Applications & Pathways

This study investigates the integration of on-site green hydrogen as a substitute for methane in steam generation in the dairy industry specifically in the production of Parmigiano Reggiano cheese. This represents a novel application of green hydrogen in industrial dairy processing with the potential to reduce greenhouse gas emissions. Hydrogen is assumed to be generated via electrolysis powered by photovoltaic energy. A comprehensive techno-economic assessment was conducted with simulations covering key design variables such as hydrogen fraction in steam production photovoltaic panel orientation and storage pressure. A wide range of scenarios was defined in order to account for variability in system structures and performance and a comprehensive economic assessment was then carried out using a Monte Carlo simulation approach and a sensitivity analysis. Results indicate that in all scenarios the net present value over a 15-year period remains negative when benefits are limited to methane savings. Indeed the high capital expenditure associated with hydrogen systems presents a major barrier. The most favorable cases occur at low hydrogen shares with seasonal storage while full conversion to hydrogen maximizes CO2 abatement but is least economical. With public funding the emissions saved per euro of public support range from 1.58 to 2.14 kg CO2eq/€.

In order to assess the decarbonization potential and overall environmental benefits of new reduction pathways in the ironmaking industry using hydrogen to produce Direct Reduced Iron (DRI) a coupled approach combining process simulation for rigorous technical and energy evaluation of iron ore conversion and Life Cycle Assessment (LCA) for environmental assessment was developed and extended to two alternative renewable heating strategies: (i) electric gas heating and (ii) solar reactor heating. The entire hydrogen-based ironmaking process including conversion in a shaft reactor gas and solid heating gas recycling and electrolysis was therefore simulated. The hydrogen-based reduction of iron ores in the shaft reactor was modeled using a rigorous reactor model describing the reduction of multi-layer iron ore pellets in countercurrent gas–solid moving beds with the particularity of representing the dual influence of particle size and temperature on conversion. The remainder of the process including gas recycling and hydrogen production was simulated using ProSim software. The hydrogen-based green ironmaking scenarios were then compared to MIDREX NG a leading natural gas-based reduction technology. Hydrogen-based scenarios powered by the French electricity mix reduce carbon footprints by 53 % for electric gas heating and 57 % for solar reactor heating potentially reaching 82 % (− 0.79 kgCO2-eq/kgDRI) with low-carbon electricity (hydro nuclear). Compared to MIDREX NG the energy requirements of both hydrogen-based scenarios are primarily determined by the use of electricity for hydrogen production illustrating the importance of hydrogen production for the assessment of future hydrogen-based green ironmaking.

Curvature effects are incorporated into a one-dimensional composition-space formulation of a non-unity Lewis number lean premixed flame with strong heat loss. The results of this new canonical problem successfully compare with direct numerical simulations (DNS) of a lean hydrogen-air flame propagating in a narrow channel with heat conduction through the confining plates. The complex dynamics of the flame front consisting of isolated flame kernels are analyzed through the various terms arising from the projection of the fuel and energy equations onto a moving scalar reference frame attached to the reaction zone. Novelty and significance statement A novel one-dimensional flame model incorporating curvature and differential diffusion effects is introduced to address non-unity Lewis number lean premixed flames with strong heat loss. This canonical flame model arises from the projection of temperature and fuel gradient magnitude onto composition space. The framework is employed to analyze flame front dynamics and identify the reaction zones governing flame kernel propagation and heat release. The composition-space flame structure shows strong agreement between the canonical problem and direct numerical simulations (DNS) of a lean hydrogen-air flame propagating in a narrow channel with heat conduction.

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.

The growing concern about the increase in European Union (EU)’s total CO2 emissions due to maritime activities and the ambitious goal of net zero emissions they are asked to fulfil by 2050 are leading the way to the adoption of new sustainable strategies. In this article a novel methodology for the classification of the sustainable actions is proposed. Moreover new indicators have been designed to compare the level of sustainable development of each port. Among them a new coefficient for the assessment of the Ports’ Potential Sustainability (PPS) have been designed. Main results showed that 56% of the actions were in the improvement and environmentally sustainable group while 19% were shift-economic actions related to the installation of technologies. As a matter of the fact all European ports under analysis have adopted cold ironing system which can reduce up to 4% of the global shipping emissions. Similarly 50% of them have already integrated renewables energies and prioritize equipment electrification in their processes. Finally the most relevant projects to optimize the energy consumption of daily operations and the main challenges that still need to be addressed have been analyzed showing the current trends maritime sector is undertaking to advance towards the sustainable development.

The last decade has been characterized by a growing environmental awareness and the rise of climate change concerns. Continuous advancement of renewable energy technologies in this context has taken a central stage on the global agenda leading to a diverse array of innovations ranging from cutting-edge green energy production technologies to advanced energy storage solutions. In this evolving context ensuring the sustainability of energy systems—through the reduction of carbon emissions enhancement of energy resilience and responsible resource integration—has become a primary objective of modern energy planning. The integration of hydrogen technologies for power-to-gas (P2G) and power-topower (P2P) and energy storage systems is one of the areas where the most remarkable progress is being made. However real case implementations are lagging behind expectations due to large-scale investments needed which under high energy price uncertainty act as a barrier to widespread adoption. This study proposes a risk-averse approach for sizing an Integrated Hybrid Energy System considering the uncertainty of electricity and gas prices. The problem is formulated as a mixed-integer program and tested on a real-world case study. The analysis sheds light on the value of synergies and innovative solutions that hold the promise of a cleaner more sustainable future for generations to come.

