Life Cycle Assessment (LCA) is a method for evaluating the environmental impacts of a product, service, or activity throughout its life cycle, from the extraction of raw materials to the end of the product's life.
This method quantifies the potential environmental impacts associated with a system of products by considering the inflows and outflows of each elementary process within the system.
How is a LCA conducted?
To conduct the Life Cycle Assessment of a product, it is necessary to compute the emissions associated with each stage of its life cycle. These stages are as follows:
Raw Material Extraction: This stage involves the collection or extraction of the natural resources required for the product's manufacture, such as metals, minerals, wood, and more.
Production: This is the phase where raw materials are transformed into components or finished products. It may encompass manufacturing, processing, treatment, and assembly processes.
Distribution: This stage includes the transportation of the product from the production site to points of sale or to end-users. It may also include storage.
Use: This is the phase during which the product is used by consumers or users. The environmental impact at this stage depends on how the product is used, its energy efficiency, its lifespan, and more. This stage also includes product maintenance, including repair or replacement of certain parts, when necessary.
End of Life: At the end of the product's useful life, it must be disposed of, recycled, or reused. This can involve processes such as recycling, incineration, landfilling, or reuse.
💡 Example
LCA of a synthetic t-shirt sold in France, with raw materials extracted in China and assembly split between China and Bangladesh. The t-shirt weighs 125g.
Raw Material Extraction:
The t-shirt is made from PET pellets. These pellets are manufactured in China. One t-shirt is manufactured using 170g of PET. The extraction of raw materials and the production of 170g of PET result in 0.62 kgCO2e.Production:
Production involves various stages. Spinning, knitting, and dyeing take place in China, while assembly occurs in Bangladesh. Emissions related to these stages are primarily due to factory electricity consumption. Depending on the country, electricity will emit more or less CO2. Ultimately, the production stages in China emit 3.93 kgCO2e, and assembly in Bangladesh emits 0.04 kgCO2e. Therefore, the t-shirt's production is responsible for 3.97 kgCO2e.Distribution:
The transport of raw materials to production facilities and between different production facilities is divided between maritime and road transportation, covering 23,000 km by boat and 800 km by road. This results in 0.06 kgCO2e for the 125g t-shirt. Between the assembly factory and the workshop in France, there's a distance of 16,314 km by boat and 1,200 km by road, leading to 0.04 kgCO2e. Emissions related to packaging amount to 0.60 kgCO2e. Finally, storage in the workshop accounts for 0.08 kgCO2e.Use:
Emissions are primarily related to electricity consumption from washing. It's estimated that over its lifetime, the t-shirt will be washed 50 times, resulting in 0.08 kgCO2e.End of Life:
The proportion of synthetic t-shirts estimated to be recycled is 19%. Taking that into account, the emissions related to the end of the t-shirt's life are 0.13 kgCO2e.
After studying each of these stages, we estimate a final value of 5.58 kgCO2e for a 125g synthetic t-shirt.
GHG emissions are computed in a LCA by using emission factors. For more information on emission factors, you can have a look at the following article.
ℹ️ If a company wants to compute the LCA of one of its products, Greenly has a team specialized in these kinds of studies.
With product LCA, companies and decision-makers can significantly contribute to protecting the environment and transitioning to a more sustainable economy (e.g. comparing GHG emissions between several scenarios and products).