Production & Supply Chain

Offshore green hydrogen emerges as a guiding light in the global pursuit of environmental sustainability and net-zero objectives. The burgeoning expansion of offshore wind power faces significant challenges in grid integration. This avenue towards generating offshore green hydrogen capitalises on its ecological advantages and substantial energy potential to efficiently channel offshore wind power for onshore energy demands. However a substantial research void exists in efficiently integrating offshore wind electricity and green hydrogen. Innovative designs of offshore hydrogen platforms present a promising solution to bridge the gap between offshore wind and hydrogen integration. Surprisingly there is a lack of commercially established offshore platforms dedicated to the hydrogen industry. However the wealth of knowledge from oil and gas platforms contributes valuable insights to hydrogen platform design. Diverging from the conventional decentralised hydrogen units catering to individual turbines this study firstly introduces a pioneering centralised Offshore Green Hydrogen Platform (OGHP) which seamlessly integrates modular production storage and offloading modulars. The modular design of facilitates scalability as wind capacity increases. Through a detailed case study centred around a 100-Megawatt floating wind farm the design process of offshore green hydrogen modulars and its floating sub-structure is elucidated. Stability analysis and hydrodynamic analysis are performed to ensure the safety of the OGHP under the operation conditions. The case study will enhance our understanding OGHP and its modularised components. The conceptual design of modular OGHP offers an alternative solution to ‘‘Power-to-X’’ for offshore renewable energy sector.

Hydrogen is widely recognized as a key component of a decarbonized global energy system serving as both a fuel source and an energy storage medium. While current hydrogen production relies almost entirely on emissionsintensive processes two low-emissions production pathways – natural-gas-derived production combined with carbon capture and storage and electrolysis using carbon-free electricity – are poised to change the global supply mix. Our study assesses the financial conditions under which natural-gas-based hydrogen production combined with carbon capture and storage would be available at a cost lower than hydrogen produced through electrolysis and the degree to which these conditions are likely to arise in a transition to a net-zero world. We also assess the degree to which emissions reduction policies namely carbon pricing and carbon capture and storage tax credits affect the relative costs of hydrogen production derived from different pathways. We show that while carbon pricing can improve the relative cost of both green and blue hydrogen production compared with unabated grey hydrogen targeted tax credits favouring either blue or green hydrogen explicitly may increase emissions and/or increase the costs of the energy transition.

Hydrogen as a clean energy carrier is of great potential to be an alternative fuel in the future. Proton exchange membrane (PEM) water electrolysis is hailed as the most desired technology for high purity hydrogen production and self-consistent with volatility of renewable energies has ignited much attention in the past decades based on the high current density greater energy efficiency small mass-volume characteristic easy handling and maintenance. To date substantial efforts have been devoted to the development of advanced electrocatalysts to improve electrolytic efficiency and reduce the cost of PEM electrolyser. In this review we firstly compare the alkaline water electrolysis (AWE) solid oxide electrolysis (SOE) and PEM water electrolysis and highlight the advantages of PEM water electrolysis. Furthermore we summarize the recent progress in PEM water electrolysis including hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalysts in the acidic electrolyte. We also introduce other PEM cell components (including membrane electrode assembly current collector and bipolar plate). Finally the current challenges and an outlook for the future development of PEM water electrolysis technology for application in future hydrogen production are provided.

The present study comprehensively examines the application of hydro wave tidal undersea current and geothermal energy sources of Canada for green hydrogen fuel production. The estimated potential capacity of each province is derived from official data and acceptable assumptions and is subject to discussion and evaluation in the context of a viable hydrogen economy. According to the findings the potential for green hydrogen generation in Canada is projected to be 48.86 megatons. The economic value of the produced green hydrogen results in an equivalent of 21.30 billion US$. The top three provinces with the highest green hydrogen production potential using hydro resources including hydro wave tidal undersea current and geothermal are Alberta Quebec and British Columbia with 26.13 Mt 7.34 Mt and 4.39 Mt respectively. Quebec is ranked first by only considering the marine sources including 4.14 Mt with hydro 1.46 Mt with wave 0.27 Mt underwater current and 1.45 Mt with tidal respectively. Alberta is listed as the province with the highest capacity for hydrogen production from geothermal energy amounting up to 26.09 Mt. The primary objective is to provide comprehensive hydrogen maps for each province in Canada which will be based on the identified renewable energy potential and the utilization of electrolysers. This may further be examined within the framework of the prevailing policies implemented by local communities and officials in order to develop a sustainable energy plan for the nation.

