During November and December last year the utility shut down the de-icing system on a Nordex 3 MW wind [...]]]> De-icing systems on wind turbines can increase the yearly production of energy with up to 10 percent, according to tests made by the utility Skellefteå Kraft at the wind farm Uljabuouda in the north of Sweden.

During November and December last year the utility shut down the de-icing system on a Nordex 3 MW wind turbine while running the system on an identical turbine.

The difference in production was clear.

- The loss of production on the turbine without blade heating was around 17 000 euro during the period, says Hans Gedda, a technical consultant, who has been managing the project for Skellefteå Kraft.

- We decided to stop the tests because the losses were so significant on the turbine without heating.

Next step will be measuring how much energy the de-icing systems consumes.

- Today we have unclear picture of the their consumption, says Gedda. There are a lot of figures around and most likely there is big differences between different suppliers.

The tests in Uljabuouda will be performed between November and March this year. According to the plans they will continue next year.

On René Cattin’s to-do-list is better forecasts, more and better measurement data, new simulation models and more effective de-icing systems.

The report, Icing of Wind Turbines [...]]]> A lot has been done, but there’s still a long way to go before icing on wind turbines are under control, concludes meteorologist René Cattin in a new report.

On René Cattin’s to-do-list is better forecasts, more and better measurement data, new simulation models and more effective de-icing systems.

The report, Icing of Wind Turbines (Elforsk report 12:13), was released during Winterwind 2012 in Skellefteå today, concludes that there’s a much better awareness of the problem with icing in the industry today than just a few years ago.

- Still, ice is tricky; hard to predict, hard to stop and hard to get rid of, says René Cattin.

René Cattin

There are some rule of thumbs about icing: it occurs from around minus 20 degrees Celsius to around zero, often when the air is humid. The degree and pace of icing is depending not only on temperature and humidity, but also on wind speed, clouds and the shape of the objects that the ice sticks to.

- For every rule there are exceptions that makes it very hard to predict icing, says Cattin.

To get better knowledge about icing he calls for the wind industry and researchers to develop better background data. Among the things he mentions are a wind turbine ice accretion model, improved cloud microphysics (MVD) and mechanical icing models for wind turbines.

- We need to get more and better measurement data and detailed case studies of icing events, says Cattin:

But research isn’t enough.

- There’s also a lack of anti-icing system which completely prevents ice accretion, de-icing systems which efficiently remove ice and efficient control system for de-icing systems.

To reach this point René Cattin advocate more field tests of anti-icing and de-icing systems.

- There’s a need for test centres, where you can test the turbines in cold climate and European collaboration, says Cattin.

 What is your offer?

“We are looking for owners of [...]]]> Some of the visitors at Winterwind 2012 may have noticed a terrain vehicle parked outside the entrance. We met with Lars Karlander and Klas Göran Asplund at the Scandinavian Terrain Vehicles stand just before they take some of the potential clients for a ride.

 What is your offer?

“We are looking for owners of a terrain vehicle that not are aware of how much better it will be if they replace the old engine with our new. We also sell second hand vehicles that we have renovated,” says Lars Karlander.

What´s the deal with a new engine?

“An old engine for gasoline needs maybe 25 litres per ten kilometers. Our turbo engines needs not more than 4 litres of diesel,” says Lars Karlander.

It seems to me that a terrain vehicel does pretty much the same work as a workhorse, that is: It makes its way where there are no roads.

”Yes, and a terrain vehicle, like a horse, has only little impact on the nature. The Caterpillar band, made in rubber, makes less damage on the ground than a person in rubber boots,” says Lars Carlander.

Why are you here at Winterwind 2012?

”We work with some of the network companies, now we are looking also at the wind power sector. We think there is a demand there, a need for vehicles for both the contruction and service. We met a lot of peaple from interesting companies that we didn´t know about before, now we will map them and maybe there will be some sort of cooperation later on,” says  Klas Göran Asplund. 

”Vi modify material in order to develop surfaces that don´t like water, or ice.”

Now he and his collegues are looking for industrial partners [...]]]> YKI , partner for research and innovation in applied surface chemistry, are trying to develop surfaces for i.e. rotor blades. Kenth Johansson at YKI explains the deal with the project TopNano.

”Vi modify material in order to develop surfaces that don´t like water, or ice.”

Now he and his collegues are looking for industrial partners to take the research and the testing further.

”We´ve met a lot of people, there has been a lot of visitors at our stand and interesting discussions”

What has [...]]]>

Researchers in Finland started to investigate the possibility of de-icing wind turbines in the early 90’s. However, most manufacturers took little notice, as these issues were only considered relevant to a narrow [...]]]> Suddenly wind energy in cold climate is a hot topic. Several of the large manufacturers are now on the verge of offering de-icing systems.

