The Mail’s Misleading Claim About Swansea Bay
By Paul Homewood
The Daily Mail has its own take on the Swansea Bay tidal lagoon.
Most of the article just rehashes the points made on other outlets, which mostly seem to have come from Hendry’s report and the Tidal Lagoon Power (TLP) website.
Intriguingly though, the Mail offers a vision of what might follow Swansea:
The ‘pathfinder’ project at Swansea would help with regeneration in South Wales, creating around 2,000 jobs in construction and manufacturing. It could go ahead as soon as 2018, and would take four years to complete.
If successful, further larger projects could be built at: Cardiff Bay; Bridgwater Bay in Somerset; Newport; Colwyn Bay and West Cumbria. If all six projects were built they could have a total capacity of 17.6 gigawatts, equivalent to around 30 per cent of the country’s current electricity capacity.
Cardiff would be more than three times bigger than Swansea and would create around 12,000 jobs and generate more power – around 2.8 gigawatts. This is comparable to the new Hinckley C nuclear power station, which will generate three gigawatts.
I have no idea whether the projected capacities are accurate, as nobody appears to have gone into that sort of detail yet.
But assuming they are reasonable, here are a few comments:
1) The capacity of Swansea Bay is set to be 320MW. Presumably the reference to Cardiff being three times bigger refers to the area of the lagoon. In terms of capacity, Cardiff at 2.8GW would be nearly nine times bigger.
2) A total capacity of 17.6GW would imply the five follow on projects would average 3.5GW.
3) TLP’s website gives a capacity utilisation of about 19%. At this level, six lagoons with a capacity of 17.6GW would generate 29 TWh a year, about 8% of UK’s total generation.
Although the Mail does refer to 30% of electricity capacity in the article itself, the headline 30% of our electricity is highly misleading, not least because very few people realise capacity bears little relation to actual generation.
4) In terms of CAPEX, the Hendry report estimates that follow on projects could work out 8-10% cheaper than Swansea.
(Note that this depends on the right framework! This suggests the government might have to cut lots of corners when it comes to planning, environmental concerns etc)
But assuming a figure of 9%, and bearing in mind Swansea Bay is costing £1.3bn, the next five lagoons could end up costing £64bn.
5) The cost of Hinkley Point is supposedly £18bn, but although it is only rated at 3.2GW, it is capable of generating 24TWh a year.
In other words, the total cost of six tidal lagoons could amount to £65bn, more than triple Hinkley Point, but for only 20% more power.
6) On top of capital costs, there are of course running costs.
The BEIS study, Electricity Generation Costs, published last year, estimates running costs, both fixed and variable, of £21/MWh for nuclear.
Their figure for tidal stream is £64/MWh. This may be well wide of the mark, but it is hard to see the cost of operation, maintenance, replacement of turbines, clearing of silt etc not being very substantial indeed.
7) There may be the opportunity for operational cost reductions in future schemes. But as Dr John Constable points out:
Perhaps, the technology has promise and might improve its productivity.
Unfortunately, this is unlikely. The load factor is principally determined by the character of tidal flows, and the optimal balance of generator size to lagoon capacity, which will not change significantly if at all. Improvements in the longevity and reliability of the materials, and thus reductions in lost output due to maintenance, are conceivable, but are not likely to be major considerations. Consequently, the load factor of future projects is unlikely to differ more than a few percentage points from the current figure of 19%. Furthermore, there is no likelihood that the capital cost of construction can be greatly reduced. While the concept of lagoon is novel, or at least untried, the major elements of the scheme, the turbines, and the impoundment are not. Indeed, the vast majority of the cost is in standard marine civil engineering to build the impoundment, a field several thousand years old, where major cost reductions are not to be expected.
8) Big play is made about the hope that tidal lagoons could last more than a century. However, what might happen in the 22ndC has absolutely no relevance whatsoever for the present or even foreseeable future.
It also has zero impact for the lagoon operators, because earnings so far in the future will be discounted to virtually nothing.
Indeed, one real concern is that they will take their profit in the early years of the project, and then do a disappearing act when things start getting tough.
A relevant point here is that the subsidy scheme TLP have proposed loads a large chunk of it upfront in the early years.
9) On top of all this, there will be the additional costs of providing standby capacity.
I’ll leave the final words to John Constable:
Even a brief review shows that this project is of low productivity and will degrade the productivity of the system of which it is a part. Furthermore, the technology has no realistic prospect of significantly improved productivity. If private investors wish to take the risk, by all means let them, but government should not gamble with consumer bills when the odds are so unfavourable.