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Monday 2 March 2015, Rob Lyons

The tide has turned for green energy

Should we really pay through the nose for clean power?

Plans for producing electricity in the UK from tidal lagoons have been unveiled today. The first, to be built off the coast of Swansea, will involve building a sea wall five miles long with turbines embedded into it. As the tide comes in, water will flow through the turbines to produce power and the process will be reversed as the tide goes out. The proposal would involve building six such lagoons – four in Wales plus two in England.

In many ways, this is good news. The plans are on a huge scale and involve billions of pounds of investment. Unlike wind power, which is unpredictable, the timing of electricity production from the lagoons would be predictable because we know exactly when tides will occur, making the electricity much easier to manage on the National Grid. And a sea wall is far less likely to incur the wrath of local residents who often hate their local landscape being covered in wind turbines. With offshore wind turbines – which are much less intermittent and more productive than their equivalents on land – proving to be stubbornly expensive, tidal lagoons could solve a number of problems.

The trouble is the cost. The developers want a guaranteed price of £168 per megawatt-hour (MWh) from the Swansea scheme. That’s far higher than the cost of electricity from coal (more like £50 per MWh) or even onshore wind at roughly £80 per MWh. The only redeeming feature of tidal lagoons is that the costs might, in the long run, come down to marginally less than the eye-bleedingly expensive price agreed for power from the Hinkley Point C nuclear-power plant, at £95 per MWh – although nuclear plants produce power almost constantly, providing vital ‘base load’ for the system and the costs of nuclear would no doubt fall as more plants were built, too.

Such is the price to be paid for low-carbon energy – and it will be end-users who pay that price. Not only will it make high energy bills even higher, but it makes the UK even less attractive to heavy industrial users of electricity. So much for ‘rebalancing’ the economy. In the dash to decarbonise the UK economy in the name of preventing climate change, the result could be far greater hardship. It is only the obsession with global warming that means schemes like these tidal lagoons are considered at all. Meanwhile, natural gas produced by ‘fracking’ is struggling to get off the ground, despite having enormous potential to produce cheap, reliable and flexible power. Is the low-carbon solution worse than the problem?

These were some of the areas discussed in a Battle of Ideas debate I took part in last year, ‘Energy futures: how can we keep the lights on?’. You can watch the debate here.

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