A new article has been released in Science of the Total Environment where the UNESCO Chair ESCI-UPF has collaborated with the Escola d’Enginyeria d’Igualada UPC, and Cyclus Vitae Solutions. The article’s title is “Product vs corporate carbon footprint: Some methodological issues. A case study and review on the wine sector” and it can be downloaded from the journal’s website.
Carbon footprint (CF) is nowadays one of the most widely used environmental indicators. It represents the sum of all Green House Gases emissions produced by a product, process or company and it’s usually expressed in CO2 equivalents. It can be calculated using different approaches, such as:
- Product Carbon Footprint (PCF): one product is evaluated throughout its life cycle (from raw materials extraction to final disposal).
- Corporate Carbon Footprint (CCF): all production processes of a company are evaluated, together with upstream and downstream processes.
But some crossovers between CCF and PCF approaches have been detected while performing PCF assessments. This happens because it is easier for companies to collect corporate data than product data.
18 wineries were used to study how this issue has been tackled until now and literature shows that companies were already collecting company data that were actually “key performance indicators” and then using them to calculate product environmental figures. This paper proposes six methodological issues (fugitive emissions, credits from waste, use of “equivalent factors”, reference flow definition, accumulation and allocation to minor products) that must be taken into account in order to ensure that it is possible to collect corporate inventory data in a per year basis to perform an accurate PCF study.
These 18 wineries were also used to exemplify how to practically address these 6 methodological issues in 18 concrete cases, creating thus a methodology that guarantees this practice not only for the wine sector but to any other product or industrial activity. As a matter of fact, the six topics identified as differences between corporate and product CF approaches are general and affect the CF results of any type of industry. Therefore, details on how they have been addressed should be included in the report.
For the wine case study, two of the studied topics (fugitive emissions and credits from waste recycling) showed very small influence while the other four topics where identified as very significant.
Example: the influence of using “equivalent factors”
Wine cooperatives produce different types of wine coming from many farmers. In order to simplify calculations, an average yield from grapes to wine has to be taken (in our case: 1kg of grapes = 0.75L wine). In reality, this equivalent factor can vary between 0.9 and 1.7 kg grape/L for the wine sector, creating an uncertainty in our calculations that can result in a 5.4% increase in the CF of one bottle of wine. Therefore, it was identified as very important to obtain an accurate value of “kg of grapes needed to produce 0.75 mL of wine”.