Long range lidar for short term wind predictions for offshore wind parks

A novel lidar prototype for horizontal Doppler wind measurements with more than 30 km maximum range is presented. The request for such long-range measurements arose from the development of methods for improved prediction of potential and actual feed-in of wind power from offshore wind farms in the project WindRamp. The target is a short-term prediction horizon of up to 30 minutes. The coherent lidar module is based on a robust fiber amplifier architecture developed within the project. This enables deployment in harsh environments in the future, e.g. at offshore wind farms. The emitted laser beam is eye save (class 1M). In order to emulate operating conditions of an offshore platform, the system was deployed at the mouth of the Elbe river at 10 m above sea level with unobstructed view in a broad SW-sector. Scans between 204 and 304 azimuth at 0.35 Elevation were performed. The averaging time was 1 s and the angular speed 0.6 s-1. The lidar performance is demonstrated by observations of wind fronts propagating through the observed area. The weather in North Germany during winter 2023/24 was characterized by unusual persistent precipitation, low hanging clouds and fog, which are unfavourable conditions for lidar operation. Therefore, the observed availability of valid data versus range represents a conservative estimate of the systems potential.