Large-Scale Wind & Solar Development Could Reshape The Sahara 

A new study published this week has revealed the possibility that large-scale development of wind and solar in the Sahara Desert could result in increases to local temperature, precipitation, and vegetation, resulting in overall beneficial environmental changes.

Researchers from the University of Illinois and the University of Maryland published a new article in the journal Science this week entitled Climate model shows large-scale wind and solar farms in the Sahara increase rain and vegetation which reveal the results of a climate-modelling study focused on the development of large-scale wind and solar in the Sahara Desert. Based on the premise that wind and solar farms are known to have local effects on heat, humidity, and other facts that may be beneficial or detrimental to the regions in which they are situated, the new study is among the first to model the impact large-scale wind and solar development has on the local climate and vegetation.

“Previous modeling studies have shown that large-scale wind and solar farms can produce significant climate change at continental scales,” said lead author Yan Li, a postdoctoral researcher in natural resources and environmental sciences at the University of Illinois. “But the lack of vegetation feedbacks could make the modeled climate impacts very different from their actual behavior.”

The researchers — including Eugenia Kalnay and Safa Motesharrei at the University of Maryland — focused on the Sahara Desert for several reasons, according to Li: “We chose it because it is the largest desert in the world; it is sparsely inhabited; it is highly sensitive to land changes; and it is in Africa and close to Europe and the Middle East, all of which have large and growing energy demands.”

The study simulated capacity well above what is needed, including 3 terawatts (TW) of wind and 79 TW of solar. “In 2017, the global energy demand was only 18 terawatts, so this is obviously much more energy than is currently needed worldwide,” Li said, but the model revealed that wind farms at such levels caused regional warming of near-surface air temperature, with greater changes in the minimum temperatures than in maximum temperatures. “The greater nighttime warming takes place because wind turbines can enhance the vertical mixing and bring down warmer air from above,” the authors explained.

The model showed that precipitation also increased by as much as 0.25 millimeters per day on average in regions with wind farm installations, “a doubling of precipitation over that seen in the control experiments,” said Li.

The increase in precipitation also created benefits in the Sahel — the region between the Sahara and the Sudanian Savanna — with average rainfall increasing by 1.12 millimeters per day, which “in turn, leads to an increase in vegetation cover, creating a positive feedback loop,” according to Li.

Solar farms had a similarly positive impact on temperature and precipitation. “We found that the large-scale installation of solar and wind farms can bring more rainfall and promote vegetation growth in these regions,” explained Eugenia Kalnay from the University of Maryland. “The rainfall increase is a consequence of complex land-atmosphere interactions that occur because solar panels and wind turbines create rougher and darker land surfaces.”