Browsing by Author "Miehe, Robert"

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Open Access
Assessing the application-specific substitutability of lithium-ion battery cathode chemistries based on material criticality, performance, and price
(2021) Kiemel, Steffen; Glöser-Chahoud, Simon; Waltersmann, Lara; Schutzbach, Maximilian; Sauer, Alexander; Miehe, Robert
The material use of lithium-ion batteries (LIBs) is widely discussed in public and scientific discourse. Cathodes of state-of-the-art LIBs are partially comprised of high-priced raw materials mined under alarming ecological and social circumstances. Moreover, battery manufacturers are searching for cathode chemistries that represent a trade-off between low costs and an acceptable material criticality of the comprised elements while fulfilling the performance requirements for the respective application of the LIB. This article provides an assessment of the substitutability of common LIB cathode chemistries (NMC 111, -532, -622, -811, NCA 3%, -9%, LMO, LFP, and LCO) for five major fields of application (traction batteries, stationary energy storage systems, consumer electronics, power-/garden tools, and domestic appliances). Therefore, we provide a tailored methodology for evaluating the substitutability of products or components and critically reflect on the results. Outcomes show that LFP is the preferable cathode chemistry while LCO obtains the worst rating for all fields of application under the assumptions made (as well as the weighting of the considered categories derived from an expert survey). The ranking based on the substitutability score of the other cathode chemistries varies per field of application. NMC 532, -811, -111, and LMO are named recommendable types of cathodes.
Open Access
Carbon-negative hydrogen production (HyBECCS) from organic waste materials in germany : how to estimate bioenergy and greenhouse gas mitigation potential
(2021) Full, Johannes; Trauner, Mathias; Miehe, Robert; Sauer, Alexander
Hydrogen derived from biomass feedstock (biohydrogen) can play a significant role in Germany’s hydrogen economy. However, the bioenergy potential and environmental benefits of biohydrogen production are still largely unknown. Additionally, there are no uniform evaluation methods present for these emerging technologies. Therefore, this paper presents a methodological approach for the evaluation of bioenergy potentials and the attainable environmental impacts of these processes in terms of their carbon footprints. A procedure for determining bioenergy potentials is presented, which provides information on the amount of usable energy after conversion when applied. Therefore, it elaborates a four-step methodical conduct, dealing with available waste materials, uncertainties of early-stage processes, and calculation aspects. The bioenergy to be generated can result in carbon emission savings by substituting fossil energy carriers as well as in negative emissions by applying biohydrogen production with carbon capture and storage (HyBECCS). Hence, a procedure for determining the negative emissions potential is also presented. Moreover, the developed approach can also serve as a guideline for decision makers in research, industry, and politics and might also serve as a basis for further investigations such as implementation strategies or quantification of the benefits of biohydrogen production from organic waste material in Germany.
Open Access
Carbon‐negative hydrogen production : fundamentals for a techno‐economic and environmental assessment of HyBECCS approaches
(2022) Full, Johannes; Ziehn, Sonja; Geller, Marcel; Miehe, Robert; Sauer, Alexander
In order to achieve greenhouse gas neutrality, hydrogen generated from renewable sources will play an important role. Additionally, as underlined in the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), new technologies to remove greenhouse gases from the atmosphere are required on a large scale. A novel concept for hydrogen production with net negative emissions referred to as HyBECCS (Hydrogen Bioenergy with Carbon Capture and Storage) combines these two purposes in one technological approach. The HyBECCS concept combines biohydrogen production from biomass with the capture and storage of biogenic carbon dioxide. Various technology combinations of HyBECCS processes are possible, whose ecological effects and economic viability need to be analyzed in order to provide a basis for comparison and decision‐making. This paper presents fundamentals for the techno‐economic and environmental evaluation of HyBECCS approaches. Transferable frameworks on system boundaries as well as emission, cost, and revenue streams are defined and specifics for the application of existing assessment methods are elaborated. In addition, peculiarities concerning the HyBECCS approach with respect to political regulatory measures and interrelationships between economics and ecology are outlined. Based on these considerations, two key performance indicators (KPIs) are established, referred to as levelized cost of carbon‐negative hydrogen (LCCNH) and of negative emissions (LCNE). Both KPIs allow deciding whether a specific HyBECCS project is economically viable and allows its comparison with different hydrogen, energy provision, or negative emission technologies (NETs).
