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Clean Power

Published on June 13th, 2016 | by Rogier van Rooij


TenneT Proposes Artificial Island For Up To 70 GW Of Offshore Wind

June 13th, 2016 by  

It has been a great week for clean energy in Europe. First, the energy ministers of nine North Sea countries met at an Energy Council in Luxembourg to discuss cooperation on offshore wind power. The nine countries: Germany, Luxembourg, the Netherlands, Norway, Sweden, France, Denmark, Ireland, and Belgium signed a Memorandum of Understanding which aims to help lower the costs of offshore wind, and increase the deployment of wind turbines in the North Sea.

Later that day, 11 power companies — including giants Vattenfall, Statoil, and RWE — declared that offshore wind costs can be driven down to about €80 per MWh by 2025.

And last Friday, a third bold announcement was added, made by TenneT, a Dutch, state-owned power grid operator.

TenneT declared that it has plans for an island energy hub in the North Sea, which would be part of a larger project to vastly expand Europe’s renewable power generating capacity and should help in keeping the costs low.

The exact size of the whole project has not yet been defined, but the fact that it will be absolutely enormous is clear. TenneT CEO Mel Kroon mentions in an interview with Dutch news radio station BNR that the wind farm will have a capacity of between 30 GW and 70 GW and will generate enough electricity for at least 10 million people.

The vast scale of the wind farm makes the idea of creating an island a viable option. The bare island itself will already cost an approximate €1.5 billion. That excludes the construction costs of facilities that include a runway, a harbor, housing for the 2,000 workers who will be stationed there, and even a park. But as the island provides the wind park operator with a much more efficient way to build and maintain the park, the investment will quickly pay itself off.

The island will be especially profitable because it also serves as an interconnector to distribute the power among the different surrounding countries. Wind turbines generate alternating current, which has to be transformed into direct current to minimize energy loss during transport. By executing the transformation into direct current onshore, or on an island, the process is at least 10% cheaper than when done offshore, TenneT’s CEO explains.

In addition, the new power lines will obviously also enhance the connection between the different energy markets of the participating countries, which should result in a better match between supply and demand and, therefore, lower energy prices overall.

The island will be located in the shallow waters of the Dogger Bank, roughly 100 km off the east coast of England, where the North Sea has a depth of only 10 to 20 meters. This makes this location ideal for both the reclamation of the island and the construction of the possibly 7,000 (give or take a few) 200-meter-tall wind turbines.

The following animation gives a realistic bird’s-eye view on the island.

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About the Author

Optimistic, eager to learn and strongly committed to society's wellbeing, Rogier van Rooij wants to share with you the latest cleantech developments, focussing on Western Europe. After graduating cum laude from high school, Rogier is currently an honours student at University College Utrecht in the Netherlands.

  • Brooks Bridges

    Sounds fantastic. I’m curious as to their estimates of sea level rise over life of this installation. Latest estimates tending towards higher rate of increase. Read of a bridge built in Canada where they included estimates of 100 years of sea level rise – that was several years ago.

  • Larry

    This sounds like a fantastic proposal. Clean electric power on a mega scale and no fear of Fukashima style meltdowns or ridiculously expensive waste to dispose of for the next 1000 years.

    • Are Hansen

      Or rather tens of thousands of years…

  • Karl the brewer

    80 euro per MWH by 2025 (£63 or $90) I wonder if UK Gov and EDF are aware of this yet, Hinkley Point will dead on arrival 🙂

    • If Hinkley becomes financially unsustainable (i.e. its power is uncompetitive even after subsidies), who ends up paying to have it decommissioned?

      • Jenny Sommer

        That’s always on the tax payer.

        Hinkley can’t become financially unsustainable. The rate payer will have to buy the power in any case.

      • Matt

        The current deal is that UK will buy 100% of the power it can produce at above market price. Even if they have to pay the EU to take the power off the UK grid.

      • Bob_Wallace

        The last version I read required the UK to purchase all the power generated for the next 35 years. The price starts at 15 US cents per kwh and rises each year with inflation.

        There’s no way to get around the 35 year agreement, regardless of how inexpensive alternatives might become.

        There are subsidies such as UK loan guarantees but the cost of electricity is not subsidized. It’s a fixed price sale at rates higher than the current retail cost of electricity.

        • Wayne Williamson

          Isn’t this like twice or three times what wind normally costs?

  • paulsnookes

    I was going to say it’s weird that the UK is not involved in this project, as it’s just 100 miles off our coastline. But then it dawned on me that we do have a Tory (Conservative) government. That might explain it.

  • Oil4AsphaltOnly

    I’m having trouble digesting this article, especially since it claims: “which has to be transformed into direct current to minimize energy loss during transport”

    There’s a reason why transmission cables are AC and not DC, resistive losses from the cabling adds up as the miles add up.

    • Omega Centauri

      Long distance transmission is better with DC. In the old days you needed AC to be able to change voltage. AC induces currents in surrounding media, (via the varying magnetic field), and this is an important loss mechanism. With DC it is a steady magnetic field, hence no inductive losses.

      • Oil4AsphaltOnly

        thanks for the correction. It seems I need to go study some more. 🙁

    • Brooks Bridges

      From Wikipedia: search for High-voltage direct current

      For long-distance transmission, HVDC systems may be less expensive and suffer lower electrical losses. For underwater power cables, HVDC avoids the heavy currents required to charge and discharge the cable capacitance each cycle. For shorter distances, the higher cost of DC conversion equipment compared to an AC system may still be justified, due to other benefits of direct current links.
      HVDC allows power transmission between unsynchronized AC transmission systems. Since the power flow through an HVDC link can be controlled independently of the phase angle between source and load, it can stabilize a network against disturbances due to rapid changes in power. HVDC also allows transfer of power between grid systems running at different frequencies, such as 50 Hz and 60 Hz. This improves the stability and economy of each grid, by allowing exchange of power between incompatible networks.

  • JamesWimberley

    Not as good for the fish as a normal offshore wind farm, which acts as a marine conservation area. Still, if the Dutch think it can be done, we should believe them. Google “Delta Plan” for proof of their ability to carry through water engineering on a gigantic scale. My guess is that advances in conventional offshore technology will make the island uneconomic, but that is just a guess.

    • Brunel

      New solar power in Dubai is 3c/kWh.

      What we should do is build East-West HVDC links to power Europe with solar power.

      And work out the cost of storing electrons. If each house has a battery – you would avoid transmission losses.

    • Hans the Elder

      I don’T think the windfarm itself we be on the island, only accomodation for the builders, the transformer/converter station, etc

      • Matt

        Yes it is just space for workers hotel, power substation, parts storage, etc. As the video shows the turbine are still located in the water. It is a smallest island, way to small to hold 70GWs of turbines.

    • Are Hansen

      Oh yes, we know the Dutch have the expertise and equipment to build land, probably the best in the world.

      Unfortunately projects like these happens in the middle of archeologically interesting sea floor landscape, from when the south of the North Sea was dry land/marsh and probably pretty densely settled. But, yeah, hard place to excavate anyhow:

  • Peter Waegemans

    At least 10 million people. Sounds like an understatement, no? That’s the population of Belgium and we can do it with 2 dying small nuclear plants and a handful of wind mills.

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