Quantitative Tool: We Saved…

We have developed a quantitative tool to measure the environmental impact of our production compared to traditional manufacturing processes used in the textile industry. It focuses on water, CO2, energy and fertilizers used in our production chain. We mostly rely on secondary scientific information sources to calculate each part of the impact, including some assumptions listed below.

The main goal of this tool is to compare and quantify our production advantages with the industry benchmarks in order to gain insight into our positive environmental impact.

In the calculation, our tool takes into account all steps from the production of the raw materials to the final product, whereby the actual consumption of the product cannot be calculated due to various factors that cannot be objectively measured (such as washing temperature, which influence the microplastic secession, etc.). The calculation is made by parallelizing the material we use with conventional material: GOTS-certified 100% organic cotton vs. conventional cotton and recycled polyester vs. virgin polyester. The total savings achieved in the course of the year are visualized on the Das Merch website.

Assumptions. We made some main assumptions to simplify the calculation because of data scarcity and complexity:

  • Data is normalised to 1kg of fabric;
  • Manufacturing processes are limited to the cultivation and harvesting of organic cotton or the production of polyester, savings through the use of fabric residues and GOTS-certified screen printing techniques, reduced plastic packaging and reduced transport emissions due to production in Europe;
  • Remnants of fabric are not recycled;
  • Organic and conventional cotton data are based on general industry reports and both fabrics have the same weight and gsm index (grams per square meter);
  • Organic cotton harvesting requires no chemicals as specified in GOTS certificate;
  • Polyester is not downcycled during the recycling process and requires a less intensive dying process than virgin polyester.

Major limitations:

  • Information scarcity. The amount of information is different for different fabrics and production steps. There is more publicly available information from some cotton growing areas than from others, which leads to differences in information. Filling the gaps from sources that differ in scope reduces the data credibility.
  • Differences in results. Scientific studies differ in their scope, the underlying assumptions and the methodology, which is why there are differences in the results. The combination of such outcomes and their normalization to fit a particular agenda reduces the credibility of the outcomes.
Organic Cotton

We only work with GOTS-certified organic cotton suppliers. GOTS certification prescribes strict regulations for production practices. One of the core restrictions is that no artificial fertilizers are allowed for cultivation and no pesticides may be used. In addition, genetically modified cotton seeds are also not permitted in certified production. Conventional cotton is estimated to require approximately 16% of the world’s insecticides and 7% of the pesticides. In summary, about 0.457 kg of fertilizer and 16 g of pesticides are used to grow 1 kg of conventional cotton.

The water needed to grow cotton is another big issue. The most important fact is that both organic and conventional cotton require similar amounts of water. However, organic cotton requires 30% less artificial irrigation from the groundwater, since most of it is fed with rain. It is due to the natural properties of chemically undamaged soil – this traps and stores more water which results in large water savings. It is estimated that a conventional cotton t-shirt requires approximately 2700 liters of water, while most of this amount is used to grow the cotton.

Calculations showed that by working with only GOTS-certified cotton material suppliers, up to 40% of the energy required for conventional cotton cultivation can be saved. In addition, further steps in our own production such as energy-saving lamps, optimized order quantities to reduce transport and the reuse of material residues help to save up to 12% of the energy previously used. Since there is no generalized report on how much energy different fabrics need for cultivation, transport and manufacturing processes, the calculation is made by combining different studies and estimates.

It is estimated that the cultivation of organic cotton reduces CO2 emissions by 42% compared to conventional cotton. CO2 emissions vary depending on the geographic location of the farm. Since our organic cotton comes from India, an average of 978 kg CO2 are emitted there to grow 1 ton of organic cotton.

 

Conventional cottonOrganic cottonImpact
Water26100 l / kg19270 l / kg6830 l / kg
CO24,64 kg CO2 / kg3,08 kg CO2 / kg1,56 kg CO2 / kg
Energy27,78 kWh / kg21,1 kWh / kg6,68 kWh / kg
Chemicals0,473 kg0,473 kg
Recycled Polyester

Man-made fibers require less water than natural fibers in their production. However, the amount of fresh water involved is still huge. The choice of recycled fibers eliminates the raw material extraction and chemical processes required to convert crude oil to polyester, which are the largest water-consuming processes. Therefore, it is estimated that recycling PET to polyester requires 90% less water than producing new PET.

Artificial fabrics require more energy to be prepared for final use. It is because of the chemical processes that are used in manufacturing. Various studies report that the production of recycled polyester requires up to 53% less energy than the production of new polyester. Common industry consensus says that the lower limit is 34%. Our tool takes 46% into account in the calculation to assess possible disparities in scientific studies.

Virgin polyester is made from crude oil, which is why significant amounts of CO2 are released throughout the process. By using recycling polyester, there is no longer any crude oil, so that CO2 emissions are significantly reduced. By combining estimates from different sources, we were able to reduce CO2 emissions by 53% compared to the production of new polyester (also called virgin polyester).

 

Virgin polyesterRecycled polyesterImpact
Water1308 l / kg131 l / kg1177 l / kg
CO23,8 kg CO2 / kg1,77 kg CO2 / kg2,03 kg CO2 / kg
Energy36,1 kWh / kg19,5 kWh / kg16,6 kWh / kg
Oil & gas1,5 kg1,5 kg