I know what you are thinking, right now you may be considering installing an offshore windfarm and here I am telling you about the problems of getting rid of the thing again.
But!
The topic is relevant whether you are installing a windfarm, nearing an end to the operational life, or actually in the process of preparing the decommissioning of the windfarm.
Why, you might ask, is this relevant, the removal of the wind turbines is actually the reverse operation of installing it or not?
The answer is that this is actually not the case. And as usual the devil is in the detail. Here are the reasons.
In the early years I was frequently asked to give a quote for how much it would cost to remove an offshore turbine, my answer was simple, the same plus inflation as it would cost to install it. This is partly the answer, however a significant number of costs will occur which we did not foresee when we were originally asked.
Firstly, the sheer number of turbines, which have to be removed, will make a significant impact to the port where you have to unload them. For the Danish and German North Sea, Esbjerg seems a good bet. But here we still be installing new turbines in the years to come and thus the space will be expensive to book and scarce in availability.
Secondly, the vessels which have to de-install the turbines and foundations are the same – by and large – as those installing the turbines and foundations in the first place. So once again we hit a bottleneck in terms of installation capacity. You may argue that the older and smaller vessels could do that and you are right, only a number of them have already gone out of service, so also are the two vessels I originally designed and built. Therefore this will be an issue to deal with. A simple addition of the turbines and foundations to be decommissioned in any given year on top of the turbines and foundations to be installed, will give you the actual size of the problem. And it is significant.
