Publications

Water photoelectrolysis cells based on photoelectrochemical water splitting seem to be an interesting alternative to other traditional green hydrogen generation processes (e.g. water electrolysis). Unfortunately the practical application of this technology is currently hindered by several difficulties: low solar-to-hydrogen (STH) efficiency expensive electrode materials etc. A novel concept based on a tandem photoelectrolysis cell configuration with an anion-conducting membrane separating the photoanode from the photocathode has already been proposed in the literature. This approach allows the use of low-cost metal oxide electrodes and nickel-based co-catalysts. In this paper we conducted a study to evaluate the economic and environmental sustainability of this technology using the environmental life cycle cost. Preliminary results have revealed two main interesting aspects: the negligible percentage of externalities in the total cost.

To address the collaborative optimization challenge in multi-microgrid systems with significant renewable energy integration this study presents a dual-layer optimization model incorporating power-hydrogen coupling. Firstly a hydrogen energy system coupling framework including photovoltaics storage batteries and electrolysis hydrogen production/fuel cells was constructed at the architecture level to realize the flexible conversion of multiple energy forms. From a modeling perspective the upper-layer optimization aims to minimize lifecycle costs by determining the optimal sizing of distributed PV systems battery storage hydrogen tanks fuel cells and electrolyzers within the microgrid. At the lower level a distributed optimization framework facilitates energy sharing (both electrical and hydrogen-based) across microgrids. This operational layer maximizes yearly system revenue while considering all energy transactions—both inter-microgrid and grid-to-microgrid exchanges. The resulting operational boundaries feed into the upper-layer capacity optimization with the optimal equipment configuration emerging from the iterative convergence of both layers. Finally the actual microgrid in a certain area is taken as an example to verify the effectiveness of the proposed method.

Hydrogen production from gasification of biowaste generates large volumes of CO2 due to endothermic biowaste decomposition. Alternatively the Sun can provide that energy. To evaluate the yield and performance of solarbased gasifiers at country scale a multi-scale approach is required. First the operation of a solar gasifier is analyzed by developing a two-phase model validated and scaled to industrial level. Next the performance and yield of such technology as a function of the radiation received is studied taking Spain as a case study. The results were promising obtaining a syngas rich in H2. However tar and char were not reduced due to insufficient temperature. Scale-up studies revealed energy losses to the environment in the industrial-scale gasifier which suggested the use of segmented heating. In turn diameters no larger than 0.8 m and biomass feeding rates below 0.85 kg/s highlight the deployment of a modular design due to particle size limitations. Finally the large-scale waste valorization showed that the gasifier can only operate in Spain in the summer months. It can run over 180 h/month and more than 250 days/year only in C´ adiz and Santa Cruz de Tenerife which also showed the highest yearly production capacities.

Water management is crucial for the performance of anion exchange membrane water electrolyzers (AEM-WEs) to maintain membrane hydration and enable phase separation between hydrogen gas and liquid water. Therefore careful material selection for the anode and cathode is essential to enhance reactant/product transport and optimize water management under ‘dry cathode’ conditions. This study investigates the wetting characteristics of two commercially available porous transport layers (PTLs) used in AEM-WE: carbon paper and carbon paper with a microporous layer (MPL). Wettability was measured under static quasi-static and dynamic conditions to assess the effect of water and electrolytes (NaOH KOH K2CO3) across concentrations (up to 1 M) and operational temperatures (20 °C to 92 °C). Carbon paper exhibits mild hydrophobicity (advancing contact angles of ∼120° however with receding contact angle ∼0°) whereas carbon paper with MPL demonstrates superhydrophobicity (advancing and receding contact angles >145° and low contact angle hysteresis) maintaining a stable Cassie-Baxter wetting state. Dynamic wetting experiments confirmed the robustness of the superhydrophobicity in carbon paper with MPL facilitating phase separation between hydrogen gas and liquid water. The presence of supporting electrolytes did not significantly affect wettability and the materials retained hydrophobic properties across different temperatures. These findings highlight the importance of MPLs in optimizing water transport and gas rejection within AEM-WEs ensuring efficient and stable operation under “dry cathode” conditions. These PTLs (with and without the addition of the MPL) were integrated into AEM-WE and polarization curves were run. Preliminary data in a specific condition suggested the presence of the MPL within the PTL enhance AEM-WE performance.

