock, CEO of Tidal Lagoon Power Swansea Bay, put it at the meeting, it’s just a matter of ‘a breakwater, a powerhouse some turbines and a coffer dam.’ Those ingredients, all tried and tested, make up a scheme that is now largely funded, presented for planning and regulatory appraisal and is supported by the vast majority of local people. The project is set for installing and generating 320 MWs of capacity by 2018 and all without serious collateral environmental impacts, or blocking searoutes. An honourable mention at the meeting should also go to the Solway Firth tidal stream project which is aiming to land considerable capacity and roll out full scale turbine power from tidal flow by 2015.  I won’t witter on too much about the Swansea Bay scheme because you can find the techie details of it now in various places such as the BBC’s  piece.

What hasn’t been covered though are any of the longer-term considerations about finances and the reality or otherwise of tidal flow ever actually making a real difference to the UK’s power base.  And that’s been the problem with a lot of wave and tidal so far – promising technologies but between them affording a minuscule power input. So what is the prospect now and how does it compare with the bangs for bucks from other prospects? We might note that Swansea Bay is likely to be able to supply virtually zero carbon power for a hundred years or so. After all, that early experiment (effectively a tidal lagoon) at Lyme Regis, the Cobb, is still standing up well after almost 200 years.

Well, Swansea is the first, but already other sites are being actively investigated, including notably a lagoon at Bridgewater, which would provide inter alia a first-class defence against future flooding in the Somerset Levels. And the price for the power, on the basis of scale and cost, looks to come down in a solar panel-type curve in the future. Swansea being a relatively small project sited out of the strongest tidal flows probably needs a CfD of about £168 per kWh over 35 years. This is relatively expensive, but then it’s already being reckoned that the third lagoon could come in at under £85 per kWh. And this makes it, after capacity payments and all other hidden subsidies are taken into account, cost competitive with gas, something no tide geek would have dreamed of being able to claim just a few years ago. Oh and by the way (1) Swansea reckons to deliver an efficiency of about 90% on the ebb tide and 81% on the flow, which in English means that it can be counted as that holy grail of new energy, the carbon free baseload/back up source.  (2) And by the way some quiet work on wave and tidal CfD levels in DECC  means that both the level and the time scale can be accommodated within present arrangements and with no special negotiations (small gold star to Greg Barker here I think.)

So after several lagoons, and perhaps by 2023, we would maybe have 1.5 gigawatts of baseload -type capacity operating at an average CfD of about £90 over 35 years. But hold on! Haven’t we heard these sort of figures before? Well, yes, indeed we have. On a good day, with binoculars, the people building the breakwater at Swansea can gaze across the Bristol Channel and check out the progress of the concrete mixing at the Hinkley C nuclear power station site (which is funded now on a similar basis). But…two small observations:  firstly, I would wager that Swansea Bay will be quietly garnering the tide and feeding it into the grid whilst Hinkley C  will still be looking for the key to turn the plant on. Secondly, looking through those binoculars much later down the line, whilst people will be hard at work dismantling Hinkley C, protecting the waste ponds on site for 160 years and transporting large amounts of other detritus to a very large (and hopefully very safe) but very expensive hole in Cumbria, Swansea Bay will be …well, like the Cobb, just still there, minding its own business and if we still want it to, producing power for all of us.

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3 thoughts on “The tide is turning (and so are the turbines)

  1. Great to see more earth powered energy 🙂

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  3. While the threat of climate change and energy shortages might be scary, stories like this are heartwarming and give me hope for the future.

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