Hurricane-force winds destroy Norwegian wind turbines: The model is widespread in Denmark
Three wind turbines broke down as Storm Ingunn passed through northern Norway. Norwegian state-owned power supplier Statkraft, which owns the now-destroyed wind turbines, assesses that it was probably the storm that caused the damage.
“A turbine blade on Smøla is broken. It’s too early to say anything about the cause, but it’s likely that a combination of lightning and extreme load over the past 24 hours has contributed to it,” Statkraft’s media spokesperson Geir Fuglseth writes in an email to Montel.
According to figures from the Danish Energy Agency, Denmark has 83 wind turbines of the same type as the ones on the Norwegian island of Smøla.
On the island of Smøla, one blade of a wind turbine has broken off in the storm, and the remaining two wind turbines have lost their blades at the Kvenndalsfjellet wind farm. The two wind turbines at Kvenndalsfjellet were already reported as faulty at the end of last year and had a loose outer shell, Geir Fuglseth says to Montel.
The three damaged wind turbines in Norway were produced by Siemens and Vestas, Geir Fuglseth states in a written reply to Ingeniøren.
Wind gusts of up to 44.9 m/s were measured around the three turbines, while the Siemens wind turbine’s upper limit is 55 m/s, and the Vestas wind turbine’s upper limit is 57 m/s.
But it is not just the wind that causes a wind turbine failure. Many other factors come into play, according to an expert.
Not just the wind
Although a wind turbine is built to withstand a certain wind speed, there are many other parameters in a wind turbine failure.
Steen Buss, technical consultant at Nordic Wind Consultants (formerly Danish Wind Turbine Owners’ Association), does not think that the blame can be placed on wind alone.
“It’s hard to say why something went wrong. There are so many parameters that come into play in a wind turbine failure. In terms of design, the wind turbine should have been able to withstand it, and if the wind speed is below the one in the technical documents, then something else has caused the failure,” he says.
For example, metal fatigue, hidden defects, and the state of maintenance have a major impact on how resistant a given wind turbine is to wind and weather.
“It’s highly likely that an accident commission will investigate whether the damaged wind turbines have been properly maintained. If they find a specific cause for the accident, measures will be implemented for similar turbine types,” Steen Buss says.
It is therefore necessary to determine one of the many possible causes of wind turbine failure before the faults that cause them can be prevented—and the wind is presumably only one of them.
No immediate danger
For the people who live near an onshore wind turbine, there is no immediate physical danger due to wind turbine failure. In Sweden, it is standard practice to mark the area around a wind turbine with signs, so that passers-by can see that there is, for example, a risk of ice falling from the wind turbine.
Problems with ice on the blades are not that extensive in Denmark, and it is difficult for the average citizen to relate to a warning sign about wind speed, Steen Buss believes.
“If we’re talking about ice on the blades, signs are put up (in Sweden, ed.) to warn against ice and snow falling from the blades. I have yet to see a place where it says that it’s forbidden to enter if the wind speed is, for example, over 30 m/s, but that’s also somewhat vague for a regular Dane.”
Future weather in Denmark
The storm in Norway was the most violent one the country has ever experienced, and NRK, among others, has reported record-breaking wind speeds. But even though we in Denmark have also been exposed to extreme weather, especially in the last six months, there is actually no consensus among the researchers as to whether we can expect more frequent extreme wind speeds in Denmark.
“According to approximately half of the climate models, we should expect more days with extreme winds nationally, and according to the other half, we should expect fewer. This conclusion is associated with relatively large uncertainties as a result of the spread between the climate models,” Rasmus Anker Pedersen, head of climate research at the Danish Meteorological Institute, writes to Ingeniøren.
