Off-shore Wind Mill Farms


During the different phases of the lifecycle of an off-shore windmill farm satellite data can provide valuable information about the environmental conditions found in a specific area. Examples of such information are listed below.

Morphology analysis - coastline dynamics
Before developing an off-shore windmill farm information about the coastal dynamics is needed in order to assess potential problems with sedimentation, environmental impact in the coast as a result of the wind farm construction etc. Coastline changes can be analysed approximately forty years back in time based on different remote sensing data sets. Recently declassified US spy satellite images provide a unique data source for information about the stability of coastal environments. When combined with modern high resolution satellite images, long time series of coastal development can be analysed. The processing of US spy data is relatively complex, but GRAS has expertise in processing these data sets for coastal monitoring in many parts of the world. Typically, 4-5 images from the period 1960 - present are included to produce coastal change maps with an accuracy of app. 15 metres. Recent years (1986 →) allows accuracies within 5 meters by using SPOT imagery and very high resolution data (2000 →) allows change mapping with accuracies of app. 1 meter, comparable to aerial photography.

Sediment distribution
The spatial and temporal distribution of sediment in the marine environment can be mapped by remote sensing. This information is important for environmental impact assessment of the shoreline and to assess sedimentation problems around the windmill structures. The sediment affects the reflectance pattern of the water and the different levels of reflectance registered by the satellite sensors can therefore be converted to a measure of the level of suspended matter in the water body. The presence of sediment in the water column is clearly visible in the full resolution MERIS image covering the Bristol Channel shown below.

Operational data for waterforecasting
In the planning, construction and maintenance phases of offshore wind farm operation it is important to be able to forecast ocean conditions such as sea level and wave height. Remote sensing data are important for validating these models and GRAS currently delivers validation input to the DHI Waterforecast. More information is available here.