Publications

Hydrogen is commonly perceived as the key player in the transition towards a low-carbon future. Nevertheless H2 low energy density hinders its easy storage and transportation. To address this issue different alternatives (liquefied hydrogen ammonia and liquid organic hydrogen carriers) are explored as hydrogen vectors. The techno-economic assessment of H2 transport through these carriers is strongly dependent on the basis of design adopted such that it is difficult to draw general conclusions. In this respect this work is aimed at performing a sensitivity analysis on the hypotheses introduced in the layout of H2 value chains. Different scenarios are discussed depending on harbour-to-harbour distances cost of utilities and raw materials and H2 application to the industrial or mobility sector. The most cost-effective carrier is selected for each case-study: NH3 is the most advantageous for industrial sector while LH2 holds promises for mobility. Critical issues are pointed out for future large-scale applications.

This Review provides an overview of the emerging concepts of catalystsmembranes and membrane electrode assemblies (MEAs) for water electrolyzers with anion-exchange membranes (AEMs) also known as zero-gap alkaline water electrolyzers. Much ofthe recent progress is due to improvements in materials chemistry MEA designs andoptimized operation conditions. Research on anion-exchange polymers (AEPs) has focusedon the cationic head/backbone/side-chain structures and key properties such as ionicconductivity and alkaline stability. Several approaches such as cross-linking microphase andorganic/inorganic composites have been proposed to improve the anion-exchangeperformance and the chemical and mechanical stability of AEMs. Numerous AEMs nowexceed values of 0.1 S/cm (at 60−80 °C) although the stability specifically at temperaturesexceeding 60 °C needs further enhancement. The oxygen evolution reaction (OER) is still alimiting factor. An analysis of thin-layer OER data suggests that NiFe-type catalysts have thehighest activity. There is debate on the active-site mechanism of the NiFe catalysts and their long-term stability needs to beunderstood. Addition of Co to NiFe increases the conductivity of these catalysts. The same analysis for the hydrogen evolutionreaction (HER) shows carbon-supported Pt to be dominating although PtNi alloys and clusters of Ni(OH) 2 on Pt show competitiveactivities. Recent advances in forming and embedding well-dispersed Ru nanoparticles on functionalized high-surface-area carbonsupports show promising HER activities. However the stability of these catalysts under actual AEMWE operating conditions needsto be proven. The field is advancing rapidly but could benefit through the adaptation of new in situ techniques standardizedevaluation protocols for AEMWE conditions and innovative catalyst-structure designs. Nevertheless single AEM water electrolyzercells have been operated for several thousand hours at temperatures and current densities as high as 60 °C and 1 A/cm 2 respectively.

Hydrogen production from electrolytic water based on Renewable Energy has been found as a vital method for the local consumption of new energy and the utilization of hydrogen energy. In this paper the hydrogen production power supply matching the working characteristics of electrolytic water production was investigated. Through the analysis of the correlation between the electrolysis current and temperature of the proton exchange membrane electrolyzer and the electrolyzer port voltage energy efficiency and hydrogen production speed it was concluded that the hydrogen production power supply should be characterized by low output current ripple high output current and wide range voltage output. To meet the requirements of the system of hydrogen production from electrolytic water based on new energy a hydrogen production power supply scheme was proposed based on Y which is the type three is the phase staggered parallel LLC topology. In the proposed scheme the cavity with three is the phase staggered parallel output is resonated to meet the operating characteristics (high current and low ripple) of the electrolyzer and pulse frequency control is adopted to achieve resonant soft in the switching operation and increase conversion efficiency. Lastly a simulation model and a 6kW experimental prototype were built to verify the rationality and feasibility of the proposed scheme.

Hydrogen has emerged as a promising new energy source that can be produced in renewable mode for example from biomass derivatives reforming or water splitting. However the conventional catalysts used for hydrogen production in renewable mode suffer from limitations in activity selectivity and/or stability. To overcome these limitations nanostructured catalysts with multicomponent active phases particularly trimetallic catalysts are being explored. This catalyst formulation significantly enhances catalyst activity and effectively suppresses the undesired production of CO CH4 or coke during the reforming of biomass derivatives for hydrogen formation. Moreover the success of this approach extends to water splitting catalysis where trimetallic based catalysts have demonstrated good performance in hydrogen production. Notably trimetallic catalysts composed of Ni Fe and a third metal prove to be highly efficient in water splitting bypassing the problems associated with traditional catalysts. That is the high material costs of state-of-the-art catalysts as well as the limited activity and stability of alternative ones. Furthermore theoretical methods play a vital role in understanding catalyst activity and/or selectivity as well as in the design of catalysts with improved characteristics. These enable a comprehensive study of the complete reaction mechanism on a target catalyst and help in identifying potential reaction descriptors allowing for efficient screening and selection of catalysts for enhanced hydrogen production. Overall this critical review shows how the exploration of trimetallic catalysts combined with the insights from theoretical methods holds great promise in advancing hydrogen production through renewable means paving the way for sustainable and efficient energy solutions.

In the wake of unprecedented global weather events and the ever-pressing urgency of climate change the discourse around energy transition has become more critical than ever.<br/>The United Kingdom once at the forefront of the energy transition movement finds itself at a crossroads. The initial rapid progress towards a low-carbon future is now facing hurdles threatening the achievement of the 'net zero by 2050' target.<br/>This revelation comes from the third edition of our UK Energy Transition Outlook (ETO) which leverages an independent model incorporating the UK's energy system's extensive connections with Europe and beyond.<br/>This report has a comprehensive analysis of:<br/>♦ Renewable energy technology scaling and costs<br/>♦ The continuing dependence on fossil fuel and need to decarbonize<br/>♦ Energy demand by sector and source<br/>♦ Energy efficiency<br/>♦ Energy supply<br/>♦ Electricity and infrastructure<br/>♦ Hydrogen<br/>♦ Energy expenditure<br/>♦ Policies driving the transition<br/>♦ Digitalization.

