Circular Economy

The circular economy is a resource-efficient model that focuses on maximizing resource use and minimizing waste by promoting products, materials and resources that can be reused, repaired or recycled in a closed loop. In contrast to linear economy, which is based on "consume and dispose", the circular economy aims to create a circular system in which resources are used continuously and the life cycle of products is extended.

Within this system, the institutes of Fraunhofer Energy Research are dedicated to a wide range of research approaches: These include a wide range of innovative technologies and concepts, from the use of residual materials to generate energy and the reuse of water to systematic analysis in life cycle assessment.

Competencies of the Fraunhofer Energy Alliance in the Field Circular Economy

Residual Materials - Material and Energy Use

The material and energy use of residual materials is a central element in the circular economy, which aims to optimize the use of resources and waste recycling. Residual materials generated in industrial and production processes can be reused as raw materials for new products. On the other hand, they also offer potential for energy use, for example by being used to generate biomass energy or to produce biogas. Experts at Fraunhofer Energy Research are working in particular on innovative processes for recovering recyclables from waste, on recycling nutrients and on converting residual materials into CO2-neutral energy sources.



Phosphorus-rich sewage sludge ashes

The aim is to make statements about the phosphorus content in the ash fractions and to derive measures for phosphorus recovery (more information in German).



The aim of the project is to automate the disassembly of future electrolyzers. For this purpose, the requirements of a digital twin as well as of the necessary software and hardware are identified at an early stage.

Biorefinery / Re-use: Water, Nutrients, Recyclables

The biorefinery is an innovative concept that involves the use of biological raw materials to obtain various products and valuable elements, including water, nutrients and recyclables. This approach is of crucial importance for the circular economy, as it is aimed at the sustainable and versatile use of biomass. Research priority of Fraunhofer Energy Research is particularly on recovering recyclables from seawater, wastewater and fertilizers.




The aim of the project is to ensure that the use of particulate organic carbon from municipal wastewater does not consist solely of the production of the climate-relevant gas methane, as has been the case to date, but that more sustainable products are created.



»SEArcularMINE« will prototype an innovative integrated process recovering energy and CRM such as magnesium, lithium, rubidium and other trace elements (TE), from waste brines in Mediterranean basin saltworks. 



The »Phy2Climate« project is testing a global approach to reclaiming agricultural land through a combination of phytoremediation, biofuel production and climate-friendly copper smelting operations.

Carbon Capture / Carbon Storage / Carbon Usage

Carbon Capture, Carbon Storage and Carbon Usage are central pillars in the fight against climate change, as they aim to reduce CO2 emissions and capture, store or use carbon dioxide that has already been released. Our experts are investigating, for example, the conversion of CO2 into chemical raw materials, the production of synthetic fuels from CO2 and hydrogen and other innovative processes. This research makes a decisive contribution to minimizing CO2 emissions and shaping a low-carbon future.




To ensure that coal can be used in the most environmentally friendly way possible, the »CoalCO2-XTM« programme aims to make the components usable for the production of products such as diesel and fertilizers.



The aim is to develop the next generation of renewable fuels that are produced from CO2 using renewable energies. To this end, an end-to-end process chain is to be demonstrated that significantly improves energy efficiency.



In the Fraunhofer project »eBioCO2n«, funded by the Max Planck Cooperation Program, a new type of modular electrobiocatalytic process is being developed. This allows CO2 to be used to produce valuable fine chemicals.



The aim is to utilize CO2-containing waste gases from the cement industry. Specifically, a process chain is to be developed to enable the synthesis of olefins and higher alcohols from carbon dioxide process gases.



In the »NuKoS« research project, slag from steel production is to be processed for further use with the help of CO2. Higher-value products for the construction, plastics, cement and paper industries are to be manufactured from slag.



The aim of the project is the direct production of alcohols from CO2 - by means of electrochemical reduction. This electrolysis is to be operated under technical and economic conditions.

Greenhouse Gas Reduction / CO2 Saving

Reducing greenhouse gases and saving CO2 emissions are key steps in the fight against climate change. Efforts in these areas are aimed at reducing emissions of climate-damaging gases, whether through improved energy efficiency, increased use of renewable energies, promotion of sustainable mobility or the implementation of innovative technologies. Measures to reduce greenhouse gases and save CO2 are essential to slow down global warming and ensure a sustainable future for generations to come. In addition to technological solutions such as renewable energies, sustainable building materials and net-zero technologies, the institutes of Fraunhofer Energy Research are also investigating the impact of social trends on CO2 emissions.




The aim of the »SCI4climate.NRW« project is to use innovation roadmaps to identify paths towards a climate-neutral and sustainable basic materials industry in 2050 - while maintaining economic efficiency and competitiveness.


Net-zero energy building

In 2018, Freiburg's »Rathaus im Stühlinger«, the world's first public building (net floor space 22,650m2) with a zero-energy concept, was completed. This means that the building supplies more energy than it consumes per year.


Climate-Neutral Energy System

The study examines development paths of the German energy system that lead to a reduction in CO₂ emissions of between 95 and 100 percent by 2050.



In the project, the use of foliage to provide heat is being analyzed from an different perspectives. The existing foliage potential and the supply chains are being examined in order to ensure a high degree of transferability (more information in German).


Life Cycle Assessment LCA

Life Cycle Assessment (LCA) is a method that evaluates the environmental footprint of a product, process or service over its entire life cycle. This includes the extraction, production, use and disposal of raw materials. In energy research at Fraunhofer, LCA plays a central role in the evaluation of energy generation systems, materials and technologies. By applying LCA, environmental impacts are analyzed and optimization opportunities are identified in order to develop more sustainable solutions. Our experts offer tailor-made support for balancing through process simulations and experimental studies. The offering was aimed in particular at customers in the chemicals, plastics, green IT and circular economy industries.




In the joint project »DreiSATS«, a process chain for decentralized phosphorus recycling from sewage sludge is currently being developed and demonstrated for the »central German tri-border area of Saxony-Anhalt, Thuringia and Saxony«.



The development of new bio-based adhesive and adhesives based on polyurethane dispersions (PUD) was the focus of the project »Thermoaktivierbare Bio-Klebstoffe« (»Thermoactivated bioadhesives« ) –ThermoBiK for short.



In the project »InteRessE« an interdisciplinary assessment of the resource requirements for the energy transition is developed. Taking into account various criteria, the project aims to evaluate the characteristics for an optimal energy system.