Within energy system analysis there is discourse regarding the role and economic benefits of nuclear energy in terms of overall system costs. The reported findings range from considerable drawbacks to substantial benefits depending on the chosen models scenarios and underlying assumptions. This article addresses existing gaps by demonstrating how subtle variations in model assumptions significantly impact analysis outcomes. Historically uncertainties associated with nuclear energy costs have been well documented whereas renewable energy costs have steadily declined and have been relatively predictable. However as land availability increasingly constrains future renewable expansion development is shifting from onshore to offshore locations where cost uncertainties are greater and anticipated cost reductions are less reliable. This study emphasizes this fundamental shift highlighting how uncertainties in future renewable energy costs could strengthen the economic case of nuclear energy within fully integrated sector-coupled energy systems especially when the costs of all technologies and weather conditions are set in the moderate range. Focusing specifically on Denmark this article presents a thorough sensitivity analysis of renewable energy costs and weather conditions within anticipated future ranges providing a nuanced perspective on the role of nuclear energy. Ultimately the findings underscore that when examining total annual system costs the differences between scenarios with low and high nuclear energy shares are minimal and are within ±5 % for the baseline assumptions while updated adjustments reduce this variation to ±1 %.

Hydrogen production from water electrolysis can not only reduce greenhouse gas emissions but also has abundant raw materials which is one of the ideal ways to produce hydrogen from new energy. The hydrogen production power supply is the core component of the new energy electrolytic water hydrogen production device and its characteristics have a significant impact on the efficiency and purity of hydrogen production and the service life of the electrolytic cell. In essence the DC/DC converter provides the large current required for hydrogen production. For the converter its input still needs the support of a DC power supply. Given the maturity and technical characteristics of new energy power generation integrating energy storage into offshore energy systems enables stable power supply. This configuration not only mitigates energy fluctuations from renewable sources but also further reduces electrolysis costs providing a feasible pathway for large-scale commercialization of green hydrogen production. First this paper performs a simulation analysis on the wind–solar hybrid energy storage power generation system to demonstrate that the wind–solar–storage system can provide stable power support. It places particular emphasis on the significance of hydrogen production power supply design—this focus stems primarily from the fact that electrolyzers impose specific requirements on high operating current levels and low current ripple which exert a direct impact on the electrolyzer’s service life hydrogen production efficiency and operational safety. To suppress the current ripple induced by high switching frequency and high output current traditional approaches typically involve increasing the output inductor. However this method substantially increases the volume and weight of the device reduces the rate of current change and ultimately results in a degradation of the system’s dynamic response performance. To this end this paper focuses on developing a virtual impedance control technology aiming to reduce the ripple amplitude while avoiding an increase in the filter inductor. Owing to constraints in current experimental conditions this research temporarily relies on simulation data. Specifically a programmable power supply is employed to simulate the voltage output of the wind–solar–storage hybrid system thereby bringing the simulation as close as possible to the actual operating conditions of the wind–solar–storage hydrogen production system. The experimental results demonstrate that the proposed method can effectively suppress the ripple amplitude maintain high operating efficiency and ultimately meet the expected research objectives. That makes it particularly suitable as a high-quality power supply for offshore hydrogen production systems that have strict requirements on volume and weight.

Achieving net-zero emissions requires major changes across a nation’s economy energy and land systems particularly due to sectors where emissions are difficult to eliminate. Here we adapt two global scenarios from the International Energy Agency—the net-zero emissions by 2050 and the Stated Policies Scenario—using an integrated numerical economic-energy model tailored to Australia. We explore how emissions may evolve by sector and identify key technologies for decarbonisation. Our results show that a rapid shift to near-zero emissions electricity is central to reducing costs and enabling wider emissions reductions. From 2030 onwards carbon removal through land management and engineered solutions such as direct air capture and bioenergy with carbon capture and storage becomes critical. Australia is also well-positioned to become a global supplier of clean energy such as hydrogen made using renewable electricity helping reduce emissions beyond its borders.

