Tidal power gets a stormy birth off coast of Scotland

Tidal array The turbines are placed on the seabed

On paper, it looks like a blindingly obvious idea: take a version of a wind turbine and plant it on the seabed so that its blades spin in the flow of the tides and so generate electricity.

Unlike wind, the tides are totally predictable for decades ahead.

The turbines, well below the waves, are also out of sight and probably out of mind. And the tidal currents are of course utterly carbon-free.

For an island nation surrounded by some of the world's most powerful tides, optimistic estimates say this form of power could - and should - play a big part in keeping British lights on.

It is one reason why Scotland has been described as a Saudi Arabia of renewable energy potential.

Well, I've been to the baking Saudi oil fields and it was hard to conjure up a resemblance during a visit this week to Orkney, the front line of tidal energy research to the north of the Scottish mainland.

A launch took us between the islands where the waters surge at high speed between the Atlantic Ocean and the North Sea and back again every six hours.

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The first challenge is the weather. This is an unbelievably harsh environment in which to build anything”

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Harnessing this massive source of energy looks like a no-brainer but will be a lot harder than laying a pipeline in the desert.

Tough climate

The first challenge is the weather. This is an unbelievably harsh environment in which to build anything, let alone manage a vast fleet of tidal machines beneath the waves.

As we lurched through a heavy swell along the shores of the tiny island of Eday, icy winds racing at up to 40mph brought a succession of heavy showers of rain, sleet and even hail. In the middle of May.

We were being taken to see one of the latest devices to go through the trial of everything Orkney could throw at it: a Norwegian turbine called the Hammerfest 1000, a giant three-bladed propeller perched atop nearly 1000 tons of steel structure sitting on the seabed.

Except that we couldn't see it because it is well below the surface, deep enough to avoid any shipping.

Only the ghostly images from a remotely-operated vehicle - a robotic submarine - confirm that the giant machine is down there, spinning in the turbulent sea.

This turbine is being tested by the energy firm Scottish Power. It was chosen because it had survived off Norway for half-a-dozen years without falling apart. In an infant industry, that counts for something.

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This must be a little like the pioneering days of steam or aviation”

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Scottish Power's plan is to deploy ten of the devices off Islay next year and then, later, up to 100 in the Pentland Firth.

As the boat heaves in the waves and the gusts tear at our waterproof clothing, I shout questions to the company's senior man on board, Keith Anderson.

The most obvious is one about scale, and it is something that relates to the dozen or so different marine renewable technologies now being tested in Orkney.

If each Hammerfest machine delivers its advertised 1MW of power, then wouldn't you need 1000 of them to hope to match the output of a typical gas or coal-fired power station?

Could one really imagine great armies of turbines scattered across the ocean floor?

Predictability challenge

Mr Anderson thinks you can. "The real aim," he says, "is to establish the predictability which you get with tidal power, and to feed that into the energy mix which includes the less predictable sources like wind or wave.

Installation Installation is a huge challenge

"The whole point of this device is to test that it can produce power, and we believe it can, and to show it's robust and can be maintained.

"We believe the UK is in a fantastic place to capture all the advantages for manufacturing and investment."

Maybe he is right but by this stage we're sheltering near the stern of the boat, clinging to the railings and wedging our boots against coils of rope to avoid sliding on the wet deck.

Weird inventions

So the first challenge is survival. And the European Marine Energy Centre (EMEC), established in Orkney in 2003, is hosting trials of a range of weird and wonderful inventions so that companies can investigate which of them can cope.

When I first visited EMEC in 2009, only a handful of technologies was being tested.

Now all 14 of its 'berths' - areas of sea connected by cable to the shore - are booked, a sign of growing interest in this fledgling source of power.

More significant is that the list of companies involved in this work has been transformed from a collection of relatively small and little-known concerns, bravely struggling with the elements and unconvinced investors, to a roll-call of some of the biggest names in engineering and energy.

Rolls Royce and Kawasaki Heavy Industries are among the giants now exploring the development of tidal power.

Voith Hydro, makers of the vast turbines fitted to gargantuan dams like the Three Gorges in China, is also involved.

Siemens is now backing SeaGen, the first commercial tidal system, deployed at Strangford Lough in Northern Ireland.

The attraction for most is a gold rush of generous subsidies.

Each unit of power fed into the grid from a marine renewable machine earns about five times more than power generated by a fossil fuel.

The question is whether this will create a mature and viable set of technologies, and how soon.

New revolution

This must be a little like the pioneering days of steam or aviation: the earliest creations have passed the first credibility test and now the big powers of industry are getting interested.

As we roll and lurch back to shore, most people on board, including this reporter, felt more subdued than at the start of the journey, and more admiring of the teams determined not just to endure Orkney's wild seas but to harness them.

A final thought: if this particular industrial revolution does take shape, and these machines multiply across the ocean floor in an unprecedented change in the seascape and the way we get our power, we'll need a new word to describe them.

'Farms' wouldn't quite serve for a collection of a thousand giant machines.

Earlier, I mentioned 'armies' but maybe that's too militaristic.

'Hordes' is perhaps slightly pejorative. 'Fleets' is suitably marine but these things won't move as ships do.

There is no rush however: deployments on this kind of scale are at least a decade away, probably more.

David Shukman Article written by David Shukman David Shukman Science editor

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  • rate this

    Comment number 85.

    The bottom of the ocean would be best place for all the turbines now littering our landscape

  • rate this

    Comment number 84.

    For years I've been wondering why it is that the Government is pumping tens of millions of £'s into solar and wind, but NOT tidal. Now I know, it's because it works. Oh, and I guess their lobby group isn't as powerful as GE's or Siemens.

  • rate this

    Comment number 83.

