Wind and Solar Projects Could Turn the Sahara GreenPosted on September 7, 2018
The effects of large scale wind and solar installations have the potential to change the local climate dramatically, scientists researching the effects say that massive wind turbine and solar panel projects installed in the Sahara Desert could turn the arid landscape “green”. The installation of huge numbers of turbines and panels would have an incredible impact of rainfall, temperatures and vegetation – doubling the amount of rainfall in the region would transform the Sahara region.
Meeting Global Demand
Dr Yan Li from the University of Illinois and his team used simulation to predict the impact and implications of huge scale energy projects in the Sahara, covering 9 million square kilometres of land. “We want to investigate if we build such large wind and solar farms in the Sahara that can provide enough clean energy to meet all human energy demand, what their impact on regional climate would be,” Dr Li said in the study. "Our model results show that large-scale solar and wind farms in the Sahara would more than double the precipitation, especially in the Sahel, where the magnitude of rainfall increase is between 20mm and 500mm per year… As a result, vegetation cover fraction increases by about 20%."
The Sahara Desert in northern Africa was chosen by the researchers due to its sparse population, exposure to the sun and winds as well as its proximity to large energy markets in Europe and the Middle East. The study showed that a massive installation in the desert could generate more than four times the amount of energy than is currently used globally, each year.
Local Climate Change
Wind turbines mix warmer air from above with cooler currents below, which creates a feedback loop leading to increased precipitation. Solar panels reduce the reflection of sunlight back into the atmosphere, known as the Albedo Effect – triggering a positive albedo-precipitation-vegetation feedback, leading to rainfall increases of about 50%. Dr Li explains:
"Wind farms increase surface roughness and therefore increase wind converging into low-pressure areas. The converging air has to rise, making it cool off and moisture condense, which will lead to increased rainfall… The panels directly reduce the surface albedo which leads to more solar energy absorption and surface warming, which in turn strengthens the Saharan heat low, leading to more rising air and precipitation.”
The study suggests these monumental changes to the local environment would have a positive impact on the local population, and addressed the “intertwined sustainability challenges of the energy-water-food nexus in this region.”
If policy makers were to adopt such an ambitious project, it would take the cooperation of several governments and many companies, and likely take decades to complete. It would be a monumental achievement that could make an incredible change to the lives of millions of people and the future of our planet.
Read the full study, published in the journal Science.