Applications & Pathways

This paper investigates the temperature control problem in hydrogen fuel cells based on the improved sliding mode control method specifically within the context of multirotor drone applications. The study focuses on constructing a control-oriented nonlinear thermal model which serves as a foundation for the subsequent development of a practical temperature regulation approach. Initially a novel sliding mode control strategy is proposed which significantly enhances the precision and stability of temperature control by reducing the impact of sensor errors and environmental disturbances. Subsequently the effectiveness and robustness of this control method under various dynamic loads and environmental conditions are demonstrated. The simulation results demonstrate that the improved sliding mode controller is effective in managing and regulating the fuel cell temperature ensuring optimal performance and stability.

This study investigates the effect of Oxygen-Enriched Combustion on hydrogen-enriched natural gas (H2 -NG) fuel mixtures at a semi-industrial scale (up to 60 kW). The analysis focuses on flame structure temperature distribu tion in the furnace NOx emissions and potential fuel savings. A multi-fuel multi-oxidizer jet burner was used to compare two oxygen enrichment configurations: premixed with air (PM) and air-pure O2 (AO) independent feed. The O2 -enriched flames remained stable across the entire fuel range. OH* chemiluminescence imaging for the H2 -NG fuel mixture delivering 50 concentration kW revealed that higher O2 increases the OH* intensity narrows and elongates the flame transitions from buoyancy- to momentum-driven shape and relocates the reaction zone. At 50 % oxygen enrichment level (OEL) flame shape OH* intensity and temperature profiles resembled pure O combustion. Up to 29 % OEL furnace temperature profiles were similar to those 2 of air-fuel combustion. The power required to maintain 1300 ± 25 ◦C at the reference position decreases with O2 enrichment. Higher OELs resulted in a sharp increase in NOx emissions. The effect of hydrogen enrichment on NOx levels was significantly less pronounced than that of oxygen enrichment. The rise in NOx emissions correlates with increased OH* in tensities. For a 50 % H2 2 blend increasing the O concentration in the oxidizer from 21 % to 50 % resulted in a 27 % reduction in flue gas heat losses. Utilizing O2 co-produced with H2 could be strategic for reducing fuel consumption facilitating the adoption of hydrogen-based energy systems.

The rapid growth in natural gas consumption by gas-fired generators and the emergence of power-to-hydrogen (P2H) technology have increased the interdependency of natural gas and power systems presenting new challenges to energy system operators due to the heterogeneous uncertainties associated with power loads renewable energy sources (RESs) and gas loads. These uncertainties can easily spread from one infrastructure to another increasing the risk of cascading outages. Given the erratic nature of RESs P2H technology provides a valuable solution for large-scale energy storage systems crucial for the transition to economic clean and secure energy systems. This paper proposes a new approach for the co-optimized operation of gas and electric power systems aiming to reduce combined operating costs by 10–15% without jeopardizing gas and energy supplies to customers. A mixed integer non-linear programming (MINLP) model is developed for the optimal day-ahead operation of these integrated systems with a case study involving the IEEE 24-bus power system and a 20-node natural gas system. Simulation results demonstrate the model’s effectiveness in minimizing total costs by up to 20% and significantly reducing renewable energy curtailment by over 50%. The proposed approach supports UN Sustainable Development Goals by ensuring sustainable energy (SDG 7) fostering innovation and resilient infrastructure (SDG 9) enhancing energy efficiency for resilient cities (SDG 11) promoting responsible consumption (SDG 12) contributing to climate action (SDG 13) and strengthening partnerships (SDG 17). It promotes clean energy technological innovation resilient infrastructure efficient resource use and climate action supporting the transition to sustainable energy systems.

