Wake loss limits value of wind turbines 

Mulling a problem with the positioning of wind turbines and the production decrease resulting from the turbulence within wind farms, the question has arisen whether they will ever be as valuable a contributor to the electric grid as they were originally hyped to be.

The turbulence cuts production by 30-35 percent of what would it be if the turbines were more cannily spaced and it is said to be an issue of computational fluid dynamics that was not understood when the wind farms were built.

Waco economist Ray Perryman and Odessa oilman Kirk Edwards say the problem is challenging.

“This issue has been around for several years,” Perryman said. “Ongoing research and new information is quite promising and may lead to improvements in wind farm design which can decrease turbulence and thus increase predictable electric power production in the future.

“Having said that, the farms currently in place are an important component of Texas electric generation. In fact there are times when wind is the leading source of electricity for the Electric Reliability Council of Texas. It can even provide all the power on the grid on mild spring and fall days.”

Even in August, Perryman said, wind and solar power comprised more than 25% of the net electricity generated in ERCOT.

“The major concern with wind power as well as solar is the unavoidably intermittent nature of production,” he said. “We remain a long way from having sufficient battery capacity or other storage mechanisms in place to meet demand at times when the wind isn’t blowing and the sun isn’t shining.

“As a result there will be a need for sufficient baseline capacity which uses conventional fuels, primarily natural gas, for the foreseeable future.”

Perryman said wind power clearly has an important role to play and the more effective future wind farm design can be the more helpful wind will be as a source of electric power to serve the growing population and economy of Texas.

“As demand accelerates with the increase in AI, data centers, chip plants, crypto mining and other power-intensive activities, the demand for power is expanding rapidly,” he said. “An ‘all of the above’ strategy to meet energy needs is essential.”

Edwards said the hidden problems of wind farms can no longer be ignored.

“Texas was an early pioneer in large-scale wind power,” he said. “Those first-generation West Texas wind farms helped put our state on the national map for renewable energy.

“But as the industry has matured so have the challenges and many of the problems built into those early projects are still with us today.”

Edwards said one of the most significant issues is something called “wake loss.”

“When wind turbines are placed too closely together each machine creates turbulence that slows and disrupts the airflow for the next one,” he said. “In some Texas wind farms, particularly the older ones, these wake losses can approach 30–35% of the power that would otherwise be produced.

“The physics were understood, but the computational tools to accurately model turbine interactions simply didn’t exist two decades ago. As a result we’re left with farms whose layouts permanently limit their performance.”

Edwards said retrofitting them is impractical and moving massive towers spaced across thousands of acres is uneconomic.

“Newer wind developments, especially offshore, are better optimized,” he said. “With modern modeling and far more land or sea room developers can space turbines more effectively and reduce internal losses.

“But that doesn’t solve the other issues facing Texas like local ‘not in my backyard’ opposition, environmental impacts and the long-term land obligations that remain unresolved.”

Edwards said bird and bat mortality around turbines is still a hot button concern.

“Even more troubling is the looming question of end-of-life cleanup,” he said. “These towers and blades will not last forever and decommissioning them will require heavy equipment, specialized disposal and millions in remediation costs.

“In the oil and gas industry operators must post bonds and carry long-term liabilities to ensure that sites are restored. The wind industry has no such statewide mechanism and that bill will come due.”

Edwards said the challenges that these intermittent resources create for the Texas electric grid also cannot be ignored.

“Transmission capacity is finite,” he said. “When wind farms occupy significant grid space only to deliver little or no power on the hottest or coldest days exactly when Texans need electricity the most, that capacity is effectively stranded.

“It could have been used for 24/7 dispatchable generation like natural gas, coal or nuclear power. Wind can contribute to our energy mix, but it cannot replicate the reliability of those baseload resources.”

Noting that Texas has always been pragmatic about energy, Edwards said honest conversations are needed as the state looks to the future about the real limitations of wind power and the long-term liabilities and importance of keeping dependable generation at the center of the grid.

“Renewable energy has a role to play, but reliability, responsibility and transparency must come first,” he said.