Christoph Streuling’s research while affiliated with German Aerospace Center (DLR) and other places

Battery‐ and hydrogen‐powered trains are emerging technologies that have the potential to play a key role in the decarbonization of railway lines for which full trackside electrification is not feasible. In this study, we examine Pareto‐optimal energy supply concepts for a specific location along the Cologne–Gerolstein railway line. We investigate two supply concepts, one for battery trains making use of overhead line islands (OHLIs), referred to as the OHLI supply concept, and another for hydrogen trains that make use of hydrogen refueling station (HRSs), referred to as the HRS supply concept. The public grid, as well as renewable energy sources such as wind and PV energy, are considered sources of electrical energy supply. The sizing of these takes into account storage technologies and load time series specific to each supply concept. Simulation models are defined to evaluate the characteristics of an OHLI and HRS supply concept located in a small town (Gerolstein, Germany). Our findings indicate that the HRS supply concept results in more than twice the cost per MWh (111%/MWh higher) compared to the OHLI supply concept. However, the HRS supply concept achieves a 24.7% higher degree of self‐sufficiency. Furthermore, the HRS supply concept requires a larger energy system in terms of installed renewable power and storage capacity. This enables the HRS to supply the entire line with energy, whereas the OHLI supply concept covers only a share of the overall energy demand of battery trains at the location under consideration. The remaining energy demand is covered by existing overhead lines or OHLI at another location.

Battery electric multiple units (BEMU) are an effective path towards a decarbonized regional rail transport on partly electrified rail lines. As a means of sector coupling, the BEMU recharging energy demand provided through overhead line islands can be covered from decentralized renewable energy sources (RES). Thus, fully carbon-free electricity for rail transport purposes can be obtained. In this study, we analyze cost reduction potentials of efficient recharging infrastructure positioning and the feasibility of covering BEMU energy demand by direct-use of locally produced renewable electricity. Therefore, we set up a model-based approach which assesses relevant lifecycle costs (LCC) of different trackside electrification alternatives comparing energy supply from local RES and grid consumption. The model-based approach is applied to the example of a German regional rail line. In the case of an overhead line island, the direct-use of electricity from adjacent wind power plants with on-site battery storage results in relevant LCC of EUR 173.4 M/30a, while grid consumption results in EUR 176.2 M/30a whereas full electrification results in EUR 224.5 M/30a. Depending on site-specific factors such as existing electrification and line lengths, BEMU operation and partial overhead line extension can lead to significant cost reductions of recharging infrastructure as compared to full electrification.

As the transport sector is ought to be decarbonized, fuel-cell-powered trains are a viable zero-tailpipe technology alternative to the widely employed diesel multiple units in regional railway service on non-electrified tracks. Carbon-free hydrogen can be provided by water-electrolysis from renewable energies. In this study we introduce an approach to assess the potential of wind-based hydrogen for use in adjacent regional rail transport by applying a GIS approach in conjunction with a site-level cost model. In Brandenburg about 10.1 million train-km annually could be switched to fuel cell electric train operation. This relates to a diesel consumption of appr. 9.5 million liters today. If fuel cell trains would be employed, that translated to 2198 annual tons hydrogen annually. At favorable sites hydrogen costs of approx. 6.40 €/kg - including costs of hydrogen refueling stations - could be achieved. Making excess hydrogen available for other consumers, would further decrease hydrogen production costs.

Im Auftrag der NOW GmbH wurde durch das Institut für Fahrzeugkonzepte des Deutschen Zentrums für Luft­ und Raumfahrt e. V. das Marktpotenzial alternativer Antriebe für Fahrzeuge im deutschen Schienenpersonennahverkehr (SPNV) analysiert. Als Ersatz für dieselbetriebene Triebzüge (engl.: Diesel Multiple Unit – DMU) werden dafür schwerpunktmäßig die Potenziale von Batterie-Oberleitungshybridtriebzügen (BEMU) und von Brennstoffzellenhybridtriebzügen (FCEMU) beschrieben. Schließlich wird das Marktpotenzial von BEMU und FCEMU für sämtliche anstehenden SPNV-­Wettbewerbsnetze, in denen heute DMU eingesetzt werden, untersucht. Diese Broschüre fasst die wesentlichen Ergebnisse der Studie zusammen.