    The damage to the sea bed has already been mentionned here. Add to that the fish that will get caught up in the turbines, and the fact that new research indicates that migratory fish (such as salmon which are already endangered) may have their sense of direction affected by any electricity generated at sea which could further endanger them. Power from the sea, or rivers is not the answer.

  • rate this

    Comment number 82.

    I hope the blade speed is slow enough to give fish and mammals a chance to avoid them.
    This is the ideal type of green energy if it can eventually be made to produce energy at a competitive price without subsidy.
    I am totally against barrages which destroy habitats.
    Around our country there are many sea defence structures, could these absorb the seas energy instead of just deflecting it?

  • rate this

    Comment number 81.

    @ 66. Kelly
    Ha ha ha, have you any idea how much energy there is in the ocean. I'm sorry, you could object that these might affect the biodiversity, but even thousands of these will have negligable effect on the tidal power.

    @54. GreenAlan "probably destroyed within a year"
    The one in Norway has been running for 6 years already, so I'd say theu probably have a longer life than that.

  • rate this

    Comment number 80.

    66. Kelly

    Taking energy out of tidal flows is the idea. That this will be damaging to nutrient flow may well be true. However the small scale of energy loss from the total in a tidal swell means that this will be a small problem.

    Being green engineers I am pretty sure they will factor it in and may even improve marine environments.

    Less damage than boiling seas in 50 years if we do "nout".

  • rate this

    Comment number 79.

    I work within renewable energy, and logic would be to keep the subsidy on commercial and domestic solar + thermal. If they did, it would produce a major surplus to the power companies. Wind is just useless, I think everyone is seeing this now, finally. Wave tidal technology is an excellent investment, as you can always rely on the tides. Fusion is a little way of being commercialised.

  • rate this

    Comment number 78.

    by 2020 Scotland has ambition to be green energy self sufficient, indepentdent and in control of the sale of the north sea oil/gas reserves. kind of like a heroin dealer who is also an addict giving up the adiction but continuing to deal, the ironry. Hope it works and supplies lots of jobs, good luck to them! Is steel really the best material for underwater? wouldn't composits be better?

  • rate this

    Comment number 77.

    This really is an exciting time in energy technology. Plenty of innovation in the renewable energies, new nuclear stations that run on nuclear waste from the older station types ( thanks to the Bill Gates foundation for this one) that will, overtime, remove all those tons of waste around the world, cleaner exploitation of fossil fuels and greater energy efficiency all gives hope for the future.

  • rate this

    Comment number 76.

    Tidal power is old news; tide-mills were built all over the country. The French have a tidal power-station on the river Rance at St.Malo and it's been going well for years.
    It is just a matter of applying modern engineering. I love the idea of the dreaded whirlpool at Corryvreckan doing something useful--like powering the whisky stills on Islay!

  • rate this

    Comment number 75.

    'Farms' wouldn't quite serve for a collection of a thousand giant machines.

    Earlier, I mentioned 'armies' but maybe that's too militaristic.

    'Hordes' is perhaps slightly pejorative. 'Fleets' is suitably marine but these things won't move as ships do.


    I think 'SHOALS' or 'REEFS' to describe a large collection of underwater turbines...

  • rate this

    Comment number 74.

    We squander money in long term projects that could be put towards far more sustainable means of energies like fusion and solar panels on the moon. The technology is there, the funding isn't. Wind, wave, solar, would take up insane amounts of space, with an expanding population, we can't have that. (I should stress, the moon idea sounds stupid but I promise you it is a real possibility)

  • rate this

    Comment number 73.

    "In the mean time money should be invested in putting solar panels on the moon and using microwaves to transmit the energy back"

    So..importing vast amounts of energy from space will do what to the temperature of our planet?

  • rate this

    Comment number 72.

    The revenue from the north sea should have been used to implement thousands of projects like this one. But no, it was used to put hundreds of mining communities on the dole and, to line the pockets of greedy speculators. Hydro electric is part of the UKs future energy supply like it or not, we have no choice. Fossil fuels have 15 years to depletion and, time is running out.

  • rate this

    Comment number 71.

    Yes there is a vaste amount of energy in the tides, but has anyone stopped to consider the effect of remove some of this energy? We are now beginning to understand that the wind turbines effect the total energy in the weather systems with definite local effects, if that is so then there will be global effects. We cannot just assume that we can do whatever we like without there being a cost.

  • rate this

    Comment number 70.

    At last, so REAL PROGRESS.
    Just shows what can be done when politicians and accountants are kept at arms length and the ENGINEERS are allowed to GET ON WITH IT.

  • rate this

    Comment number 69.

    David S, I hope your science is better than your graphics. The picture shows a wind turbine under water. There is a good reason why a ship's propeller is different to an aircraft propeller.
    There are some good images of underwater turbines available and it would be good to show them to dispel the fears of damage to marine life.

  • rate this

    Comment number 68.

    What's the carbon footprint of producing 1000 tonnes of steel (or 1 million tonnes for a 1GW turbine 'farm')? I don't think this is as green as it first appears. More of a greyish colour.

  • rate this

    Comment number 67.

    What an awesome idea.

    I guess the propellers will move quite slowly so this won't be a problem, but they should check that fish won't get sliced inhaf, maybe put a mesh cage round the propellers.

    But wow, it is amazing what people can do. I wish them all the luck in developing this technology

  • rate this

    Comment number 66.

    There are many hidden side effects that man's footprint makes, which turn out to be detrimental to the environment.

    Taking energy out of the tidal flows in the deep oceans will reduce the flow and subsequent transference of nutriments between one place and another.

    Envisage an extreme: a stagnant ocean which presently produces much of our oxygen.

    Humans are not excluded from extinction rules.


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