Expanding scenario diversity in prospective LCA: Coupling the TIAM-UCL integrated assessment model with Premise and ecoinvent
Joris Šimaitis, Isabela Butnar, Romain Sacchi, Rick Lupton, Christopher Vagg, Stephen Allen
Abstract
Prospective life cycle assessment (pLCA) using scenarios from integrated assessment models (IAMs) can explore future environmental impacts. However, results are sensitive to the IAM used and only scenarios from two IAMs – REMIND and IMAGE – have been soft-coupled with pLCA using Premise. Here, we establish a new linkage to a third IAM - TIAM-UCL - which diversifies available IAM scenarios and strengthens potential conclusions from pLCA. Over 200 variables across 16 global regions were linked to over 300 LCA processes, representing future technological changes across seven major sectors, including electricity, fuels, and steel. We analyse the future life-cycle impacts of the global electricity mix per kWh delivered to low-voltage consumers using TIAM-UCL scenarios, ecoinvent v3.9.1, and the EF 3.1 impact assessment method. In 1.5–2.0 °C futures, projected reductions in climate change impact from fossil-fuel phase-out have substantial co-benefits in ten categories, such as acidification reducing over 90 % by 2050. Trade-offs are found in five categories, such as critical material shortages. Comparing pLCA results based on all three IAM models showed consistent reductions in climate change impact to meet 1.5–2.0 °C futures. However, differences in other impact category results arose due to variations in low-carbon technologies deployed, such as IMAGE showing smaller environmental co-benefits due to preferences for CCS-fitted fossil generation, while REMIND had increased land use from greater solar uptake. Therefore, it is essential to consider the influence of IAM choice when interpreting pLCA outcomes. The addition of TIAM-UCL, now available in Premise, will enable more robust modelling of prospective environmental impacts. • New TIAM-UCL scenarios in Premise enhance scenario diversity in prospective LCA. • Decarbonising electricity reduces 10 life-cycle impacts but may add 5 trade-offs. • Comparing IAMs shows consistent life-cycle GWP reductions for 1.5–2.0 °C futures. • Environmental performance of decarbonised electricity varies across IAMs. • Diversity of IAMs in pLCA improves impact assessment of decarbonisation pathways.