Global Blockage Effect in Offshore Wind (GloBE)

Understanding how the wind flows through, over and around large offshore wind farms.

GloBE project

The Global Blockage Effect (GBE) has become a hot topic in offshore wind in recent years. While there is a broad industry consensus that the GBE causes decelerations in front of offshore wind farms which reduce the energy yield, different opinions exist on how to consider its downstream impacts and how to account for redistribution of energy, for example. This is commercially relevant as uncertainty in wind farm performance drives a high cost of capital for offshore sites. Any over estimation of the GBE leads to the de-valuation of offshore wind projects.

The GloBE project aims to:

  • Measure the decelerations and accelerations of the wind around the Heligoland windfarm cluster 
  • Understand their sensitivity to atmospheric parameters such as the height of the boundary layer
  • Test various hypotheses and modelling approaches against the measured data
  • Build an industry consensus around how blockage should be modelled and how the corresponding uncertainty should be assessed

This should allow offshore wind developers to reduce the uncertainties assigned to blockage effects, making it easier to finance the construction of new offshore wind farms.

Project status

The measurement campaign at the Kaskasi Gap has been completed and the data are in the final stages of being processed. Numerous model predictions have been produced by multiple parties, ready for blind validation against the measurements. Initial results were presented at the Wind Energy Science Conference in Glasgow on 24 May 2023. The slides are available online here.

Scheduled completion

November 2023


€5.9m including in-kind contributions

Lead Partner


RWE logo

EDF Renouvelables, EnBW, Equinor, Ørsted, Shell, ScottishPower Renewables, Vattenfall, Vaisala, the Technical University of Denmark, TotalEnergies, Ocean Winds, The Crown Estate

Globe partner logos
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Offshore Wind Accelerator (OWA)

Neil Adams

Neil Adams, Project Manager, 

Related news

Mar 2022 - OWA GloBE measurement campaign extended

Feb 2021 Offshore wind industry consortium gears up to conduct first of a kind full-scale measurement campaign focused on ‘Global Blockage Effect’