Wind turbines can offer a double whammy in the fight against climate change.
In addition to using the wind to generate clean energy, turbines can help channel carbon dioxide into systems that extract the greenhouse gas from the air (SN: 8/10/21). The researchers say their simulations show that wind turbines can drag dirty air from above a city or smokestack into the wake of the turbines. This increases the amount of CO2 which reaches machines that can remove it from the atmosphere. The researchers plan to describe their simulations and wind tunnel test of a reduced system at a meeting of the Fluid Dynamics Division of the American Physical Society in Indianapolis on Nov. 21.
Tackling climate change will require drastic reductions in the amount of carbon dioxide that humans put into the air, but that alone will not be enough (SN: 3/10/22). One part of the solution may be direct air capture systems that remove some of the CO2 from the atmosphere (SN: 9/9/22).
But the large amounts of CO2 produced by factories, power plants and cities are often concentrated at heights that put them beyond the reach of machines on the ground that can remove them. “We’re looking at the fluid dynamics benefits of using wind turbine wakes to divert higher concentrations” to carbon capture systems, says mechanical engineer Clarice Nelson of Purdue University in West Lafayette, Indiana.
As large power-generating wind turbines spin, they create turbulence that pulls air down toward the waves behind them, says mechanical engineer Luciano Castillo, also of Purdue. It’s an effect that can concentrate carbon dioxide enough to make capture possible, especially near large cities like Chicago.
“That’s what beauty is [around Chicago], you have one of the best wind resources in the region, so you can use the wind turbine to take some of the dirty air in the city and capture it,” says Castillo. Wind turbines do not require the cooling that nuclear and fossil fuel plants need. “So not only are you producing clean energy,” he says, “you’re not using water.”
Deploying systems to capture the energy produced by wind turbines can also address the financial burden that often goes along with removing CO2 from the air. “Even with tax credits and the potential sale of CO2, there’s a huge difference between the value you can get from capturing it and the actual cost” that comes with powering the capture with energy that comes from other sources, Nelson says. “Our method would be an added benefit at no cost” to wind turbines.
There are probably many factors that will affect CO2 transport from turbines in the real world, including the interactions the turbine stirs up with water, plants and land, says Nicholas Hamilton, a mechanical engineer at the National Renewable Energy Laboratory in Golden, Colo., who was not involved in the new studies. “I’m interested to see how this group scales up their wind tunnel research experiment.”