Vincent Kalchschmid

Power-to-X processes where renewable energy is converted into storable liquids or gases are considered to be one of the key approaches for decarbonizing energy systems and compensating for the volatility involved in generating electricity from renewable sources. In this context, the production of “green” hydrogen and hydrogen-based derivatives is being discussed and tested as a possible solution for the energy-intensive industry sector in particular. Given the sharp, ongoing increases in electricity and gas prices and the need for sustainable energy supplies in production systems, non-energy-intensive companies should also be taken into account when considering possible utilization paths for hydrogen. This work focuses on the following three utilization paths: “hydrogen as an energy storage system that can be reconverted into electricity”, “hydrogen mobility” for company vehicles and “direct hydrogen use”. These three paths are developed, modeled, simulated, and subsequently evaluated in terms of economic and environmental viability. Different photovoltaic system configurations are set up for the tests with nominal power ratings ranging from 300 kW_p to 1000 kW_p. Each system is assigned an electrolyzer with a power output ranging between 200 kW and 700 kW and a fuel cell with a power output ranging between 5 kW and 75 kW. There are also additional variations in relation to the battery storage systems within these basic configurations. Furthermore, a reference variant without battery storage and hydrogen technologies is simulated for each photovoltaic system size. This means that there are ultimately 16 variants to be simulated for each utilization path. The results show that these utilization paths already constitute a reasonable alternative to fossil fuels in terms of costs in variants with a suitable energy system design. For the “hydrogen as an energy storage system” path, electricity production costs of between 43 and 79 ct/kWh can be achieved with the 750 kW_p photovoltaic system. The “hydrogen mobility” is associated with costs of 12 to 15 ct/km, while the “direct hydrogen use” path resulted in costs of 8.2 €/kg. Environmental benefits are achieved in all three paths by replacing the German electricity mix with renewable energy sources produced on site or by substituting hydrogen for fossil fuels. The results confirm that using hydrogen as a storage medium in manufacturing companies could be economically and environmentally viable. These results also form the basis for further studies, e.g., on detailed operating strategies for hydrogen technologies in scenarios involving a combination of multiple utilization paths. The work also presents the simulation-based method developed in this project, which can be transferred to comparable applications in further studies.

Durch den zunehmenden Ausbau der regenerativen Energieerzeugung entstehen immer häufiger Netzengpässe, es steht also mehr Strom zur Verfügung als das Netz transportieren kann. Über das sogenannte Einspeisemanagement, werden die Anlagen dann häufig abgeschaltet. Um die Energiewende ökologisch und ökonomisch zu gestalten, ist es jedoch erforderlich, alternative Lösungen zu finden und zu etablieren. Im vorliegenden Beitrag wird beschrieben, welche Potenziale sich durch das Aufschmelzen von Aluminium direkt am Windrad, mit anschließendem Flüssigmetalltransport zu Gießereien ergeben können. Die Ergebnisse zeigen, dass der Ansatz zur Direktnutzung von Windstrom sowohl eine attraktive Möglichkeit zur Dekarbonisierung der energieintensiven Gießereibranche bietet als auch Kostenvorteile für die Gießereien und dezentralen Schmelzdienstleister erwirken kann.

Production planning and control pursues high delivery reliability and short delivery time of the production system at the lowest possible costs. Especially in energy-intensive industries, energy cost account for a significant amount of manufacturing costs. The consideration of variable electricity market prices using energy-flexibility measures facilitates reduced costs by adapting the load profile of production to an electricity price forecast. However, it also increases the production planning and control system’s complexity by additional input variables and possible risks due to the influence of flexibility measures on the production system. In the case of unexpected events, such as failure of machines or faulty materials, it is difficult to adapt the complex production system to the new situation quickly. There is a risk of high additional costs by various causes, such as delays in deadlines or load peaks. Therefore, this paper presents an approach for developing and evaluating risk treatment paths, which include possible combinations of risks and measures for the mitigation of risk effects. The advantage of these paths compared to a situational reaction is that all effects and possible further interactions can be considered and thus overall cost-efficient solutions can be found. The approach is based on the determination of interactions through interpretive structural modelling and the calculation of conditional probabilities using Bayesian Networks. The approach was implemented in MATLAB^® and applied using real order and energy data from a foundry. The results show that the presented approach enables structured and data-based comparison of risk treatment paths.