This study explores a multi-faceted approach to improving the combustion performance and emission characteristics of a single-cylinder four-stroke direct injection (DI) compression ignition engine through the combined effects of butanol enrichment green-synthesized copper oxide (CuO) nanoparticles and hydrogen supplementation. The baseline fuel was a B20 biodiesel blend further enriched with 10 % butanol to enhance oxygen availability and atomization. CuO nanoparticles were synthesized via an eco-friendly aloe vera extractmediated method and dispersed into the fuel to promote oxidation kinetics and stabilize combustion. Experimental results revealed that the B20+But10 %+CuO100 blend achieved the highest brake thermal efficiency (BTE) of 33.6 % at full load alongside notable reductions in carbon monoxide (CO) unburned hydrocarbons (HC) nitrogen oxides (NOx) and smoke opacity compared to neat B20. Reactivity controlled compression ignition (RCCI) trials further demonstrated that hydrogen enrichment at 5 LPM and 10 LPM improved flame propagation Brake thermal efficiency (33.89 % & 35.43 %) and reduced brake-specific fuel consumption of nearly 10 % (0.26 Kg/KWh) & 0.25 Kg/KWh). While excessive hydrogen supply (10 LPM) marginally increased HC emissions (110 PPM) at higher loads due to localized incomplete oxidation overall results confirm significant emission mitigation. The findings highlight that the synergistic integration of butanol oxygenation catalytically active CuO nanoparticles and optimized hydrogen enrichment offers a viable pathway toward cleaner combustion improved energy efficiency and reduced pollutant emissions in biodiesel-fueled CI engines.

Ammonia represents a promising alternative fuel and hydrogen carrier for power generation due to its advantages in storage and transportation compared to those of hydrogen. However challenges persist in the direct use of ammonia in solid oxide fuel cells (SOFCs) particularly with respect to performance degradation—an issue that necessitates comprehensive investigation at the full-stack scale. This study examines a ten-cell full-size SOFC stack under various operating conditions to evaluate the viability of ammonia as a direct fuel. Experiments were conducted using pure ammonia pure hydrogen fully reformed ammonia and 50 % pre-reformed ammonia at three operating temperatures (660◦C 710 ◦C and 760 ◦C). Performance was characterized through current–voltage curves electrochemical impedance spectroscopy and continuous monitoring of residual ammonia in the exhaust using Fourier-transform infrared spectroscopy. A 200-hour durability test was performed to assess long-term stability. The results demonstrated that at temperatures of ≥ 710 ◦C ammonia-fueled SOFCs performed comparably to hydrogen-fueled configurations within typical operating ranges (0.2–0.5 A/cm2 ). The stack achieved optimal performance at 55–80 % fuel utilization. The ammonia-fueled configurations exhibited different voltage behaviors at higher fuel utilizations compared with those of the hydrogen-fueled configurations. The residual ammonia concentration in the anode off-gas remained well below the safety thresholds. Long-term testing demonstrated an initial degradation that eventually stabilized at a more sustainable rate. These findings validate ammonia as a viable fuel for SOFC stacks when operated at appropriate temperatures (≥710 ◦C) and optimal fuel utilization offering a pathway toward sustainable carbon-free ammonia energy systems.

This study develops and applies a life cycle assessment (LCA) framework combined with predictive market models to evaluate the environmental impacts of electricity and hydrogen for transport in the EU27+UK from 2020 to 2050. By linking evolving power sector scenarios with hydrogen supply models we assess the wellto-wheels (WTW) performance of battery electric vehicles (BEVs) and fuel cell electric vehicles (FCEVs) under consistent energy assumptions. Results show that electricity decarbonization can reduce GWP by up to 80% by 2050 but increases land use and mineral/metal demand due to renewable infrastructure expansion. The environmental impacts of hydrogen production are strongly influenced by the electricity mix especially in high electrolysis scenarios. WTW analysis indicates that while BEVs consistently achieve lower WTW GWP than FCEVs across all scenarios both drivetrains exhibit notable trade-offs in other impact categories. Scenarios dominated by blue hydrogen although not optimal in terms of GWP present a more balanced environmental profile making them a viable transitional pathway in contexts that prioritize minimizing other environmental impacts.