Life cycle assessment of γ-glycine bio-piezoelectric energy harvesting sensors

Despite the remarkable piezoelectric properties of sesnsors such as PZT, the presence of lead (Pb), a toxic element, poses significant human and environmental hazards. The advent of γ-glycine sensors provide non-heavy metal alternatives to Pb-based sensors. In light of the development of such Pb-free biodegradable alternatives, this study presents a cradle-to-gate life cycle assessment (LCA) of γ-glycine sensors in compliance with ISO-14040 and ISO-14044 standards. It quantifies the environmental burdens due to production of 506 g of γ-glycine sensors, including raw material sourcing, transportation, and various stages of manufacturing. Inventory modelling was performed using OpenLCA and Ecoinvent 3.11 (2025) database. Impact categories such as terrestrial ecotoxicity, global warming, water consumption, and human carcinogenic and non-carcinogenic toxicity were evaluated using the ReCiPe 2016 Midpoint (H) method. Key emissions identified include 578.729 kBq of radon- 222, 110.718 kBq of noble gases, and 36.991 kg of CO₂ to the air. Sensitivity evaluation with Spearman’s correlation and uncertainty analysis using Monte-Carlo simulations were carried out to provide more realistic and robust results. The results identified electricity consumption as the most sensitive parameter (ρ>0.94) across all the selected impact categories and the dominant contributor, particularly affecting global warming potential (93.9%) and water consumption (86.28%). This work ensures a foundational understanding of the environmental profile of γ-glycine sensors and informs future comparisons of conventional piezoelectric sensors with non-heavy metal alternatives.