If wind power and solar power are deployed on a large scale in the Sahara Desert in Africa, ideally, not only will it meet global energy needs, but it will also double the precipitation in the region and increase vegetation coverage by 20%. University of Maryland, University of Illinois, Beijing Normal University, Italian International Center for Theoretical Physics, an international team of scientists from the Institute of Atmospheric Sciences of the Chinese Academy of Sciences, conducted the results of dynamic climate simulation experiments. Related papers published in the early September 7th Beijing time in the top international academic journals On Science.
'This is an exciting result,' the first author of the paper, Dr. Li Wei from the University of Illinois, said in a press release that 'in order to alleviate global warming, the current renewable energy is not enough. Before, we are still worried. If such a large-scale renewable energy facility is built on the Sahara Desert, there will be any negative impact. The result is multiple benefits. 'He is about to join the Department of Geography of Beijing Normal University.
The study originated from a 'reverse thinking' by Li Wei at the University of Maryland tutor Eugenia Kalnay. Carney was the first female doctor of the Department of Meteorology at the Massachusetts Institute of Technology, and studied under the famous meteorologist Zhu. Jule Charney. In 1975, Charney proposed a mechanism to explain the drought in Sahel in the transitional region of southern Sahara: overgrazing increased ground reflectivity, reduced precipitation, and further Reduced vegetation coverage and formed a vicious circle.
Carney then thought of a reverse possibility: Large-scale photovoltaic panels would reduce the ground reflectivity, which would have the opposite effect.
Similarly, wind power installations will increase surface roughness, reduce wind speed, enhance air concentration and form updrafts, and increase precipitation. Precipitation promotes vegetation growth and reduces ground reflectivity.
The international team has established a dynamic meteorological model to calculate the interaction between atmospheric, terrestrial, vegetation, water cycle and other components, just like a weather forecasting system.
The model simulation results show that wind power construction will bring about an increase in regional temperature (+2.16K), and the average daily precipitation increases by 0.25 mm in the wind power coverage area, which is equivalent to double the precipitation in the entire Sahara region. Especially in the Sahel region, Daily average precipitation can increase by 1.12 mm.
Solar panels will also trigger similar albedo - precipitation - positive vegetation feedback mechanism, increasing daily average precipitation by about 0.13 mm.
When wind power and photovoltaic are built at the same time, the increase of precipitation can reach a maximum of 0.35 mm per day.
According to Li Wei, the biggest highlight of the study is the addition of dynamic vegetation feedback. In wind power experiments, the feedback effect of vegetation accounts for 80% of the simulated precipitation increase. Previously, the climate model that only considered static vegetation underestimated wind and solar energy. The impact of power generation on the climate.
The Sahara Desert is the largest desert in the world, sparsely populated, and wind and photovoltaic facilities do not occupy agricultural land. The area is highly sensitive to land changes. In addition, the Sahara Desert is located in Africa, close to Europe and the Middle East, and these regions are huge and growing. Energy demand. It is estimated that if the 9 million square kilometers of the Sahara Desert are fully covered by wind power and solar power, 3 terawatts (10 12 square watts) and 79 terawatts of electricity can be supplied each year, which can fully meet the present and future global. Energy demand.
In the simulation experiment, the increase of precipitation and vegetation caused by wind power and solar energy can greatly benefit the development of rainfed agriculture and livestock industry in this area. In addition, a large amount of clean energy generated can be used for seawater desalination and transportation to areas with severe fresh water scarcity. Thereby improving public health, expanding agriculture and food production, and bringing far-reaching social, economic and ecological impacts.
However, Li Wei emphasized that this is only an ideal model. In reality, there are many technical, economic, environmental and social challenges in building huge wind and solar power generation facilities, but the possibilities are gradually increasing.
The team also tried to perform similar simulations on other deserts around the world, but its climate impact was not as significant as that of Sahara. Li Wei explained that this may be due to the small size of other deserts, scattered distribution, and the need for more accurate models. However, there are still many uncertainties in the model itself, especially in the analysis of mesoscale weather processes and realistic small-scale wind power and solar effects.