This study investigates the integration of green hydrogen into building energy systems using local solar power with the electricity grid serving as a backup plan. A comprehensive bottom-up analysis compares six energy system configurations: the natural gas grid boiler system all-electric heat pump system natural gas and hydrogen blended system hydrogen microgrid boiler system cogeneration hydrogen fuel cell system and hybrid hydrogen heat pump system. Energy efficiency evaluations were conducted for 25 homes within one block in a neighborhood across five typological house stocks located in Stoke-on-Trent UK. This research was modeled using a spreadsheet-based approach. The results highlight that while the all-electric heat pump system still demonstrates the highest energy efficiency with the lowest consumption the hybrid hydrogen heat pump system emerges as the most efficient hydrogen-based solution. Further optimization through the implementation of a peak-shaving strategy shows promise in enhancing system performance. In this approach hybrid hydrogen serves as a heating source during peak demand hours (evenings and cold seasons) complemented by a solar energy powered heat pump during summer and daytime. An hourly operational configuration is recommended to ensure consistent performance and sustainability. This study focuses on energy performance excluding cost-effectiveness analysis. Therefore the cost of the energy is not taken into consideration requiring further development for future research in these areas.

Dual fuel combustion has gained attention as a cost-effective solution for reducing the pollutant emissions of internal combustion engines. The typical approach is combining a conventional high-reactivity fossil fuel (diesel fuel) with a sustainable low-reactivity fuel such as bio-methane ethanol or green hydrogen. The last one is particularly interesting as in theory it produces only water and NOx when it burns. However integrating hydrogen into stock diesel engines is far from trivial due to a number of theoretical and practical challenges mainly related to the control of combustion at different loads and speeds. The use of 3D-CFD simulation supported by experimental data appears to be the most effective way to address these issues. This study investigates the hydrogen-diesel dual fuel concept implemented with minimum modifications in a light-duty diesel engine (2.8 L 4-cylinder direct injection with common rail) considering two operating points representing typical partial and full load conditions for a light commercial vehicle or an industrial engine. The numerical analysis explores the effects of progressively replacing diesel fuel with hydrogen up to 80% of the total energy input. The goal is to assess how this substitution affects engine performance and combustion characteristics. The results show that a moderate hydrogen substitution improves brake thermal efficiency while higher substitution rates present quite a severe challenge. To address these issues the diesel fuel injection strategy is optimized under dual fuel operation. The research findings are promising but they also indicate that further investigations are needed at high hydrogen substitution rates in order to exploit the potential of the concept.

CO2 emission reduction of sectors such as aviation maritime shipping road haulage and chemical production is challenging but necessary. Although these sectors will most likely continue to rely on carbonaceous energy carriers they are expected to gradually shift away from fossil fuels. In order to do so the prominent option is to utilize alternative carbon sources—like biomass and CO2 originating from carbon capture—for the production of non-fossil carbonaceous vectors (biofuels and e-fuels). However the limited availability of biomass and the varying nature of other carbon sources necessitate a comprehensive evaluation of trade-offs between potential carbon uses and existing sources. Then it is primordial to understand the origin of carbon used in sustainable aviation fuel (SAF) to understand the implications of defossilizing aviation for the energy system. Moreover the production of SAF implies deep changes to the energy system that are quantified in this work. This study utilizes the linear programming cost optimization tool EnergyScope TD to analyze the holistic French energy system encompassing transport industry electricity and heat sectors while ensuring net greenhouse gas neutrality. A novel method to model and quantify carbon flows within the system is introduced enabling a comprehensive assessment of greenhouse gas neutrality. This study highlights the significance of fulfilling clean energy requirements and implementing carbon dioxide removal measures as crucial steps toward achieving climate neutrality. Indeed to reach climate neutrality a production of 1046 TWh of electricity by non-fossil sources is needed. Furthermore the findings underscore the critical role of efficient carbon and energy valorization from biomass providing evidence that producing fuels by combining biomass and hydrogen is optimal. The study also offers valuable insights into the future cost and impact of SAF production for air travel originating from France. That is the European law ReFuelEU would increase the price of plane tickets by +33% and would require 126 TWh of hydrogen and 50 TWh of biomass to produce the necessary 91 TWh of jet fuel. Finally the implications of the assumption behind the production of SAF are discussed.

