Field Assessment of Vertical Bifacial Agrivoltaics with Vegetable Production : A Case Study in Lahore, Pakistan

Akbar, Asfandar and Mahmood, Farrukh and Alam, Habeel and Aziz, Farhan and Bashir, Khurram and Butt, Nauman Zafar (2024) Field Assessment of Vertical Bifacial Agrivoltaics with Vegetable Production : A Case Study in Lahore, Pakistan. Renewable Energy, 227: 120513. ISSN 0960-1481

Abstract

Sustainable energy and food production face significant challenges due to the increasing population, land-use conflicts, and rapidly changing environmental conditions. Coupling solar energy and food production on the same land (Agrivoltaics; AV) could revolutionize the sustainable food-energy nexus and the land ecosystem. We explore a vertical AV system in Lahore using bifacial modules and vegetables, including okra, calabash, and potato, which is the 1st field assessment of AV in the semi-arid climate of Pakistan. Food-energy performance and microclimate were monitored across multiple seasons for the AV system having 10.5 kW nominal power capacity covering a land area of ∼85 m2. Results were compared with reference systems, including an adjacent full sun crop treatment and a nearby rooftop photovoltaic (PV) system of matched capacity installed at a standard south-tilted orientation. Crop rotation includes okra and calabash, which were grown in summer, and potato in the winter. The net biomass AV yield for okra and calabash was reduced by 15.97 % and 38.17 %, respectively, while potato yield increased by ∼8.7 % relative to the corresponding yield in the control treatment. The annual energy production for the vertical bifacial AV system was reduced by ∼25 % compared to the rooftop PV system, which is attributed mainly to the difference in their tilt and orientation. The microclimate measurements showed 26 % more soil moisture and 0.5 °C reduced air temperature for AV treatment relative to the control, demonstrating potential synergies between solar energy and crops. The soiling measurements at the AV and rooftop locations showed 1.9 % and 1.5 % daily energy loss due to the dust effect. These results indicate that AV systems offer sustainable solutions for the food-energy nexus to cater to the demands of the expanding cities.