SAFETY

CATASTROPHIC COLLAPSE OF TURBINES

See 'Live Leak' video (22.02.08).

Minister demands investigation.

The Danish Climate Minister, Connie Hedegaard, has called for an investigation to determine the cause of the two violent wind turbine collapses in Denmark in the past week. Hedegaard's request to the Energy Board comes after other accidents have been reported in Denmark and elsewhere during the past two months.

People here have been reminded of a similar accident in the Scottish Borders in 2005 when a 100m turbine at Crystal Rig had a blade break up after a failure of the control mechanism (see photograph). Blade failure is a fairly common occurrence and occasionally causes structural damage to the turbine tower.

There is concern here that Your Energy propose siting one of the 110m (360 ft) 'Moorsyde' turbines less than 200 metres from the B6354 road. Its turbine blades would measure 40m (over 130 ft) and would weigh 7-8 tons.

The author of the Danish video clip comments:

“The braking system failed while 2 technicians worked in the turret in the top. They got out before the collapse.
A 19 metre piece of the wing was thrown 200 metres away. Smaller pieces were sent more than 500 metres away..!!”

In 2007, there was an accident involving 7 turbine blades at the Allegheny Ridge Wind Farm in the USA. The blades were 140 feet long, 14 feet wide and weighed some 7 tons, according to the manufacturers. Pieces of the blades were thrown more than 500 feet.

An analyst who covers the wind-energy industry was quoted as saying, “It's something the size of a yacht flying through the air”. (See the Facts page).

Problems on the horizon?

An article in Der Spiegel on turbine safety quotes wind industry technicians and insurers who have major concerns about the technology.
Jan Pohl, who works for major German insurer Allianz stated that on average, “an operator has to expect damage to his facility every four years, not including malfunctions and uninsured breakdowns.”

In the headlong rush to exploit the heavily subsidised expansion of wind power generation, companies have rushed to market with bigger and bigger turbines that suffer enormous stresses to everything from foundations to gearboxes and blades. This has led to problems such as Vestas experienced with their “market-leading” V90 3MW turbine which was recently withdrawn by the manufacturers from offshore use after repeated gearbox failures.
There is also a growing problem with poorly maintained older turbines that are exhibiting frequent mechanical failures and even occasional structural failures as seen in the recent tower collapses of 2 small Vestas V47 turbines in the UK.

Vestas V47 collapse in Cumbria, January 2008.
© Roger Savage.

‘Minister demands explanation for windmill collapse‘. The Copenhagen Post, 25 February, 2008.
‘Wuthering Heights, The Dangers of Wind Power.’ Spiegel Online, August 20, 2007.
‘Probe into wind turbine collapse.’ BBC News, 2 January, 2008.

It should be noted that turbine 2 is close to the absolute minimum recommended safe separation distance of 150m from roads and turbine 1 is within 200m. The Countryside Agency recommends a safe separation distance of four times turbine height (i.e. 440m). The British Horse Society recommends a minimum of 200m from all roads and bridleways used by horses.

BBC News Scotland story.

These events are not as rare as the industry likes to pretend to the public. A Dutch company whose core business is blade repair admits that, "Rotor blade lightning damage is a common problem" (NGup Rotor Blades).

There was a similar accident on a Blyth Offshore turbine some years ago and everybody knows about the recent Nissan fire [see our Windpower Page] where roads had to be closed to avoid falling debris.

Turbine accident - Holland, October 31 2006.

There have been 255 turbine accidents in Germany since 1997, see this link).

In Cornwall in 2006, "Part of a wind turbine blade weighing more than half a ton snapped off and crashed into a field during high winds.".
"Operators Cumbria Windfarms said the site has been running since April 1993 and nothing like this had happened there before." It had, as several locals pointed out - in 1993, a month after the turbine park opened, they had had a similar accident.

Nor is Your Energy immune - their only operating turbine array at Burton Wold in Northants was closed for days shortly after it opened by electrical storm damage (12 July 2006).

In its public pronouncements, the wind industry claims that turbine accidents are very rare. It is more honest in private: for example, a Dutch company whose core business is blade repair admits that, "Rotor blade lightning damage is a common problem" (NGup Rotor Blades).

In 2005, with comparatively few [as yet] turbines in this area, we saw the high speed break-up of a 38.8 metre (127 ft.) turbine blade at Crystal Rig [see pic] and a turbine fire at Nissan. One of the two Blyth offshore turbines suffered a blade failure in 2002 (see story) and since April, 2006, both turbines have been shut down with an underwater cable fault.

Turbine fires are far from uncommon, which is no great surprise when you consider the combination of large volumes of lubricants, highly stressed bearings and electrical generating sets - all on top of a 350-425 ft. high lightning conductor.

Turbines of this height are too high for the fire brigade to tackle with their ladder equipment and are normally left to burn out, burning off quantities of oil and other noxious materials in the process.

‘MISHAPS, BREAKDOWNS AND ACCIDENTS

‘WUTHERING HEIGHTS - The Dangers of Wind Power.

‘Wind turbines continue to multiply the world over. But as they grow bigger and bigger, the number of dangerous accidents is climbing. How safe is wind energy?

‘After the industry's recent boom years, wind power providers and experts are now concerned. The facilities may not be as reliable and durable as producers claim. Indeed, with thousands of mishaps, breakdowns and accidents having been reported in recent years, the difficulties seem to be mounting. Gearboxes hiding inside the casings perched on top of the towering masts have short shelf lives, often crapping out before even five years is up. In some cases, fractures form along the rotors, or even in the foundation, after only limited operation. Short circuits or overheated propellers have been known to cause fires. All this despite manufacturers' promises that the turbines would last at least 20 years.

