How wind energy sensors behave in icing conditions?

Wind energy in cold climates is growing rapidly around the world [1] but measuring the different phases of icing with weather sensors and ice detectors is not an easy task. See a Youtube testing video here.

Sensors and ice detectors are needed to evaluate the risks on wind farm icing in pre-constructions energy assessments and safety as well as to control operational wind turbines during icing events. Some outdoor, full-scale ice detector benchmark tests have been performed in the past two decades but little focus has been put so far on controlled laboratory testing in realistic icing conditions [2] [3] [4]. Thus there is a large need from the industry to develop and test ice detectors for wind power purposes and potentially other industry sectors.

Testing 5 winter seasons in one week

VTT has over 25 years of experience working with icing challenges within wind power sector and today, one high priority topic is revolving around VTT Icing Wind Tunnel (Figure 1) testing. Based on the industry needs and VTT knowhow, VTT has initiated and coordinates an industry consortium project with aim to increase ice detector reliability and substantially reduce time-to-market of new ice detector products. The goal is to shift from current slow ”winter season” outdoor full-scale testing of ice detectors to accelerated, controlled and repeatable laboratory “5 winters in one week” testing at VTT Icing Wind Tunnel. The novelty content of this project is high and the results will benefit both industry and research community.

Project industry partners are Vattenfall AB, Statkraft AS and Labkotec Oy.

Icing Wind Tunnel

Figure 1. Layout of VTT Icing Wind Tunnel, operational since 2008.

So far 6 wind energy sensors have been tested at VTT Icing Wind Tunnel ranging from ice detectors (Labkotec LID) to standard cup anemometers and other “normal” weather sensors used for ice detection today by the wind industry. See some ice cool results in this Youtube video.

See also more information and pictures from WinterWind 2017 presentation “Standardizing ice detector tests in icing wind tunnel”.

As future plans, further analysis of already performed tests will take place. The project continues until end of 2017 and key results and inter-comparisons of sensor behaviour and performance in icing conditions will be presented at WinterWind 2018 conference.

For more information please do not hesitate to contact me.

Ville Lehtomäki VTT

Ville Lehtomäki
Senior Scientist, Wind power
Mobile: +358 50 370 7669
Email: ville.lehtomaki (a)



[2]: B. Tammelin and a. et, “Wind Turbines in Icing Environment: Improvement of Tools for Siting, Certification and Operation – NEW ICETOOLS,” Finnish Meteorological Institute, Helsinki, Finland, 2005.

[3]: S. Fikke, G. Ronsten, A. Heimo, S. Kunz, M. Ostrozlik, P. E. Persson, J. Sabata, B. Wareing, B. Wichura, J. Chum, T. Laakso, K. Säntti and L. Makkonen, “COST 727: Atmospheric Icing on Structures Measurements and data collection on icing:,” MeteoSwiss, Zurich, 2007.

[4]: H. Wickman, “Evaluation of field tests of different ice measurement methods for wind power,” Uppsala Univ (MSc thesis), 2013.

Two free cold climate wind energy reports out from IEA Wind Task 19 expert group

Olos low clouds

Wind energy in cold climates (encompassing both low temperatures and icing climates) is expanding rapidly with an amazing 12 GW/year rate [1] equivalent of 4,000 large 3MW wind turbines. This large market has some special challenges especially regarding atmospheric icing conditions leading to ice accretion for wind turbines and low temperature effects on components. These markets are located all around the world and as an example please see this free online icing and low temperature map for more details. Ice accretion on turbine blades may cause severe production losses up to 20% of annual energy production, increase turbine mechanical loading and sound emissions from blades as well as increasing of ice throw hazards.

VTT has been coordinating an international expert group called IEA Wind Task 19 “Wind Energy in Cold Climates” since 2002 with the mission to enable large scale deployment of cold climate wind power in a safe and economically feasible manner. The purpose of this expert group is to gather and provide information about wind energy in cold climates, including project development, operation and maintenance (O&M), health, safety and environment (HSE), operational experiences, and recent research. The current Task 19 working period is January 2016 to December 2018. For more information, please go to:

Task 19 has recently published two very important documents:

The Available Technologies – report ed1 summarizes all key technologies available for cold climate wind energy applications ranging from listing available icing maps to icing weather models, ice detectors, turbines equipped with ice protection system (de- and anti-icing), ice throw assessment, operation and maintenance, standards and testing. This is the quickest way to find a solution to your icing or low temperature challenge in just a few minutes.

The Recommended Practices – report ed2 is basically an international pre-standard summarizing all best practices from numerous experts for development and operation of wind farms in cold climates. By reading this report, you will lower your risks and uncertainties substantially when developing or operating turbines in cold climate conditions.

Next in 2017–2018, Task 19 will focus on among others:

  • developing international ice throw guidelines
  • development of turbine ice protection system (anti- and de-icing systems) performance evaluation guidelines
  • and continue working with cold climate aspects for international standard IEC 61400-15 ed1 “Site energy yield assessment”

Stay tuned on Task 19 website for more!

 Ville Lehtomäki VTT

Ville Lehtomäki

Senior Scientist, Wind power

Operating Agent of IEA Task 19: Wind Energy in Cold Climates

Mobile: +358 50 370 7669