Agrivoltaic layout types drive changes in raspberry summer microclimate

Zoë Scheerlinck^1,2James Macdonald³Cas Lavaert^4,5Jan Cappelle^4,5Stijn Scheerlinck³Jan Diels^2,6*Bram Van de Poel^2,7*Thomas Reher^2,7*

• ¹Molecular Plant Hormone Physiology, Division of Crop Biotechnics, Department of Biosystems, KU Leuven, Willem de Croylaan 42,, Leuven, Belgium
• ²KU Leuven Plant Institute (LPI), KU Leuven, Kasteelpark Arenberg 30, Leuven, Belgium
• ³ENGIE Research & Innovation - Laborelec, Solar Lab, Rodestraat 125, Linkebeek, Belgium
• ⁴KU Leuven Campus Gent ESAT - Electa, Gebroeders De Smetstraat 1, Gent, Belgium
• ⁵EnergyVille, Thor Park 8310, Genk, Belgium
• ⁶Department of Earth and Environmental Sciences, Division of Forest, Nature and Landscape, KU Leuven (University of Leuven), Celestijnenlaan 200E, Leuven, Belgium
• ⁷Molecular Plant Hormone Physiology, Division of Crop Biotechnics, Department of Biosystems, KU Leuven, Willem de Croylaan 42, Leuven, Belgium

Soft fruit such as raspberry (Rubus idaeus L.) are commonly cultivated under protective structures to shield plants from adverse weather and extend harvest periods. Agrivoltaic systems offer an alternative to disposable plastic hoop covers by combining crop cultivation with solar energy production, yet their effects on crop microclimate remain poorly understood in temperate regions. In this study, we investigated summer canopy microclimate responses to different agrivoltaic layouts at two raspberry production sites in the Netherlands. At the first site, we compared semi-transparent portrait panels and landscape opaque panels with a conventional polyethylene tunnel. At the second site, an opaque panel system was evaluated alongside an open-field control. We monitored photosynthetically active radiation, canopy air temperature, humidity, and vapor pressure deficit from July to late August and compared both daily averages and diurnal maxima and minima. Agrivoltaic structures substantially reduced incoming radiation, with semi-translucent panels providing more uniform light distribution than opaque arrays. Average daily canopy temperature differed little across treatments (≤0.5 °C), but distinct diurnal patterns emerged: opaque arrays consistently cooled around solar noon on high-radiation days (up to 0.5 °C cooler than control), while semi-translucent arrays occasionally induced midday warming of about 0.4 °C under wind-calm conditions. Vapor pressure deficit under polyethylene tunnels was more similar to agrivoltaic systems than to open-air plots. Wind and rainfall modulated the microclimate changes independently of PV layout. Our findings highlight within-season design-specific trade-off for summer conditions: opaque panels favor thermal buffering but reduce light uniformity, whereas semi-translucent panels improve spatial light distribution at the cost of limited buffering and occasional warming. Microclimate contrasts depended on panel material properties, and are consistent with differences in radiation balance arising from material properties and ground coverage ratio among polyethylene films, opaque panels, and semi-translucent modules. They provide initial evidence that agrivoltaic systems can offer microclimate moderation comparable to conventional plastic polytunnels, while simultaneously generating renewable energy.