Applications & Pathways

In sustainable energy transitions the utilization of hydrogen is crucial providing flexibility in the operation of net-zero emission renewable-based energy systems. This paper presents a study on the optimal operation of netzero emission multi-energy future microgrids that utilize hydrogen as an alternative fuel instead of natural gas. The electrolyzers’ output is injected into the hydrogen grid to meet demand or converted back to electricity later using generating units owing to the storage capability of pipes called linepack. For this purpose a detailed mathematical model is developed to simulate the main characteristics of grids (e.g. voltage current hydrogen flow and pressure) as well as various components (e.g. renewable systems electrolyzers and hydrogen-fired units). To become more realistic a possibilistic-robust approach is developed to account for the uncertainty arising from the lack of real-world implementation. By representing a case study a test is performed to evaluate the possibility of employing a low-pressure gas grid to meet the demand for hydrogen. After that the effects of electrolyzers are analyzed in the presence and absence of the uncertainty consideration approach. The result indicates that despite hydrogen’s lower energy density compared to natural gas it is still feasible to satisfy the same energy demand level considering the technical characteristics of the grid. The integration of electrolyzers can reduce wind curtailment by 2 % and supplement hydrogen demand by 50 %. A higher level of conservatism in the possibilistic-robust approach leads to an increase in the mean value of the objective function and a reduction in the standard deviation under the realization of uncertain parameters which provides the decisionmakers with a more realistic insight.

Fuel cell electric vehicles (FCEVs) are zero-emission but face cost and power density challenges. To mitigate these limitations a novel 3D-ordered nano-structured self-supporting membrane electrode assembly (MEA) has been developed. This paper investigates the optimal component sizing of the battery and fuel cell in FCEVs equipped with 3D-ordered MEAs integrating the energy management. To explore the trade-offs between component cost operational cost and fuel cell degradation the sizing and energy management problem is formulated into a multi-objective optimisation problem. A Pareto frontier (PF) study is conducted using the decomposed multi-objective evolutionary algorithm (MOEA/D) for a more diverse distribution of feasible solutions. The modular design of fuel cells is derived from a scaled and stressed experiment. After executing MOEA/D across the three aggressive driving cycles power source configurations are selected from the corresponding PFs based on objective trade-offs ensuring robustness of the overall system. The optimisation performance of the MOEA/D is compared with that of the multi-objective Particle Swarm Optimisation. In addition the selected powertrain configurations are evaluated and compared through standard and realworld driving cycles in a simulation environment. This paper also performs a sensitivity analysis to reveal the influence of diverse component unit costs and hydrogen price. The results indicate that the mediumsized configuration consisting of a 63.31 kW fuel cell stack and a 52.15 kWh battery pack delivers the best overall performance. It achieves a 26.71% reduction in component cost and up to 12.76% savings in hydrogen consumption across various driving conditions. These findings provide valuable insights into the design and optimisation of fuel cell systems for FCEVs.

Coastal regions in Cameroon including Douala Kribi Campo Dibamba and Limbe faced persistent electricity challenges driven by grid instability growing demand and dependence on fossil fuels. Solar resource availability was high but intermittent whereas tidal energy was predictable and energy-dense yet underused. This pilot delivers the first Cameroonian assessment of an off-grid tidal/PV/electrolyzer/hydrogen-storage/fuel-cell architecture explicitly co-optimizing electricity service and green hydrogen production and evaluating performance with a tri-metric economic lens (net present cost levelized cost of electricity and the levelized cost of hydrogen). The system was optimized to minimize net present cost (NPC) levelized cost of electricity (LCOE) levelized cost of hydrogen (LCOH) and three tidal-flow scenarios were analyzed to represent hydrokinetic variability. The design served households small businesses fishing activities schools and health facilities with a baseline demand of 389.50 kWh/day; surplus renewable power drove the electrolyzer to produce hydrogen for later reconversion in the fuel cell. Under the first scenario (1.25 m/s average speed) the optimal mix comprised 137 PV modules (600 W each) a 100 kW fuel cell six 40 kW tidal turbines six 10 kW electrolyzers a 19.5 kW converter and 41 hydrogen tanks (40 L each) yielding an NPC of US$ 2.16 million an LCOE of US$ 0.782/kWh and a LCOH of US$ 19.2/kg of hydrogen. The second scenario (1.47 m/s) required only 12 PV modules one electrolyzer and an 11.3 kW converter lowering costs to an NPC of US$ 1.52 million an LCOE of US$ 0.553/ kWh and a LCOH of US$ 15.4/kg of hydrogen. In the third scenario (1.61 m/s) the configuration shifted to 298 PV modules three tidal turbines eight electrolyzers and a 39.6 kW converter resulting in the highest NPC (US$ 2.47 million) and LCOE (US$ 0.901/kWh) with a LCOH of US$ 18.8/kg of hydrogen. The study also contributes a transparent component-wise employment indicator linking installed capacities/energies to jobs; deployment is expected to create about seven local jobs during installation and early operation tidal turbines (3) solar panels (1) electrolyzers (1) hydrogen tanks (1) and fuel cell (1) with additional minor operation and maintenance positions thereafter. Social analysis indicated improved energy access support for local livelihoods and job creation; environmental results confirmed clean operation with limited marine disturbance. A sensitivity study varying capital and replacement-cost multipliers showed robust performance across economic conditions. Taken together these contributions provide a decision-ready blueprint for coastal communities: a first-of-its-kind Cameroonian hybrid that quantifies both electricity and hydrogen costs (including feasible LCOH) and demonstrates socio-economic co-benefits offering a cost-effective pathway to strengthen energy security foster local development and reduce environmental impact.

