Utah wind farm steers turbine wakes as a coordinated swarm to increase total energy across 165 machines
Across the high desert of Utah, there are 165 turbines in operation at the Milford Wind Farm in Beaver and Millard counties, with each turbine rotating within the vortex of turbulent wake created by its neighbors. Up until now, wind farms have worked under the assumption that each turbine functions independently and therefore should be optimized separately.
The engineers have turned the conventional understanding upside down, where the turbines talk to each other and change the angle of the rotor blades in order to shift the turbulent wake of each turbine away from the turbines that come behind it.
A farm that thinks as one
Although wake steering is not necessarily a novel concept, deploying it over an entire 165-turbine farm is something entirely new.
Milford Wind presently accounts for about $85.5 million in Utah business spending, including wages, subcontracts, and operational costs from both project phases.
Understanding how wake steering works requires one to understand what a wake actually entails. As soon as a rotor starts spinning, energy is being extracted from the incoming wind, and a cone of slower, more disturbed air is left behind. If another turbine finds itself within this cone, it will generate less energy because of poor airflow conditions.
Milford Wind turned out to be a perfect testing ground for the application of farm coordination principles. Not only because it is the first utility-scale wind farm constructed on federal land in the United States, but also because it is located in the high desert of Utah’s Beaver and Millard counties and has 165 turbines producing 306 MW of electricity.
The invisible traffic jam inside a wind farm
The physics of wake interaction are harsh. Even a perfectly optimized wind turbine could slash the production of a neighboring wind turbine by approximately 10–20% of power, depending on the wind speed, distance, and weather conditions. Such power loss accumulates when multiplied over multiple rows of wind turbines.
Classic control systems ignore this effect completely. Each wind turbine tries to produce maximum possible power, which makes sense until you consider that, in trying to do so, it actually reduces the power produced by all wind turbines after it. This phenomenon is similar to the situation with motorists driving on a highway who keep accelerating without looking in rearview mirrors, resulting in slower speeds for everyone else. Solving this problem for all 165 turbines is many orders of magnitude more difficult than optimizing just one of them.
Steering wakes like a coordinated swarm
Wake steering is achieved through slight yawing of the turbines from the flow angle of the incoming winds. The offset in angle causes deflection of the turbine wake; hence, the downstream turbine will receive clean and fast-moving wind compared to the turbulence experienced if it received the turbine wake.
In the case of the Milford site, there is a continuous calculation of optimal yaw offset at each of the 165 turbines within the wind farm depending on the live wind speed, direction, and the position of the individual turbines relative to other turbines in the wind farm.
Paradoxical as it may seem, the sacrifice of some amount of output by some of the upstream turbines helps increase the farm efficiency. From an individual perspective, the result is a loss, but mathematically the process is justified. The US Department of Energy’s Wind Energy Technologies Office has funded collaborative research in this area.
What the numbers reveal across 165 turbines
There is no sudden increase in efficiency for any one turbine. The incremental increases in efficiency that result from coordinated wake steering are minor, but when combined in an overall 306 MW array, they grow rapidly. Through the life of a wind farm project, small improvements in aggregate efficiency will yield large amounts of additional profit.
Milford Wind presently accounts for about $85.5 million in Utah business spending, including wages, subcontracts, and operational costs from both project phases. Phase I was completed in 2009 and included 204 MW and 97 turbines. Phase II came in 2011, bringing another 68 turbines and 102 MW to the project. Old technology, but made better without changing any physical aspect of it.
The gains come entirely from software and coordination logic—no new hardware, no new permits. Just a smarter control strategy applied to machines that were already spinning.
What Milford’s swarm strategy means for wind energy’s future
The conclusions of the study have implications far beyond the wind farm in Utah. There are thousands of existing wind farms globally whose common flaw is the optimization of each turbine alone and the silent energy lost because of wake interference. Without the need to build a single additional turbine, the swarm-coordination technology could be applied to a large number of such installations.
For DOE, such an approach seems highly promising. Working with the existing infrastructure to produce more energy from it fits perfectly into the bigger picture of the American policy on renewable sources and allows avoiding all problems associated with the long process of building new facilities, according to WindESCo, U.S. Department of Energy. For Utah, where more than 50% of the territory is owned by the federal government, the optimization of existing installations becomes particularly important before the next permit cycle starts.
The next step would be validation of the algorithm in different wind conditions and array geometries throughout all seasons. If the results confirm the efficiency of the algorithm, the case for adoption will become irrefutable. The turbines at Milford are already turning. The question is how many more farms will start thinking in swarms.
Kelly is an experienced writer with 15 years of experience exploring the big stories that shape our world, from tech breakthroughs and space exploration to climate, energy, and the fascinating quirks of science. She has a talent for turning complex ideas into sharp, memorable insights that stay with readers long after they’ve finished reading.
