The Global Blockage Effect in Offshore Wind (OWA GloBE) project is the latest joint industry initiative to be delivered under the Offshore Wind Accelerator and is designed to improve understanding of the true impact of the global blockage effect (GBE) by undertaking a first of a kind measurement campaign under real offshore conditions.
GBE is a phenomenon that occurs as a complex interaction between the wind farm and the atmosphere as the wind flows through, over and around large offshore wind farms. The effect is subtle, difficult to measure and hard to extract from legacy campaign data, therefore assumptions incorporated into performance calculations are impacted by existing magnitude and model uncertainties.
The OWA GloBE project is led by RWE with support from the Carbon Trust as part of the Offshore Wind Accelerator programme. The project consortium currently consists of six additional wind farm developers: EDF Renewables, EnBW, Equinor, ScottishPower Renewables, Shell and Vattenfall, along with research and industry partners DTU Wind Energy and Leosphere. The project budget, including in-kind contributions, is €3.9 million.
The OWA GloBE project centres around the planning, realisation and evaluation of a measurement campaign to be conducted in the second half of 2021, which is designed to assess the multiple aspects of the GBE at full scale and observe the atmospheric phenomena that drive it. The aim is to produce a dataset that can be used as the industry benchmark for assessing and quantifying the impact of the GBE on energy production.
The campaign will be conducted at the Helgoland windfarm cluster in the German Bight, at the Nordsee Ost and Amrumbank West wind farms which are both wholly-owned by RWE. The two wind farms are separated by a strip of empty seascape approximately 4km wide, known as the ‘Kaskasi gap’, in which RWE will construct the Kaskasi wind farm, anticipated to go online in 2022. This provides an opportunity to create a unique experimental setup for GBE using multiple remote sensing techniques, including dual doppler scanning light detection and ranging (LiDAR) measurements in combination with turbine production data. In addition, the combination of Nordsee Ost, Amrumbank West and the ‘Kaskasi gap’ is expected to concentrate the flow features that the project aims to observe.