Experts at DNV GL warned last year that ‘blockage effects’ – one of the factors cited by Orsted in its downgrade of long-term offshore wind production forecasts – were being ignored, skewing forecasts on the upside.

A paper from the global energy group on efforts to better understand the impact of blockage effects said dynamic flow modelling to date has almost exclusively concentrated on wake effects between turbines.

Blockage effects – where wind slows in front of a turbine – are tougher to observe and measure, said DNV GL in a 2018 paper on the topic.