When Solar Resource Is Not the Deciding Factor: An Integrated Screening Framework for Investment in Farmland Photovoltaics

This case study uses data from Greece, specifically the Region of Eastern Macedonia and Thrace, to examine the trade-offs of siting ground-mounted photovoltaic (PV) systems on agricultural land. Although PV siting is often guided primarily by solar yield, relatively small differences in solar resource may conceal substantial agricultural and environmental opportunity costs. The study applies an integrated screening framework that combines estimates from the Photovoltaic Geographical Information System (PVGIS) using the SARAH-3 database, parcel-level agricultural revenue data, and foregone carbon sequestration. Annual PV yield ranged from 1437 to 1516 kWh/kWp (coefficient of variation = 2.19%). Historical cumulative differential gross revenue over 2009–2021 reached €338.91 million, of which 90.52% was associated with arable parcels; Evros and Xanthi accounted for approximately 77% of this component, while Xanthi contributed 71% of the tree-crop component. Correlations between capacity factor and benefit share were 0.10 for arable parcels and −0.70 for tree crops, indicating that solar and economic rankings may diverge substantially. In 2021, differential gross revenue amounted to €10.884 million. Valuing the foregone carbon sink of 28,650 t CO2 yr−1 at approximately €380/t CO2 would close this gap, whereas at €200/t CO2, €5.154 million would remain. The findings indicate that PV siting should consider, beyond solar resource and grid adequacy, agricultural value and land capability, perennial investment, environmental factors such as carbon, biodiversity, water and landscape, distributional effects, and the feasibility of agrivoltaic or non-farmland alternatives. Excluding investment costs, discounting, grid constraints and lifecycle emissions, the proposed framework functions as a screening rather than a project-appraisal tool, supporting the identification of lower-opportunity-cost locations and the assessment of agrivoltaic options on high-value farmland.