Open Access
Comparative life cycle sustainability assessment of mono- vs. bivalent operation of a crucible melting furnace
(2022) Schutzbach, Maximilian; Kiemel, Steffen; Miehe, Robert; Köse, Ekrem; Mages, Alexander; Sauer, Alexander
The benefits of energy flexibility measures have not yet been conclusively assessed from an ecological, economic, and social perspective. Until now, analysis has focused on the influence of changes in the energy system and the ecological and economic benefits of these. Therefore, the objective of this study was to perform a life cycle sustainability assessment of energy flexibility measures on the use case of a bivalent crucible melting furnace in comparison with a monovalent one for aluminum light metal die casting. The system boundary was based on a cradle-to-gate approach in Germany and includes the production of the necessary process technologies and energy infrastructure and the utilization phase of the crucible melting furnaces in non-ferrous metallurgy. The LCSA is performed for different economic and environmental scenarios over a 25-year lifetime to account for potential adjustments in the energy system and volatile energy prices. In summary, it can be said that over the entire service life, no complete ecological, economic, and social advantage of energy flexibility measures through a bivalent system can be demonstrated. Only a temporarily better life cycle sustainability performance of the bivalent furnace can be shown. All results must be considered with the caveat that the bivalent crucible melting furnace has not yet been investigated in actual operation and the calculations of the utilization phase are based on the monovalent crucible melting furnace. To further sharpen the results, more research is needed and the use of actual data for bivalent operation.
Open Access
A conceptual framework for biointelligent production : calling for systemic life cycle thinking in cellular units
(2021) Miehe, Robert; Buckreus, Lorena; Kiemel, Steffen; Sauer, Alexander; Bauernhansl, Thomas
A sustainable design of production systems is essential for the future viability of the economy. In this context, biointelligent production systems (BIS) are currently considered one of the most innovative paths for a comprehensive reorientation of existing industrial patterns. BIS are intended to enable a highly localized on-demand production of personalized goods via stand-alone non-expert systems. Recent studies in this field have primarily adopted a technical perspective; this paper addresses the larger picture by discussing the essential issues of integrated production system design. Following a normative logic, we introduce the basic principle of systemic life cycle thinking in cellular units as the foundation of a management framework for BIS. Thereupon, we develop a coherent theoretical model of a future decentralized production system and derive perspectives for future research and development in key areas of management.
Open Access
Cradle-to-gate life cycle assessment of cylindrical sulfide-based solid-state batteries
(2024) Rietdorf, Chantal; De la Rúa, Cristina; Kiemel, Steffen; Miehe, Robert
PurposeSolid-state batteries (SSBs) are a current research hotspot, as they are safer and have a higher energy density than state-of-the-art lithium-ion batteries (LIBs). To date, their production only occurs on a laboratory scale, which provides a good opportunity to analyze the associated environmental impacts prior to industrialization. This paper investigates the environmental impacts of the production of cylindrical SSB, to identify environmental hotspots and optimization potentials.MethodsHere, an attributional cradle-to-gate life cycle assessment (LCA) is performed, focusing on SSBs that use a NMC811/lithium germanium phosphorous sulfide (LiGPS) composite cathode, a sulfide-based solid separator electrolyte, and a lithium metal anode. The life cycle impact assessment (LCIA) is performed in Umberto 11 using the Environmental Footprint 3.1 method with primary and literature data and the Evoinvent 3.9 database for background data.Results and discussionThe results show climate change impacts of 205.43 kg CO2 eq./kwh (for the base case), with hotspots primarily attributable to the electrolyte and cathode production, and more specifically to the LiPS and LiGPS synthesis as well as to the cathode active material. Additionally, the scenario analysis shows that an upscaling of the LiPS and LiGPS synthesis reduces environmental impacts across all assessed impact categories. In addition, it was shown that the use of an in situ anode further improves the overall environmental performance, while the use of alternative cathode active materials, such as NMC622 and LFP did not lead to any improvements, at least with reference to the storage capacity.ConclusionThe article highlights the environmental hotspots of sulfide-based SSB production, namely electrolyte and catholyte synthesis. The results show that upscaling the synthesis reduces the environmental impact and that cells with higher energy density show a favorable environmental performance. However, SSBs are still in the development stage and no final recommendation can be made at this time.
