New Understanding of Wind Farm Efficiency

Trinity postgraduate Andrew Kirby has published a paper investigating the power produced by large offshore wind farms. The article, published in the Journal of Fluid Mechanics, provides new insights into the aerodynamics of large wind farms.

Wind energy will play a key role in meeting the world’s energy demands while mitigating climate change. However, predicting the power produced by large wind farms is very difficult. When wind turbines are placed together in wind farms they produce less power than in isolation.

Andrew Kirby says: ‘The commonly observation reduction in power is due to two different effects: firstly, there is a wake behind every turbine with a reduced wind speed. When these wakes affect other turbines, it can reduce the farm power by up to 40%. Secondly, the farm power can be reduced by the farm interacting with the atmosphere and slowing the wind. Both industry and academia struggle to model these two effects accurately. This uncertainty makes wind farm projects more expensive to finance.’

‘Our paper proposes new concepts to better understand the impact of these two effects. We found that for large wind farms the interaction with the atmosphere was the most important. This is contrary to the approach taken by the wind energy industry and suggests that large wind farms should be designed differently in the future.’

This work was carried out in collaboration with the UK Met Office. The article was recently featured in the ‘Focus on Fluids’ series, where one particularly interesting article is reviewed and discussed each month by a recognised expert.