Published on August 16th, 2016 | by Joshua S Hill0
Winds At Cape Wind Could Be “More Powerful, Turbulent Than Expected”
August 16th, 2016 by Joshua S Hill
Researchers at the University of Delaware have concluded in a new report that the offshore winds in the waters of the northeastern United States might be “more powerful, yet more turbulent than expected.”
The findings were published in the Journal of Geophysical Research: Atmospheres earlier this month in an Open Access article available to the public to read. Led by Cristina Archer from the University of Delaware and Brian Colle at the Stony Brook University, the study analyzes historical data from 2003 to 2011 and collected data from 2013 to 2014 at the Cape Wind tower located near the center of Nantucket Sound off the coast of Martha’s Vineyard.
The authors note that their findings could have important ramifications for the future development of offshore wind farms off the northeast coast of the US, including assessing how much wind power can be produced, what types of turbines should be used, and how many turbines can or should be installed and the necessary spacing between each turbine.
The primary findings from the report are that atmospheric conditions around Cape Wind “are predominantly turbulent, or unstable” — quite unlike data collected from European offshore wind farms in the Baltic Sea and the North Sea. In fact, similar European studies into wind conditions in the Baltic and North Seas show conditions are predominantly neutral — which is to say, neither too windy nor too still, a Goldilocks porridge of wind conditions.
“By contrast, our study found that wind conditions at Cape Wind are unstable between 40 and 80 percent of the time, depending on season and time of day,” explained Archer.
“The advantage of these turbulent conditions is that, at the level of the turbines, these bumps bring high wind down from the upper atmosphere where it is typically windier,” Archer continued. “This means extra wind power, but that extra power comes at a cost: the cost of more stress on the turbine’s blades.”
But the increased turbulence will result in necessary changes to the development and design of wind farms in such locations.
“If you have increased turbulence, you’re going to design a different farm, especially with regard to turbine selection and spacing,” Archer adds. “And guess what? Even the wind turbine manufacturing standards are based on the assumption of neutral stability.”