Sim­u­la­tion prom­ises rain for the Sa­hara

So­lar and wind farms could bring water and green­ery to this gi­ant desert

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With its blis­ter­ing sun­shine and strong winds, the Sa­hara at­tracts nu­mer­ous en­ergy pro­jects, but new re­search sug­gests that these wind and so­lar farms are do­ing more than just pro­duc­ing clean re­new­able en­ergy. “We found that the large-scale in­stal­la­tion of so­lar and wind farms can bring more rain­fall and pro­mote veg­e­ta­tion growth in these re­gions,” ex­plains Eu­ge­nia Kal­nay from the Univer­sity of Mary­land, US. “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.” A mod­el­ling tech­nique has re­vealed that the en­vi­ron­ment around the tur­bine blades and so­lar pan­els may be trans­formed, which could more than dou­ble rain­fall in the area. “As a re­sult veg­e­ta­tion cover in­creases by about 20 per cent,” says the first au­thor of the study, Yan Li. “This in­crease in pre­cip­i­ta­tion in turn leads to an in­crease in veg­e­ta­tion, creat­ing a pos­i­tive feed­back loop.” The trans­for­ma­tion is a re­sult of the tur­bines con­tribut­ing to the mix­ing of heat in the at­mos­phere by push­ing the warmer air down to the sur­face and in­creas­ing land sur­face fric­tion, which leads to a higher chance of rain. So­lar pan­els also re­duce the amount of light re­flect­ing from the desert, fur­ther in­creas­ing the like­li­hood of rain­fall. The sim­u­la­tion was based on a so­lar farm about the size of the United States built along­side wind tur­bines cov­er­ing around 20 per cent of the Sa­hara. If a project of this size was es­tab­lished, it would mean not only the green­ing of the desert but also the pro­duc­tion of sig­nif­i­cant amount of green en­ergy.

The Sa­hara en­gulfs most of North Africa, cov­er­ing ap­prox­i­mately 9.4 mil­lion square kilo­me­tres

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