Clean Power openhydro tidal turbine

Published on November 14th, 2011 | by Zachary Shahan


World’s Largest Tidal Power Array — Off French Coast

November 14th, 2011 by  

Tidal array off the coast of France will be world’s largest when complete in 2012.


A reader actually shared news about this project with me over 2 months ago, but due to the steady stream of so many interesting cleantech stories, other responsibilities, and the fact that the shared page was in French and I had to learn French first (ok, just used Google Translate), it took me a while to get to it. The project is a “gigantic” (for tidal power) project off the coast of Paimpol-Bréhat in Brittany, France. It is a project of Irish tidal technology specialist OpenHydro and the large French utility company EDF.

The project will eventually include four 2-MW tital turbines from OpenHydro. The turbines are being installed 35 meters (115 feet) deep. They are 22 meters (72 feet) high and weigh 850 tonnes.

openhydro tidal turbine

When completed in 2012, the tidal power project will be able to power up to 4,000 homes. EDF started the project in 2004 and began work on it in 2008. Total cost? About 40 million euros ($55 million).

While this is the world’s first large-scale, grid-connected tidal energy farm, OpenHydro has projects in the US, Canada, France, Scotland and the UK’s Channel Islands.

OpenHydro won the Engineers Ireland Continuing Professional Development (CPD) Company of the Year award last month and was a winner of the 2011 Later Stage Awards announced today by the Global Cleantech Cluster Association.

Tidal power is, obviously, still a nascent industry. But its advantages, such as low environmental impact and it being “out of sight” (i.e. not in anyone’s backyard), make it a renewable energy source that can certainly grow in use in the coming decades. I think the main issues are are just bringing costs down and getting initial project like this up, proving its viability and utility.

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About the Author

is tryin' to help society help itself (and other species) with the power of the typed word. He spends most of his time here on CleanTechnica as its director and chief editor, but he's also the president of Important Media and the director/founder of EV Obsession, Solar Love, and Bikocity. Zach is recognized globally as a solar energy, electric car, and energy storage expert. Zach has long-term investments in TSLA, FSLR, SPWR, SEDG, & ABB — after years of covering solar and EVs, he simply has a lot of faith in these particular companies and feels like they are good cleantech companies to invest in.

  • Kelvin12382

    This is really good to know that apart from wind and solar energy the world is also try to harness energy generated from the moon’s gravitational pull. Siemens is also turning to tidal power as it strives to exploit alternative forms of energy. The company has recently secured a stake in SeaGen, the world’s first commercial power plant to generate electricity from tidal energy. A larger plant, with an output of 8 MW, is due for completion off the coast of Scotland by 2014. This will be able to supply some 8,000 households with electricity generated from tidal energy. (blog[dot]siemens[dot]co[dot]in)

  • Anonymous

    Anyone know if this is connected to the Rance Tidal Power Station? I can’t find information connecting them other than they are both in Brittany and run by EDF. Rance Tidal was the first tidal power station way back in the 60’s. France is certainly forward thinking and should be looked to more often for leadership in these areas. Hopefully this will lead to replacing their numerous nuclear power stations which will soon be reaching the end of their commissioned lives.

    • John

      They’re located on the same coastline, but nearly 100km apart, so there’s no connection between the facilities (other than through the grid).

      La Rance is a barrage across a river mouth on the coast at 48.6180N 2.0233W.

      The turbine is deployed off the Île-de-Bréhat, near Paimpol in Côtes-d’Armor, on the seabed at a depth of 35 meters. The island is at 48.8461N 3.0047W butI don’t know exactly where the turbine is located.

      There are some very strong currents on this coast, some peaking at over 6 knots, but the tidal flow will depend on the turbine’s location.

  • Matthew Peffly

    First I have thought for a while we (USA) should have a bunch of something like this in the Gulf stream. Runs 24/7/365 at ~4mile/hour. Yes faster down south, slower up north; but 4 is the NOAA published average.

    If I look at the wind info page I see

    “The cost of electricity generated from wind is now at record lows: several projects in high resource areas (US, Brazil, Sweden, Mexico) display a levelised cost of energy – excluding the impact of subsidies but after including the cost of capital and maintenance – below EUR 50/MWh ($68/MWh). This compares to current estimated average costs of $67 per MWh for coal-fired power and $56 per MWh for gas-fired power.” (In $/kWh, the figures would thus be less than $0.068/kWh for wind, $0.067/kWh for coal, and $0.056/kWh for gas-fired power.)”

    How do I guess the approx number for these tidal turbine.
    Not sure I read the number right but looks like $55millionUS/(4*2MW turbine) = $6.875M/MW
    Is the about MWh for one year? 365*24 is 8790hours a year
    $784.82/MWh in one year (assume up 100%)

    Or do the numbers on the wind page assume a life span for the plant.
    If I assume X% up time? Cost MWh over N years with (X% up time), round to nearest dollar
    $78(100%), $87(90%), $112(70%), $157(50%) — 10 year life
    $39(100%), $44(90%), $56(70%), $78(50%) — 20 year life
    $26(100%), $29(90%), $37(70%), $52(50%) — 30 year life

    I know it the first large scale grid connected, so cost will come down; and no one really know how long they will last or how much down time they will have. But just wondering where current engineering WAG (will ass guess) puts them now compared to wind/solar/coal. These are NOT put together in someones back yard; there must be number which back up investing $55m.

    Should I be thinking good first baby step, or best dream ever.

    • Anonymous

      Good discussion. I suspect your MWh figure is high. In a tidal zone the flow is going to alternate between in-flow and out-flow with slack tide periods in between. And at some point the flow is going to be too low to produce power even when there is tidal movement.

      As for assumptions, I would bet on 30+ year life once the bugs are worked out. First generation wind turbines lasted for ~30 years before maintenance costs started being a major problem. Wind turbines are subject to a lot more stress with rapidly changing wind speeds where these underwater turbines will undergo fewer and more gradual changes in speed.

      And because the speed range of tidal flow will be smaller than the conditions in which wind turbines operate it will probably be easier to build them without gear trains, the weakest part of wind turbines. Also, blades can be shorter (but fatter) which may also reduce stress.

      And they are not going to get beat up by storms, sitting in deeper water. They are not going to experience much thermal stress.

      I’d guess closer to 90% up time with mature tech. Not much to go wrong, alternator/generator hooked to a set of blades. A few bearings, a few water seals.

      I’m thinking that tidal is going to be BFD….

  • Anonymous

    Any idea what the average tidal flow is here?

    Off the coast of Florida we have the very abundant Gulf Stream which flows 24/365 at 4 knots. We have hundreds of miles of available real estate for flow harvesting.

    Or move down to the Keys to the Straights of Florida where the end of the state and Cuba force the flow into a narrower channel and the flow is more like six knots.

    • Anonymous

      I didn’t see anything on that (and, to be honest, wouldn’t even know how to compare it). Wikipedia, here i come.. 😀

      • Anonymous

        With true tidal you’ve got periods of high flow in one direction, a tapering off to slack tide, a buildup of flow in the other direction, and another fall off. I’m guessing that average flow is roughly half peak flow. There could be power lost with tidal once the flow drops too low to spin the blades.

        With constant flow streams like the Gulf Stream or rivers the flow might not be as fast as peak tide flow, but it’s constant. Four knots of stream flow might produce the same amount or more power as a tidal flow that peaked at eight knots.

        Larger blades will likely harvest that power once the technology matures a bit more.

  • This system is very promising and is sure to be an important part of clean, renewable energy for coastal areas. Congratulations to this team, and I hope to see more of these installed.

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