Those are the key findings of a new report published by The Offshore Renewable Energy (ORE) Catapult, which explores the potential of the UK’s emerging tidal stream sector alongside the less-developed wave energy sector.

According to the report, tidal stream technology could generate £1.4bn in benefits to the nation’s economy by 2030, while wave energy could add an extra £4bn and around 8,100 jobs by 2040.

“The findings of our research are encouraging, with the potential for significant economic benefits to be realised from the UK marine energy resources,” ORE Catapult’s research and innovation director Dr Stephen Wyatt said.

“We will now continue our work with the tidal stream and wave energy industries, as well as relevant government departments, to discuss these findings and establish the best way forward for future support that will enable the UK to capture such advantage, in terms of growing our economy, creating jobs and exporting goods and services all over the world.”

The report assumes that annual deployment of 100MW of tidal stream capacity from 2021 will generate vast economic sums for the UK, with wave energy eventually reaching similar levels of commercialisation following a 10-year lag.

As for carbon emission reductions, the report predicts that marine energy has the potential to displace natural gas generation on the grid by permanently reducing annual CO2 emissions by a minimum of 1Mt after 2030, rising to 4Mt after 2040 – a higher figure than for biomass and advanced conversion technologies, the report notes.

UK’s global advantage

The research notes that for every kWh of energy, marine power saves 937g CO2 compared to the same power from coal; 394g compared with Combined Cycle Gas Turbines or 120g CO2 compared to biomass. According to the report, this emphasises the UK’s “global advantage” in its position as a world leader in hydropower development and exportation. 

“The UK has led the world in developing tidal stream and wave technologies, and this report shows that marine renewables could follow the UK’s offshore wind industry in achieving significant cost reductions,” commented RenewableUK’s chief executive Hugh McNeal.

Notably, the research highlights the costs reductions for developing marine technologies, highlighting that improvements to efficiencies could make it cost-competitive with other energy sources.

For tidal stream, for example, costs could eventually fall from £300/MWh to less than £90/MWh, providing capacity can reach 1GW.

The UK is primed to lead Europe’s £46bn wave energy market opportunity. Research from Marine Power Systems estimates that estimated global wave resources could potentially reach 4,000TWh annually provided the commercial case for the technology improves.

Fortunately, progress is being made in the UK. Last August, turbines harnessing tidal energy in the Pentland Firth set a then-world record for monthly tidal stream power production, after phase one of the MeyGen marine project produced more than 700 MWh.

Sarah George & Matt Mace

Comments (13)

  1. Andy Clarke says:

    Even 90 per MWh costs are over double spot prices for last winter. Assuming the owners want to make a profit we are still looking at a comparatively expensive source of power. I hope they can make this very environmentally friendly technology competitive as its predictability has great advantages for the network and its low emissions will help fight Climate Change.

  2. Keiron Shatwell says:

    Subsidise the roll out of this technology to the same extent they did with wind turbines and this will be a fantastic source of clean, reliable power. There’s already a start with the Pentland Firth scheme and an experimental site on Loch Linnhe at Connel but the opportunities for Tidal Stream and even river stream power are immense.

    The tides at Corran Narrows, Loch Eil Narrows and at Ballachulish Narrows, all near where I live, all run at over 6kts. That’s a lot of moving water that can be easily harness to provide local settlements with "baseload" power.

  3. Richard Phillips says:

    Tidal streams ebb and flow. Power is not available on demand. It is available, on a moving time line for about 14 out of 24 hours. It varies in strength from spring to neaps.

    A typical "grab it when you can get it" power source.

    But lots of public money is available for "research" and "development", because the average member of the HoC, and thus the Cabinet, simply does not understand the physical, unalterable, reality of power generation.

    Meanwhile we all pay over the odds for a poor product.

    Richard Phillips

  4. Keiron Shatwell says:

    Richard, actually the tidal stream is only "slack" for approximately 1hr per tide so the water is moving for 22 of 24hrs. As the time of the tides varies from place to place the slack periods never coincide so a turbine will be turning somewhere providing power 24/7/365.

    Given everyone is banging on about battery storage how difficult is it to build a local store to cover the hour when a tidal turbine might be producing minimal power?

    Not like wind turbines don’t have slack periods, sometimes as long as a few days

  5. Trevor Smith says:

    according to this website capacity factors for tidal are in the range 20-35% so I’m a little sceptical about the ‘1 hour per tide’ figure. Even so, 20-35% is comparable to wind and better than solar PV; tidal provides useful diversity to those other sources and as a bonus there’s potential to use tidal for energy storage. 300 per MWh though, is way, way too expensive, especially if that is before network and other distribution costs are added. Contrast with the 89.50 per MWh strike price being offered for a putative Sizewell C project, which would provide near 100% capacity factor. It OUGHT to be possible to structure a support scheme like CfD, but with a tapering strike price, so the investors get a quick return for the upfront capital cost but the price paid in the long term reflects operating costs (La Rance has run since 1966!). That need not hurt the business case, short-termism works in our favour in this case, the higher rate of return sought, the more heavily discounted the cash flow from the third … fourth … fifth decade

  6. Keiron Shatwell says:

    Trevor, as a sailor I know slack water is only an hour at high water and another hour at low water. Each tide is 6 1/2hrs from low to high then 6 1/2hrs from high to low. Even then the water does not stop moving but is just "pausing".

