Plastics LCA: bio-based, recycled and fossil sources compared

Plastic producers have been pushing the "bio-based plastic = lower carbon" narrative for years. The reality is more nuanced: bio-based plastic can yield 30-60% GWP improvement over fossil counterpart, but it may carry disadvantages in land use (LULUC), water deprivation (WDP) and eutrophication (EP). LCA shows transparently which source wins in which category.

The five main plastic categories

• PE (polyethylene) — LDPE, HDPE; packaging, pipe, insulation. Typical GWP: 1.8-2.5 kg CO₂eq/kg fossil; bio-based (Brazilian sugarcane) 0.8-1.2
• PP (polypropylene) — automotive, packaging, textile. GWP: 1.7-2.3 kg fossil; bio-based not yet industrial scale
• PVC — window profiles, pipe, cable. GWP: 1.9-2.4 kg; chlorine production needs special modelling
• PET — bottles, textile, packaging. GWP: 2.5-3.2 kg fossil; bio-PET (partly corn-based) 1.6-2.0
• PS / EPS — insulation, single-use packaging. GWP: 3.2-4.0 kg; no bio-based option at scale

Recycled content (PCR — post-consumer recycled)

Recycled plastic (PCR) yields 30-70% lower GWP than virgin — the main saving from skipping polymer production and the cracker. But PCR has two limits: (1) chain shortening — mechanical recycling shortens polymer chains and degrades mechanical properties. PVC window profiles or structural-load parts cannot reach 100% PCR; typical ceiling is 30-50% PCR. (2) sorting contamination — collection systems mix polymers, degrading quality. Going from PET bottle to PET textile is "down-cycling".

The bio-based plastic debate

Bio-based plastic (PE, partially PET, PLA, PHA) is made from agricultural feedstock — sugarcane, corn, cassava. It delivers large GWP savings because atmospheric CO₂ is captured during plant growth (biogenic carbon). But across all LCA categories: land use (LULUC, growing crops), water deprivation (WDP, irrigation), eutrophication (EP, fertiliser use) all worsen relative to fossil plastic. This is why EN 15804+A2 splits GWP into total/fossil/biogenic/luluc — the biogenic advantage is transparent but LULUC disadvantage is not hidden.

PlasticsEurope eco-profile methodology

PlasticsEurope, the EU plastics producers' association, maintains the "eco-profile" sectoral LCA methodology. It aligns with EN 15804+A2 but adds plastic-specific rules — co-product allocation in the cracker, polymer production conditions, extrusion energy intensity. Verifiers expect this methodology in plastic EPDs.

End-of-life — incineration vs landfill vs recycle

Plastic end-of-life has three paths: energy recovery (incineration), landfill, recycling. EU average: 42% energy recovery, 26% landfill, 32% recycling. In Turkey recycling is lower (15-20%) and landfill higher. Module D credit scales with recycle rate; landfill yields no positive credit (only a small effect under long-term carbon-storage assumptions). Localising C-module rates is critical for modern plastic EPDs.