UK-based chemical recycler Plastic Energy has published a new Life Cycle Assessment (LCA) of its pyrolysis technology, called TAC.
The assessment was conducted by Sphera, a sustainability consultant. The findings build on the company’s first LCA released in 2020. The new study was commissioned to assess the impact of developments to TAC since then, including higher efficiencies in throughput and energy usage.
The LCA compares the chemical recycling process to two status quo scenarios. First, a waste management scenario with energy incineration and, second, a virgin LDPE production scenario.
The comparison takes Europe and the year 2023 as reference points.
Waste incineration vs. TAC
In the first scenario, the global warming potential (GWP) of TAC is compared with that of incineration of 1 tonne of sorted mixed plastic waste with energy recovery.
The evaluation of TAC’s GWP includes waste collection, sorting, extra sorting, pyrolysis, and hydro treatment of the pyrolysis oil, called Tacoil. A credit for recovered naphtha is assigned to the hydro treated Tacoil output.
The status quo includes waste collection, sorting, and incineration with energy recovery. A credit is assigned for the energy recovery.
Results show TAC has a GWP of 348 kg CO2 equivalent, 78% less than waste incineration at 1,592 kg CO2 equivalent.
Virgin production vs. TAC
In the second scenario, the GWP of producing 1 tonne of LDPE via TAC is compared with that of producing 1 tonne of virgin LDPE.
The evaluation of TAC’s GWP includes waste collection, sorting, extra sorting, pyrolysis, hydro treatment of Tacoil, cracking, and polymerisation.
Virgin production’s GWP includes fossil naphtha, cracking, polymerisation as well as the GWP of incinerating 1.46 tonnes of mixed plastic waste with energy recovery.
The justification for this addition is that when chemical recycling does not take place, the amount of mixed plastic waste required to produce 1 tonne of LDPE (1.46 tonnes, according to the LCA’s calculation) is not diverted from incineration. Therefore, the study assumes the burden of that waste management belongs to the status quo scenario.
Results show TAC has a GWP of 2,554 kg CO2 equivalent, 42% less than virgin production at 4,376 kg CO2 equivalent.
If the additional GWP of incinerating 1.46 tonnes of mixed plastic waste with energy recovery is removed from the virgin production scenario, the virgin GWP is 2,160 kg CO2 equivalent.