6a Introduction: Energy Markets (Part 2) PDF

IØ8303: Energy Markets (Part 2) Lecture 6a – Introduction (Overview, Basics of Energy Econ, Sustainable Energy Transition, Flexibility Options) Prof. Dr. rer. soc. oec. Reinhard Madlener 1. FCN at RWTH Aachen University...

IØ8303: Energy Markets (Part 2) Lecture 6a – Introduction (Overview, Basics of Energy Econ, Sustainable Energy Transition, Flexibility Options) Prof. Dr. rer. soc. oec. Reinhard Madlener 1. FCN at RWTH Aachen University Mathematics, Computer Science and Natural Sciences Medicine Architecture 47,078 Students in the winter semester of 2022/2023 Faculty 8 Business & Civil Economics Engineering RWTH Aachen Energy Economics, University Energy Resource & Innovation Economics FCN 6,264 Other academic staff (including externally funded staff), 2,979 Non- faculty staff (including externally Mechanical Philosophy funded staff), 472 Trainees and Engineering interns Electrical Geore- Engineering sources & & Materials Information Engineering Technology Source: http://www.rwth-aachen.de/cms/root/Die-RWTH/Profil/~enw/Daten-Fakten/, (March 23, 2023) NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 1. FCN / E.ON Energy Research Center Prof. Dr. rer. soc. oec. Reinhard Madlener Director FCN (est. Jun 2007), Full Professor of Energy Economics and FCN City Branch Office Management (FCN-ECO) (Consultation Prof. Madlener*)  2 Postdocs Augustinerbach 2a, 52062 Aachen  7 PhD Students 2nd Floor, Rooms 201-204  1 External Doctoral Student  2 Affiliated Post-Doc Researchers  2 Admin Officers (Fr. Schill, Mr. Höppener)  5 Student Assistants Prof. Dr.-Ing. Aaron Praktiknjo Full Professor of Energy System Economics (FCN- ESE) E.ON ERC Main Building  1 Postdoc (RWTH Campus Melaten)  6 PhD Students Mathieustraße 10,  2 Admin Officers 52074 Aachen  9 Student Assistants 1st Floor, Rooms 10.16 – 10.30 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 1. FCN / E.ON Energy Research Center June 2016: research and development contract research co-operation between (E.ON SE) and RWTH Aachen university was signed Four Institutes with 7 professors in the field of energy technology belong to core group of center. Cooperation with two Associate Institutes (GGE and ISEA) started. Research areas: energy savings, efficiency and sustainable power sources for the urban environment (buildings and city quarters, energy distribution systems, automation and services) Energy Economics 4 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 1. E.ON ERC at RWTH Aachen Campus Melaten See also the E.ON ERC 3 min Image Video (YouTube)!  The RWTH Aachen Campus  Up to 250 industrial research partners (currently about 120)  Area: 800,000 m²  Capital pre-commitments: € 2,000,000,000  New direct and indirect jobs created: approx. 10,000 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 1. Intro E.ON ERC and FCN AixPeriments in Energy Economics 6 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 1. Some Energy Research Networking (incl. student exchange) NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 1. Intro E.ON ERC and FCN 8 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 2. Intro Energy Markets course (Part 2) (Selected Topics in) Advanced Energy Economics Why the course?  Rising energy demand and limited supplies question the fossil fuel economy upon which the modern world is built  Unrestricted energy use, whether through fossil or biofuels, is a significant contributor to escalating levels of CO2 and other pollutants  New market designs needed in a world with high shares of renewables, digitalization, and decentralization  Research and investment in alternative sources of energy and energy storage is growing rapidly (paradigm shift towards the “Prosumer”)  Energy policies are neither always effective nor efficient, thus improve- ments in policy design by economic theory should provide useful ‘Toolbox’ explored here: Theories, Models and Approaches Used in (Advanced) Energy Economics 9 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 2. Intro Energy Markets course (Part 2) Learning goals  To get a deep and critical understanding of energy supply and use, and how it impacts our national and global economies  To discuss the energy policy tradeoffs (‘Energy Trilemma’) and the need for regulation and reform  To give dominant theoretical and empirical perspectives on energy and its supply and demand (e.g. the standard models of renewable and non-renewable resource extraction and the econometrics of energy systems)  To get a deeper knowledge of energy efficiency and rebound effects  To focus on the negative consequences of energy use (e.g. problem of pollution and how it can be controlled through economic mechanisms)  To focus on individual sources of energy (e.g., nuclear energy, ‘renewables’) 10 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024  2. Intro Energy Markets course – Lecture Overview (Part 2) Session Date Session Title 6 Sep 27 (a) Introduction (E.ON ERC etc., Orga & Contents of course); (Fri) (b) Market Reform and Regulation; (c) Bottom-up Modeling of Energy Demand Presentation: tbd 7 Sep 30 (a) Top-down Modeling of Energy Demand; (b) Economy-Wide (Mon) Modeling Presentation: Zerrahn et al. (Kristine) 8 Oct 1 (a) Econ of Energy Efficiency; (b) Energy Rebound (Tue) Presentation: tbd 9 Oct 2 (a) Econ of Optimal (Quasi-) Renewable Resource Extraction; (Wed) (b) Non-Market Valuation Presentation: Balancing Markets (Stephany) 10 Oct 3 (a) Econ of Nuclear Energy; (b) Electr. Markets; (c) Real Options; (Thu) (d) High Shares of Renewables, Smart Grid Econ Presentation: tbd 11 Oct 4 (a) Machine Learning in Energy Econ & Energy Finance; (b) (Fri) Summary/ Wrap-up/ Prep. Final Exam (Part 2) Daily 10:00-15:00 h, with a lunch break 11:30-12:30 h and a coffee / health break ca. 14:30-14:45 h (on Friday, Oct 4, we will finish at around 12:00 h) 11 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 3. Intro Energy Econ: Energy Market Mechanism Figure 1.1 Market price coordinating supply and demand Energy price pE (Inverse) energy supply function (= marginal pmax production cost) ** pE A1 pE* A0 (Inverse) energy demand function (marginal willingness to pay / opportunity cost) Q* Q** Quantity Q Source: Zweifel, Praktiknjo, Erdmann (2017). Energy Economics – Theory and Applications (Springer) 12 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 3. Intro Energy Econ: Energy Policy Trilemma Figure 1.2 Magical triangle of energy policy goals ü Competition policy Competitiveness Price control Regulation Safety control Eco-taxes Trade policy Innovation policy Strategic reserves Environmental protection Security of supply Source: Zweifel, Praktiknjo, Erdmann (2017). Energy Economics – Theory and Applications (Springer) 13 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 3. Intro Energy Econ: Short- and Long-Term Effects on Energy Markets Figure 5.3 Short-term and long-term effects of a reduction in energy supply Energy price pE Energy supply B pE* C pE A Long-term energy demand Short-term energy demand Q* Q Energy quantity Q Source: Zweifel, Praktiknjo, Erdmann (2017). Energy Economics – Theory and Applications (Springer) 14 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 3. Intro Energy Econ: Price Formation on Electricity Markets, Merit Order Curve Figure 12.4 Price formation on the electricity spot market Peak demand Marginal cost, willingness to pay WTP, 100 [EUR/MWh] 80 Off-peak demand 60 40 Oil and gas Hard coal 20 Lignite 0 20 30 40 50 60 70 Available load without wind power [1,000 MW] Source: Zweifel, Praktiknjo, Erdmann (2017). Energy Economics – Theory and Applications (Springer) 15 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 3. Intro Energy Econ: Regulation and Reform of Energy Markets The energy supply industry including the network operators represent the problems of natural monopoly and related monopoly problems. To solve these challenges, two solutions are proposed: 1. to allow monopolies to operate under a system of regulation or 2. to use public ownership to capture monopoly rents and redistribute the proceeds through state policies. Scope for the reform of energy markets Government / political system Stable Unstable Short Opportunistic / rent- Quick fixes Political term seeking practices perspective Long Major reforms Reforms unlikely term possible Fig. 2: Importance of rule makers‘ stability in reform Source: Bhattacharyya (2011), p.691 16 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 3. Intro Energy Econ: Useful Textbooks Recommended Literature:  Subhes C. Bhattacharyya: Energy Economics – Concepts, Issues, Markets and Governance (Springer, 2011) ≡ ISBN: 978-0857292674 ≡ Hardcopy: € 97.99  R. Perman, Y. Ma, J. McGilvray, M. Common: Natural Resource and Environmental Economics (Pearson Education Limited, 2003) ≡ ISBN: 978-0-273-65559-6 ≡ Hardcopy: € 81.89  P. Zweifel, A. Praktiknjo, G. Erdmann, Energy Economics – Theory and Applications ≡ ISBN: 978-3-662-53020-7 ≡ Hardcopy: € 69.54 17 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024  3. Intro Energy Econ: Sustainable Energy Transition, the 3Ds etc. – it‘s not all about electricity, it‘s not all sustainable … Many (fascinating) ideas, but the world needs solutions, soon… Anthropozene 18 Introduction (Overview) | Prof. Dr. rer. soc. oec. Reinhard Madlener | Institute for Future Energy Consumer Needs and Behavior (FCN) | NTNU, Sep 16, 2019 4. Sustainable Energy Transition What does the sustainable energy transition (“Energiewende”) entail? Which challenges arise from it? 19 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 4. Sustainable Energy Transition Targets for the German Energy Transition Status quo 2025 2030 2035 2040 2050 (2020) Greenhouse Reduction of CO2-emissions -40.8% -70% -80 – 95% gas emissions in all sectors compared to 1990 levels Nuclear Gradual shut down of all Gradual shut down phase-out nuclear power plants by of remaining 6 2022 reactors Renewable Share in final energy 19.3% 30% 45% min. 60% energies consumption Share in gross electricity consumption 45.4% 40 – 45% 80% 55 – 60% min. 80% Energy Reduction of primary energy -18.7% -50% efficiency consumption compared to 2008 levels Reduction of gross -11% -25% electricity consumption