It all depends on the limits
When considering the green footprint of a product or service, the entire product life cycle should be considered. This means that all material and energy flows should be included in the calculation, from creation through use to disposal. An internationally used method is known as Life Cycle Assessment (LCA).
In an LCA, the first step is to define the target and the accounting framework. Often, the entire life cycle is not considered, but only parts of it. Basically, the following system boundaries are distinguished:
- Cradle-to-grave: from the extraction of raw materials to production, application, possible recycling and final disposal.
- Cradle-to-gate: from the extraction of raw materials through production in the plant to the producer's company gateway
- Cradle-to-cradle: considers a complete circular economy
An important parameter in LCA is the functional unit. It defines the reference value that enables comparisons to be made. Examples are numbers of units or mass data in kg or tons.
Data is the be-all and end-all
The essential basis of an LCA, after defining the system boundaries, is the collection of data relevant to the defined scope of the study. This includes data on energy flow (e.g., electricity, heat) or material flow (raw materials, intermediates, or waste), process information (efficiencies, losses, etc.) or product use information (e.g., application, maintenance, service life), and end-of-life information (processing method, disposal, recycling).
In a further phase of the LCA, the data obtained is linked to specific impact indicators in order to be able to determine the environmental impacts. Different emissions, such as SO2 or CH4, are converted into CO2 equivalents in order to make their environmentally damaging potential comparable. For example, 1 kg of nitrous oxide (N2O) corresponds to 310 kg of CO2 equivalent.
Is sustainability just a fig leaf for the economy?
No, it isn't. Companies that invest in sustainability and make the not inconsiderable effort of carrying out a life cycle assessment study, e.g. in the form of an LCA, not only improve their image but are also able to identify optimization potential, save resources and energy and reduce the negative environmental impact of their product thanks to the comprehensive and detailed analysis of their production process.
Turning the tide in steel production
Exemplary change: With the SALCOS project, the Salzgitter steel and technology group is planning a new era in steel production.