Novel Insights into Variations of Wind Energy with Implications for Policy and Engineering

On specific windy days, for instance, surges in power released by wind turbines have been known to overwhelm the electronic grid, leading to power outages. To avoid this, operators of giant power plants sometimes resort to offer consumers to utilize electricity on specific windy and sunny days when there is too much excess power in the system, for balancing the demand and supply of energy at the grid.

Dealing with the troughs and peaks of intermittent renewable energy will become greatly challenging as governments attempt to phase out of more stable coal-powered energy sources in the coming decades, for mitigating or managing these variations better. Lecturer Mahesh Bandi, a leading member of the Collective Interactions Unit as the Okinawa Institute of Technology and Science Graduate University has used turbulence theory linked with experimental wind plant information to explain the statistical nature of wind power variations.

Wind speed patterns can be analysed as a wind speed spectrum on a graph. In 1941, the Russian scientists Andrei Kolmogorov worked out the spectrum of wind speed variations. It was revealed that the spectrum for wind power is based on the exact same pattern. But till now, it was simply assumed that such spectra were similar due to the relationship between speed and power, where power equals speed of wind cubed. But this proved to be a red herring. Lecturer Bandi has shown for the very first time that the spectrum of wind power variations is based on similar pattern as the wind speed fluctuations for a distinct reason.

Kolmogorov’s 1941 results apply to estimates of wind speed made at multiple distributed points in space at the same time. But wind power variations at a turbine are estimated at a fixed location over an elongated time period. The two estimates are basically distinct, and by meticulously accounting for such difference, Lecturer Bandi was able to explain the spectrum of wind power variations for a single turbine.

“Comprehending the nature of variations in wind turbine power has instant implications for political and economic decision making,” says Lecturer Bandi.

Due to variations of renewables, coal-fired power plants offering back-up energy is kept operating in case of unexpected power outages, implying that more energy is released than required. It implies that ‘green’ energy is still contributing to carbon based emissions, and there is a linked expense of maintaining reserve energy that will just boost the proportion of renewable increases in the years to come