By Jon C
Introduction
Wind turbines are promoted as one of the several “green” energy sources that can be used to prevent Global Warming and Climate Change by replacing CO2 generating fossil fuel power stations for the generation of electrical energy. As such they are touted as environmentally friendly, non-polluting “green” ways of generating electricity.
In this brief article the problems of intermittency (that wind turbines don’t work when winds are too weak or too strong) and variability (the amount of power also varies with wind-speed) are not going to be considered.
This article considers the increasing problem of pollution from wind-turbines, or – more precisely – their blades. The information for this article is taken from “Leading Edge erosion and pollution from wind turbine blades 5 th. Edition – English” by Asbjørn Solberg, Bård-Einar Rimereit and Jan Erik Weinbach. “THE TURBINE GROUP” JULY 2021
Wind-turbines
Wind turbines have a life-expectancy of approximately 20 years. After this time the entire turbine and in particular its blades (also called sails) will have to be replaced. A fossil-fuel power plant, on the other hand, has a life-expectancy of at least 30 years and some last over sixty with proper maintenance. This means that, typically, 2 wind-turbine “power plants” will have to be built to replace one (new) fossil-fuel plant. This has economic as well as environmental implications for wind-farms and their turbines.
In addition, most of the materials used in the turbo-generators of a modern gas-fired power plant are metals. Metals are infinitely recyclable. On the other hand the blade surfaces of wind-turbines are made either of fibre-glass or carbon-fibre composites which are not recyclable and it is these composites that are causing increasing concern about pollution from wind-turbine blades, both whilst the turbine is in operation and when the blades have to be disposed of.
When wind-turbines are in operation and the weather is inclement (rainfall, snow or hail) the leading edge of the turbine blade is impacted by water and/or ice with sufficient force that micro-plastic and nano-plastic fragments of the blade are ripped away and the larger the turbine blades the worse is the problem, due to increased tip speed¹.
Over time, the damage rips through the coatings on the blade and starts to erode the glass or carbon fibre composite underneath. An example of this Leading Edge Erosion (LEE) is shown below.
Glass and carbon-fibre composites depend for their strength on resins that set hard. One important component of such resins (up to 33%) is a chemical called Bisphenol-A ². The epoxy resin makes up roughly half the mass of the composite and thus Bisphenol-A accounts for about 14% of the total mass of the blade. Put another way, each blade of a modern turbine contains several tonnes of Bisphenol-A.
Bisphenol-A is toxic and poses a serious threat to both human health and the environment². The wind-industry estimates that a modern wind-turbine blade may, on average, “shed” 150g of micro-plastics per year. If the wind-turbine is offshore, this rate is much higher due to the corrosive nature of salt water and if the turbine is in an area prone to hail and snow, this too will increase the erosion rate.
According to laboratory experiments, a single large wind-turbine ( >100m diameter), in a marine environment subject to high wind-speeds, snow and hail, could shed over 60 kg of plastics per year, a much higher figure than previously thought, of which about 60×0.14 = 8.4kg could be Bisphenol-A.
How much of this shed material will actually be Bisphenol-A is uncertain, but 1 kg of bisphenol-A is enough to pollute 10 000 Megalitres of water to a level above the “safe” level set by the World Health Organisation. To give a sense of scale to that figure, the UK uses about 14 megalitres of potable (drinking) water a day, so 1 kg of bisphenol-A can pollute 10,000/14 = 714 days (almost two years) worth of UK drinking water.
Depending on the location of the wind-turbine, prevailing winds etc., these Bisphenol-A containing micro- and nano-plastics may pollute either the land or the sea and will enter food-chains and water supplies sooner or later and the larger the wind-turbine, the further these particles will be carried before they settle out of the air, so this pollution can be easily spread over long distances and wide areas.
The leading edges of most wind-turbine blades are coated with a covering designed to reduce Leading Edge Erosion (LEE), they do so by being the first part of the blade to be eroded away.
However, LEE is not steady. Blades also suffer from pitting. Simply, pitting is a hole though the covering that reaches the underlying materials. This is turn leads to the protective films flaking off the blade (fancy term “delamination”) and so greatly speeds up LEE (evidence of flaking can be seen in the picture above) and this can greatly reduce the time it takes for the protective layers to be worn through.
To make matters worse, many of the coatings used contain chemicals (e.g. isocyanates) that are cancer causing agents (carcinogens), so the erosion of these “protective” layers also has impacts on the environment and (potentially at least) human health.
To actually prevent loss of Bisphenol-A from the blades (as part of the loss of the composite), the blades must undergo regular, often annual, maintenance before the coatings are likely to be worn through, this is expensive³, and as explained may simply replace one environmentally harmful pollutant with another.
At end-of-life wind-turbines have to be decommissioned and dismantled. Metal components can be recycled, but the blades cannot. At present the blades are (ultimately) buried in landfill where they will (eventually) decay and release all their remaining Bisphenol-A. The blades of a large turbine typically have a mass of ~60 Tonnes, of which ~14%, or almost 8 tonnes, is Bisphenol-A. Over time this Bisphenol-A will be released into the environment, possibly polluting ground water that is used for drinking.
