Decarbonizing industrial systems in a circular economy framework



Start date 2021-01-01

End date 2024-12-31

Recent developments

Two new Subtasks were approved by the IETS ExCo in May 2022:

The Final Report from Subtask 1 is available.

Task Members

Contributions from Austria, Canada, Denmark, Finland, France, Germany, Italy, Netherlands, Norway, Portugal, Sweden

Task Manager

Simon Moser, Energieinstitut an der Johannes Kepler Universität Linz, Austria


This Task aims to investigate the topic of circular carbon from an industry perspective, i.e. to describe industrial energy systems in the context of a sustainable, fossil-free economy, striving to meet the targets of both concepts, the circular economy and a sustainable energy system.
The resource sector’s vision is the so-called circular economy, which aims to avoid the excessive use of limited resources and resource depletion. It aims to reuse and recycle resources and products that are already in use or built. The energy sector’s vision is a sustainable, carbon-neutral energy system that almost exclusively relies on renewables and, in order to achieve this and minimize environmental impact, is very energy efficient. Circularity, efficiency and renewability will inevitably play an important role in a sustainable economy.1 Both future systems are rarely considered together in science and discourse, although they interact or often contradict each other.

Carbon is a key element in both systems. For industrial production, carbon in its various forms (hydrocarbons) plays an essential role as a raw material that can hardly be replaced. While the use of energy cannot enter a closed loop, fossil carbon must not be released at the balance sheet. Consequently, carbon shall be circulated both in the energy and in the product sector, striving for a Carbon Cycle or a Circular Carbon economy.

Objectives and Scope

The general objectives are:

  • to develop the annex as a platform for exchange of information, experiences and lessons in R&D projects in the area of circular carbon.
  • to identify, and when possible, find pragmatic ways to align information, knowledge, definitions, approaches and methodologies used and generated in current and recent projects by annex members
  • to broaden awareness and knowledge regarding the system impacts
  • to facilitate international meetings to share experiences, methodologies and project findings among annex participants

 Subtask 1 (finished)

The specific objectives are:

  • to provide preliminary results and
  • to clearer specify the questions and methods to answer them in Task 2, for example on time horizon and physical system boundaries, and
  • to identify white spots to be included in Subtask 2.

Proposed contents of the current subtasks:

Subtask A: Definition and metrics
In some of its aspects or parts, the concepts of circular economy and sustainable energy systems overlap, interact with each other or contradict each other. Aside from illustrative examples, it is important to make these interactions measurable or derive a clear causality and thus identify them scientifically. The various definitions of the concepts known in literature and applied in the participants’ projects are collected, merged and compared. Key parameters are identified or derived. Based on this, the interactions should be clearly discussed or measurable.

Subtask B: Integrative modeling
The mutual influence of the concepts of circular economy and sustainable energy system are not limited to theoretical or exemplary aspects. In modeling the circular economy (e.g. life cycle analysis) and in modeling the future energy system, the extent to which the other concept is included plays an essential role in the robustness of the results. For example, if circularity actually decreases mining or industrial production of goods and intermediates, this effects macroeconomic energy consumption. If the energy systems decreases its carbon emissions, a product’s life cycle assessment must be adopted.
Based on the participants’ projects, applied and existing models are chosen and it is analyzed to what extent both concepts are already integrated and to estimate the effect of this integration.

Subtask C: Industrial carbon technologies and systems
Carbon is the element where the two concepts of circular economy and sustainable energy system interact the most. In the sustainable energy system, it is important to avoid fossil carbon emissions and to circulate the carbon needed to store energy. In the circular economy, no new fossil carbon should be used as a basis for products. Moreover, due to the property of better storage in the form of hydrocarbons and the usability of hydrocarbons as a basic material in industry, the interaction of carbon with hydrogen plays a special role. This WP focuses on the industrial technologies and systems to capture, (temporarily) store, further process and reuse carbon.

Subtask D: Industrial Symbiosis
Companies often focus on their technical core competence. Collecting, processing or re-supplying carbon or hydrocarbons are usually not one of the core competencies of those industries most affected by CO2 emission mitigation. Industrial symbiosis, i.e. the beneficial integration of third parties and the regional cooperation with other companies is part of the so-called industrial symbiosis.
Industrial symbiosis can make value chains economical. The interaction of the actors means advantages, but also a high degree of complexity. This subtask deals with the possibilities of cooperation in the area of carbon or hydrocarbons, summarizes the findings (drivers and barriers) for industrial symbiosis but also from other areas such as raw material cooperation, waste recycling or waste heat utilization.

Subtask E: Exchange with other IEA TCPs and IETS Annexes
This is a broad topic and its scope overlaps with part of the work done in many other IETS annexes as well as other IEA TCPs. It is therefore important to develop channels of communication that allow for not only exchange of information but also to explore possibilities for carrying out joint actions (for instance workshops) that would be of mutual benefit. This WP aims to establish collaboration between the proposed annex and other annexes in IETS as well as with the Hydrogen TCP, the GHG TCP and the Biomass TCP. The first step will be to identify joint activities that can be conducted with minimal extra efforts from the parties. This could include participating in each other workshops, disseminating information from each other among Annex members, organizing short conference calls, etc. As a second step, it will be explored the possibility to carry out a joint activity, for instance, a joint workshop or even a new subtask for a continuation of this Task.


The results will be:

  • a synthesis report on joint findings and individual project findings or findings elaborated in the subtasks, including
  • detailed clarification of subtask content (to be included in the synthesis report)
  • identification of knowledge gaps and further research needs, potentially leading to new subtasks (to be included in the synthesis report)
  • discussion points and key findings in the workshops included in the Task (to be included in the synthesis report)
  • a report of the activities conducted with other IETS annexes and or IEA TCPs
  • dissemination activities of each participating country