Decarbonizing long-haul heavy-duty transport in Europe focuses on batteryelectric trucks with high-power chargers or electric road systems and fuel-cell-electric vehicles with hydrogen refueling stations. We present a comparative life cycle assessment and total cost of ownership analysis of these technologies for 20% of Germany’s heavy-duty long-haul transport alongside internal combustion engine vehicles. The results show that fuel cell vehicles with on-site hydrogen have the highest life cycle emissions (65 Mt CO2e) followed by internal combustion engine vehicles (55 Mt CO2e). Battery-electric vehicles using electric road systems achieve the lowest emissions (21 Mt CO2e) and the lowest costs (EUR 45 billion). In contrast fuel cell vehicles with on-site hydrogen have the highest costs (EUR 69 billion). Operational costs dominate total expenses making them a compelling target for subsidies. The choice between battery and fuel cell technologies depends on the ratio of vehicles to infrastructure transport performance and range. Fuel cell trucks are better suited for remote areas due to their longer range while integrating electric road systems with high-power charging could offer synergies. Recent advancements in battery and fuel cell durability further highlight the potential of both technologies in heavy-duty transport. This study provides insights for policymakers and industry stakeholders in the shift towards sustainable transport. The greenhouse gas emission savings from adopting battery-electric trucks are 54% in our high-power charging scenario and 62% in the electric road system scenario in comparison to the reference scenario with diesel trucks.

The integration of hydrogen technologies is widely regarded as a transformative step in the energy transition. Recently the German government unveiled a Power Plant Strategy to promote H2-Ready Combined-Cycle Gas Turbines (H2-CCGT) which are intended to initially run on natural gas and transition to green hydrogen by 2040 at the latest. This study assesses the role of H2-Ready power plants in a low-carbon transition and explores plausible pathways using a capacity expansion model for Germany. This topic is particularly relevant for other countries aiming to deploy a large share of renewables and considering H2-CCGT as a flexible backup solution to ensure system flexibility and achieve deep decarbonization. Our results indicate that H2-CCGT enhance system flexibility and significantly alleviate the investments need for additional flexibility and renewable generation capacity and reduce renewable-energy curtailment by more than 35 %. Moreover our results also demonstrate that allowing hydrogen in CCGT does not entirely reduce the need for fossil fueled power plants as hydrogen becomes economically viable only with deep decarbonization or direct subsidies. We show that policy interventions can alter the transition pathways for achieving a decarbonized energy system. Our research challenges a prevailing narrative that financial support for hydrogen is needed to ensure a cost-efficient system decarbonization. More straightforward market-based policy instruments such as intensified CO2 pricing or regulatory frameworks such as earlier mandatory hydrogen shifts in H2-CCGT prove more efficient at cutting emissions and costs.

The report addresses the environmental challenges faced by European sea ports and aims to provide guidance to smaller ports for improving their environmental performance while achieving sustainability goals through experiences gained by implementing noteworthy green initiatives in practice. Larger ports possess significant advantages in terms of financial resources risk tolerance and organisational capacity. They often have the means to invest in innovative solutions and actively participate in research and development projects leading to co-funded pilot implementation of green initiatives. They typically have more skilled personnel stronger influence and stakeholder leverage which position them better to lead the way in sustainability efforts. Finally larger ports often form robust collaborations to drive collective action towards sustainable goals. Smaller ports face unique challenges stemming from typically limited resources and risk aversion. They often prioritise mature solutions relying on tested practices to mitigate potential risks. They may lack internal expertise requiring guidance and capacity-building programmes to navigate the selection and implementation of green practices. Also they require financial and technical support particularly as they may underutilise available funding mechanisms and have limited participation in R&D programmes. They may benefit from partnerships with other ports and stakeholders to create synergies and gain experience from their lessons learned to boost their capacity to implement green practices

Offshore wind power construction has seen significant development due to the high density of offshore wind energy and the minimal terrain restrictions for offshore wind farms. However integrating this energy into the grid remains a challenge. The scientific community is increasingly focusing on hydrogen as a means to enhance the integration of these fluctuating renewable energy sources. This paper reviews the research on renewable energy power generation water electrolysis for hydrogen production and large-scale hydrogen storage. By integrating the latest advancements we propose a system that couples offshore wind power generation seawater electrolysis (SWE) for hydrogen production and salt cavern hydrogen storage. This coupling system aims to address practical issues such as the grid integration of offshore wind power and large-scale hydrogen storage. Regarding the application potential of this coupling system this paper details the advantages of developing renewable energy and hydrogen energy in Jiangsu using this system. While there are still some challenges in the application of this system it undeniably offers a new pathway for coastal cities to advance renewable energy development and sets a new direction for hydrogen energy progress.