Life cycle assessment of high-tech vertical aquaponics for grape tomato and rainbow trout production

The adoption of innovative and combined cultivation practices, such as aquaponics, has gained traction as a pathway to intensify food output on limited land. However, the environmental performance of these intensive systems warrants systematic assessment. In this study, a pilot high-tech aquaponic system was developed for greenhouse grape tomato and rainbow trout production, and three fertilization regimes were evaluated: (i) standard hydroponic solution, (ii) trout effluent supplemented with mineral fertilizers, and (iii) trout effluent without additional fertilization. Life Cycle Assessment was performed using actual operational data by using SimaPro v.9.4.0.2 and EF v.3.0 method. Results showed that the complemented aquaponic system represented the most balanced aquaponic configuration, maintaining higher productivity compared to the non-supplemented system. The hydroponic treatment exhibited lower values across most midpoint categories due to the absence of aquaculture-related hotspots, such as electricity. An alternative scenario was further modelled with increased fish biomass, additional tanks, and photovoltaic integration, while the robustness of the results was examined through Monte Carlo uncertainty analysis and deterministic sensitivity analysis. Replacing grid electricity with photovoltaic energy led to a consistent reduction in environmental impacts across all energy-related categories. A comparative scenario showed that replacing rainwater with tap water and relocating the aquaculture unit increased water use (15.2 to 19.9 m 3 deprivation) and land use (70.0 to 153.0 Pt), highlighting that system design plays a key role in improving land and water efficiency. Consequently, on-site renewable energy sources and optimized system configuration appear as the most effective levers to improve sustainability. The approach provides a reproducible template for assessing and optimizing circular aquaponic systems under real operational conditions.