Researchers in Finland started to investigate the possibility of de-icing wind turbines in the early 90’s. However, most manufacturers took little notice, as these issues were only considered relevant to a narrow and small niche market.

It wasn’t until a few years ago that the industry started looking at sites in cold regions. Then it dawned upon the developers that there were plenty of cold climate locations with excellent wind conditions.

Among the highlights during the first day at Winterwind 2012 was a stage presentation of de-icing solutions by six of the world’s leading manufacturers. Five of these systems are brand new and some have yet to enter the commercial market.

- Two years ago this session would have been unthinkable, the market just wasn’t there, says Göran Ronsten, program coordinator of Winterwind 2012.

Enercon’s de-icing system has been around the longest time. The company’s first commercial ice detection and de-icing system was installed in 2004. The system is based on hot air inside the blades.

Siemens (or Bonus, as the company was called before Siemens bought it) has been experimenting with blade de-icing since the middle of the 90′s. Two years ago Siemens Wind Power took the knowledge from the past and built it into a new blade de-icing system.

- The blade heating is integrated at factory, there’s no wiring on the outside of the blade, said Finn Daugaard Madsen, innovation manager at Siemens.

- That means there’s a low risk of transport damages, full retention of the aerodynamic profile and no effect on noise levels.

Today Siemens has 15 wind turbines with de-icing systems installed in four different locations in Sweden. About 70 new turbines with this system have been ordered.

Vestas is testing a new de-icing technology, and ice detection. Expected release for sales is 2012. The Danish world leader manufacturer of wind turbines is opting for the Enercon-solution: a system with hot air inside the blades.

- We didn’t pursue a leading edge system because of several reasons of which risk of damages due to lightning strikes was the most important, said Morten Sloth, product manager at Vestas Wind Systems, during his presentation.

According to Vestas the losses in energy production with leading edge heating was too large during summer compared to the gain during icing conditions. Operation and maintenance also proved to be too costly, as well as the system itself, said Morten Sloth:

- Costs of components and lightning protection were too high and we couldn’t guarantee a reasonable lifetime, he concluded.

German manufacturer Nordex has signed a frame work agreement with the municipally-owned utility Skellefteå Kraft to supply a total of 118 turbines  with a leading edge anti-icing system. The project concerned is “Blaiken”, which with 250 megawatts (MW) will be the largest wind farm in Sweden.

- Our anti-icing system can add 25 percent production during the icy season, said Lars Holm, senior vice-president of project development.

Finnish WinWind has been partnering with VTT research centre and has been carrying out tests with leading edge de-icing systems in cold climates since the early 1990’s (sub-megawatt and 1MW machines).

In 2008 WinWind received a contract with Skellefteå Kraft to deliver wind turbines to the Uljabuouda project and conduct a pilot project development of an ice prevention system.

- An important lesson so far is that the heating system can’t be too close to the lightning protection system, said Anders Sjögren from WinWind.

Indian-German Repower has chosen yet another path: the company put it’s faith into passive de-icing, special coating and other features that hopefully will keep ice off the blade.

- We will install over 500 cold climate turbines in the coming years, many in Canada. There’s no anti-icing solution that fits every situation, and if we develop an active system we can easily retro-fit it into our blades, said Kurt Stürken, managing director at Repower Systems Scandinavia.

Kurt Stürken also said that his company will have test turbines in Sweden next winter and a product ready for the market in 2014.

But whatever system the manufacturers choose to develop one thing is for certain, concluded Lars Holm:

- In the future anti-icing systems will become a must have in some regions.

Signals like that are already coming from the Swedish H&S Authority (Arbetsmiljöverket). Bel Bergenwall from the authority recently said that when de-icing systems are commercially available it won’t be legally possible for the potential owner to deselect such a safety feature in areas prone to icing.

- This implies big consequences, says Göran Ronsten: If you have no de-icing, you might not be able to sell.

- Especially Norway is interesting for us, because Norway is now part of our quota system, says Gunnar Eikeland, [...]]]> Skellefteå Kraft has grown rapidly in wind energy the last three years. Now the utility plans for 90 more wind turbines in the own region. Next step might be projects in Norway or Finland.

