University of Bayreuth, Press Release No. 024/2024, 28/02/2024

Bayreuth researchers develop a more precise carbon footprint

A study has been carried out at the University of Bayreuth that shows a way to measure the CO2 footprint of companies more accurately. The results of this research can help commercial enterprises to drive forward CO2 savings in the right places. A white paper has now been published in collaboration with the DFGE - Institute for Energy, Ecology and Economy.

What for?

With the Corporate Sustainability Reporting Directive (CSRD), a new EU directive on sustainability reporting has also been introduced in Germany. It is intended to ensure that companies report more transparently on sustainability. Around 15,000 companies in Germany must disclose their carbon footprint when the CSRD comes into force. This is calculated in three scopes. Scope 1 covers the direct release of climate-damaging gases within a company. Scope 2 covers the indirect release of climate-damaging gases by energy suppliers. Scope 3 emissions describe greenhouse gas emissions along the value chain outside the company. Scope 3 emissions in particular often harbour potential for savings. In their study, Bayreuth researchers have now compared the common expenditure-based calculation method for Scope 3 for purchased goods and capital goods with a weight-based approach and found that the results of the usual calculation are starting to make savings in the wrong places.

Bayreuth researchers want to calculate the carbon footprint of companies more accurately in future. The term carbon footprint stands for the recording of climate-impacting greenhouse gases and the compilation of these in a greenhouse gas balance. For the more precise calculations, Nora Kuhn compared 8,500 products in her Bachelor's thesis at the Chair of Environmental Production Technology (LUP) at the University of Bayreuth with the support of Dr Bernd Rosemann, Academic Director of the LUP, and Dominik Roppelt, Nora Kuhn's Bachelor's thesis supervisor and doctoral student in this department. The products were analysed on the basis of their weight, in contrast to the previously used spend-based method. Spend-based emission factors estimate how much greenhouse gas a company emits based on the money it spends on products. But this can be inaccurate because it assumes that all products in a category emit the same amount of greenhouse gases. In addition, prices can fluctuate due to market conditions, but the weight remains the same.

The Bayreuth study uses a weight-based approach and compares 8,500 products in 200 sub-categories and seven main procurement categories. 

The study found that the spend-based approach in a real-life case study showed an overestimation of 11 per cent. "One of the reasons for this is that the categories used in the spend-based approach are much broader. The calculated carbon footprints are therefore only imprecise average values," says Nora Kuhn.

However, the spend-based approach is easier for companies to use as the data is usually already available. "But it is simply too generalised. The deviations within the purchasing categories are 61 per cent on average, which can lead to incorrect prioritisation," she explains. "In order to reduce greenhouse gas emissions, it is necessary to find the right areas. The weight-based method is proving to be a more reliable and accurate tool for targeting strategies to reduce carbon emissions."

With the help of Dr Bernd Rosemann and Dominik Roppelt, Nora Kuhn's research has now been compiled into a white paper for the DFGE - Institute for Energy, Ecology and Economy.

For over 20 years, DFGE has been offering companies consulting, software and auditing services to help them realise a green vision and integrate it into their business processes. In its latest newsletter, it provides information about its core business of addressing the question of whether and, above all, how a sensible combination of ecology and economic efficiency can be achieved.

"The comparison that Ms Kuhn has made is also groundbreaking for the economy," says Dr Bernd Rosemann. "The decision-making basis for reduction measures is much better and companies can reduce their CO2 emissions more effectively."

Bernd Rosemann

Dr.-Ing. Bernd Rosemann

Academic Director of the Chair of Environmental Production Technology

Tel. +49 (0)921 55-7599
E-Mail: bernd.rosemann@uni-bayreuth.de

Jennifer Opel

Jennifer Opel (on maternity/parental leave)Deputy Press & PR Manager

Phone: +49 (0)921 / 55-5357
E-mail: jennifer.opel@uni-bayreuth.de