Sustainability Framework

A Meta-Analysis of the Global Warming Potential (GWP) on Polylactic Acid

Saal A
Mittwoch, 11.09.2024, 13:30 - 13:55 Uhr

1. great variety in methods and results 2. no clear reduction in GWP compared to fossil-based polymers, however the data used for PLA production are potentially outdated 3. renewable energies seem important for low GWP

Frequently cited advantages of bio-based polymers include a lower carbon footprint compared to fossil-based poly-mers and biodegradation to avoid microplastic pollution. This also applies to polylactic acid (PLA), one of the most advanced bio-based polymers on the market. Over 80 life cycle assessments and carbon footprinting studies of PLA have been performed since the early 2000s. In this review, the results from these studies were compared to clarify, whether an overall conclusion can be made about the advantages of PLA. The main focus was placed on global warm-ing potential (GWP). When looking at cradle-to-gate (resin) scope, the median GWP value for PLA was 1.63 kg CO2 eq/kg PLA, which is lower than that of fossil-based polymers such as PET, PP, or PE. However, the median value of PLA from cradle-to-grave studies was 3.91 kg CO2 eq/kg, which is comparable to the GWP of fossil-based polymers. This discrepancy is primarily a result of biogenic carbon accounting, where the cradle-to-gate results benefit from the CO2 uptake by feedstock. A great variation was observed in the GWP for PLA between the different studies, stemming from the different choices made by the authors. Those include type of feedstock, electricity mix, end-of-life option, or aforementioned biogenic carbon accounting.