How can the sustainability of a product be measured? One of the most common methods to date has been to calculate a product’s carbon footprint. This approach focuses exclusively on greenhouse gas emissions and their impact on climate change and global warming. It includes CO2 emissions from a company’s own production and from purchased energy, as well as the carbon footprint of the raw materials used and emissions caused by logistics.
However, Life Cycle Assessment (LCA) is also being used – a method already applied by numerous companies in the chemical, packaging, and consumer goods industries. This method considers a much broader range of environmental impacts to assess a product’s environmental footprint. Rather than relying on a single metric, LCA uses several indicators, each specific to the environmental category being examined. These categories include, for example resource use, ecotoxicity, i.e., the impact of substances on freshwater ecosystems, acidification of soil or water, ozone depletion, eutrophication of water or land use. The carbon footprint is therefore well suited to quantifying progress toward climate targets using a single metric; Life Cycle Assessment, on the other hand, takes a more holistic view of sustainability and provides one metric for each category examined.
How Sustainable Is a Product?
The impact of LCA criteria on the assessment of a specific product was examined using
a sodium benzoate as an example. The substance is used as a preservative in personal care products, food,
and pharmaceuticals. In its production, “green” toluene made from 100% used cooking oil is used instead of conventional toluene. This significantly reduces the product’s carbon footprint. These products either contain at least 50% sustainable raw materials or have a carbon footprint that is at least 50% lower than that of conventional products.
When assessed according to LCA criteria, conventional sodium benzoate also performs very well. In almost all LCA categories, the use of “green” toluene made from used cooking oil in the production of sodium benzoate has a clearly positive impact. Particularly in the categories of “resource use” and “acidification,” the values decrease compared with sodium benzoate produced with conventional toluene.
However, there are also opposing effects in some categories, although at a low level. Plant-based products sometimes perform significantly worse than petrochemical products. In the case of sodium benzoate with “green” toluene, the value for “eutrophication of water” increases by around 30%. However, it is still significantly lower than that of sustainable products based on plants grown specifically for the product. In the “land use” category – i.e., environmental impacts resulting from the use or transformation of land – the use of “green” toluene also has only a slightly negative impact.
Determining the Life Cycle Assessment
The LCA follows a “cradle-to-gate” approach, which includes the raw materials used, transportation to the production site, and production, including the energy used, in the environmental assessment of the respective product. In addition, outputs from the manufacturing process – such as emissions to water and air – are included in the assessment. Beyond the aspects covered by a traditional LCA analysis, preservatives involve another consideration: By extending a product’s shelf life both in retail and during consumer use, they can help reduce waste and conserve resources. This positive effect on the environmental footprint is becoming increasingly relevant in holistic sustainability assessments.
Conclusion
Life Cycle Assessment does not determine just one value for the sustainability of a product, as is the case with the carbon footprint. It examines a wide range of environmental categories. Manufacturers or consumers therefore need to select the categories that are relevant to their decisions and to their assessment of a product. The sodium benzoate from Lanxess performs well in both types of analysis. The already low carbon footprint of the conventional product variant is reduced significantly further through the use of a recycled raw material – toluene made from used cooking oil.
Within the Life Cycle Assessment, conventional sodium benzoate already achieves good results in all categories compared with other preservatives. The “green” variant delivers even better values in almost all LCA categories. The exceptions are “land use” and “eutrophication of water”; here, the environmental footprint deteriorates slightly. Compared with other preservatives, however, the values in these categories remain at a very low level.
Matthias Kunze
Business Development Manager, Lanxess AG, Cologne, Germany, www.lanxess.com