Spatial and temporal variation of photosynthetic photon flux density within agrivoltaic system in hot arid region of India

Abstract

Ground-mounted photovoltaic (PV) arrays of an agrivoltaic system (AVS) creates shade in the interspace areas as well as below PV areas of the AVS. Therefore, availability of photosynthetic photon flux density (PPFD) and daily light integral (DLI) in the AVS is negatively affected, which restricts optimum crop growth and yield. Therefore, in this study, spatial and temporal variation of PPFD and DLI in the AVS (105 kWp) developed at Jodhpur, India were quantified. Among three designs of PV arrays in the AVS, the proportion of shaded area in interspace was found highest in single row design and lowest in triple row design. The amount of PPFD varied widely in the AVS and even within the shaded area. Following semivariogram and kriging approach, spatial variation of PPFD and DLI was quantified within the AVS. Highest amount of PPFD was observed near noon in unshaded areas (1295 μmol m−2 s−1) whereas lowest amount was observed during morning at below PV array (24 μmol m−2 s−1). Based on the maps of PPFD and DLI, three distinct zones in the AVS were identified: (i) below PV array (DLI = 0–5 mol m−2 d−1), (ii) interspace area with partial shade (DLI = 5–20 mol m−2 d−1) and (iii) interspace areas with no shade (DLI = 20–30 mol m−2 d−1). Knowledge of spatial and temporal variation of PPFD and DLI may help in selection of suitable crops for the AVS.