Abstract
The cultivation of the horticultural crops inside photovoltaic greenhouses (PVG) should be studied in relation to the shading cast by the photovoltaic (PV) panels on the roof. This work evaluated the green bean cultivation inside PVGs with a percentage of the greenhouse area covered with PV panels (PV cover ratio, PVR) ranging from 25 to 100%. Three dwarf green bean cycles (Phaseolus vulgaris L., cv. Valentino) were conducted inside an iron–plastic PVG with a PVR of 50%. The average yield was 31% lower than a conventional greenhouse. Adverse effects on quality were noticed under the PV roof, including a reduction of pod weight, size, and caliber. Negative net photosynthetic assimilation rates were observed on the plants under the PV roof, which adapted by relocating more resources to the stems, increasing the specific leaf area (SLA), leaf area ratio (LAR), and the radiation use efficiency (RUE). The fresh yield increased by 0.44% for each additional 1% of cumulated PAR. Based on the linear regressions between measured yield and cumulated PAR, a limited yield reduction of 16% was calculated inside a PVG with maximum PVR of 25%, whereas an average yield loss of 52% can occur with a PVR of 100%. The economic trade-off between energy and green bean yield can be achieved with a PVR of 10%. The same experimental approach can be used as a decision support tool to identify other crops suitable for cultivation inside PVGs and assess the agricultural sustainability of the mixed system.
Highlights
The European Union (UE) recently approved the “European Green Deal,” an imposing roadmap to fund the EU transition toward a green and circular economy with no net gas emissions by 2050 (European Commission, 2020)
The linear regression between yield and solar radiation was calculated to estimate the productivity inside other common PV greenhouse (PVG) types with a PV cover ratio (PVR) ranging from 25 to 100%, based on their light availability
The heterogeneous distribution of the solar radiation negatively affected most of the measured quantity and quality parameters, depending on the position of the plant row under the greenhouse roof
Summary
The European Union (UE) recently approved the “European Green Deal,” an imposing roadmap to fund the EU transition toward a green and circular economy with no net gas emissions by 2050 (European Commission, 2020). The ground-based PV systems in agricultural land are not allowed in some southern EU countries such as Italy and France, due to their conflict between land and energy, including land deterioration and speculation behind the public incentives provided for the PV energy production (Poncet et al, 2012; Colantoni et al, 2015). For this reason, the installation of PV systems in agriculture was moved to rural buildings or greenhouses, leading to the spread of the PV greenhouse (PVG), which integrates the PV panels on the roof (Castellano, 2014; Sgroi et al, 2014). Inside PVGs, the shading cast by the PV panels inside would have the same effect on the crops, while part of the shaded solar radiation can be used to produce electricity
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call