OWA GloBE: Global Blockage Effect in Offshore Wind

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 its redistributive effect. 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 has succeeded in:

Measuring the decelerations and accelerations of the wind around the Heligoland windfarm cluster
Understanding their sensitivity to atmospheric parameters such as the height of the boundary layer
Testing various hypotheses and modelling approaches against the measured data
Building an industry consensus around how blockage should be modelled

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

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