Wind Turbines: The Ghost in the Gearbox

I first came across this shocking industrial wind turbine (IWT) gearbox problem some time back and posted about it (Here) and originally (Here). The basis of these posts was this article (Here)

This long running problem is so serious that since 2007, the US Government has been coordinating research into it through the NREL. (More on that further down.)

By the looks of it nothing has got better, although there is a lot of industry spin claiming the fix is just over the hill. Some of it quite recent  (See Here)

So what is the problem and why is it kept so quiet?

Industrial Wind turbines (IWT's) have a generic, long standing and apparently intractible problem with gearbox reliability.

Many gearboxes need a rebuild within 5 -7 years instead of lasting 25 years as designed. Many suffer catastrophic failure within the 5-7 period or even earlier. Depending on the age of the turbine, a gear box failure may effectively write it off. Even when repaired, these gearbox failures are highly expensive and often take out the turbine for months.

Replacing the gearbox adds massively to the overall cost of the IWT. Manufacturers increase the cost to cover warranty repairs in the first 5 years. When out of warranty, the cost of a maintenance contract sky-rockets, eventually to a point where the operation of the IWT becomes untenable.

Why does this matter? After all it is the operators/manufacturers problem isn't it?

It matters because IWT's are capital intensive. That means that most of their operating cost is mostly soaked up in purchasing the thing - and maintaining it. If the IWT has a much shorter life (or a much higher maintenance cost) and so produces less money than anticipated, their ability to ever live without massive government subsidy becomes an even bigger illusion than it already is.

So, you may say, "It is only a technical glitch 'll all come right in the end."

Well, maybe. But first of all this is a glitch that has lasted since the 1980's

Unfortunately the evidence suggests that nobody actually knows what to fix yet let alone how too fix it. So possibly the answer is - maybe not.

We need to get an idea of how bad this problem is but for obvious reasons the wind industry isn't telling and they are certainly not releasing any meaningful figures

But there are a number of alarming markers out there.

The  US Government (in association with the wind industry) formed a little known group called the "Gearbox Reliability Collective" (GRC) (See Here)  The GRC is no less than a section of the USA government NREL. (That National Renewable Energy Laboratory).

In other words the problem is so bad the US Government is having to tackle the problem.

The leading sentence on the GRC website blandly states...
Premature gearbox failures have a significant impact on the cost of wind farm operations.

To quote from the latest finding report from GRC testing...(Here)
Despite reasonable adherence to these accepted design practices, many wind turbine gearboxes do not achieve their design life goals of 20 years—most systems still require significant repair or overhaul well before the intended life is reached. 

These guys in the NRC are (to put it mildly) clever people. But they have been at this since 2007 and so far they are still, by all appearances, quantifying the problem. In otherwords on a scale of ten, the intractibility of the gearbox issue probably rates a nine.

The NREL does not allocate such significant resources lightly. This is a bad problem.

The GRC are trying to build a failure database as well as running a series of tests on prototype gearboxes. Unfortunately this failure database is not for public consumption and is subject to a strict NDA so we will probably never know the full facts.

Manufacturing members of the GRC can (and mostly do) remain anonymous. One exception is Vestas. While I have little time for any wind industry company at least Vestas appear to be willing to stand up and be identified rather than just pretend their is no problem like the rest.

Of course, while we do not have full access to the database we do have some access to data held within it from the research papers published by GRC

For example, from an early sample set from 2010 and This Paper  covering 37 failures we have this:

Notice that while this early table covers 37 failures there were many more problems found in the strip downs. It looks like the problem is poorly localised and is probably caused by a number of different issues.

So what is the point of this post?

Simply to show that the current fleet of IWTs (yes - whole fleet ) are really not fit for a production environment. They are still suffering intractible and major operational problems and are highly unlikely to ever be able to operate without a huge government subsidy. To suggest they have a lifespan of 25 years is laughable.

This is bad enough for land based turbines.

But anyone who suggests that we can successfully and economically place these things out in the North Sea and English Channel for long term energy generation, is in need of medication.