Circular Economy (CE) is a growing topic, especially in the European Union, that promotes the responsible and cyclical use of resources possibly contributing to sustainable development. CE is an umbrella concept incorporating different meanings. Despite the unclear concept, CE is turned into defined action plans supported by specific indicators. To understand what indicators used in CE measure specifically, we propose a classification framework to categorise indicators according to reasoning on what (CE strategies) and how (measurement scope). Despite different types, CE strategies can be grouped according to their attempt to preserve functions, products, components, materials, or embodied energy; additionally, indicators can measure the linear economy as a reference scenario. The measurement scope shows how indicators account for technological cycles with or without a Life Cycle Thinking (LCT) approach; or their effects on environmental, social, or economic dimensions. To illustrate the classification framework, we selected quantitative micro scale indicators from literature and macro scale indicators from the European Union 'CE monitoring framework'. The framework illustration shows that most of the indicators focus on the preservation of materials, with strategies such as recycling. However, micro scale indicators can also focus on other CE strategies considering LCT approach, while the European indicators mostly account for materials often without taking LCT into account. Furthermore, none of the available indicators can assess the preservation of functions instead of products, with strategies such as sharing platforms, schemes for product redundancy, or multifunctionality. Finally, the framework illustration suggests that a set of indicators should be used to assess CE instead of a single indicator.

https://biblio.ugent.be/publication/8617340/file/8617343.pdf

Circular economy indicators: What do they measure?

On the sustainability of lithium ion battery industry – A review and perspective

Application of electrochemical impedance spectroscopy to commercial Li-ion cells: a review

Environmental aspects of fuel cells: A review.

Recent progress in metal-organic framework-based supercapacitor electrode materials

This work assesses the environmental impacts of an industrial-scale Solid Oxide Fuel Cell (SOFC) plant fed by sewage biogas locally available from a Waste Water Treatment Plant (WWTP). Three alternative scenarios for biogas exploitation have been investigated and real data from an existing integrated SOFC-WWTP have been retrieved: the first one (Scenario 1) is the current scenario, where biogas is exploited in a boiler for thermal-energy-only production, while the second one is related to the installation of an efficient SOFC-based cogeneration system (Scenario 2). A thermal energy conservation opportunity that foresees the use of a dynamic machine for sludge pre-thickening enhancement is also investigated as a third scenario (Scenario 3). The life cycle impact assessment (LCIA) has shown that producing a substantial share of electrical energy (around 25%) via biogas-fed SOFC cogeneration modules can reduce the environmental burden associated to WWTP operations in five out of the seven impact categories that have been analyzed in this work. A further reduction of impacts, particularly concerning global warming potential and primary energy demand, is possible by the decrease of the thermal request of the digester, thus making the system independent from natural gas. In both Scenarios 2 and 3, primary energy and CO2 emissions embodied in the manufacture and maintenance of the cogeneration system are neutralized by operational savings in less than one year.

Silvia Bobba

Papers

Life Cycle Assessment of a Biogas-Fed Solid Oxide Fuel Cell (SOFC) Integrated in a Wastewater Treatment Plant

Analysing the contribution of automotive remanufacturing to the circularity of materials

Ten years of scientific support for integrating circular economy requirements in the EU ecodesign directive: overview and lessons learnt

SASLAB - Sustainability Assessment of Second Life Applications of Automotive Batteries

Sustainable Use of Materials Through Automotive Remanufacturing to Boost Resource Efficiency in the Road Transport System (SMART)