Life cycle assessment is a well-established tool for environmental assessment. It is effective for generating numerical results but more valuable as a learning process.
PlastLIFE aims for a safe and sustainable circular economy for plastics in Finland. Circular solutions such as recycling, reuse and repair reduce the need for primary production of materials and for waste treatment methods such as incineration or landfill. This often results in an environmental benefit.
However, the environmental benefit of plastics recycling depends heavily on what material the recycled plastic substitutes. In some cases, recycled plastics replace plastics produced from oil and natural gas, but in other cases it replaces completely different types of material, such as wood.
Incineration of plastic waste often a poor choice for the environment
Waste incineration can bring environmental benefits, when the recovered energy substitutes energy sources with significant environmental impact, due to the fact that waste plastics contain a lot of energy.
However, if the plastics are produced from fossil resources, they also contain much fossil carbon. The carbon content per unit of energy is higher for most plastics compared to fuel oil. This makes incineration of plastic waste a poor choice for the environment.
How bad it is can depend on what energy source is displaced by the energy from the waste incineration. It can also depend on how the incineration of waste plastics affects the treatment of other types of waste.
It is vital to account for the avoided processes when assessing circular solutions of plastics
An environmental assessment of circular solutions for plastics needs a broad systems perspective to account for potentially important system impacts.
It is vital to account not only for the impacts of recycling and repair processes, but also for the avoided production of substituted primary materials and products and for the avoided waste incineration and landfills.
Life cycle calculations and life cycle thinking are integrated into EU legislation
Life cycle assessment (LCA) and carbon footprint calculations are tools for environmental assessment with a wide systems perspective. An LCA is a compilation and evaluation of the inputs, outputs and potential environmental impacts of a product from cradle to grave, i.e. from raw material acquisition or generation from natural resources to final disposal. Carbon footprints share the same life cycle perspective but are limited to the climate impact of greenhouse gases.
Life cycle calculations and life cycle thinking are well established in both industry and policymaking. For the past decades, they have been integrated into many pieces of EU legislation on waste management, resource efficiency, and elsewhere.
How and what can you learn from LCA studies?
Although LCA is well established, the LCA results depend on input data that are often uncertain. They can also depend strongly on decisions made by the LCA practitioner.
For example, should the net environmental benefits of recycling be assigned to the product that is recycled after use, or to the product where the recycled material is used? Uncertainties and subjective choices of methods are inevitable in an LCA, because the life cycle is a large and complex system.
Ask why the LCA got these results?
For this reason, LCA results should not be accepted at face value. Instead, you should ask why the LCA got these results. If you can find information on the input data and choices made in the calculations, you should ask yourself if these data and choices are reasonable.
If you ask the LCA and yourself these questions, you often learn new things about the life cycle and about the circular economy.
Ask yourself:
- What choice of input data and calculation methods led to the LCA results?
- Are these choices reasonable?
- What can I learn from the study?
Study the report
Read more
- Mudersbach et al. (2025): Life Cycle Assessment in a Nutshell—Best Practices and Status Quo for the Plastic Sector
- Ekvall et al. (2025): The basket-of-functions approach applied to compare the climate aspects of high-quality mechanical recycling and downcycling of plastics
About the author
Tomas Ekvall is a Swedish researcher and consultant and an internationally recognized expert on LCA and recycling. He supported the PlastLIFE team in refining the LCA methodology used for assessing circular solutions in the project.
