## 3 Life Cycle Impact Assessment: Results and Interpretations
### NMC Battery Impact Assessment
By introducing these hypotheses into our LCA model, a GWP = 14.5 kgCO\({}_{2}\)/kgbattery-pack was estimated (a reduction of about 28% with respect to the case study). As far as cumulative energy demand (CED) is concerned, recycling (red bar) plays the most important role after the energy required for manufacturing. The main contributor to recycling is the consumption of nonrenewable fossil fuels, with diesel oil consumption accounting for 68%. The cathode production stage (green bar) influences the CED result by 14%, partially because of the electricity demand and partially because of raw material extraction (especially Cobalt and Nickel). The main contributor among the non-cell materials (dark blue bar) is Aluminium extraction, whereas, in cell production (orange bar), Aluminium extraction, electricity, and heat are the primary contributors to CED. The impact of Photochemical Oxidation (POP) is primarily attributable to the production of cathode materials (green bar). Aluminium extraction plays the main role in cell production (orange bar), whereas the credits (yellow bar) are mainly due to the avoided extraction of Nickel. With reference to the Acidification (AP) impacts, the cathode is usually one of the most significant contributors to all battery chemistries [34]. In our study, it accounts for 63% of the total impact (green bar), mainly because of the upstream production of Nickel, which generates substantial Sulphur Dioxide emissions (94% of the cathode production impact) as a reaction by-product. The energy required for manufacturing (light blue bar) and cell material production (orange bar) are other significant contributors to AP. The main contributor to the latter is Aluminium extraction. Credits (yellow bar) involve a 30% saving of the total impact because of the avoided extraction of Nickel (87%). Eutrophication (EP) is mainly affected by cathode production (green bar), because of the impact of Nickel (56%) and Cobalt (20%) extraction. The recycling process (red bar) accounts for about 6% of EP, mainly due to the use of electricity (41%) and Sodium Hydrooxide (15%). Credits (yellow bar) significantly lower the total impact (\(-\)18%), because of the avoided production of Nickel, Copper and Aluminium. Figure 4 reports a cradle-to-grave life cycle assessment of the NMC111 battery. The contributions to the LCA are split into production (cathode, cell, non-cell material, energy use, and battery transport from the manufacturing plant to the customer; green bars), further waste disposal related to the impact of incineration and landfilling of the materials (purple bars), environmental credits and recycling (orange bars), including collection and transport of the used batteries, and battery losses (magenta bars), estimated according to Section 2.2.2.2 \"Battery use phase\". The results of each impact category are normalised so that the total height of each bar is equal to 100%. As already mentioned, environmental credits are considered as negative contributions to the considered impact category, and the negative values of the orange bars therefore indicate that the environmental benefits derived from the credits overcome the burden of the recycling phase. The results in Figure 4 show that the orange bars are negative for all the examined impact categories, with the exception of ODP (as also reported in [43]), CED and Abiotic Depletion-Fossil Fuels (ADP-FF). This is mainly due to the use of diesel oil and sodium hydroxide in the recycling process. The total life cycle environmental impacts and credits of all the impact categories examined in this study are also summarised in Table S8 (credits are presented as negative values), whereas Tables S19 and S23 report detailed EoL results of the cell and non-cell materials, respectively. Overall, EoL produces environmental benefits that range from 3% to 25% of the total battery impact shown in Figure 4 for most of the considered categories. The highest benefitsare shown for HTP (25%), POP (22%), AP (22%), and ADP (21%).