Scuttlebutt has it that wind turbine foundations in the UK are cracking.
If this turns out to be true, it will be a crisis of gargantuan proportions.
While foundations have been built to code, it may well be that the designs are inadequate, and cannot accommodate the huge stresses brought about by the large turbines and rotating blades.
This will have to be resolved quickly; otherwise there is a danger that wind turbines will collapse.
Then there is the question: “What about wind turbines built in the United States?”
The Oneida Daily Dispatch in New York, on June 21 of this year, reported the comments by Enel North America relating to the collapse of one of its wind turbines at the Fenner wind farm.
Turbine 18, a 187 ton behemoth, fell over on December 27, 2009, for no apparent reason. The other 19 units have been shut down because the cause of the failure has not yet been determined.
As reported in the Oneida Daily Dispatch, Enel Spokesman Hank Sennott said: “The investigation showed the foundation supporting the turbine was built to specifications. No corners were cut on materials or construction.”
The question then becomes, “Were the specifications adequate?”
There were few liability issues with the Fenner failure because the tower, turbines and blades all fell into an open field. The farmer will have to be reimbursed for not being able to use his land, but no one was killed and no buildings were damaged. The liability issue will be more important if a turbine collapses onto buildings or roadways where people may be injured.
Part of the problem with wind turbines is that there has been little operating history to establish points of failure. How long should parts last under normal operating conditions? How often should towers be inspected? Plus all the other questions that arise when machinery is put to use.
Advances in wind turbine design have been so rapid that there is no established operating history for wind turbines. Manufacturers say their units will last twenty years, but few, if any, of the units have actually been in service that long.
Another example of why operating experience is important is that it has been reported that some of the off-shore wind turbines built in Europe have shifted on their foundations by around three inches. Apparently, this is an industry-wide problem, and not associated with any specific manufacturer.
If foundations are cracking, their repair will be extraordinarily difficult. The entire structure, turbines and blades included, will have to be dismantled.
Foundations are essentially huge concrete blocks with re-bar. Can they be added to, or will they have to be removed? For example, can pilings be added around the existing foundation to help support the load?
These are difficult engineering questions. No matter what the answer, the repairs will take an extremely long period of time – and be very costly.
The media has not devoted much time to the failures in Europe, so it’s very possible you are hearing about this for the first time.