Renewable energy sources such as solar and wind power reduce humans' dependence on fossil fuels. This is an attempt to curb carbon emissions. A new study now shows that if solar panels and wind turbines are built on a large scale in the desert, it will bring additional rainfall to the local area and promote the growth of desert vegetation.
The lead author of the study is Yan Li, a postdoctoral researcher at the University of Illinois at Urbana-Champaign. The team used computer simulations to predict that if solar plants and wind farms were built on a massive scale in the Sahara Desert and the Sahel region (Reference 1), these equipment would be able to change surface albedo of sunlight and air flow, triggering a climate feedback loop. Within about 4,500 years, some of the arid landscapes will become green.
There are reasons for picking up this place for simulation research. The researchers believe that this is a reasonable place to promote renewable energy on a large scale. Firstly, it is quite close to Europe and Middle East countries where there is a huge amount of energy demand. Secondly, whether it is to install wind or solar energy equipment, natural resources (wind or sunshine) are quite abundant.
However, the scale of hypothetical solar farms and wind farms in the study is very large, equivalent to 38 times of the UK's land area (more than 9 million square kilometers). For the simulation in this area, 90 meters high wind turbines are densely built up. Solar panels cover more than 20% of the total area. The power output are about 82 terawatts (TW). This amount of power is far more than the current global energy demand (18TW was the global energy demand in 2017). This enormous scale doesn't match any existing large-scale renewable energy case.
After setting the data of this super large solar and wind power generation field, researchers have input the data into a complex computer program that simulates the Earth's dynamic climate, predicting how the power farm will change the local environment.
Photo credit: University of Illinois at Urbana-Champaign
The simulation shows that the wind farms will mix the warmer air from above with cooler air below. Thus, the land surface temperature will increase at night. Solar panels are responsible for reducing sun reflections. In the end, the two equipment will increase the local rainfall by a factor of 1.5 and the average daily rainfall will escalate to 0.59 mm. Research co-author Safa Motesharrei, from University of Maryland’s Department of Atmospheric and Oceanic Science, said that increased rainfall will promote vegetation growth, reduce the amount of sunlight reflected on the desert surface, increase livestock production, and create a cycle of positive climate feedback.
This research is very interesting, but to realize it, there will be a lot of challenges. The desert landscape is desolate but still culturally valuable. Whether the local countries will support this idea with policies and can export the green electricity to Europe and the Middle East is the biggest problem. The new paper was published in the journal "Science".
Reference 1: Sahel (French: sahel, meaning "marginal") is a narrow strip of more than 3,800 kilometers between the Sahara Desert and the Sudanese grasslands region, spanning nine countries and including Senegal, Mauritania, Mali, Burkina Faso, Niger, Nigeria, Chad, the Republic of Sudan and Eritrea.
(Article by TechNews; Image credit: Pixabay)
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