Open Access
Defining material compliance : a comprehensive analysis
(2021) Buckreus, Lorena; Nuffer, Anne-Kathrin; Miehe, Robert; Sauer, Alexander
The increase in the number of environmental regulations has resulted in great challenges for corporations in the manufacturing industry, especially within the electronic and electrical and the mechanical engineering sector. To address these compliance requirements, specialized management fields such as environmental compliance, substructures and management approaches have been implemented in industry. Recently, adherence to requirements concerning the composition of products and the use of materials and substances within products has become increasingly important and is referred to as material compliance (MC). Although the topic is of increasing importance, there is no generally accepted definition for MC nor a management framework. Corporations are thus unable to systematically address MC, and compliance violations occur frequently. We derived a definition for MC based on extensive literature research, which we subsequently evaluated in a quantitative survey. Our results indicate that MC is commonly understood as the adherence to requirements concerning the composition of a product and the use of substances and materials within products. By proposing a definition for MC, we aim to introduce a common understanding, enable future research to systematically address the topic and develop a framework for the management of MC.
Open Access
Enzyme-assisted circular additive manufacturing as an enabling technology for a circular bioeconomy : a conceptual review
(2024) Protte-Freitag, Kristin; Gotzig, Sophia; Rothe, Hannah; Schwarz, Oliver; Silber, Nadine; Miehe, Robert
Additive manufacturing (AM) is a decisive element in the sustainable transformation of technologies. And yet its inherent potential has not been fully utilized. In particular, the use of biological materials represents a comparatively new dimension that is still in the early stages of deployment. In order to be considered sustainable and contribute to the circular economy, various challenges need to be overcome. Here, the literature focusing on sustainable, circular approaches is reviewed. It appears that existing processes are not yet capable of being used as circular economy technologies as they are neither able to process residual and waste materials, nor are the produced products easily biodegradable. Enzymatic approaches, however, appear promising. Based on this, a novel concept called enzyme-assisted circular additive manufacturing was developed. Various process combinations using enzymes along the process chain, starting with the preparation of side streams, through the functionalization of biopolymers to the actual printing process and post-processing, are outlined. Future aspects are discussed, stressing the necessity for AM processes to minimize or avoid the use of chemicals such as solvents or binding agents, the need to save energy through lower process temperatures and thereby reduce CO2 consumption, and the necessity for complete biodegradability of the materials used.
Open Access
How to simplify life cycle assessment for industrial applications : a comprehensive review
(2022) Kiemel, Steffen; Rietdorf, Chantal; Schutzbach, Maximilian; Miehe, Robert
Life cycle assessment (LCA) has established itself as the dominant method for identifying the environmental impact of products or services. However, conducting an LCA is labor and time intensive (especially regarding data collection). This paper, therefore, aims to identify methods and tools that enhance the practicability of LCA, especially with regard to product complexity and variance. To this end, an initial literature review on the LCA of complex products was conducted to identify commonly cited barriers and potential solutions. The obtained information was used to derive search strategies for a subsequent comprehensive and systematic literature review of approaches that address the identified barriers and facilitate the LCA process. We identified five approaches to address the barriers of time and effort, complexity, and data intensity. These are the parametric approach, modular approach, automation, aggregation/grouping, and screening. For each, the concept as well as the associated advantages and disadvantages are described. Especially, the automated calculation of results as well as the automated generation of life cycle inventory (LCI) data exhibit great potential for simplification. We provide an overview of common LCA software and databases and evaluate the respective interfaces. As it was not considered in detail, further research should address options for automated data collection in production by utilizing sensors and intelligent interconnection of production infrastructure as well as the interpretation of the acquired data using artificial intelligence.
