The majority of CO2 produced by humans is present in high concentrations in the atmosphere. Turbines could direct it to the ground for disposal.
Wind turbines have the potential to provide a double whammy in the fight against climate change.
Aside from harnessing the wind to generate clean energy, turbines may aid in the removal of carbon dioxide from the atmosphere (SN: 8/10/21). According to the researchers' simulations, wind turbines can drag dirty air from above a city or a smokestack into their wake. This increases the amount of CO2 that reaches machines capable of removing it from the atmosphere. On November 21, the researchers plan to present their simulations and a wind tunnel test of a scaled-down system at the American Physical Society's Division of Fluid Dynamics meeting in Indianapolis.
Addressing climate change will necessitate drastic reductions in the amount of carbon dioxide that humans emit into the atmosphere — but this alone will not suffice (SN: 3/10/22). Direct air capture systems that remove some CO2 from the atmosphere could be part of the solution (SN: 9/9/22).
However, the large amounts of CO2 produced by factories, power plants, and cities are frequently concentrated at heights beyond the reach of ground-based machinery that can remove it. "We're looking into the fluid dynamics benefits of using the wake of the wind turbine to redirect higher concentrations" down to carbon capture systems, says Clarice Nelson, a mechanical engineer at Purdue University in West Lafayette, Indiana.
According to Purdue mechanical engineer Luciano Castillo, as large, power-generating wind turbines rotate, they create turbulence that pulls air down into the wakes behind them. It's an effect that can concentrate carbon dioxide to the point where capture is feasible, especially near major cities like Chicago.
"The beauty is that [in the Chicago area], you have one of the best wind resources in the region, so you can use the wind turbine to capture some of the city's dirty air," Castillo says. Wind turbines do not require the cooling required by nuclear and fossil fuel plants. "You're not only producing clean energy," he says, "but you're also not using water."
Running the capture systems on wind turbine energy can also alleviate the financial burden that often comes with removing CO2 from the atmosphere. "Even with tax credits and the possibility of selling the CO2, there's a huge gap between the value that you can get from capturing it and the actual cost" of powering capture with energy from other sources, Nelson says. "Our method would be a no-cost added benefit" to wind turbine farms, according to the researchers.
According to Nicholas Hamilton, a mechanical engineer at the National Renewable Energy Laboratory in Golden, Colorado, who was not involved in the new studies, "there are probably a lot of factors that will impact CO2 transport by real-world turbines, including the interactions the turbine wakes have with water, plants, and the ground." "I'm curious how this group scaled their experiment for wind tunnel testing."
C. Nelson. On carbon entrainment in the wind turbine wake. American Physical Society Division of Fluid Dynamics meeting, Indianapolis, November 21, 2022.
A.E. Moser. Experimental study of CO2 capture in a model wind turbine array. American Physical Society Division of Fluid Dynamics meeting, Indianapolis, November 21, 2022.