compared to 2008 levels Critical acclaim: energy efficiency in 2020 might be affected by the Covid-19 pandemic  strong reduction in energy demand compared to 2019 data Source: Based on Agora Energiewende (2017), with 2020 data from BMU (2021) 20 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 4. Sustainable Energy Transition Long-term Trends 1.000 Break- Other renewables Nuclear Policy through Stagnation Phase-out 900 Mandatory use of Shift to imported hard Decline & phase-out Biomass Coal Policy domestic coal coal & hard coal decline of hard coal & lignite 800 Take-off & Stabilized Main source of Solar Renewables Policy breakthrough growth electricity 700 Wind 600 Hydro TWh 500 Other fossil 400 Natural gas Hard coal 300 Lignite 200 Nuclear 100 * 1950-1954: Western Germany only 0 1950* 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050 Source: Matthes (2019) 21 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 4. Sustainable Energy Transition What are variable renewable energy sources (VRES)? Mainly wind (onshore/offshore), solar The “4Ds” in a Smart Grid environment: (1) Decarbonization, (2) Decentralization, (3) Digitalization, (4) Democratization What are the challenges of integrating high shares of RES into the existing electricity grid? ≡ Decentralization of electricity production – electricity grid needs to be transformed from centralized to decentralized electricity production ≡ Capacity increase of electricity production – due to lower full-load hours of RES (imperfect substitutes) ≡ Volatility of RES electricity production – energy storage ≡ Social acceptance issues (NIMBY-ism), large investments, financial risks etc. 22 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 5. Flexibility Options Demand-side flexibility options − Demand Response (DR), Demand Side Management (DSM) − Energy Efficiency − Unconventional energy consumption forms Supply-side flexibility options − Strategic RES power curtailment − (Enhanced) Conventional generation Network-side flexibility options − Smart grids − Dynamic network reconfiguration − Micro-grid and islanding control − Network interconnections − Network expansion planning Other sources of flexibility − Energy storage systems − Energy systems integration Source: Cruz et al. (2018) − Energy markets 23 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 5. Flexibility Options Flexibility needs and options in power systems Source: Cruz et al. (2018) 24 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 5. Flexibility Options Demand Response Alteration of energy consumption levels/patterns in response to dynamically changing prices and incentives Incentive-based programs: direct load control, curtailable load services, demand bidding or buyback programs Price-based programs: time-of-use (ToU), critical peak pricing (CPP), peak time rebate (PTR), and real-time pricing (RTP) programs Source: Cruz et al. (2018) 25 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 5. Flexibility Options Demand Response Three categories of potential benefits: 1. System reliability − DR is becoming an important balancing resource with increasing shares of VRES − DR can be used for regulation and ramp constraints mitigation − DR can help in the balancing of schedule deviations − DR combined with storage units, can contribute towards the provision of frequency control reserves − DR can be used to respond to contingency events 2. Environmental benefits − Some DR programs can lead to energy conservation. − Primary environmental benefits derive from the fact that DR is a low-carbon power system ‘resource’ 26 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 5. Flexibility Options Demand Response Three categories of potential benefits: 3. Economic efficiency − By providing balancing capacity − In the long run, DR can enable deferral of capital expenditures, both in generation capacity and in transmission and distribution upgrades − DR entails a potential to lower the wholesale prices of electricity − Exposing end-users to dynamic real-time prices (pricing) can provide the incentive to consume electricity in an economically efficient manner − DR can enable utilities and other parties to provide consumers with better service/s − Market-based virtual power plant (VPP) operations also ensure that DR resources compete on the market − DR increases competition and innovation in the electricity market − DR can reduce unscheduled load-shedding and associated penalties − DR can contribute to increasing energy autonomy of regions through an increased capacity to use local renewable energy resources 27 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 5. Flexibility Options Efficiency Voluntary reduction of consumer energy usage Requires investments in energy-efficient technologies or participation in energy conversion initiatives Often in response to incentives designed to entice consumers Source: Cruz et al. (2018) 28 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 5. Flexibility Options RES Curtailment Power outputs from variable renewable energy sources (VRES; e.g. wind, solar) are subject to high level of