Optimal size: wind farm efficiency drops as installations become bigger. (Courtesy: iStock/ssuaphoto)
Topics: Alternate Energy, Climate Change, Existentialism, Global Warming, Green Tech, Thermodynamics
Optimizing the placement of turbines within a wind farm can significantly increase energy extraction – but only until the installation reaches a certain size, researchers in the US conclude. This is just one finding of a computational study on wind turbines’ effects on the airflow around them, and consequently the ability of nearby turbines – and even nearby wind farms – to extract energy from that airflow.
Wind power could supply more than a third of global energy by 2050, so the researchers hope their analysis will assist in better designs of wind farms.
It is well known that the efficiencies of turbines in a wind farm can be significantly lower than that of a single turbine on its own. While small wind farms can achieve a power density of over 10 W/m2, this can drop to a little as 1 W/m2 in very large installations The first law of thermodynamics dictates that turbines must reduce the energy of the wind that has passed through them. However, turbines also inject turbulence into the flow, which can make it more difficult for downstream turbines to extract energy.
“People were already aware of these issues,” says Enrico Antonini of the Carnegie Institution for Science in California, “but no one had ever defined what controls these numbers.”
Optimal size for wind farms is revealed by computational study, Tim Wogan, Physics World