The new, open-source framework was developed through a study by academics from the University of British Columbia’s (UBC) Okanagan campus in Kelowna, Canada, and Delft University of Technology (TU Delft) in the Netherlands.
The study is titled ‘Tosca – an open-source, finite-volume, large-eddy simulation (LES) environment for wind farm flows’, with Tosca standing for ‘toolbox for stratified convective atmospheres’ (eddies are fluid, often circular currents that differ from the primary flow of wind or water).
It built on existing research by feeding new modelling into a supercomputer, which then performed myriad calculations looking at how both typical wind farms and a theoretical ‘infinite’ wind farm interacted with various wind conditions.
One of the key factors explored in the study was how large wind farms created a “blockage” of wind — slowing it down before it interacted with the wind farm and thus reducing the amount of energy it was expected to produce.
“A large wind farm will slow down the oncoming wind even before it reaches the wind farm. [This] blockage has been significantly underestimated because the design tools used by wind farm designers neglected the interactions that may occur between the wind farm and the atmosphere. As a result, wind farms may produce less power than expected when they were designed,” explained Joshua Brinkerhoff, lead researcher on the project and associate professor at UBC's Clean Energy Research Centre.
“Our study presents a new software tool that is specifically tailored to accurately capture the interaction of wind farms and the atmosphere, forming a basis for designing more productive wind farms,” he said.
Overestimation over?
The new framework could have various beneficial applications in the wind industry, not least in the persistent problem of overestimation, which continues to blight forecasting and finances for the owners and operators of wind energy projects.
In 2019, Danish utility Ørsted admitted it overestimated output from its portfolio, its former chief technical officer Marianne Wiinholt describing overestimation as an "industry-wide issue".
Earlier this month, UK energy regulator Ofgem said it was investigating after a report by Bloomberg suggested various wind farm owner-operators in the UK were routinely overestimating their output, effectively costing consumers millions of pounds unnecessarily.
The Bloomberg report did not establish conclusively whether the detailed overestimations were deliberate or unintentional.
Nevertheless, the more accurate forecasts possible with the new framework Brinkerhoff and his team developed – which was constructed using a "supercomputer" that “consists of more 10,000 processors” – could reduce the chance of any overestimation due to inaccurate data.
“Our study presents a new research tool that more accurately captures blockage losses in wind farms. Using this research tool, my team is developing new engineering models that developers and operators can use to ensure that blockage effects are accurately estimated in new or existing projects,” Brinkerhoff said.
“This will ensure forecasts of wind power of new wind farms are as accurate as possible,” he added.
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