Publications

The rapid increase in global warming requires that sustainable energy choices aimed at achieving net-zero greenhouse gas emissions be implemented as soon as possible. This objective emerging from the European Green Deal and the UN Climate Action could be achieved by using clean and efficient energy sources such as hydrogen produced from nuclear power. “Renewable” hydrogen plays a fundamental role in decarbonizing both the energy-intensive industrial and transport sectors while addressing the global increase in energy consumption. In recent years several strategies for hydrogen production have been proposed; however nuclear energy seems to be the most promising for applications that could go beyond the sole production of electricity. In particular nuclear advanced reactors that operate at very high temperatures (VHTR) and are characterized by coolant outlet temperatures ranging between 550 and 1000 ◦C seem the most suitable for this purpose. This paper describes the potential use of nuclear energy in coordinated and coupled configurations to support clean hydrogen production. Operating conditions energy requirements and thermodynamic performance are described. Moreover gaps that require additional technology and regulatory developments are outlined. The intermediate heat exchanger which is the key component for the integration of nuclear hybrid energy systems was studied by varying the thermal power to determine physical parameters needed for the feasibility study. The latter consisting of the comparative cost evaluation of some nuclear hydrogen production methods was carried out using the HEEP code developed by the IAEA. Preliminary results are presented and discussed.

Underground hydrogen storage is critical for supporting the transition to renewable energy systems addressing the intermittent nature of solar and wind power. Despite its promise as a carbon-neutral energy carrier there remains limited understanding of the geomechanical behavior of subsurface reservoirs under hydrogen storage conditions. This knowledge gap is particularly significant for fast-cycling operations which have yet to be implemented on a large scale. This review evaluates current knowledge on the geomechanics of underground hydrogen storage focusing on risks and challenges in geological formations such as salt caverns depleted hydrocarbon reservoirs saline aquifers and lined rock caverns. Laboratory experiments field studies and numerical simulations are synthesized to examine cyclic pressurization induced seismicity thermal stresses and hydrogen-rock interactions. Notable challenges include degradation of rock properties fault reactivation micro-seismic activity in porous reservoirs and mineral dissolution/precipitation caused by hydrogen exposure. While salt caverns are effective for low-frequency hydrogen storage their behavior under fast-cyclic loading requires further investigation. Similarly the mechanical evolution of porous and fractured reservoirs remains poorly understood. Key findings highlight the need for comprehensive geomechanical studies to mitigate risks and enhance hydrogen storage feasibility. Research priorities include quantifying cyclic loading effects on rock integrity understanding hydrogen-rock chemical interactions and refining operational strategies. Addressing these uncertainties is essential for enabling large-scale hydrogen integration into global energy systems and advancing sustainable energy solutions. This work systematically focuses on the geomechanical implications of hydrogen injection into subsurface formations offering a critical evaluation of current studies and proposing a unified research agenda.

This article presents an innovative approach to address the optimization and planning of hydrogen network transmission focusing on minimizing computational and operational costs including capital operational and maintenance expenses. The mathematical models developed for gas flow rate pipelines junctions and storage form the basis for the optimization problem which aims to reduce costs while satisfying equality inequality and binary constraints. To achieve this we implement a dynamic algorithm incorporating 100 scenarios to account for uncertainty. Unlike conventional successive linear programming methods our approach solves successive piecewise problems and allows comparisons with other techniques including stochastic and deterministic methods. Our method significantly reduces computational time (56 iterations) compared to deterministic (92 iterations) and stochastic (77 iterations) methods. The non-convex nature of the model necessitates careful selection of starting points to avoid local optimal solutions which is addressed by transforming the primal problem into a linear program by fixing the integer variable. The LP problem is then efficiently solved using the Complex Linear Programming Expert (CPLEX) solver enhanced by Monte Carlo simulations for 100 scenarios achieving a 39.13% reduction in computational time. In addition to computational efficiency this approach leads to operational cost savings of 25.02% by optimizing the selection of compressors (42.8571% decreased) and storage facilities. The model’s practicality is validated through realworld simulations on the Belgian gas network demonstrating its potential in solving large-scale hydrogen network transmission planning and optimization challenges.