This study presents an experimental investigation of a direct injection ammonia-fuelled engine using hydrogen pre-chamber jet ignition. All tests have been conducted in an optically accessible combustion chamber that is installed in the head of a single-cylinder engine. The effect of ammonia injection timing on ignition and combustion characteristics was investigated with the timing varied from 165 CAD BTDC to 40 CAD BTDC. The experiments were conducted with a fixed spark timing of 14 CAD BTDC while ammonia injection duration was adjusted to maintain a main chamber global equivalence ratio of 0.6. Two pre-chamber nozzle configurations a single-hole and a multi-hole were tested. The results show that the later NH3 injection timing (40 CAD BTDC) significantly improved combustion with a peak in-cylinder pressure of 80 bar measured compared to a peak in-cylinder pressure of 50 bar with earlier injection (165 CAD BTDC). This study indicates the importance of optimising ammonia injection timing in order to enhance combustion stability and efficiency. The hydrogen pre-chamber jet ignition combined with a late ammonia injection is a promising approach for addressing the combustion challenges of ammonia as a zero-carbon fuel for maritime applications.

Hydrogen-based Local Energy Communities (LECs) play a pivotal role in modern energy systems and form the fundamental building blocks of hydrogen cities. This review provides a comprehensive assessment of how hydrogen-based LECs advance the hydrogen city concept by examining the technological economic environmental regulatory and social dimensions that shape the integration of green hydrogen into local energy networks. The paper explores the structure of hydrogen cities focusing on the role of multiple LECs in alignment with the European Union’s Clean Energy Package (CEP). Furthermore a case study and mathematical model are presented where the hydrogen city is modelled and the impact of Electric Parking Lot (EPL) and Hydrogen Parking Lot (HPL) management on the hydrogen city’s operation cost is evaluated. The results show that optimised EPL and HPL management can reduce overall operational costs by 5.53 % demonstrating the economic advantages of intelligent scheduling strategies in hydrogen cities.

The recent updates to the Single Day-Ahead Coupling (SDAC) framework in the European energy market along with new rules for providing manual frequency restoration reserve (mFRR) products in the Nordic Energy Activation Market (EAM) have introduced a finer Market Time Unit (MTU) resolution. These developments underscore the growing importance of flexible assets such as power-to-hydrogen (PtH) facilities in delivering system flexibility. However to successfully participate in such markets well-designed and accurate bidding strategies are essential. To fulfill this aim this paper proposes a Mixed Integer Linear Programming (MILP) model to determine the optimal bidding strategies for a typical PtH facility accounting for both the technical characteristics of the involved technologies and the specific participation requirements of the mFRR EAM. The study also explores the economic viability of sourcing electricity from nearby wind turbines (WTs) under a Power Purchase Agreement (PPA). The simulation is conducted using a case study of a planned PtH facility at the Port of Hirtshals Denmark. Results demonstrate that participation in the mFRR EAM particularly through the provision of downward regulation can yield significant economic benefits. Moreover involvement in the mFRR market reduces power intake from the nearby WTs as capacity must be reserved for downward services. Finally the findings highlight the necessity of clearly defined business models for such facilities considering both technical and economic aspects.