Open Access
Market perspectives and future fields of application of odor detection biosensors within the biological transformation : a systematic analysis
(2021) Full, Johannes; Baumgarten, Yannick; Delbrück, Lukas; Sauer, Alexander; Miehe, Robert
The technological advantages that biosensors have over conventional technical sensors for odor detection and the role they play in the biological transformation have not yet been comprehensively analyzed. However, this is necessary for assessing their suitability for specific fields of application as well as their improvement and development goals. An overview of biological basics of olfactory systems is given and different odor sensor technologies are described and classified in this paper. Specific market potentials of biosensors for odor detection are identified by applying a tailored methodology that enables the derivation and systematic comparison of both the performance profiles of biosensors as well as the requirement profiles for various application fields. Therefore, the fulfillment of defined requirements is evaluated for biosensors by means of 16 selected technical criteria in order to determine a specific performance profile. Further, a selection of application fields, namely healthcare, food industry, agriculture, cosmetics, safety applications, environmental monitoring for odor detection sensors is derived to compare the importance of the criteria for each of the fields, leading to market-specific requirement profiles. The analysis reveals that the requirement criteria considered to be the most important ones across all application fields are high specificity, high selectivity, high repeat accuracy, high resolution, high accuracy, and high sensitivity. All these criteria, except for the repeat accuracy, can potentially be better met by biosensors than by technical sensors, according to the results obtained. Therefore, biosensor technology in general has a high application potential for all the areas of application under consideration. Health and safety applications especially are considered to have high potential for biosensors due to their correspondence between requirement and performance profiles. Special attention is paid to new areas of application that require multi-sensing capability. Application scenarios for multi-sensing biosensors are therefore derived. Moreover, the role of biosensors within the biological transformation is discussed.
Open Access
Methodik zur Quantifizierung der nachhaltigen Wertschöpfung von Produktionssystemen an der ökonomisch-ökologischen Schnittstelle anhand ausgewählter Umweltprobleme
(Stuttgart : Fraunhofer Verlag, 2018) Miehe, Robert; Bauernhansl, Thomas (Prof. Dr.)
Nachhaltige Wertschöpfung ist das Diktum einer zukunftsfähigen Wirtschaftsform. Damit es gelingen kann, Produktionssysteme nach dieser Maßgabe zu konzipieren, ist eine quantitative Bezifferung von essentieller Bedeutung. Gründend auf den ethisch-normativen Lehren Immanuel Kants‘ und Hans Jonas‘, wird in der vorliegenden Arbeit nach einer kategorischen Objektivierung der Wertschöpfung an der ökonomisch-ökologischen Schnittstelle gesucht. Das hier vorgelegte Konzept erweitert die betriebliche Wertschöpfungsrechnung um die sozio-ökologischen Folgen produktionstechnischer Handlungen. Mit dem eco²-Value-Added wird ein rein pekuniärer Indikator präsentiert, der sowohl die betriebs- als auch die gesellschaftszweckdienlichen Effekte der Leistungserstellung zu inkludieren vermag. Einem produzierenden Unternehmen eröffnet das Konzept die Überprüfung der gesellschaftlichen Legitimation, die Antizipation von Unternehmensrisiken sowie eine zielorientierte Ausrichtung des soziotechnischen Systems im Hinblick auf die immanente Gerechtigkeitsherausforderung. Ebenso ist eine ordnungspolitische Verwendung des Ansatzes in Form gezielter Steuer- und Regelungsmechanismen möglich.