The maritime sector’s transition to sustainable energy is critical for achieving global carbon neutrality with container terminals representing a key focus due to their high energy consumption and emissions. This study explores the potential of hydrogen energy as a decarbonization solution for port operations using the Chuanshan Port Area of Ningbo Zhoushan Port (CPANZP) as a case study. Through a comprehensive analysis of hydrogen production storage refueling and consumption technologies we demonstrate the feasibility and benefits of integrating hydrogen systems into port infrastructure. Our findings highlight the successful deployment of a hybrid “wind-solar-hydrogen-storage” energy system at CPANZP which achieves 49.67% renewable energy contribution and an annual reduction of 22000 tons in carbon emissions. Key advancements include alkaline water electrolysis with 64.48% efficiency multi-tier hydrogen storage systems and fuel cell applications for vehicles and power generation. Despite these achievements challenges such as high production costs infrastructure scalability and data integration gaps persist. The study underscores the importance of policy support technological innovation and international collaboration to overcome these barriers and accelerate the adoption of hydrogen energy in ports worldwide. This research provides actionable insights for port operators and policymakers aiming to balance operational efficiency with sustainability goals.

Recent advancements in membrane-assisted seawater electrolysis powered by renewable energy offer a sustainable path to green hydrogen production. However its large-scale implementation faces challenges due to slow powerto-hydrogen (P2H) conversion rates. Here we report a modular forward osmosis-water splitting (FOWS) system that integrates a thin-film composite FO membrane for water extraction with alkaline water electrolysis (AWE) denoted as FOWSAWE. This system generates high-purity hydrogen directly from wastewater at a rate of 448 Nm3 day−1 m−2 of membrane area over 14 times faster than the state-of-the-art practice with specific energy consumption as low as 3.96 kWh Nm−3 . The rapid hydrogen production rate results from the utilisation of 1 M potassium hydroxide as a draw solution to extract water from wastewater and as the electrolyte of AWE to split water and produce hydrogen. The current system enables this through the use of a potassium hydroxide-tolerant and hydrophilic FO membrane. The established waterhydrogen balance model can be applied to design modular FO and AWE units to meet demands at various scales from households to cities and from different water sources. The FOWSAWE system is a sustainable and an economical approach for producing hydrogen at a record-high rate directly from wastewater marking a significant leap in P2H practice.

Infrastructure and processes for handling liquid hydrogen (LH2) is needed to decarbonize aviation with hydrogen aircraft. Large airports benefit from pipeline refuelling systems which must be operated to keep the fuel subcooled due to LH2 vaporization challenges. In this paper we estimate LH2 demand for aircraft and the gaseous H2 demand for ground support equipment (GSE) at Schipol in 2050. Modelling and simulation of aircraft refuelling via pipelines show that continuous LH2 recycling is required to maintain subcooling. Vaporization of LH2 during refuelling is heavily influenced by pipeline temperatures. Refuelling aircraft in the morning causes the highest vaporization (2.2 %) due to a long period with low LH2 flow (no refuelling at night). The vaporization decreases to 0 % throughout the day. Furthermore increasing the recycle rate during night lowers the pipeline temperatures reducing the vaporization to 1.7 %. The amount of vaporized hydrogen corresponds well with the GSE demand for gaseous H2.

Improving the efficiency and range of hydrogen-powered electric vehicles (HPEVs) is essential for their global adoption especially in developing countries with limited resources. This study systematically evaluates regenerative braking and suspension systems in HPEVs and proposes a deployment-focused framework tailored to the needs of developing nations. A comprehensive search was performed across multiple databases to identify relevant studies. The selected studies are screened assessed for quality and analyzed based on predefined criteria. The data is synthesized and interpreted to identify patterns gaps and conclusions. The findings show that regeneration systems such as regenerative braking and regenerative suspension are the most effective energy recovery systems in most electric and hydrogen-powered vehicles. Although the regenerative braking system (RBS) offers higher energy efficiency gains that enhance cost-effectiveness despite its high initial investment the regenerative suspension system (RSS) involves increased complexity. Still it offers comparatively efficient energy recovery particularly in developing countries with patchy road infrastructure. The gaps highlighted in this review will aid researchers and vehicle manufacturers in designing optimizing developing and commercializing HPEVs for deployment in developing countries.

