How sustainable are our products?

New methods for assessing a product’s carbon footprint

The product carbon footprint (PCF) assesses a product’s impact on climate change across its entire lifecycle. On the path to a climate-neutral, circular economy, this will be a significant index for all manufacturers. Solutions are currently being developed for efficiently and reliably measuring the PCF.

Residual current operated circuit breakers (RCCBs) are a favorite example of an electrical product that’s installed by the millions in electrical systems and in virtually every building to protect against severe power failures. A small circuit breaker weighs about 200 grams and is made of various plastics as well as different iron and copper alloys and a little precious metal. A circuit breaker is expected to function for 20 years in continuous operation with a power loss of about 0.4 Watts. It’s then disposed of: and while several of its components are recyclable, it usually winds up as landfill.

Every life phase and every component of a product produces climate-related emissions that are quantified by a product carbon footprint (PCF). The PCF is becoming an important index for suppliers and customers in all industries. The Sustainability Engineering Team, an interdisciplinary team at Siemens, is pursuing research across the entire PCF value chain as part of the Siemens DEGREE program

Systematic and detailed analysis

“In a systematic procedure known as the LCIA (lifecycle impact assessment), we determine the overall impact of a specific product on the environment. We call this the product environmental footprint (PEF). It starts with a product parts list that contains all the individual parts used to make the product, their materials, and how they were processed. In the LCIA, we examine the entire product lifecycle, including manufacturing, operation, and recycling or disposal as well as additional parts and raw materials purchased. So for example, if a product contains copper parts, we also take into account the fact that the copper first had to be mined, purified, processed, and transported,” explains Frank Walachowicz, a Berlin-based expert on the Sustainability Engineering Team. “The product environmental footprint evaluates a number of impact categories. What’s especially important for us is the PCF, which includes the output of CO² and other climate-related gases. But we also analyze other environmentally relevant influences like ecotoxicity and water consumption.”

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Ten times faster with a mathematical approximation

Admittedly, an LCIA is costly. If each individual electrical product type – every switch, fuse, and electric motor – had to be assessed, the manufacturer would be hit with massive additional expenditures. But if we manage to divide the entire product portfolio into suitable classes – for example, a class for RCCBs, which are designed for different power outputs but basically have the same structure – then an entire portfolio can be assessed using a few detailed analyses. “From our piloting of product assessments for circuit breakers, we learned that a detailed analysis of about 20 reference products was sufficient for a portfolio of approximately 200 different product versions.  That’s a leverage factor of 1:10 in the portfolio,” says Walachowicz. “In each product class, we perform a detailed LCIA of at least three products in the class. For the remaining products, we can then calculate the PCF, for example, extremely accurately using a mathematical approximation process. This process is much faster and we can still provide our customers with reliable product data.”

The supplier dilemma

In the future, even manufacturers of complex products like a Simatic controller will need to be able to provide their product’s PCF, which incorporates the PCFs of all the individual parts installed. “In order to manufacture our Simatic products, we buy a lot of components from other manufacturers. We estimate that over 90 percent of our system’s PCF originates in the supply chains of our suppliers. So it’s extremely important that we know how high the PCF is for the components that we buy from external suppliers,” explains Florian Albrecht of Siemens Digital Industries. “We rely on the information provided by the manufacturers because – without knowledge of a supplier’s internal processes, which we typically don’t have – we can only make a very rough estimate of the PCF based on average values. But with this method, we can’t show our customers that we and our suppliers are better than average. Basically, it’s the same for us as for people who try to buy sustainable products in their private lives. There’s no way to tell whether a product was sustainably produced by looking at the product itself: You can only rely on the information provided by the manufacturer.” This is where the dilemma arises. A product’s PCF can be correctly determined only if the PCF information for all the components is complete and accurate so that it can be correctly interpreted.

ESTAINIUM: For reliable PCFs even for complex products

To solve this dilemma, Siemens initiated the global ESTAINIUM network. “The ESTAINIUM network enables a secure exchange of reliable PCF data across the supply chain. Trust technology ensures that the PCF data is trustworthy and verifiable while at the same time protecting the confidentiality of the supplier’s supply chain,” says Albrecht. “If all the suppliers of a product are connected to ESTAINIUM, the PCF of even complex products can be reliably and efficiently determined. We take advantage this transparency to optimize our supply chains in terms of emissions. And we can prove that the PEF of our products is better than average.”

Aenne Barnard  November 2021

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