Open Access
A new perspective for climate change mitigation : introducing carbon-negative hydrogen production from biomass with carbon capture and storage (HyBECCS)
(2021) Full, Johannes; Merseburg, Steffen; Miehe, Robert; Sauer, Alexander
The greatest lever for advancing climate adaptation and mitigation is the defossilization of energy systems. A key opportunity to replace fossil fuels across sectors is the use of renewable hydrogen. In this context, the main political and social push is currently on climate neutral hydrogen (H2) production through electrolysis using renewable electricity. Another climate neutral possibility that has recently gained importance is biohydrogen production from biogenic residual and waste materials. This paper introduces for the first time a novel concept for the production of hydrogen with net negative emissions. The derived concept combines biohydrogen production using biotechnological or thermochemical processes with carbon dioxide (CO2) capture and storage. Various process combinations referred to this basic approach are defined as HyBECCS (Hydrogen Bioenergy with Carbon Capture and Storage) and described in this paper. The technical principles and resulting advantages of the novel concept are systematically derived and compared with other Negative Emission Technologies (NET). These include the high concentration and purity of the CO2 to be captured compared to Direct Air Carbon Capture (DAC) and Post-combustion Carbon Capture (PCC) as well as the emission-free use of hydrogen resulting in a higher possible CO2 capture rate compared to hydrocarbon-based biofuels generated with Bioenergy with Carbon Capture and Storage (BECCS) technologies. Further, the role of carbon-negative hydrogen in future energy systems is analyzed, taking into account key societal and technological drivers against the background of climate adaptation and mitigation. For this purpose, taking the example of the Federal Republic of Germany, the ecological impacts are estimated, and an economic assessment is made. For the production and use of carbon-negative hydrogen, a saving potential of 8.49-17.06 MtCO2,eq/a is estimated for the year 2030 in Germany. The production costs for carbon-negative hydrogen would have to be below 4.30 € per kg in a worst-case scenario and below 10.44 € in a best-case scenario in order to be competitive in Germany, taking into account hydrogen market forecasts.
Open Access
Perspectives of biogas plants as BECCS facilities : a comparative analysis of biomethane vs. biohydrogen production with carbon capture and storage or use (CCS/CCU)
(2023) Full, Johannes; Hohmann, Silja; Ziehn, Sonja; Gamero, Edgar; Schließ, Tobias; Schmid, Hans-Peter; Miehe, Robert; Sauer, Alexander
The transition to a carbon-neutral economy requires innovative solutions that reduce greenhouse gas emissions (GHG) and promote sustainable energy production. Additionally, carbon dioxide removal technologies are urgently needed. The production of biomethane or biohydrogen with carbon dioxide capture and storage are two promising BECCS approaches to achieve these goals. In this study, we compare the advantages and disadvantages of these two approaches regarding their technical, economic, and environmental performance. Our analysis shows that while both approaches have the potential to reduce GHG emissions and increase energy security, the hydrogen-production approach has several advantages, including up to five times higher carbon dioxide removal potential. However, the hydrogen bioenergy with carbon capture and storage (HyBECCS) approach also faces some challenges, such as higher capital costs, the need for additional infrastructure, and lower energy efficiency. Our results give valuable insights into the trade-offs between these two approaches. They can inform decision-makers regarding the most suitable method for reducing GHG emissions and provide renewable energy in different settings.
Open Access
Process model and life cycle assessment of biorefinery concept using agricultural and industrial residues for biohydrogen production
(2024) Gamero, Edgar; Ruppert, Sophia; Miehe, Robert; Sauer, Alexander
Sustainable waste management strategies are urgently needed due to an increasing global population and increased waste production. In this context, biorefineries have recently emerged as a promising approach to valorize waste streams and supply a broad range of products. This study presents the process model and life cycle assessment (LCA) of a biorefinery concept using a novel biochemical method, a so-called “dark photosynthesis” conversion. This process is coupled to a photo-fermentation using microalgae. Overall, the biorefinery concept can produce hydrogen, lutein, β-carotene, and proteins for animal feed. Apple pomace from apple juice production is used as feedstock for the primary conversion step. A process model was created with the process simulation software Aspen Plus ® using experimental and literature data. Results from this model were then used in an LCA. The environmental impacts of the proposed biorefinery concept are relatively high, showing the need for process optimization in several areas. Energy system integration, stream recycling, and higher hydrogen yields are recognized as especially important for improving the environmental performance of this concept. Despite these findings, the model shows the feasibility of implementing the biochemical conversion technologies in a biorefinery concept for effectively utilizing residue streams.
