Energy from an island

Yesterday I read about “new” plans of a pumped storage installation in Belgium in the hard copy of the newspaper Het Laatste Nieuws. The plans concern building an energy island before the coast of De Haan. It is also called an energy atoll. It would consist of a huge reservoir that will be emptied by pumps when demand is low and filled via turbines when demand is high. Therefor balancing the load on the grid.

“New” between parentheses because I heard about similar plans beginning of 2013. Different politicians, the same location and the same resistance from the people of the village. In The Netherlands there were also similar projects born and later put to rest.

In a way I think it has some merits. If one want to build upon an intermittent energy source, one need a way to “store” the energy that is produced but can’t be used right away, for example at high production and/or at low consumption. In Belgium we currently have such a installation in Coo. It was build as a buffer for the nuclear power plant of Tihange. At night when there was an excess of energy, it is used to pump water to higher elevation and in the morning/evening peak the water flows back through the turbine to generate electricity.

The new plans are brought as a project that could avoid 80% of our electricity shortage, so I was thinking that the island would have a huge capacity. I was a bit disappointed to learn that the pumps have a capacity of only 550 MW, only half that of the Coo installation. The journalists putting it a bit different: they write it has the capacity of a small nuclear power plant. Everybody is comparing power plants with small nuclear plants nowadays. While it is technically true that the turbine has a capacity of a small nuclear power plant, there is of course a big difference here. The pumped storage will only produce this power on the condition that:

  1. the reservoir is empty
  2. only for a maximum of 4 hours

Although the pumped storage has the same capacity as a nuclear plant, they doesn’t release their power in the same way. When the reservoir is empty, the energy island can produce power for 4 hours. But after that it is finished and the reservoir has to be emptied again. While a nuclear power plant still merrily hums along. Same capacity, but two different animals altogether.

I agree that a peak shaver would be a good thing, but there are some things that make me a bit wary. First, the politicians that want this project so badly, also add that they at the same time want to double the number of off shore wind mills. If the conventional capacity gets cut down further, this means we will again have the same problem as we have now… To shave a peak you first need to have … a peak to shave. The Coo installation works because nuclear plants can’t easily be powered up or down, so there is a constant supply and this gives the possibility to use that power at night to pump the water up and release it when it is needed later. But when we rely more and more on intermittent energy, then it will be those peaks that have to be shaved. Let’s look at the output of wind and solar over the last month.

Wind Belgium from 2014/11/10 until 2014/12/09

Wind Belgium from 2014/11/10 until 2014/12/09 Source:

Solar Belgium from 2014/11/10 until 2014/12/09

Solar Belgium from 2014/11/10 until 2014/12/09 Source:

Remember, the energy island can deliver power for about 4 hours, then it has to pump the water back out of the reservoir. Conventional power sources have to take over when there is a period of little wind/solar of longer than 4 hours. Look at above graph to the periods November 14 – 19, also to November 26 – 27 and December 4 – 5. In those cases there was only very little wind and also very little solar. At those days more reliable sources need to kick in and not much shaving of intermittent energy can be done.

Interesting to know is what it costs: 1.3 billion euro to build it and 5.6 million operational cost per year. It is repeated ad nauseum that no subsidies will be given to this project. It is carried completely by iLand, a consortium including companies like Electrabel (electricity provider) and DEME (dredging company). This sounds very nice of course, but as far as I know none of those two companies is actually a charity. Call me skeptic, but I don’t really believe they will build and operate that island for free.

Will this be the end of subsidies for alternative energy sources? Well, not exactly. As far as I know subsidies are still given for offshore wind mills, so doubling the number of windmills will still generate a subsidy flow.

In the end, this is NOT additional capacity we have above what there is now. This is capacity to make better use of the intermittent energy sources, in order to not loose the energy produced when there is no demand for it. This should have been there in the first place to make use of intermittent energy.

One thing is for sure, this cost will not be counted when calculating the cost of that “free” energy.

7 thoughts on “Energy from an island

  1. Richard

    I’m surprised at this. It’s offshore… yet it isn’t a tide mill; it uses pumped water. Why not tides as well? A modern tide mill can derive energy from both inflow and outflow. So that’s odd.

    Of course, load balancing via pumped water storage is a licence to print money: disgraceful that the UK government sold off equivalent (onshore) capacity to private businesses that are raking it in. Still, if ever we needed some more, offshore is a great way to do it. Expensive, obviously, but so is the vanadium-based electricity storage system.

    Unlike the intermittent supply from solar and wind, tides can be predicted for the next 400 years or more. Aren’t we missing a trick here. Hybrid tide mill and reservoir storage? Time will tell.


  2. manicbeancounter

    It could be useful to match wind power with peak demand. On the days when it is windy, the reservoir can be filled during the peak periods and pumped out during the periods of low demand. This could obviate the need to power up fossil-fuelled power stations for short periods on those days.
    On days of low wind, it could be emptied by using surplus nuclear and fossil-fuelled power in the periods of low demand.
    However, such schemes have both a large capital cost and have an energy loss. This is why the Dinorwic pump storage scheme in North Wales is very rarely used at its full capacity. Originally it was there to offset nuclear and coal power stations. Gas-fired power stations are a more efficient and cost-effective solution.


    1. trustyetverify Post author

      True, those pumps could also be powered by nuclear or fossil fuel when demand and wind/solar output is low. That is no surprise, intermittent energy sources need backup and this is also an illustration of that. As you said, it involves huge costs and energy loss. Not accounted for when counting the cost for alternative energy.



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