OK, here comes one of the more nerdy articles.
We just finished a project with the Danish company Barons and would like to give some insights into the process of doing carbon calculations on a product.
Barons have made a vow to focus solely on perfecting the shirt. On the path to doing so, they figured that not only the quality and comfort but also the environmental impact of the shirt is an area to focus on. Therefore Climaider and Barons scoped a project to map out the carbon footprint (CF) and the reduction opportunities of their four products: The Consultant, The CEO, The Lawyer, and The Founder. This paper aims to give insights into the process.
First and foremost we had to define a scope of the calculations: What to include and what to exclude? Taking the data quality into concern, we agreed to scope the calculations from cradle to customer. This means that the use-phase and end-of-life are excluded from the calculations. Also due to low-quality data, emissions from the warehouse in Switzerland and Denmark, water in the finishing process, and the use of chemicals in the manufacturing part are excluded. To compensate for this, an uncertainty factor is added to the final result.
The CF is a reflection of the emissions related to materials, manufacturing, and transportation.
Barons do only have four products. This made the calculations easier, but we still had to decide on a functional unit to use in the calculations. We chose a functional unit of 2.21 m2/shirt that’s equivalent to an average of all sizes.
When calculating the CF of a product like this, you look at the mass of the materials and their origin. Also, you have to map out the manufacturing route — in a case like this, the product has often traveled through six to seven countries before ending up in the final warehouse. In every country there is a process, you should take into account and find the CF for energy use.
The shirts are made of 100% cotton from the US. The raw fibers account for the biggest part of the CF. The use of fertilizer and water is to blame. The second-largest contributor to the CF is spinning. This is an energy-heavy process in a country with quite a high carbon intensity in the energy grid.
Things to consider
As addressed the raw cotton and the spinning process are the two biggest contributors to the CF. Therefore the focus should be on these when looking at things to change and improve. There is a big difference between the CF from conventional and organic cotton. If both are from the US organic cotton has a CF that’s 4-5 times lower than conventional. We are familiar with the problems about the lacking quality of organic cotton, but together with Barons, we have defined this as being the nr. 1 place for improvement. Secondly, the search for a new country for the spinning process should be established — the potential of carbon reductions is quite big here as well.
Since we have not been able to get 1st hand data from all the parts in the process of creating a shirt some assumptions have been made whereas the most important ones are:
— A material loss of respectively 13%, 3%, and 10% at spinning, finishing, and sewing.
— Spinning and knitting are done in the same place.
— Department for Environment, Food and Rural Affairs 2020
— California ISO
— Moro, A., Lonza, L. Electricity carbon intensity in European Member States: Impacts on GHG emissions of electric vehicles
— Baydara, G., Cilizab, N. & Mammadovab, A. Cotton Ginners Handbook
— Mayfield W., Anthony, W.S. Life cycle assessment of cotton textile products in Turkey
Der er efterhånden mange gode grunde til at adressere din virksomheds CO2-aftryk - læs med og lær hvorfor
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