Wind Power : Material Fatigues

Image Credit : Cape Cod Living

James Delingpole follows in a long line of commentators with zero engineering experience in pouring scorn on a technology that could quite possibly save our skins :-

https://blogs.telegraph.co.uk/news/jamesdelingpole/100056158/wind-farms-yet-another-brewing-disaster/

I don’t know what he harbours in his heart against wonderful wind turbines, but he seems to be part of a movement who delight in their failure. Just ask the Internet to show you “exploding wind turbines”.

For example :-

https://www.youtube.com/watch?v=HKkTUY2slYQ
https://www.youtube.com/watch?v=7nSB1SdVHqQ
https://www.youtube.com/watch?v=rkGXoE3RFZ8
https://www.youtube.com/watch?v=MOfHxINzGeo

Clearly, you need to be in full protective fatigues when battling this kind of bad press…in fact “fatigue” is exactly the right word to come back at Mr Delingpole’s cracked warning (of cracks in wind turbine bases).

Any engineer worth their sprocket set will be able to tell you that materials “fatigue”, that over time, in working machines, things wear out, metal bends and cracks as the internal structure is pulled out of shape by external stress, things that get hot and cold regularly contort, anything that turns needs lubricating or it will wear down.

Over time, cement and concrete crumble, stone erodes in the elements, wood splits or rots in inclement conditions, brakes wear down, pathway stones smooth with the treads of thousands of feet, sheds collapse in the wind…and so we get back to wind.

Wind Turbine masts bend in the wind, and so it’s easy to imagine that the concrete base of a wind turbine might be under stress from repeated bending of the mast. Plus, there’s the forces generated by the turning of the wind turbine blades, that add a pull, moving the mast slightly in one direction or other.

It’s all entirely predictable, and can be calculated. And mast turbine bases can be built to withstand these kinds of stress – if they’re built well. There are heaps of guidelines, for example :-

https://www.risoe.dk/vea/recoff/Documents/Sec_5/RECOFFdoc050.pdf
https://ecocem.ie/downloads/Offshore_Wind_Farms.pdf
https://www.ecocem.ie/index.php?p=technical&q=wind_farms

And naturally, once machines are in the field, lessons can be learned from real-life running :-

https://www.middelgrunden.dk

Nick Balmer of the Claverton Energy Research Group wrote recently,

“…Middelgrunden…This pioneering offshore windfarm used concrete gravity foundations and grouted sockets. In a well recorded incident the concrete sockets were found to have developed micro-cracking. It was a major media event and lots of people used it to hit back at wind turbines. In the event it was fixed very quickly…”

All engineering carries a risk of mechanical failure, but what would you personally prefer in terms of risk : a wind turbine falling over in a remote area, or into the sea, from time to time; or a nuclear reactor cracking and sending radioactive gas over the whole of North Wales and the Irish Sea ? Just asking. These technologies both rely on concrete, after all.

Wind Farm projects built for the big energy companies are under the usual contracts. As one contact has pointed out, “The proof of the pudding will be in the Technology and Construction court – if bases are cracking, then owners will start to seek redress.”

Engineering is not a perfect art. There are known unknowns. Time will tell if one design works better than another, or one location or type of location works better than another.

Some mechanical failures are to be expected in developing any technology, but over-protective construction seems to be a theme, as Nick Balmer points out :-

“…As somebody who has priced installing wind turbine bases, I am aware that most are built to some extremely conservative designs used for many years in Germany…[criticisms] of the turbine manufacturers designs have been that generally they are over designed for the purpose. They would say that for the savings in a few cubic metres of concrete at say £70/m3 and say 50kg of steel it is just not worth skimping on materials and design. If the worst came to the worst it is not a big job to repair the turbine bases…”

And what about safety in general ? They might have to re-write the old proverb to read “as safe as wind turbines” :-

https://www.whywind.org/pb/wp_a1b4e1bf/wp_a1b4e1bf.html

“…Odds of Death Due to Injury, United States, 2003 : The odds of anyone being killed in a wind turbine related accident in the U.S. over his/her lifetime was 1 in 3,777,272. This compares to a 1 in 84 risk of dying in a motor vehicle accident, a 1 in 1,134 risk of drowning, and a 1 in 56,789 risk of dying from a hornet, wasp or bee sting…”

“…A Summary of Fatal Accidents in Wind Energy by Paul Gipe details the worldwide accidents in wind energy : Over the course of past 35 years their have been 20 fatal accidents in wind energy worldwide. Falling from the tower is the single most apparent occupational hazard of working with wind energy. Most accidents are due to the same common sense fatal mistake, where people did not use any form of fall protection…”

So, wind turbines are less dangerous than cars, and even bees.

And as for that other common accusation – that wind turbines are inefficient, let’s look at some data shall we ? Actually, let’s look at some data from an anti-wind farm organisation.

The group CLOWD, the Campaign to Limit Onshore Wind Development, according to data collected from Ofgem on 18th June 2010, relating to the period April 2009 to March 2010, Scottish wind power as a whole was running at 54.45% capacity – in other words, producing over half its rated power. The rated power is the figure given for the amount the turbine would produce it the wind was blowing at the right speed all the time. And for England, the same figure was 34.95% of capacity. Since Scotland has twice the wind profile on average to England, that seems like a reasonable result.

Non-expert commentators use this kind of information to talk about the “efficiency” of wind turbines, and berate the low figures. But, when thinking about efficiency and wind turbines, it is necessary to compare wind power to other forms of electricity production.

For example, in the use of Fossil Fuels to deliver electricity to our homes and offices in the UK, a large proportion of the energy from the Natural Gas and Coal used is wasted :-

When gas and coal are wasted, that’s real expense.

By contrast, when a wind turbine fails to capture some wind, that’s no cost at all.

If you’re going to argue against Wind Power, you need some arguments that have solid, uncracked foundations.

And you don’t have any, do you James ? Tilting at windmills is a complete waste of your time.