    Are you talking about Tidal Barrages per chance? I’m talking about harnessing the tidal streams themselves not building a big wall across a bay like they suggest in Swansea. Basically putting a smaller version of a wind turbine on the sea bed so the water turns the blades. As water is 10x as dense as air you need a much smaller turbine to produce the same power.

    I agree that we, as a nation, must make use of all our alternate power sources and where there is a will there is a way to fund the development of multiple different systems. Perhaps getting investors to accept a longer payback term?

  7. Richard Phillips says:

    As an ex-windsurfer, I recall that the advice to the wary was to sail during the two hours covering the times of high and low tides. Two highs and two lows per day, eight hours of poor water velocity. From other sources, is not the power to be derived from a fluid flow proportional to the cube of the velocity?

    Certainly tide times vary greatly, but I’ll bet that nature does not gaze particularly generously upon us!

    I cannot regard the marine environment a particularly gentle.

    The water to air density ratio is rather greater than 10x

    For truly low carbon, high reliability and a better landscape, quietly forget renewables try 70-80% nuclear and the residue natural gas CCGT. The gas preferably fracked here in the UK.

    I am immune from fire and brimstone, just too old to care, say it as it is!!

    Richard P

  8. Keiron Shatwell says:

    Richard, you are right that the marine environment is harsh, just look at what happened to Dawlish Warren in a single storm. That is why wave power and to an extent tidal barrages are not a good idea. To survive storms they have to be so heavily engineered. By putting the tidal turbines on the sea bed they are actually out of the worst of the storms, especially in places like the Corran Narrows on Loch Linnhe. Oh and pretty much out of sight too.

  9. Trevor Smith says:

    As a landlubber I must confess I’m approaching this on a theoretical basis. If I model the tide as a sine curve, velocity zero at high and low tide and maximum +/- 1 in between the average absolute velocity (in either direction) is 63.5% of max. Taking the CUBE of the velocity as Richard stated this figure is 42.4% of max. So a ‘real world’ capacity between 20-35% as given in the reference I cited before has credibility. This is not a defect of the technology, just a consequence of the variable nature of tides. In exactly the same way and for the same reason (velocity-cubed law) wind turbines have the same issue with capacity factor.

  10. Keiron Shatwell says:

    Trevor, yes there is no changing the laws of physics but the one thing the tides have over wind is they are predictable and reliable. You can go to any point on the coast and find exactly when high or low tide is going to me within a minute and a very accurate indication of how high or low that tide will be above chart datum (Lowest Astronomical Tide at Newlyn) for every day of the next year. Unlike the wind which as we all know even the Met Office supercomputers can’t model accurately more than 48hrs in advance.

    It is this predicatability that gives tidal streams their edge. As the National Grid would know when and where the "slack" periods were around the coasts they can adjust the supply accordingly. Add in a local battery back up for each tidal stream station and my guess is you’d never notice the "slack".

    The other good thing is tidal turbines would not need to be "feathered" to protect them from storms as storms do not affect tidal streams as dramatically as they do air streams and wind turbines. At present a wind turbine does not produce meaningful power below 10mph and above 35mph they are throttled back to protect them so produce no meaningful power above about 40mph wind speed.

  11. Richard Phillips says:

    The power generated by individual turbines is quite limited, and likely to be of the same order, eventually, as large wind turbines, about 10MW. A farm of 100 would be needed to have a nominal equation to a standard power station, 1GW. But the capacity, as pointed out, is likely to be 20-35%, so for a mean output of 1GW, some 300 would be required. The output varies not only over each tide, but over every tidal type between the spring and the ebb. Batteries are hideously expensive, and for the foreseen future, cannot realistically supply more power than that needed for frequency stabilisation.

    I come back to my original thesis, tidal turbines are variable generators, "storage" cannot bridge the deficiency, the size of installation has to be immense to yield real power station equivalents and even then they are cannot be demand lead.

    We really need to get on with the real part of the power programme, nuclear and gas.

    Sorry, as the Beach Boys had it "Wouldn’t it be nice if ……."

    Richard P

  12. Keiron Shatwell says:


    Exactly the same as wind turbines but with a predictability that knocks them flat and a reliability that can be easily managed by National Grid. With an additional benefit they don’t destroy the visual environment.

    As for battery storage I happen to agree with you that chemical batteries are not the solution but everyone is talking about them so might as well add them into the mix.

    I wouldn’t hold my breath for gas from Hydraulic Fracture Stimulation in this country so unless we suddenly build nuclear generation like there’s no tomorrow (also highly unlikely) we have got to look at harnessing every single energy source this country is blessed with.

  13. Trevor Smith says:

    Found this report: which concludes CfD payments 168/MWh (falling to 92/MWh for the larger scale operation) deliver a discounted cash flow rate of return around 6.5%; not phenomenal but the projects would ‘wipe their faces’ and with the revenues guaranteed by UK gov this might appeal to pension funds. Note the lower ( 92) figure is very close to the strike price for Hinkley Point C

Action inspires action. Stay ahead of the curve with sustainability and energy newsletters from edie