Green hydrogen is gaining global attention as a zero-carbon energy carrier with the potential to drive sustainable energy transitions particularly in regions facing rising fossil fuel costs and resource depletion. In sub-Saharan Africa financing mechanisms and structured off-take agreements are critical to attracting investment across the green hydrogen value chain from advisory and pilot stages to full-scale deployment. While substantial funding is required to support a green economic transition success will depend on the effective mobilization of capital through smart public policies and innovative financial instruments. This review evaluates financing mechanisms relevant to sub-Saharan Africa including green bonds public–private partnerships foreign direct investment venture capital grants and loans multilateral and bilateral funding and government subsidies. Despite their potential current capital flows remain insufficient and must be significantly scaled up to meet green energy transition targets. This study employs a mixed-methods approach drawing on primary data from utility firms under the H2Atlas-Africa project and secondary data from international organizations and the peer-reviewed literature. The analysis identifies that transitioning toward Net-Zero emissions economies through hydrogen development in sub-Saharan Africa presents both significant opportunities and measurable risks. Specifically the results indicate an estimated investment risk factor of 35% reflecting potential challenges such as financing infrastructure and policy readiness. Nevertheless the findings underscore that green hydrogen is a viable alternative to fossil fuels in subSaharan Africa particularly if supported by targeted financing strategies and robust policy frameworks. This study offers practical insights for policymakers financial institutions and development partners seeking to structure bankable projects and accelerate green hydrogen adoption across the region.

Due to the high cost of hydrogen utilization and the uncertainties in renewable energy generation and load demand significant challenges are posed for the operation optimization of hydrogen-containing integrated energy systems (IESs). In this study a robust operational model for an electric–heat–gas IES (EHG-IES) is proposed considering the hydrogen energy system heat recovery (HESHR) and multiple uncertainties. Firstly a heat recovery model for the hydrogen system is established based on thermodynamic equations and reaction principles; secondly through the constructed adjustable robust optimization (ARO) model the optimal solution of the system under the worst-case scenario is obtained; lastly the original problem is decomposed based on the column and constraint generation method and strong duality theory resulting in the formulation of a master problem and subproblem with mixed-integer linear characteristics. These problems are solved through alternating iterations ultimately obtaining the corresponding optimal scheduling scheme. The simulation results demonstrate that our model and method can effectively reduce the operation and maintenance costs of HESHR-EHG-IES while being resilient to uncertainties on both the supply and demand sides. In summary this study provides a novel approach for the diversified utilization and flexible operation of energy in HESHR-EHG-IES contributing to the safe controllable and economically efficient development of the energy market. It holds significant value for engineering practice.

The main aim of this study deals with the potential evaluation of a fluidized bed membrane reactor (FBMR) for hydrogen production as a clean fuel carrier via methanol steam reforming reaction comparing its performance with other reactors including packed bed membrane reactors (PBMR) fluidized bed reactors (FBR) and packed bed reactors (PBR). For this purpose a two-dimensional axisymmetric numerical model was developed using computational fluid dynamics (CFD) to simulate the reactor performances. Model accuracy was validated by comparing the simulation results for PBMR and PB with experimental data showing an accurate agreement within them. The model was then employed to examine the effects of key operating parameters including reaction temperature pressure steam-to-methanol molar ratio and gas volumetric space velocity on reactor performance in terms of methanol conversion hydrogen yield hydrogen recovery and selectivity. At 573 K 1 bar a feed molar ratio of 3/1 and a space velocity of 9000 h−1 the PBMR reached the best results in terms of methanol conversion hydrogen yield hydrogen recovery and hydrogen selectivity such as 67.6% 69.5% 14.9% and 97.1% respectively. On the other hand the FBMR demonstrated superior performance with respect to the latter reaching a methanol conversion of 98.3% hydrogen yield of 95.8% hydrogen recovery of 74.5% and hydrogen selectivity of 97.4%. These findings indicate that the FBMR offers significantly better performance than the other reactor types studied in this work making it a highly efficient method for hydrogen production through methanol steam reforming and a promising pathway for clean energy generation.