Just when it seemed that our national energy policy — alongside defence of the realm, an absolute priority, to keep the lights on — couldn’t be managed in a madder or more alarming way, along comes the most bizarre project of all.
This is a £1 billion scheme to build a colossal U-shaped stone breakwater, six miles long, enclosing the whole of Swansea Bay in South Wales, containing 16 giant submerged turbines, whose blades would be seven metres across.
The idea is that these would be driven by the water pouring through them from both directions by the 30ft daily rise and fall of the Bristol Channel’s tides, the second highest in the world.
This mammoth scheme, recently given a glowing plug on the BBC’s Countryfile, is said to have everything going for it.
It is backed by an array of financial investors, led by the giant Prudential insurance company. Also behind it are our most influential ‘green’ lobby groups, such as Friends of the Earth, the World Wildlife Fund and the Royal Society for the Protection of Birds.
The ‘tidal lagoon’ project, which would be like nothing else built anywhere before, is favoured by politicians of all parties, led by Lib Dem Energy and Climate Change Secretary Ed Davey, who can barely contain his excitement, saying that tidal power offers Britain ‘fantastic economic opportunities’.
The plan was given positive mention in George Osborne’s recent Budget speech, and has now been included in the Conservative manifesto.
On the internet, there is a picture of David Cameron meeting the chief executive of Tidal Lagoon Power (TLP), the company behind the scheme. So, the project certainly has friends in high places.
Fast-tracked through the planning process, it has already been approved by government inspectors, so all that remains to start construction is a final go-ahead from the energy minister.
In fact, the man responsible for the scheme, TLP’s Mark Shorrock, hopes five more such schemes will follow — including one six times as big which he is planning for Cardiff Bay up the coast.
Between them, it is claimed, these lagoons will not just ‘power every home in Wales’ but will put the Principality ‘at the heart of a hugely lucrative global tidal lagoon industry’.
However, when one looks carefully at the figures used to support this wave of euphoria, some rather large and troubling doubts begin to emerge.
For a start, the immense capital cost means that TLP is asking the Government to agree to it being given a uniquely high subsidy.
The project will only work, it says, if the power produced can be sold to the National Grid at the so-called ‘strike price’ of a staggering £168 per megawatt hour.
This is well over three times the wholesale price of unsubsidised electricity from coal or gas-fired power stations.
It is even more costly than the £155 per megawatt hour given to the hugely subsidised offshore wind farms the Government is erecting round our coasts. Even more than the £92.50 offered to the proposed nuclear power station at Hinkley Point in Somerset.
It would make Swansea’s tidal power easily the most expensive electricity in the world, paid for by every UK householder through green surcharges on our electricity bills.
But more astonishing is how little electricity the turbines are likely to produce. Although their full capacity, if they could produce at full power 24 hours a day, is rated at 320 megawatts, in fact they would turn, at varying speeds, for only some 14 hours a day, as the tides flow in and out.
So the figure coyly given by the project’s backers is merely that they will produce about ‘500,000 megawatt hours’ a year, enough supposedly to power ‘155,000 homes’.
But divide that by the number of hours in the year (8,760) and it means the average output of all the turbines would be only 57 megawatts, or 18 per cent of their capacity.
Compared with other power stations, this is peanuts. By comparison, the gas-fired power station being built by a French firm at Carrington in Manchester for the same capital cost of £1 billion will be capable of generating 880 megawatts — that’s 15 times as much.