# Life Cycle Assessment of Land Use Trade-Offs in Indoor Vertical Farming +
## 3 Results and Discussion
### Environmental Footprint Results  
Characterization impact scores of each impact category are reported in Table 1. It shows that the GM scenario consistently yields higher environmental impact scores than the PV scenario across all 16 EF categories for the IVF producing microgreens. Relative differences in impacts between the PV and GM scenarios range from 5% lower in the PV scenario for Freshwater Ecotoxicity (FE) to 59% for Water Use (WU), with an average difference of approximately 20%. Notable lower impacts are observed in the PV scenario for Land Use (LU; 50%), Climate Change (CC; 27%), and Resource Use, fossils (RUf; 24%), primarily due to the GM scenario's reliance on fossil-based electricity. Human Toxicity, cancer (HTc; 11% lower) and Human Toxicity, non-cancer (HTnc; 7% lower) also show smaller differences. In four of these categories (FE, HTc, HTnc, RUf), however, the savings from adopting the PV scenario over the GM scenario amount to approximately 10%. Among the standout categories, LU shows a significant difference, with the PV scenario exhibiting nearly half the impact of the GM scenario (PV = 5.7 \(\times\) 10\({}^{1}\) Pt vs. GM = 1.15 \(\times\) 10\({}^{2}\) Pt), reflecting the spatial efficiency of BIA systems employing IVF producing microgreens. This result aligns with the PV scenario's use of a non-ground-mounted solar system, as assumed in the study design, which limits direct land occupation compared to traditional ground-mounted systems. These results are consistent with those obtained in two very recent studies that highlight the advantages of applying photovoltaic technology to urban agriculture. The study by [PERSON] et al. (2022) [41] proposes the co-location of photovoltaic panels and vegetable gardens on urban rooftops as a solution to achieve clean energy production together with \"zero-kilometer\" agricultural output. By integrating a Geographic Information System (GIS) with modeling simulations, the study estimates the annual electricity production and the amount of horticultural products that could simultaneously be obtained in the city of Shenzhen, China, yielding interesting results. In an even more recent article by [PERSON] et al. (2024) [42], it is highlighted how the high electricity demand of vertical farming systems can be addressed through the use of renewable energy sources (solar and wind) and more efficient electrical equipment. However, neither of the two cited studies applies an LCA to the proposed systems and therefore do not quantify the benefits in terms of avoided environmental impacts resulting from the use of photovoltaic technology in IVF systems. These findings reinforce the well-documented environmental advantages of photovoltaic systems in both land use and climate change impact categories. For land use, rooftop-mounted PV avoids the need for ground-mounted infrastructure, enabling electricity generation without additional land transformation. Moreover, the compact spatial footprint of PV infrastructure contrasts sharply with the indirect land occupation and ecosystem disruption linked to fossil-based energy sources. Regarding climate change, PV electricity production is virtually emission-free during operation, significantly reducing lifecycle greenhouse gas emissions compared to grid mix scenarios reliant on fossil fuels. As seen in this study, the PV scenario reduced CC impacts by 27%, which can be directly attributed to the substitution of fossil energy inputs with solar-based electricity for high-demand processes such as LED lighting. These operational benefits are amplified when considering the avoided upstream emissions from fossil extraction, transport, and combustion, further confirming the systemic climate advantages of photovoltaic integration into IVF systems. Figure 2 shows the relative contributions of the five processes (Construction, Installation, Cultivation, Packaging, and Delivery) to each impact category in both scenarios. As explained in Section 2.2, the two scenarios differed primarily in terms of the electricity source.