‘Gearboxes have already had to be replaced “in large numbers,” the German Insurance Association is now complaining. “ In addition to generators and gearboxes, rotor blades also often display defects,” a report on the technical shortcomings of wind turbines claims. The insurance companies are complaining of problems ranging from those caused by improper storage to dangerous cracks and fractures.

‘[...]

‘Wind power expert Martin Stöckl knows the problems all too well. The Bavarian travels some 80,000 kilometers (49,710 miles) across Germany every year, but he is only rarely able to help the wind farmers. It is not just the rotors that, due to enormous worldwide demand, take forever to deliver, but simple replacement parts are likewise nowhere to be found. “You often have to wait 18 months for a new rotor mount, which means the turbine stands still for that long,” says Stöckl.

‘“Sales Top, Service Flop” is the headline on a recent cover story which appeared in the industry journal Erneuerbare Energien. The story reports the disastrous results of a questionnaire passed out to members of the German WindEnergy Association asking them to rank manufacturers. Only Enercon, based in Germany, managed a ranking of “good.” The company produces wind turbines without gearboxes, eliminating one of the weakest links in the chain.

‘Even among insurers, who raced into the new market in the 1990s, wind power is now considered a risky sector. Industry giant Allianz was faced with around a thousand damage claims in 2006 alone. Jan Pohl, who works for Allianz in Munich, has calculated that on average “an operator has to expect damage to his facility every four years, not including malfunctions and uninsured breakdowns.”

Many insurance companies have learned their lessons and are now writing maintenance requirements -- requiring wind farmers to replace vulnerable components such as gearboxes every five years -- directly into their contracts. But a gearbox replacement can cost up to 10 percent of the original construction price tag, enough to cut deep into anticipated profits. Indeed, many investors may be in for a nasty surprise. “Between 3,000 and 4,000 older facilities are currently due for new insurance policies,” says Holger Martsfeld, head of technical insurance at Germany's leading wind turbine insurer Gothaer. “We know that many of these facilities have flaws.”

‘Flaws And Dangers

‘And the technical hitches are not without their dangers. For example:

• In December of last year, fragments of a broken rotor blade landed on a road shortly before rush hour traffic near the city of Trier.

• Two wind turbines caught fire near Osnabrück and in the Havelland region in January. The firefighters could only watch: Their ladders were not tall enough to reach the burning casings.

• The same month, a 70-meter (230-foot) tall wind turbine folded in half in Schleswig-Holstein -- right next to a highway.

• The rotor blades of a wind turbine in Brandenburg ripped off at a height of 100 meters (328 feet). Fragments of the rotors stuck into a grain field near a road.

‘At the Allianz Technology Center (AZT) in Munich, the bits and pieces from wind turbine meltdowns are closely examined. “The force that comes to bear on the rotors is much greater than originally expected,” says AZT evaluator Erwin Bauer. Wind speed is simply not consistent enough, he points out. “There are gusts and direction changes all the time,” he says.

‘But instead of working to create more efficient technology, many manufacturers have simply elected to build even larger rotor blades, Bauer adds. “Large machines may have great capacity, but the strains they are subject to are even harder to control,” he says.

‘Even the technically basic concrete foundations are suffering from those strains. Vibrations and load changes cause fractures, water seeps into the cracks, and the rebar begins to rust. Repairs are difficult. “You can't look inside concrete,” says Marc Gutermann, a professor for experimental statics in Bremen. “It's no use just closing the cracks from above.”

‘The engineering expert suspects construction errors are to blame. “The facilities keep getting bigger,” he says, “but the diameter of the masts has to remain the same because otherwise they would be too big to transport on the roadways.”

‘Not Sufficiently Resilient

‘Still the wind power business is focusing on replacing smaller facilities with ever larger ones. With all the best sites already taken, boosting size is one of the few ways left to boost output. On land at least. So far, there are no offshore wind parks in German waters, a situation that Minister Gabriel hopes to change. He wants offshore wind farms to produce a total of 25,000 megawatts by 2030.

‘Perhaps by then, the lessons learned on land will ward off disaster at sea. Many constructors of such offshore facilities in other countries have run into difficulties. Danish company and world market leader Vestas, for example, had to remove the turbines from an entire wind park along Denmark's western coast in 2004 because the turbines were not sufficiently resilient to withstand the local sea and weather conditions. Similar problems were encountered off the British coast in 2005.

‘German wind turbine giant Enercon, for its part, considers the risks associated with offshore wind power generation too great, Enercon spokesman Andreas Düser says. While the growth potential is tempting, he says, the company does not want to lose its good standing on the high seas.’

(See Der Spiegel, August 20, 2007).

'Car plant windfarm fire forces motorists off A19

'A HUGE wind turbine [167 ft. [51m.], 193 ft. smaller than 'Moorsyde' turbines!] went up in smoke in a massive blaze seen for miles across Wearside.

The 200ft structure at the Nissan factory, part of a £2.3million wind farm built in August, burst into flames just after 12.30pm yesterday.

The fire was so fierce all three 75-ft long fibreglass blades eventually dropped off and thick black smoke could be seen for miles around.

Almost 200 people dialled 999 to alert emergency crews as flames engulfed the turbine.

Police closed both the A1231 and the A19 for an hour-and-a-quarter amid worries that parts of the metal tower could fall on to the busy roads.'

(Read the full story: Northern Echo, 23 December, 2005)

Nissan turbine fire 23 December, 2005. (© Northern Echo.)



Nissan turbine fire 23 December, 2005. (© Sunderland Echo.)



A Small Continental Turbine on Fire (note the burning oil spilling down the tower).
Courtesy of Lewis campaign website.



The American solution - bomb it!
Courtesy National Wind Watch)

One thing is certain - turbines should not be built anywhere near housing or roads or on high fire-risk sites.