The Relevance of Life Cycle Assessment Tools in the Development of Emerging Decarbonization Technologies

Abstract

The development of emerging decarbonization technologies requires advanced tools for decision-making that incorporate the environmental perspective from the early design. Today, Life Cycle Assessment (LCA) is the preferred tool to promote sustainability in the technology development, identifying environmental challenges and opportunities and defining the final implementation pathways. So far, most environmental studies related to decarbonization emerging solutions are still limited to midpoint metrics, mainly the carbon footprint, with global sustainability implications being relatively unexplored. In this sense, the Planetary Boundaries (PBs) have been recently proposed to identify the distance to the ideal reference state. Hence, PB-LCA methodology can be currently applied to transform the resource use and emissions to changes in the values of PB control variables. This study shows a complete picture of the LCA's role in developing emerging technologies. For this purpose, a case study based on the electrochemical conversion of CO₂ to formic acid is used to show the possibilities of LCA approaches highlighting the potential pitfalls when going beyond greenhouse gas emission reduction and obtaining the absolute sustainability level in terms of four PBs.

Figure 1

Role of life cycle assessment.

Figure 2

Cradle-to-gate system boundaries for CO₂ER and fossil routes of HCOOH production. The functional unit for the case study is defined as producing 1 kg of commercial HCOOH.

Figure 3

(A) Cradle-to-gate global warming potential (GWP) of HCOOH production from methyl formate hydrolysis (fossil) and CO₂ electroreduction (CO₂ER). The fossil route is calculated using LCI inventory from ref (51), and the CO₂ER route uses the model from refs ( and 57). (B) Sensitivity analysis of the GWP from the CO₂ER route as a function of electrolyzer variables (endogenous conditions). Base values are given in the legend for each variable, which is varied individually from −90% to +100%.

Figure 4

(A) Global warming potential of the CO₂ER route under baseline and improvement scenarios. ER performance assumes increasing the energy efficiency up to 40% and HCOOH preconcentration up to 20% wt. PV energy comes from the Ecoinvent database, while heat electrification assumes an electric boiler. All steps are additive. The fossil route is shown in the dotted line (2.95 kg CO_2e/kg,). Land use (LU) in m²·a (B) and water depletion potential (WDP) in m³/kg (C) of CO₂ER and fossil routes. CO₂ER uses the best-case scenario. All values are referred to the production of 1 kg of HCOOH.

Figure 5

(A) Environmental performance in selected PB indicators for producing 1 kg of HCOOH in CO₂ER route (best-case scenario). The fossil route is noted as a dotted line. (B) The ratio between the environmental burdens for the production of HCOOH by CO₂ER and fossil routes. (C) Change in the level of transgression from anthropogenic pressures when HCOOH production changes from the fossil to the CO₂ER route.