The decarbonization of heavy industries demands large volumes of green hydrogen. To produce green hydrogen via electrolysis the EU’s Renewable Energy Directive II imposes rules to ensure the use of renewable electricity. Hydrogen producers can use portfolios of power purchase agreements (PPAs) to buy renewable electricity. These portfolios must meet hydrogen demand cost-effectively and battery storage can help by shifting excess renewable generation. However high uncertainty around future electricity prices and demand complicates optimal portfolio design. Current literature lacks comprehensive models that evaluate such portfolio optimization under uncertainty for real-world case studies including battery storage. This work addresses the gap by introducing a stochastic mixed-integer linear programming model tailored to industrial applications. We demonstrate the model using a real-world glass manufacturing site in Germany. Our findings show that portfolio optimization alone can reduce the levelized cost of hydrogen (LCOH) by 6.24% under EU rules. Adding a battery further cuts costs achieving an LCOH of 11.8 e2024 kg−1 . Exploring different temporal matching schemes reveals that weekly matching reduces LCOH by 2 e2024kg−1 while maintaining a high share of renewable energy. The model offers a flexible tool for optimizing PPA portfolios in various industrial settings.

Green ammonia is a promising hydrogen derivative which enables intercontinental transport of dispatchable renewable energy. This research describes the development of a model which optimizes a global green ammonia network considering the costs of production storage and transport. In generating the model we show economies of scale for green ammonia production are small beyond 1 million tonnes per annum (MMTPA) although benefits accrue up to a production rate of 10 MMTPA if a production facility is serviced by a new port or requires a long pipeline. The model demonstrates that optimal sites for ammonia production require not only an excellent renewable resource but also ample land from which energy can be harvested. Land limitations constrain project size in otherwise optimal locations and force production to more expensive sites. Comparison of current crude oil markets to future ammonia markets reveals a trend away from global supply hubs and toward demand centers serviced by regional production.

The transition toward low-carbon energy systems requires reliable tools for assessing renewable-based hydrogen production under real-world climatic and economic conditions. This study presents a novel probabilistic framework integrating the following three complementary elements: (1) a Photovoltaic Geographical Information System (PVGIS) for high-resolution location-specific solar energy data; (2) Metalog probability distributions for advanced modeling of variability and uncertainty in photovoltaic (PV) energy generation; and (3) Levelized Cost of Hydrogen (LCOH) calculations to evaluate the economic viability of hydrogen production systems. The methodology is applied to three diverse European locations—Lublin (Poland) Budapest (Hungary) and Malaga (Spain)—to demonstrate regional differences in hydrogen production potential. The results indicate annual PV energy yields of 108.3 MWh 124.6 MWh and 170.95 MWh respectively which translate into LCOH values of EUR 9.67/kg (Poland) EUR 8.40/kg (Hungary) and EUR 6.13/kg (Spain). The probabilistic analysis reveals seasonal production risks and quantifies the probability of achieving specific monthly energy thresholds providing critical insights for designing systems with continuous hydrogen output. This combined use of a PVGIS Metalog and LCOH calculations offers a unique decision-support tool for investors policymakers and SMEs planning green hydrogen projects. The proposed methodology is scalable and adaptable to other renewable energy systems enabling informed investment decisions and improved regional energy transition strategies.

The concept of sustainability and green energy has become increasingly relevant in our lives especially in the face of climate change and the growing demand for sustainable solutions in the energy sector. Driven by renewable energies there is a continuous effort to research and develop alternative energy sources and fuels. In this context the European Union (EU) Strategy for Hydrogen (H) has emerged placing this source as one of the central pillars in the fight against climate change. Hydrogen is seen as a potential fuel and energy source of the future. However in addition to political and structural challenges this new approach also faces significant technical obstacles. With the increase in population and human needs the need for energy continues to grow. The world population is projected to reach ten billion people by the year 2050 (Tarhan and Çil 2021). To meet this growing demand and promote a transition to clean energies many countries are incorporating renewable energy sources into their energy mix while still relying on fossil fuels. Developed countries are gradually reducing their use of fossil fuels in energy production. Considering that 80 per cent of our daily energy needs are still met by these sources the complete transition is complex and not immediate but it is an achievable goal.

Maintaining frequency stability is one of the biggest challenges facing future power systems due to the increasing penetration levels of inverter-based renewable resources. This investigation experimentally validates the frequency provision capabilities of a real Polymer Electrolyte Membrane (PEM) hydrogen electrolyser (HE) using a power hardware-in-the-loop (PHIL) setup. The PHIL consists of a custom 3-level interleaved buck converter and a hardware platform for real-time control of the converter and conducting grid simulation associated with the modelling of the future Iberian Peninsula (IP) and Continental Europe (CE) systems. The investigation had the aim of validating earlier simulation work and testing new responses from the electrolyser when providing different frequency services at different provision volumes. The experimental results corroborate earlier simulation results and capture extra electrolyser dynamics as the double-layer capacitance effect which was absent in the simulations. Frequency Containment Reserve (FCR) and Fast Frequency Response (FFR) were provided successfully from the HE at different provision percentages enhancing the nadir and the rate of change of frequency (RoCoF) in the power system when facing a large disturbance compared to conventional support only. The results verify that HE can surely contribute to frequency services paving the way for future grid support studies beyond simulations.