- Especially Norway is interesting for us, because Norway is now part of our quota system, says Gunnar Eikeland, CEO Skellefteå Kraft.
Skellefteå Kraft has up and running wind turbines in Uljabuouda (10 since 2010), Jokkmokksliden (10 since 2011), Storliden, (8 since 2010) and Bureå (3 since 2003). All are situated in areas with cold climate.
The next big project is Blaiken, a huge development with up to 100 wind turbines. The first 30 turbines are going to be in place this summer. Partner in this project is utility Fortum.
- We’re moving fast ahead i an industry that is growing quickly, but I can see potential problems ahead,” says Eikeland and mentions three things:
* The need of long term reliable anti-icing systems to keep the rotor blades free of ice and the wind turbins running even under harsh conditions.
* The prices in the quota system has fallen recently, due to uncertainty in the market. “We need a stable system be able make our investments,” says Eikeland.
* The lack of power grids in the north. In some areas in the north it might not possible to build more wind turbines in the future due to lack of net capacity. “We need a longer planning horizon when it comes to grid development, ” says Eikeland.
* The government have risen taxes for hydro power substantially the last years. There’s a risk that the same can happen with wind energy.

Despite the commonly believed prediction of a declined growth in the domestic wind power market, 20GW of new installation was added onto the Chinese landscape during year 2011. The [...]]]> Envision Energy, Chinese turbine manufacturer, focuses on the Scandinavian market and seeks to cooperate with a Nordic technology supplier in order to solve the icing challenge.

Despite the commonly believed prediction of a declined growth in the domestic wind power market, 20GW of new installation was added onto the Chinese landscape during year 2011. The cumulative wind power capacity in China has thus exceeded 65GW, of which 45GW grid connected. Meanwhile, Chinese wind turbine manufacturers are seriously heading for the international market. A number of deals have been signed in Europe. Two turbines by Chinese Sinovel are already being installed near Karlstad in Sweden.

Unlike in Sweden, wind turbine icing is generally regarded as a less remarkable problematic in China, thanks to the low humidity in the country’s wind-rich areas. Nevertheless, de-icing technology is receiving increasing attention within the Chinese wind industry. Demand arises from the domestic market as well as international market.

- Scandinavia is currently our major potential market abroad. De-icing is simply a huge must for our turbines, which is why we are establishing a close cooperation with a Nordic technology supplier, says Mr. Bo Ben at Envision Energy, a Shanghai-based wind turbine supplier with its global research centre in Denmark.

Chinese Wind Energy Association (CWEA) has since 2010 been a member of the International Energy Agency collaboration under name Wind power in cold climate. Besides icing, the research project also covers low temperature operation of wind turbines, which is of more relevance in China. Professor He Dexin, president of CWEA and WWEA (World Wind Energy Association), is among the speakers at Winterwind 2012.

Text: Wang Zhi, analyst at the Swedish Network for Wind Utilization

”We are looking for a spot with an icing probability of 90%, and an average wind speed of approximately 7 m/s at 100 [...]]]> The first center for research and testing of wind power in cold climates may soon be established in Sweden. Five municipalities, Luleå, Piteå, Storuman, Sorsele and Arjeplog, are competing for the plant.

”We are looking for a spot with an icing probability of 90%, and an average wind speed of approximately 7 m/s at 100 meters height,” says Matthias Rapp, chairman of the Swedish Wind Power Technology Center (SWPTC).

”The plant must also be located relatively close to an airport, with roads that can withstand heavy transport.”

SWPTC at Chalmers University of Technology in Gothenburg has, together with Vindforsk and Power Circle, produced a preliminary study of what is needed to build a test center for wind energy in cold climates. This work is now progressing into Phase II. This includes cost estimates and market potential, i.e. how many of the world’s manufacturers would be interested in coming to Northern Sweden to test their turbines.

In one of the candidate municipalities, Arjeplog, there is already a world famous cold climate testing center for cars, and now drivers and engineers from all over the world come to this small municipality to drive cars in the depths of winter.

Matthias Rapp hopes for a similar development for the center for cold climate wind power. “The concept is to find a suitable location to construct a number of stable base plates with access to the electricity grid. Then manufacturers could transport their towers and turbines to the site and install them for testing. The plans also include placing a number of measuring systems in front of the wind turbines and providing a building to house workstations, conference rooms and overnight staff accommodation.
“We could also, perhaps, construct a few permanent wind turbines in order to generate revenue,” says Matthias Rapp.

What will the project cost?
“We don´t know the exact costs at present, but 15 million SEK would be a rough estimate for building the test plate, excluding operating costs.”

Who will be the principals?
“We don’t know that either at the moment. The work in Phase II also includes identifying potential owners/principals and suitable financing.”

For further information contact:
Matthias Rapp
Chairman of Swedish Wind Power Technology Center, (SWPTC)
mr@straits.se
+46 70 453 11 38