Wind farms can be part of our future energy mix assuming the cost of offshore turbine energy versus their efficiency can be made manageable. A new computer projection found a better way to arrange the turbines is a step in the right direction. A team from the University of Delaware found that staggering and spacing out turbines in an offshore wind farm can improve performance by as much as 33 percent.
The researchers used an existing offshore wind farm near Sweden as the basis for their study, comparing the existing tightly packed, grid-like layout to six alternative configurations. In some models, they kept the turbines in neat rows but spaced them farther apart. In others, they shifted the alignment of every other row, similar to how rows of theater seats are staggered to improve the views of people further back.
In their simulations, the team took into account the eddies, or swirls of choppy air, that wind turbines create downwind as their blades spin — and how that air movement would impact surrounding turbines. They found that the most efficient arrangement was a combination of two approaches. By both spacing the turbines farther apart and staggering the rows, the improved layout would decrease losses caused by eddies and improve overall performance by a third.
The optimal configuration had the rows oriented to face the prevailing wind direction, for example from the southwest in the summer along the U.S. East Coast. Most locations, however, have more than one dominant direction from where wind blows throughout the year. The optimal configuration for a season may not be optimal in another season, when the prevailing wind changes direction and intensity.
"Staggering every other row was amazingly efficient," said Cristina Archer, associate professor of physical ocean science and engineering and geography at the University of Delaware.
Considering these various factors could better inform where and how to configure future offshore wind farms, Archer explained.
"We want to explore all these trade-offs systematically, one by one," she said.
Last year, Archer and colleague Mark Jacobson of Stanford University ran a model and declared that wind turbines could power half the world's future energy demands with minimal environmental impact. In a follow-up to that study, Archer and Jacobson examined how worldwide wind energy potential varies seasonally. They found that in most regions where wind farms could feasibly be built on land and offshore, capacity is greatest from December to February.
However, even factoring in seasonal variability, the researchers found there is enough wind to cover regional electricity demand.
"I'm hoping these will be tools for giving a general overview of wind at the global scale," Archer said.
Published last month in Geophysical Research Letters