Austria

The EU targets 10 Mt of green hydrogen production by 2030 but has not committed to targets for 2040. Green hydrogen competes with carbon capture and storage biomass and imports as well as direct electrification in reaching emissions reductions; earlier studies have demonstrated the great uncertainty in future costoptimal development of green hydrogen. In spite of this we show that Europe risks little by setting green hydrogen production targets at around 25 Mt by 2040. Employing an extensive scenario analysis combined with novel near-optimal techniques we find that this target results in systems that are within 10% of cost-optimal in all considered scenarios with current-day biomass availability and baseline transportation electrification. Setting concrete targets is important in order to resolve significant uncertainty that hampers investments. Targeting green hydrogen reduces the dependence on carbon capture and storage and green fuel imports making for a more robust European climate strategy.

To reduce fossil fuel dependency in shipping adopting alternative fuels and innovative propulsion systems is essential. Solid Oxide Fuel Cells (SOFC) powered by hydrogen carriers represent a promising solution. This study investigates a multi-fuel SOFC system for ocean-going vessels capable of operating with ammonia methanol or hydrogen thus enhancing bunkering flexibility. A thermodynamic model is developed to simulate the performance of a 3 kW small-scale system subsequently scaling up to a 10 MW configuration to meet the power demand of a container ship used as the case study. Results show that methanol is the most efficient fueling option reaching a system efficiency of 58% while ammonia and hydrogen reach slightly lower values of about 55% and 51% respectively due to higher auxiliary power consumption. To assess technical feasibility two installation scenarios are considered for accommodating multiple fuel tanks. The first scenario seeks the optimal fuel share equivalent to the diesel tank’s chemical energy (17.6 GWh) minimizing mass increase. The second scenario optimizes the fuel share within the available tank volume (1646 m3 ) again minimizing mass penalties. In both cases feasibility results have highlighted that changes are needed in terms of cargo reduction equal to 20.3% or alternatively in terms of lower autonomy with an increase in refueling stops. These issues can be mitigated by the benefits of increased bunkering flexibility

This paper explores cleaner and techno-economically viable solutions to provide electricity heat and cooling using green hydrogen (H2) and green ammonia (NH3) across the entire decarbonized value chain. We propose integrating a 100% hydrogen-fueled internal combustion engine (e.g. Jenbacher JMS 420) as a stationary backup solution and comparing its performance with other backup technologies. While electrochemical storage systems or battery energy storage systems (BESSs) offer fast and reliable short-term energy buffering they lack flexibility in relocation and typically involve higher costs for extended backup durations. Through five case studies we highlight that renewable-based energy supply requires additional capacity to bridge longer periods of undersupply. Our results indicate that for cost reasons battery–electric solutions alone are not economically feasible for longterm backup. Instead a more effective system combines both battery and hydrogen storage where batteries address daily fluctuations and hydrogen engines handle seasonal surpluses. Despite lower overall efficiency gas engines offer favorable investment and operating costs in backup applications with low annual operating hours. Furthermore the inherent fuel flexibility of combustion engines eventually will allow green ammonia-based backup systems particularly as advancements in small-scale thermal cracking become commercially available. Future studies will address CO2 credit recognition carbon taxes and regulatory constraints in developing more effective dispatch and master-planning solutions.

The thermal management system and the balance-of-plant (BoP) in fuel cell electric vehicles (FCEV) are characterized by a particularly high level of complexity and a number of interfaces. Optimizing the efficiency of the overall vehicle is of special importance to maximize the range and increase the attractiveness of this technology to customers. This paper focuses on the optimization potential of the air supply system in the BoP whereby the charging concepts of the electric supercharger (ESC) and the electrically assisted turbocharger (EAT) as well as the integration of water spray injection (WSI) at the compressor inlet are investigated in the framework of an FCEV complete vehicle co-simulation. As a benchmark for the integration of these optimization measures the complete vehicle co-simulation is designed for a fuel cell electric passenger car of the current generation. Here thermo-hydraulic fluid circuits in the thermal management software KULI are coupled with mathematical-physical models in MATLAB/Simulink. Applying advanced simulation methodologies for the components of fuel cell powertrain and vehicle cabin enables the mapping of the effects of realistic operating conditions on the FCEV characteristics. The EAT offers the advantage over the ESC that due to the arrangement of an exhaust gas turbine a part of the exhaust gas enthalpy flow downstream of the fuel cell stack can be recovered which reduces the electrical compressor drive power. Moreover an additional reduction of this power consumption can be achieved by WSI as the effect of evaporative cooling lowers the initial compression temperature. For analysis and comparison these concepts are again modeled with high degree of detail and integrated into the benchmark overall vehicle simulation. The results indicate considerable reductions in the electric compressor drive power of the EAT compared to the ESC with noteworthy potential for reducing the vehicle’s hydrogen consumption. At an operating point in Worldwide harmonized Light Duty Test Cycle (WLTC) under 35 ◦ C ambient temperature and 25 % relative humidity the electrical compressor drive power shows a reduction potential of −40 % which corresponds to a vehicle-level hydrogen consumption reduction of up to −3 %. In addition the results also highlight the effect of the WSI in both charging concepts whereby its potential to reduce the hydrogen consumption on the overall vehicle level is relatively small. In WLTC at 35 ◦C ambient temperature and 25 % relative humidity the compressor drive power reduction potential for ESC and EAT averages −5 % while the effect on hydrogen consumption is only around −0.25 %.

Refrigeration units in semi-trucks or rigged-body trucks have an energy demand of 8.2–12.4 MWh/y and emit 524.26 kt CO2e/y in Germany. Electrification with fuel cell systems reduces the CO2 emission but an increase of efficiency is necessary because of rapidly increasing hydrogen costs. A metal hydride refrigeration system can increase the efficiency. Even though it was already demonstrated in lab scale with 900 W this power is not sufficient to support a truck refrigeration system and the power output of the lab system was not controllable. Here we show the design and validation of a MATLAB© Simulink model of this metal hydride refrigeration system and its suitability for high power applications with a scaled-up reactor. It was scaled up to rated power of 5 kW and efficiency improvements with an advanced valve switching as well as a controlled cooling pump were implemented. Two application-relevant use cases with hydrogen mass flows from hydrogen fuel cell truck systems were analyzed. The simulation results of these use cases provide an average cooling power of 4.2 and 6.1 kW. Additionally the control of the coolant mass flow at different temperature levels a controlled hydrogen mass flow with a bypass system and an advanced valve switching mechanism increased the system efficiency of the total refrigeration system by 30 % overall.