Contemporary research into decarbonized fuels such as H2/NH3 has highlighted complex challenges with applied combustion with marked changes in thermochemical properties leading to significant issues such as limited operational range flashback and instability particularly when attempts are made to optimize emissions production in conventional lean-premixed systems. Non-premixed configurations may address some of these issues but often lead to elevated NOx production particularly when ammonia is retained in the fuel mixture. Optimized fuel injection and blending strategies are essential to mitigate these challenges. This study investigates the application of a 75 %/25 %mol H2/NH3 blend in a swirl-stabilized combustor operated at elevated conditions of inlet temperature (500 K) and ambient pressure (0.11–0.6 MPa). A complex nonmonotonic relationship between swirl number and increasing ambient combustor pressure is demonstrated highlighting the intricate interplay between swirling flow structures and reaction kinetics which remains poorly understood. At medium swirl (SN = 0.8) an increase in pressure initially reduces NO emissions diminishing past ~0.3 MPa with an opposing trend evident for high swirl (SN = 2.0) as NO emissions fall rapidly when combustor pressure approaches 0.6 MPa. High-fidelity numerical modeling is presented to elucidate these interactions in detail. Numerical data generated using Detached Eddy Simulations (DES) were validated against experimental results to demonstrate a change in flame anchoring on the axial shear layer and marked change in recirculated flow structure successfully capturing the features of higher swirl number flows. Favorable comparisons are made with optical data and a reduction in NO emissions with increasing pressure is demonstrated to replicate changes to the swirling flame chemical kinetics. Findings provide valuable insights into the combustion behavior of hydrogen-rich ammonia flames contributing to the development of cleaner combustion technologies.

While renewable energy deployment has accelerated in recent years fossil fuels continue to play a dominant role in electricity generation worldwide. This necessitates the development of transitional strategies to mitigate greenhouse gas emissions from this sector while gradually reducing reliance on fossil fuels. This study investigates the potential of blending green hydrogen with natural gas as a transitional solution to decarbonize Jordan’s electricity sector. The research presents a comprehensive techno-economic and environmental assessment evaluating the compatibility of the Arab Gas Pipeline and major power plants with hydrogen–natural gas mixtures considering blending limits energy needs environmental impacts and economic feasibility under Jordan’s 2030 energy scenario. The findings reveal that hydrogen blending between 5 and 20 percent can be technically achieved without major infrastructure modifications. The total hydrogen demand is estimated at 24.75 million kilograms per year with a reduction of 152.7 thousand tons of carbon dioxide per annum. This requires 296980 cubic meters of water per year equivalent to only 0.1 percent of the National Water Carrier’s capacity indicating a negligible impact on national water resources. Although technically and environmentally feasible the project remains economically constrained requiring a carbon price of $1835.8 per ton of carbon dioxide for economic neutrality.

The increasing penetration of renewable energy sources in power systems poses significant challenges for maintaining grid reliability mainly due to the variability and uncertainty of solar and demand profiles. Microgrids equipped with diverse storage technologies have emerged as a promising solution to address these issues.This paper proposes an integrated day-ahead and real-time power scheduling approach for grid-connected microgrids equipped with both conventional and hydrogen-based ESSs. While existing strategies often address day-ahead and real-time scheduling separately or rely on a single storage technology this work introduces a unified framework that exploits the complementary characteristics of batteries and hydrogen systems. The proposed approach is based on a novel two-stage stochastic optimization model embedded within a hierarchical optimization framework to address these two intertwined problems efficiently. For the day-ahead scheduling a two-stage stochastic programming energy management model is solved to optimize the microgrid schedule based on forecasted load demand and PV production profiles. Building upon the day-ahead schedule another optimization model is solved which addresses real-time power imbalances caused by deviations in actual PV production and load demand power profiles with respect to the forecasted ones with the aim of minimizing operational disruptions. Simulation results demonstrate the validity of the proposed approach achieving both cost reductions and minimal power imbalances. By dynamically adjusting energy flows and using both conventional batteries and hydrogen systems the proposed approach ensures improved reliability reduced operational costs and enhanced integration of RES in microgrids. These findings highlight the potential of the proposed hierarchical framework to support the large-scale deployment of RES while ensuring resilient and cost-effective microgrid operations.

Achieving net zero by 2050 will require decarbonising stand-alone energy applications. Hydrogen is increasingly viewed as a promising energy carrier but its economic viability remains uncertain due to the lack of consensus on future demand and limited deployment of key components such as fuel cells in stationary stand-alone applications. This study investigates whether hybridising batteries with hydrogen can deliver meaningful cost benefits under future cost trajectories. Using a Monte Carlo framework we simulate 8000 scenarios across constant and seasonal load profiles varying the capital costs of batteries fuel cells electrolysers and hydrogen tanks based on 2025 estimates and 2050 projections. Our results show that hydrogen integration only becomes economically attractive when multiple component costs decline simultaneously. The fuel cell-to-battery power capital cost ratio emerges as the dominant driver of levelised cost of energy (LCOE) improvements. For constant loads median LCOE savings remain below 12 % with more than 5 % savings only achieved when the fuel cell cost is less than 7 times that of the battery. Seasonal nighttime loads offer a wider theoretical LCOE savings range (0–156 %) but substantial gains occur only under unrealistic cost mixes where battery costs remain high and fuel cell costs fall sharply. These findings highlight the sensitivity of hydrogen viability to load profile characteristics and cost interdependencies. They underscore the need for targeted cost reduction strategies particularly for fuel cells to justify added system complexity. These findings are important considerations for future investment and policy decisions.