Big is beautiful: 12 MW wind turbines

Denmark makes good use of the wind resources. The Danish wind turbine industry has a 40 per cent share of the global market and employs more than 20,000 people, making it the world leader in wind power. Furthermore, some 20 per cent of our domestic electricity production comes from wind.

The development of wind power in Denmark is characterized by a close collaboration between publicly financed research and industry in key areas such as research and development, certification, testing, and the preparation of standards.

Wind power meteorology

The exact location of a wind turbine is critical to its overall energy production and actual lifetime. Research in fields such as turbulence, climatology, atmospheric flow and boundary-layer meteorology all contribute to the development of both physical models and calculation methods that are used for the prediction of a turbine’s production and lifetime.

Aeroelastic modelling

The design of a wind turbine and the choice of materials affect its lifetime as well as its safe operation and energy output. New physical and mathematical models, based on aerodynamics, structural dynamics and control, contribute to design improvements that will help extract maximum energy output from the wind. At the same time, any negative impact on the wind turbine itself or the surrounding environment must be kept to a minimum.

Optimisation and cost reduction

The economics of a wind turbine are increasingly dependent on the operational phase of its lifetime. We employ probabilistic design and modelling to map the operational uncertainties as well as optimise the operation and maintenance strategy. The main purpose of this work is to improve production revenue by reducing the number of stoppages and overall downtime.

New concepts, components and materials

The development of new materials, components and concepts produces new and improved properties, which in themselves accelerate technological development. For a long time now, the wind turbine sector has been focused on the reduction of weight and increase in strength of turbine blades. However, components such as the gear train and generator can also be improved further with the use of new materials.

Wind power and the energy system

The fluctuating nature of the wind poses a significant challenge to energy systems. By using simulation tools that are able to model wind turbines together with the overall system, we can study the impact of wind power on the energy system. We also analyse the control properties of individual wind turbines as well as entire wind farms, and we develop new concepts for modelling and controlling the entire electricity network.

Risø’s experimental electricity network, SysLab, has enabled us to work hands-on with a distributed energy system, which may be scaled up using simulation models, thus enabling us to gain valuable insight into real-life energy systems.

Offshore wind power

An ever increasing number of wind farms are being located offshore, where difficult access is an impediment to construction as well as operation and maintenance. Furthermore, the turbines themselves are exposed to harsh weather conditions in a very corrosive environment. Research fields such as geophysics and meteorology are employed when calculating the impact of weather conditions on offshore wind farms. Through this work, we aim to improve the reliability of wind turbines, thereby reducing the need for maintenance and repair.

Improvement of offshore winds and turbulence predictions based on available remote sensing equipment, wind and turbulence quantification, and modelling.

12 MW wind turbines: the scientific basis for their operational 70 to 270 m height offshore. The 12MW project runs in years 2005 and 2009 with funding from the Danish Research Agency, The Strategic Research Council, Program for Energy and Environment.

Wind turbine dimensions have evolved from rapidly 1980 to now. At the moment turbines up to 8 MW can be tested at Høvsøre Test Station, Risø. The size of commercial wind turbine design may grow to 12 MW. The very large turbines will be used offshore. This development puts a strong demand on our understanding of the atmospheric flow and turbulence characteristics at very high heights offshore.

Small turbines operate in the lower part of the atmospheric boundary layer. Here the logarithmic wind profile is valid and turbulence statistics are well known from offshore and coastal masts. Higher up winds are largely unknown due to severe practical offshore measurement difficulties.

The challenge is to improve our knowledge on offshore wind and turbulence characteristics for the next generation of multi-MW wind turbines that will come to operate at heights ranging from 70 to 270 m above sea level.

In the 12MW project we will improve offshore winds and turbulence prediction capabilities at these heights based on available new and proven remote sensing equipment, wind and turbulence quantification, and modelling.


The goal of the project is to experimentally investigate the wind and turbulence characteristics between 70 and 270 m above sea level and thereby establish the scientific basis relevant for the next generation of huge 12 MW wind turbines operating offshore. This will be done using state of the art wind remote sensing measurement techniques for data collection at an offshore wind farm site in Denmark.

The strategic aim is to supply the wind power industry relevant results.


To establish new wind and turbulence design models for the next generation of 12 MW turbines operating in the offshore marine environment from 70 to 270 m’s height. The design models will be evaluated from observations from Doppler Laser LIDAR, SODAR, backscatter aerosol LIDAR, radiosondes, ceilometer and satellite.


Risø National Laboratory, Wind Energy Department Charlotte Bay Hasager (PI), Torben Mikkelsen, Ioannis Antoniou, Rebecca Barthelmie, Sven-Erik Gryning, Hans E. Jørgensen, Ph.D. student Alfredo Peña

Elsam Engineering: Paul Sørensen


Pena, A.; Gryning, S.-E.; Hasager, C.B., LiDAR observations of offshore winds at future wind turbine operating heights. 2007 European offshore wind conference and exhibition, Berlin (DE), 4-6 Dec 2007. Unpublished. Paper available

Hasager, C.B.; Peña, A.; Mikkelsen, T.; Courtney, M.; Antoniou, I.; Gryning, S.-E.; Hansen, P.; Sørensen, P.B., 12MW Horns Rev experiment. Risø-R-1506(EN) (2007) 83 p.

Hasager, C.B.; Astrup, P.; Christiansen, M.B.; Nielsen, M.; Pena, A., Mapping of offshore wind resources. Meeting between a Taiwanese delegation and Wind Energy Department at Risø, Risø (DK), 11 Oct 2007. Unpublished. PowerPoint presentation available

Pena, A.; Hasager, C.B.; Gryning, S.-E.; Courtney, M.; Antoniou, I.; Mikkelsen, T.; Sørensen, P., Offshore winds using remote sensing techniques. International conference: The science of making torgue from wind, Lyngby (DK), 28-31 Aug 2007. J. Phys.: Conf. Ser. (2007) 75 , 11 p.

Peña, A.; Hasager, C.B.; Gryning, S.-E.; Courtney, M.S.; Sørensen, P., Evaluation of the offshore wind resource using LIDAR. EGU General Assembly 2007, Vienna (AT), 15-20 Apr 2007. Geophys. Res. Abstr. (CD-ROM) (2007) 9 (no.Abstr. EGU2007-A-11467)