For wind farms, a bit of separation is a good idea
Putting facilities too close together reduces overall efficiency, research finds. Samantha Page reports.
The wake from a wind farm can extend 50 or more kilometres, potentially costing downwind farms millions in revenue.
That’s according to a new case study appearing in the journal Nature Energy that analyses the impact of an upwind farm in Texas, US, on its downwind neighbour. The research reveals that the downwind farm produced 5% less energy on average because of the wake from the upwind facility, decreasing revenue between 2011 and 2015 by up to an estimated $3.7 million.
“Using two different scientific techniques, we demonstrate that wind farm wake effects are real, discernible and arise from clearly understood physical processes,” write the authors, led by Julie Lundquist of the University of Colorado, Boulder, in the US.
“These differences in wind power generation due to wakes have significant economic and environmental impacts.”
In addition to the lost value of the generated power, the downwind farm offset roughly 111,000 fewer tonnes of carbon dioxide between 2009 and 2016 than it would have if it were not in the wake of the upwind farm.
Wind farms are generally built along wind corridors and in close proximity to major transmission lines, the authors write, which increases the likelihood for overlapping wakes.
Wind energy has grown significantly in the past decade. For instance, 10 years ago in the US it accounted for less than 1% of electricity generation. In 2016, it topped 6%.
That growth has come with a significant financial investment. According to the American Wind Energy Association, developers in the US have spent more than $145 billion on projects over the past decade.
As the authors note, regulation over wind wakes from wind farms is non-existent in the US, despite the clear financial implications. They call for additional study and public policies that could help prevent legal complications in the future.
“The failure to recognise the issue and predictably provide solutions for conflicts may raise the cost of wind energy and thereby slow development,” they write.
“Given ongoing increases in global wind development, we highlight the need to understand physical, economic and legal interactions between wind farms to ensure sustainable development and stewardship of wind resources.”