(662d) Techno-Ecological Synergies in Life Cycle Assessment: A General Computational Framework

Life cycle assessment (LCA) is among the most widely used methods to support sustainable engineering. Generalized computational structures have been developed for process model based LCA, input-output LCA, and hybrid LCA [1-3]. However, LCA does not explicitly account for the role of ecosystem services (ES) and the capacity of ecosystems to supply the services demanded throughout the life cycle. Also, the conclusions made by LCA are based on comparisons between alternatives, measuring only relative sustainability performance. This approach encourages technological systems to do “less bad” by reducing environmental impact rather than “more good” by protecting and restoring ecosystems. Therefore, decisions based on relative sustainability and without accounting for the role of ecosystems may, (1) unintentionally increase reliance on scarce ES, and (2) miss out on ecological opportunities for improving the life cycle.

Furthermore, to quantify absolute environmental sustainability, the product’s life cycle impacts need to be compared with absolute environmental references such as ecological capacity in the serviceshed of the selected ecosystem service. The framework of techno-ecological synergy (TES) aims to address these challenges [4] by explicitly including the role of ecosystem in mitigating impacts, and referring to ecological carrying capacity as the base for absolute environmental sustainability.

This work develops a rigorous computational framework for incorporating techno-ecological synergies into life cycle assessment, and identifies practical challenges and approaches to enable the proposed extension. The resulting TES-LCA framework extends the computational structure of LCA to explicitly account for ecosystems. Just as technological systems are included in LCA as modules, TES-LCA also includes ecosystems as modules. Interaction between various ecological processes and with technological systems are also captured. Metrics are also defined to quantify ecological overshoot at multiple spatial scales. The basic TES-LCA computational structure is then adapted to account for ES allocation, regional variations and absolute environmental sustainability at the largest scale at which the ES operates (serviceshed). This framework can thus provide unique insights about absolute environmental sustainability for both individual activities and product’s life cycles.

Applications demonstrate that compared to conventional LCA, TES-LCA can capture interaction between ES in an explicit manner, account for absolute sustainability, and identify novel improvement strategies through ecosystem restoration. The framework will be applied to a biofuel supply chain to demonstrate the robustness of TES-LCA while identifying the associated challenges, which point out the directions for future research work.

References:

[1] Hunt, Robert G., et al. "Case studies examining LCA streamlining techniques." The International Journal of Life Cycle Assessment 3.1 (1998): 36-42.

[2] Joshi, Satish. "Product environmental life‐cycle assessment using input‐output techniques." Journal of industrial ecology 3.2‐3 (1999): 95-120.

[3] Suh, Sangwon, et al. "System boundary selection in life-cycle inventories using hybrid approaches." Environmental science & technology 38.3 (2004): 657-664.

[4] Bakshi, Bhavik, Guy Ziv, and Michael Lepech. "Techno-ecological synergy: A framework for sustainable engineering." Environmental Science & Technology 49.3 (2015): 1752-1760.