Researchers Investigate Solar Panel and Olive Grove Synergies

Summary

Researchers from the University of Jaén and Sapienza University of Rome have pro­posed a method for installing solar pan­els in super-high-den­sity olive groves with­out harm­ing yield, uti­liz­ing the shade-tol­er­ant nature of olive trees. By opti­miz­ing the instal­la­tion of solar pan­els between olive tree rows at the appro­pri­ate height and angle, the researchers found that energy gen­er­a­tion could be max­i­mized while only result­ing in minor pro­duc­tiv­ity decreases for olive vari­eties.

Spain has long been syn­ony­mous with sun­shine and olive groves.

Perhaps unsur­pris­ingly, roughly one-fifth of Spain’s energy require­ments, about 25.54 gigawatts, come from solar power. Meanwhile, olive groves com­prise one-quar­ter of the country’s arable land, about 2.8 mil­lion hectares.

Land use con­flict has long been a point of con­tention between renew­able energy devel­op­ers and farm­ers, with solar pan­els tak­ing up vast amounts of space in rural areas.

Now, researchers from the University of Jaén in south­ern Spain and the Sapienza University of Rome have pub­lished a study in Applied Energy mod­el­ing the most effi­cient way to install bifa­cial solar pan­els in super-high-den­sity olive groves with­out harm­ing yield or qual­ity.

The team of agron­o­mists and engi­neers pro­posed olive trees as an ideal can­di­date since they are C3 plants, which require less light to pho­to­syn­the­size suc­cess­fully and are, there­fore, more shade tol­er­ant.

Despite mak­ing up three per­cent of the world’s olive-grow­ing sur­face area, the researchers said super-high-den­sity groves’ uni­form spac­ing and height allow for the most effi­cient instal­la­tion of solar pan­els.

The pho­to­syn­thetic and other genetic char­ac­ter­is­tics of Picual, Manzanilla and Chemlali olives, along with irra­di­ance and tem­per­a­ture data from a ​“typ­i­cal mete­o­ro­log­i­cal year” in Jaén, Spain, the world’s largest olive-grow­ing province, were used in the sim­u­la­tion.

The researchers con­cluded that south-fac­ing solar pan­els installed between olive tree rows at the appro­pri­ate height and the right angle can har­ness the energy of direct and reflected sun­light while allow­ing olive trees enough light to pho­to­syn­the­size.

Due to the need to har­vest super-high-den­sity groves mechan­i­cally, the researchers con­cluded that the solar panel instal­la­tion must be at least three meters tall.

Based on their mod­el­ing, the researchers deter­mined that solar pan­els installed between three and 4.5 meters at an angle between 20 and 40 degrees (depend­ing on the time of year) allowed the solar pan­els to har­ness as much energy as pos­si­ble and only resulted in minor pro­duc­tiv­ity decreases for all three vari­eties.

Along with opti­miz­ing land use to gen­er­ate elec­tric­ity and pro­duce olives, the researchers said the solar pan­els could improve olive grove effi­ciency by pow­er­ing irri­ga­tion pumps.

They added that the shade cre­ated by the angled solar pan­els has also been shown to retain soil mois­ture dur­ing the sum­mer and insu­late trees from heat waves and frost.

The study comes at an opti­mal moment for inter­ested olive farm­ers, as solar panel prices reached a record low of $0.11 (€0.10) per watt at the end of March, half of what it cost to pur­chase solar pan­els in March 2023.

“These find­ings can pro­vide guid­ance for future agri­v­oltaic projects involv­ing olive trees and con­tribute to the devel­op­ment of sus­tain­able and effi­cient dual land use in agri­v­oltaic setups,” the researchers wrote.

“However, exper­i­men­tal val­i­da­tion would be ben­e­fi­cial to ver­ify the mod­els using real crop yield data,” they con­cluded. ​“Such val­i­da­tion would not only assess model accu­racy but also under­score the poten­tial util­ity of the study.”

• PV Magazie
• FT