Exaggerated assertions that wind wakes are being greatly underestimated are both harmful and misleading – current models are capable of predicting these effects accurately, provided they are applied correctly.
The rapid growth of offshore wind energy has reignited discussions about wind wakes – a natural phenomenon where wind speeds decrease downstream of turbines and nearby farms.
Despite decades of development in wind wake modelling, some voices argue that these models are still flawed and fail to fully capture the extent and impact of wind wakes.
Developers could still face unforeseen wake losses and legal disputes over “wind theft”, but accurate modelling to support decision-making is available. This already helps to minimise potential losses and provides clear information to resolve legal disputes.
Debates of this nature are necessary and healthy, and wind wakes must be taken seriously – especially as the seabed fills with ever-larger turbines and projects. However, it’s imperative the sector avoids a sensationalist or one-sided narrative.
The reality of wake modelling is far more positive than some have stated, and the dominant reason for the existence of underestimates is the propensity for models to be incorrectly applied.
Far from being caught off guard, the offshore wind industry has been able to support confident financial decision-making by reliably modelling wakes for a long time.
Underestimates are largely down to outdated application of models
The application of wake models has been evolving alongside the wider wind industry since the early 1980s, when the first models were developed.
The complexity and significance of modelling wind wakes became more pronounced with the rise of large-scale offshore wind farms in the early 2000s, especially in the North Sea and Nordic coastal areas.
Recently, the increase in turbine and project size, and the need for greater efficiencies, have brought wakes into sharper focus, as illustrated by the complex conversations around blockage effect and long-distance wakes.
There’s no denying that calculating wind wakes is a complicated process that requires consideration of a plethora of factors, including turbine design, atmospheric physics and wind farm layout. Accounting for interactions between multiple offshore wind farms compounds the challenge further.
Wind wake modelling has had to evolve to maintain accuracy in this rapidly evolving environment – and at times this has led to high-profile under-predictions of the wake impact, leading to over-prediction of energy generation.
Increased data sharing key to further enhancing models
As the industry grows, and areas such as the North Sea become more populated with large-scale wind farms, we will need to ensure that models are continually refined to reflect the new reality. The models must also be validated using the most recent data from more diverse geographies.
To ensure large-scale validations can take place leading to continual and confident improvement of wind wake models, the industry should take the following steps:
- Increased data sharing Sharing energy production data from operational wind farms in different geographies is critical to enhancing accuracy and improving wake modelling. This will enable developers to compare real-world wake effects with model predictions, leading to better understanding and refinement of models. The industry will benefit from even greater energy yield accuracy, better wind farm layouts and designs that minimise the impact of wakes.
- Learning from high fidelity modelling techniques Reynolds-averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) models have been developed that will lead to improved wind wake modelling accuracy. For now they remain expensive resources, but continual investment in and development and testing of these new models will reduce their cost, bringing them closer to widespread adoption. In the meantime, learnings from the results of these models should be considered to ensure optimal application of current methods.
At a regulatory level, we need to ensure that frameworks are in place that protect developers and owners against wake losses from unforeseen future projects. While some legal mechanisms exist – such as wake loss agreements – a more comprehensive, global regulatory framework would ensure all parties are protected and compensated appropriately.
Wind wakes are just one of the constant technical challenges facing the offshore wind industry as it rapidly expands to hit net-zero targets. But the argument that it is not possible to accurately predict the impact of wakes with the readily available models is unhelpful and creates unnecessary worry across the industry.
By continuing to validate, carefully apply and build upon the strong models that we already have in place, we will ensure wind wakes continue to be accurately predicted and contribute to the offshore wind industry realising its full potential.
Written by Joel Manning, Innovation & Development Lead and Manager, Analysis Services at K2M. The full article was published in Recharge. For more information, visit:
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