Renewable Energy

Lord Cameron of Dillington Excerpts

Wednesday 5th June 2019 Lords Chamber

Asked by

[Lord Cameron of Dillington]

To ask Her Majesty’s Government what plans they have to (1) harness the potential of tidal ranges to generate renewable energy, and (2) encourage the private sector to invest in this area.

[Lord Cameron of Dillington (CB)]

My Lords, I have put down this Question for debate because I believe that, in our uncertain world, it is imperative that the UK plays to its strengths, and in energy one of its real strengths is the range of its tides. Whereas at somewhere such as Gibraltar the tidal range is only about one metre, it can be eight metres in the Solway Firth or higher than 15 metres in the Bristol Channel. We also have tidal races around our shores and between our islands which flow at great speeds and with considerable power.

Of course, tidal power output is classed as intermittent, but it is a guaranteed and predictable supply. We know now how much power we can produce from a given site between the hours of, say, 6 am and 8 pm on today’s date in 2121. I say 2121 because, if we build a tidal lagoon now, we know that it will still be producing electricity, almost for free, in over 100 years’ time. We will be like the Norwegians, who get their current electricity for almost nothing because they harnessed their natural hydropower advantage many years ago.

Tidal power is our natural advantage, and we must harness it as soon as we can. Our territorial waters include around half of the European tidal resource. We have tidal races in the Solway Firth and the Severn Bore, with speeds of six and 15 miles per hour respectively. We have 11 out of 60 of the world’s top tidal bores and we must harness them. We also have tidal races between our islands, such as in the Pentland Firth or the infamous Gulf of Corryvreckan. Research in Shetland and Orkney has shown that anchored floating barges with large turbines underneath are an effective way of tapping into these races, albeit with each barge providing only up to five megawatts. But together, and from the north to the south of the country, they could create an attractive and constant supply, as could the Deep Green slow-current kite system being trialled by Minesto off north Wales.

There are also possibilities for barrages, especially where they provide other services such as transport links that enhance their cost-benefit analysis. Morecambe Bay is a very good example here, giving access and a much-needed economic boost from the M6 to Barrow-in-Furness in west Cumbria.

To me, the most compelling solution for harnessing our tidal power are large offshore tidal lagoons. Any site with a depth of between five and 10 metres and a tidal range in excess of five metres can produce guaranteed power. They are better than a barrage across a bay, because you can have turbines all round and not just on one side. This means they are almost half the price per output of power. They are different from the Swansea Bay barrage and other shore-to-shore barrages. They can be any shape—oblong, square, round or rectangular —and curve in any direction to follow exactly the required underwater contours for producing maximum return on investment. For instance, a 16 square kilometre lagoon planned for the Solway Firth would produce 350 megawatts.

There are about 20 ideal sites around the UK coastline. I invite your Lordships to imagine a wall of water in the Severn estuary that is about the height of this Chamber and several miles long. That is the sort of power that the Severn can produce four times a day. One lagoon in Bridgwater Bay alone, right next door to Hinkley Point, could produce 1,900 megawatts.

The advantages of these lagoons are many. First, unlike coal-fired, gas or nuclear power stations, they do not have to be shut down for repairs. If a turbine needs servicing, it is only one of 20 or 30. It is lifted out for maintenance and the effect on output is minimal as the rest just keep turning. Secondly, they do not upset shipping traffic in any serious way, because they sit at the side of any shipping channel in waters normally too shallow for large ships. Thirdly, their environmental effect makes only peripheral difference to the course of the tide, migratory fish, wading birds and so on. They have the support of the RSPB, Friends of the Earth, the WWF and other environmental NGOs.

There are numerous sites for these lagoons in the UK, from north to south. With a seven-hour tidal difference between Bristol and Solway, and with the tides being used on both the flood and the ebb, that gives an almost consistent baseload power for England, even before we tap into the Scottish tidal ranges. Tidal lagoons could provide three times the capacity of Hinkley Point.

However, the UK supply chain desperately needs government engagement now. What the industry is seeking from the Government is enough support to allow for an initial project currently planned for the Solway Firth at a contract for difference strike price of £82 per megawatt hour for 25 years. The latest wind auction costs were at £57 per megawatt hour, to which one has to add £20 to deliver predictable power, so £77 for wind compared to £82 for a first-of-its-kind tidal power project compares very favourably, and is certainly much better than nuclear. Just remember the huge costs of the early wind farm contracts before its industry costs began to fall. The same rapid drop in costs would almost certainly happen to tidal power as the skills develop. Think, too, of the export potential of those skills; Canada, Alaska, Argentina, Chile and France all have suitable estuaries.

It is thought that, after this pilot project, subsequent tidal lagoons could have a strike price of £60 per megawatt hour, or even less, which brings the technology well into line with offshore wind schemes, and clearly well below the latest nuclear strike price. However—and this is important—even with the pilot project in Solway, if you take the mid-case forecast for wholesale electricity prices, it is likely that for the final decade of the support contract, the Treasury would actually make money from the Solway project. Then, after the first 25 years, for the following 100 years, the cost of the electricity would be minimal. Think of the benefit of that to UK industry, particularly in comparison with the relative short-termism of the more expensive nuclear options.

Above all, what we need from today’s debate is a clear signal from the Government that they would in principle support a value-for-money tidal lagoon proposition, or at least negotiate seriously with the main players. This would allow the businesses concerned to move forward and begin to create this exciting new industry here in the UK. As I said, we have the tidal strength in the UK—more than any other country in the world—and we must play to our strengths and harness our tidal power now.