Open Access
Sodium-based batteries : in search of the best compromise between sustainability and maximization of electric performance
(2020) Karabelli, Duygu; Singh, Soumya; Kiemel, Steffen; Koller, Jan; Konarov, Aishuak; Stubhan, Frank; Miehe, Robert; Weeber, Max; Bakenov, Zhumabay; Birke, Kai Peter
Till 2020 the predominant key success factors of battery development have been overwhelmingly energy density, power density, lifetime, safety, and costs per kWh. That is why there is a high expectation on energy storage systems such as lithium-air (Li-O2) and lithium-sulfur (Li-S) systems, especially for mobile applications. These systems have high theoretical specific energy densities compared to conventional Li-ion systems. If the challenges such as practical implementation, low energy efficiency, and cycle life are handled, these systems could provide an interesting energy source for EVs. However, various raw materials are increasingly under critical discussion. Though only 3 wt% of metallic lithium is present in a modern Li-ion cell, absolute high amounts of lithium demand will rise due to the fast-growing market for traction and stationary batteries. Moreover, many lithium sources are not available without compromising environmental aspects. Therefore, there is a growing focus on alternative technologies such as Na-ion and Zn-ion batteries. On a view of Na-ion batteries, especially the combination with carbons derived from food waste as negative electrodes may generate a promising overall cost structure, though energy densities are not as favorable as for Li-ion batteries. Within the scope of this work, the future potential of sodium-based batteries will be discussed in view of sustainability and abundance vs. maximization of electric performance. The major directions of cathode materials development are reviewed and the tendency towards designing high-performance systems is discussed. This paper provides an outlook on the potential of sodium-based batteries in the future battery market of mobile and stationary applications.
Open Access
A system thinking normative approach towards integrating the environment into value-added accounting : paving the way from carbon to environmental neutrality
(2022) Miehe, Robert; Finkbeiner, Matthias; Sauer, Alexander; Bauernhansl, Thomas
Life Cycle Assessment (LCA) is increasingly being applied in corporate accounting. Recently, especially carbon footprinting (CF) has been adopted as ‘LCA light’ in accordance with the Greenhouse Gas Protocol. According to the strategy ‘balance, reduce, substitute, compensate’, the approach is intended to provide the basis for optimization towards climate neutrality. However, two major problems arise: (1) due to the predominant focus on climate neutrality, other decisive life-cycle impact categories are often ignored, resulting in a misrecognition of potential trade-offs, and (2) LCA is not perceived as an equal method alongside cost and value-added accounting in everyday business, as it relies on a fundamentally different system understanding. In this paper, we present basic considerations for merging the business and life-cycle perspectives and introduce a novel accounting system that combines elements of traditional operational value-added accounting, process and material flow analysis as well as LCA. The method is based on an extended system thinking, a set of principles, a calculation system, and external cost factors for the impact categories climate change, stratospheric ozone depletion, air pollution, eutrophication and acidification. As a scientifically robust assessment method, the presented approach is intended to be applied in everyday operations in manufacturing companies, providing a foundation for a fundamental change in industrial thought patterns on the way to the total avoidance of negative environmental impacts (i.e., environmental neutrality). Therefore, this is validated in two application examples in the German special tools industry, proving its practicability and reproducibility as well as the suitability of specifically derived indicators for the selective optimization of production systems.
Open Access
Tackling xEV battery chemistry in view of raw material supply shortfalls
(2020) Karabelli, Duygu; Kiemel, Steffen; Singh, Soumya; Koller, Jan; Ehrenberger, Simone; Miehe, Robert; Weeber, Max; Birke, Kai Peter
The growing number of Electric Vehicles poses a serious challenge at the end-of-life for battery manufacturers and recyclers. Manufacturers need access to strategic or critical materials for the production of a battery system. Recycling of end-of-life electric vehicle batteries may ensure a constant supply of critical materials, thereby closing the material cycle in the context of a circular economy. However, the resource-use per cell and thus its chemistry is constantly changing, due to supply disruption or sharply rising costs of certain raw materials along with higher performance expectations from electric vehicle-batteries. It is vital to further explore the nickel-rich cathodes, as they promise to overcome the resource and cost problems. With this study, we aim to analyze the expected development of dominant cell chemistries of Lithium-Ion Batteries until 2030, followed by an analysis of the raw materials availability. This is accomplished with the help of research studies and additional experts’ survey which defines the scenarios to estimate the battery chemistry evolution and the effect it has on a circular economy. In our results, we will discuss the annual demand for global e-mobility by 2030 and the impact of Nickel-Manganese-Cobalt based cathode chemistries on a sustainable economy. Estimations beyond 2030 are subject to high uncertainty due to the potential market penetration of innovative technologies that are currently under research (e.g. solid-state Lithium-Ion and/or sodium-based batteries).