Since falling ice fragments can be a security risk for the environs of the wind turbine, the authorities request measures to reduce the risk from icefall to an acceptable level. Thus, it is established in Austria to shut down wind turbines over the entire persistence of icing. However, falling ice fragments during de-icing of the turbine still present a potential security risk.
For the modelling of resulting ice-fall zones and an estimation of the energy losses from icing, site-specific information about the number and intensity of icing events is required.
As there is, also in the international context, only little experience on ice formation on rotor blades and on the properties of the falling ice pieces (size distribution, flight trajectories, falling distances), this project focused on the foundations and effects of wind turbine icing, with special consideration of the Austrian conditions. An important part were suitable measures and regulations, to ensure the observation of permissible risk limits in approval procedures of wind energy projects.
The project included of the following work packages:
- Modelling and provision of an icing map in a spatial resolution of 3x3km for the entire of Austria (ice accumulation on a 3cm standard cylinder, acc. to ISO 12494).
- Evaluation of the icing map using long-term wind turbine operating data and provision of a regional icing climatology for wind turbines with including average number, duration and intensity of icing events.
- Monitoring of icing events at wind turbines using an innovative imaging method to generate a data base in terms of number, size, distance and possible flight trajectories of falling ice fragments.
- Determination of ice-fall zones around the wind turbines through modelling of the falling trajectories of the ice fragments.
- Development of scientifically based measures and policies for possible further reduction of the ice fall ice-fall, in collaboration with law experts and technical experts.
Project duration: April 2016 to June 2019