The above does not take account of another major problem with wind-turbines. They are prone to weather damage.
In fact strong winds have a nasty habit of destroying wind turbines quite easily.
An example of this is shown below:
“Damaged” is putting what happened mildly. Most of those turbines and in particular the nacelles (the bit at the top of the tower) and the blades will have to be replaced and the towers may also have structural damage. “Destroyed” would probably be more accurate.
The London Array, in the east of England, the world’s largest offshore wind system, required extensive repairs after only five years of operation, the costs have not been disclosed. Danish wind operator Ørsted needed to repair undersea cables to offshore wind systems in the North Sea at a cost that exceeded $100 million. Both of these repairs were largely the result of weather damage.
Turbine wind systems are designed to try to protect wind towers and blades in high winds. When winds exceed 55 mph (88km/h) (so force 9/10 “severe gale/storm” on the Beaufort scale), a braking system brings the rotor to a standstill to try to avoid turbine damage. Tower blades are also “feathered” – oriented so that they no longer catch the wind.
But strong wind gusts can change direction rapidly and powerfully, too fast for damage-prevention systems to react. The result is destroyed blades and damaged towers.
Around the UK coast-line gales and severe gales are relatively common in winter. A gale (wind speed up to 54 mph (86 km/h)) may well gust to a substantially greater speed raising the distinct possibility of turbine “damage”.
In July 2024 a single 108m offshore turbine blade splintered in America’s Nantucket bay and washed up ashore. Beaches were closed and over 6 truckloads of debris had to be removed (and even then not all of the debris would have been found) and this was from a single blade.
Conclusion
Various materials used in modern wind-turbines have serious potential consequences for human health and the environment. These toxic materials are released as micro- and nano-plastics over the life-time of the turbine and present further risks when the turbine blades (in particular) are disposed of to landfill.
The question then arises as to how “green” wind turbines are and whether or not their installation should be at least paused until environmentally sound solutions to these problems can be found.
In addition, their vulnerability to storm damage also potentially adds large costs in terms of clean-up, restoration or rebuilding and the mitigation of environmental harm. At present these costs are basically unknown (being based on weather events) but the evidence points to these costs running into many £100 millions of pounds if multiple turbines are destroyed. Large onshore commercial wind-turbines cost somewhere between £2 million – £4 million each, so to use the example in the picture above, replacing those turbines (just 6 are visible) could cost £24 million and that neglects the clean-up, disposal and other costs. Offshore turbines are both far more expensive and far more vulnerable to storm damage exacerbated as it is by the corrosive nature of salt water.
Notes:
1. The longer the blades, the bigger the circle they make and so the faster the tip of the blade has to move to travel a full circle in a given time. Large turbines have tip speeds of more than 100 m/s.
2. Bisphenol-A
3. Estimates of the yearly cost of servicing a 500MW wind-farm are in the range £2 million to £8 million depending on the type and location of the wind-farm. The UK currently (2024) has roughly 30GW of installed wind-turbines, thus the annual maintenance costs for Leading Edge Erosion and other issues are estimated to range from a minimum of £120M up to £480M. (The upper figure is roughly equivalent to the build cost of a 500MW combined-cycle gas turbine power plant.) Looked at another way, this could be up to £80,000 per turbine per year and lifetime costs of £1.6 million per turbine, neglecting any extra end-of-life costs to ensure that disposal does not generate further pollution.
Addendum#1:
As an example of the lies that we are continuously fed about renewable energy, consider this: https://notalotofpeopleknowthat.wordpress.com/2024/12/01/national-grid-the-hornsea-battery/
The claim: “By co-locating assets like this [battery], excess wind power can be stored and used when needed.”
The reality. The Hornsea battery has a capacity of 600 MWh. The Hornsea windfarm has an installed capacity of 6.0GW = 6000 MW. Thus a 600MWh battery can store 600/6000 = 0.10 hours or six minutes of energy from the Hornsea array (if generating at its “installed capacity”).
So this battery cannot be used “store wind power and use it when needed”. The energy store is far too small to “back-up” a wind-farm. It’s purpose is to help frequency stability on the grid, which is becoming ever more of a problem due to the moment-to-moment fluctuations from wind.
Addendum#2
It’s not just wind-farms that are susceptible to storm-damage.
Storm Darragh (early December, 2024, UK) leaves UK’s Biggest solar farm in pieces – and off-line.
This wind farm, the 50MW Port Wen farm in Anglesey, commissioned in early 2024, was taken offline by the storm and will take months (if not years) to rebuild and repair. The owners estimate “early 2025”, but this could be optimistic depending on how much damage to the actual panels is found.
Nearby:
The storm also destroyed a wind-turbine, shearing the blades and hub off the nacelle. Reports say that the nacelle then caught fire (as evidenced by the blackening at the top of the turbine-less tower).
The remains of the nacelle may also be shown in the picture.