uncertainty as these sources heavily depend on weather conditions which are partially unpredictable Actual power potential could be substantially lower/higher than the forecasted value Either case leads to large unforeseen demand-supply imbalances in the system A strategic curtailment of RES power could be justified under the following situations: − over-generation − oversupply of RES power outputs − congestions and widespread use of inflexible baseload generators Strategic curtailment can also be done to dampen quick changes in power production or in the provision of reserve power capacity by a ramp-up margin Source: Cruz et al. (2018) 29 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 5. Flexibility Options Smart Grids Today’s power grid Future power grid Not designed to allow “up-stream” power Bi-directional power flow flow Source: Harmann 30 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 5. Flexibility Options Smart Grids Traditional power grid Future power grid  Centralized generation  Decentralized generation  Hierarchical topology following “top-  Cellular “bottom-up” approach down philosophy” 31 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 5. Flexibility Options Smart Grids The smart grid concept (intelligent electricity supply systems) includes linking and controling intelligent generation devices, storage, appliances and network equipment by means of information and communication technology. The objective is a transparent and cost-efficient as well as secure and robust system operation and sustainable and ecological energy supply. Source: DKE- Smart Grid Roadmap : http://www.dke.de/de/infocenter/seiten/artikeldetails.aspx?eslshopitemid=35380119-4346-4335-b5f1-8d77d9c6a853 32 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 5. Flexibility Options Smart Grids 33 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 5. Flexibility Options Smart Grids Coordination of renewable generation devices Technical problems / challenges:  intermittent character of supply  Supply must equal demand  Supply independent from demand Technical Solution Economic Solution  Decentralized energy storage  Flexible demand  Batteries at home  Price elasticity  Batteries at the generation device  Customers‘ behavior  Thermal storage (cold storage  Automated control house, fridge)  Smart buildings 34 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 5. Flexibility Options Network Expansion Planning Important means to improve power system flexibility Expansion planning process encompasses: ≡ reinforcement of existing transmission and distribution corridors ≡ building alternative paths ≡ installing power flow controllers ≡ reactive power sources such as smart inverters Helps to meet multiple objectives: ≡ enhancing market efficiency ≡ motivating new market players ≡ proper and optimal management of congestions ≡ Supporting more RES integration Source: Cruz et al. (2018) 35 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 5. Flexibility Options Energy Storage Systems Storage technologies according to capacity and storage time 36 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 5. Flexibility Options Energy Storage Systems ESS can be integrated on the supply, demand, or network side Option to provide additional support through ancillary services Various technologies available: physical (e.g. hydro), electromechanical, electrochemical (e.g. fuel cells, batteries), electrostatic, electromagnetic Source: Cruz et al. (2018) 37 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 6. Summary (Sust. Energy Transition, Flexibility Options)  The sustainable energy transition (Energiewende) is a challenging – but no doubt indispensable and already ongoing – major undertaking  Integration of high shares of VRES into the existing system creates technical as well as economic and systemic challenges due to high volatility  Many technologies and strategies for meeting these challenges exist; the respective costs and optima are, however, not easily estimated (path dependence / lock-ins; dynamic co-evolution; need for re-regulation)  High shares of VRES requires an increasing system flexibility; there are numerous options available (supply side, demand side, grid side), controlled by various stakeholders; (sometimes) “missing money problem” due to Merit Order Effect, imposes add’l risk  The power system is the most advanced regarding the transition, but energy system integration bears much further potential (synergies vs. unbundling)  A lot of research is going on to better understand optimal solutions in a rapidly changing energy world  Economics matters, as does social acceptance, political will, regulation etc. 38 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024 Contact Institute for Future Energy Consumer Needs and Prof. Dr. Reinhard Madlener Behavior (FCN) T +49 241 80 49 820 E.ON Energy Research Center [email protected] Mathieustraße 10 52074 Aachen, Germany http://www.eonerc.rwth-aachen.de/FCN 39 NTNU IØ 8303, Energy Markets, Part 2: Lecture 6a (Introduction, Overview) | Prof. Dr. Reinhard Madlener | FCN | RWTH Aachen University | Sep 27, 2024