Global Blockage Effect in Offshore Wind (GloBE)

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

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

Budget

€5.9m including in-kind contributions

Lead Partner

RWE

Partners

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