To address the economic and reliability challenges of high-penetration renewable energy integration in electricity-heat-hydrogen integrated energy systems and support the dualcarbon strategy this paper proposes an optimal dispatch method integrating Information Gap Decision Theory (IGDT) and Fuzzy Chance-Constrained Programming (FCCP). An IES model coupling multiple energy components was constructed to exploit multi-energy complementarity. A stepped carbon trading mechanism was introduced to quantify emission costs. For interval uncertainties in renewable generation IGDT-based robust and opportunistic dispatch models were established; for fuzzy load uncertainties FCCP transformed them into deterministic equivalents forming a dual-layer “IGDT-FCCP” uncertainty handling framework. Simulation using CPLEX demonstrated that the proposed model dynamically adjusts uncertainty tolerance and confidence levels effectively balancing economy robustness and low-carbon performance under complex uncertainties: reducing total costs by 12.7% cutting carbon emissions by 28.1% and lowering renewable curtailment to 1.8%. This study provides an advanced decision-making paradigm for low-carbon resilient IES.

In northern China the long winter heating period is accompanied by severe wind curtailment. To address this issue a joint optimization scheduling strategy of electric vehicles (EVs) and electro–olefin–hydrogen electromagnetic energy supply device (EHED) is proposed to promote deep wind–solar integration. Firstly the feasibility analysis of EVs participating in scheduling is conducted and the operation models of dispatchable EVs and thermal energy storage EHEDs within the scheduling period are established. Secondly a control strategy for the joint optimization scheduling of wind–solar farms EVs EHEDs and power grid is constructed. Then an economic dispatch model for joint optimization of EVs and EHEDs is established to minimize the system operation cost within the scheduling period and the deep wind–solar integration of the joint optimization model is studied by considering EVs under different demand responses. Finally the proposed model is solved by CPLEX solver. The simulation results show that the established joint optimization economic dispatch model of EV-EHEDs can improve the enthusiasm of dispatchable EVs to participate in deep wind–solar integration reduce wind curtailment power and decrease the overall system operation cost.

High-temperature proton exchange membrane fuel cells (HT-PEM FCs) represent a promising avenue for generating carbon dioxide-free electricity through the utilization of hydrogen fuel. These systems present numerous advantages and challenges for mobile applications positioning them as pivotal technologies for the realization of emission-free regional aircraft. Efficient thermal management of such fuel cell-powered systems is crucial for ensuring the safe and durable operation of the aircraft while concurrently optimizing system volume mass and minimizing parasitic energy consumption. This paper presents four distinct heat transfer principles tailored for the FC-system of a conceptual hydrogen-electric regional aircraft exemplified by DLR’s H2ELECTRA. The outlined approaches encompass conductive cooling air cooling liquid cooling phase change cooling and also included is the utilization of liquid hydrogen as a heat sink. Approaches are introduced with schematic cooling architectures followed by a comprehensive evaluation of their feasibility within the proposed drivetrain. Essential criteria pertinent to airborne applications are evaluated to ascertain the efficacy of each thermal management strategy. The following criteria are selected for evaluation: safety ease of integration reliability and life-cycle costs technology readiness and development as well as performance which is comprised of heat transfer weight volume and parasitic power consumption. Of the presented cooling methods two emerged to be functionally suitable for the application in MW-scale aircraft applications at their current state of the art: liquid cooling utilizing water under high pressure or other thermal carrier liquids and phase-change cooling. Air cooling and conductive cooling have a high potential due to their reduced system complexity and mass but additional studies investigating effects at architecture level in large-scale fuel cell stacks are needed to increase performance levels. These potentially suitable heat transfer technologies warrant further investigation to assess their potential for complexity and weight reduction in the aircraft drivetrain.

This report evaluates the role of Hybrid Renewable Energy Systems (HRESs) in supporting South Africa’s energy transition amidst persistent power shortages coal dependency and growing decarbonisation imperatives. Drawing on national policy frameworks including the Integrated Resource Plan (IRP 2019) the Just Energy Transition (JET) strategy and Net Zero 2050 targets this study analyses five major HRES configurations: PV–Battery PV–Diesel–Battery PV–Wind–Battery PV–Hydrogen and Multi-Source EMS. Through technical modelling lifecycle cost estimation and trade-off analysis the report demonstrates how hybrid systems can decentralise energy supply improve grid resilience and align with socio-economic development goals. Geographic application cost-performance metrics and policy alignment are assessed to inform region-specific deployment strategies. Despite enabling technologies and proven field performance the scale-up of HRESs is constrained by financial regulatory and institutional barriers. The report concludes with targeted policy recommendations to support inclusive and regionally adaptive HRES investment in South Africa.