Energy transition is a key driver to combat climate change and achieve zero carbon future. Sustainable and costeffective hydrogen production will provide valuable addition to the renewable energy mix and help minimize greenhouse gas emissions. This study investigates the performance of in-situ hydrogen production (IHP) process using a full-field compositional model as a precursor to experimental validation The reservoir model was simulated as one geological unit with a single point uniform porosity value of 0.13 and a five-point connection type between cell to minimize computational cost. Twenty-one hydrogen forming reactions were modelled based on the reservoir fluid composition selected for this study. The thermodynamic and kinetic parameters for the reactions were obtained from published experiments due to the absence of experimental data specific to the reservoir. A total of fifty-four simulation runs were conducted using CMG STARS software for 5478 days and cumulative hydrogen produced for each run was recorded. Results generated were then used to build a proxy model using Box-Behnken design of experiment method and Support Vector Machine with RBF kernel. To ascertain accuracy of the proxy models analysis of variance (ANOVA) was conducted on the variables. The average absolute percentage error between the proxy model and numerical simulation was calculated to be 10.82%. Optimization of the proxy model was performed using genetic algorithm to maximize cumulative hydrogen produced. Based on this optimized model the influence of porosity permeability well location injection rate and injection pressure were studied. Key results from this study reveals that lower permeability and porosity reservoirs supports more hydrogen yield injection pressure had a negligible effect on hydrogen yield and increase in oxygen injection rate corelated strongly with hydrogen production until a threshold value beyond which hydrogen yield decreased. The framework developed in the study could be used as tool to assess candidate reservoirs for in-situ hydrogen production.

Low temperature water electrolysers such as Proton Exchange Membrane Water Electrolysers (PEMWEs) Alkaline Water Electrolysers (AWEs) and Anion Exchange Membrane Water Electrolysers (AEMWEs) are known to be sensitive to water quality with a range of common impurities impacting performance hydrogen quality and device lifetime. Purification of feed water adds to cost operational complexity and design limitations while failure of purification equipment can lead to degradation of electrolyser materials and components. Increased robustness to impurities will offer a route to longer device lifetimes and reduced operating costs but understanding of the impact of impurities and associated degradation mechanisms is currently limited. This critical review offers for the first time a comprehensive overview of relevant impurities in operating electrolysers and their impact. Impurity sources degradation mechanisms characterisation techniques water purification technologies and mitigation strategies are identified and discussed. The review generalises already reported mechanisms proposes new mechanisms and provides a framework for consideration of operational implications.

This study presents a new three-step Cu-Cl cycle that can operate with heat input without electrolysis. While the sensitivity analyses of the system are performed to evaluate the system performance through the Aspen Plus thermodynamic analyses of the system are performed with energetic and exergetic approaches. The highest exergy destruction among the components in the system was the decomposition reactor with a rate of 50.6%. Furthermore the energy and exergy values for the simulated system to produce 1 mol of hydrogen were determined by calculating the energy requirements of all components in the system. The total energy required for the system to generate 1 mol of hydrogen is calculated to be 997.81 kJ/mol H2. It was found that the component that required the most energy 504.76 kJ/mol H2 in the system was the decomposition reactor. Moreover the overall energy and exergy efficiencies are calculated to be 72.50% and 46.70% respectively.

Hydrogen plays a pivotal role in transitioning to CO2-free energy systems yet challenges regarding costs and sourcing persist in supplying Europe with renewable hydrogen. Our paper proposes a simulation-based approach to determine cost-optimal combinations of electrolyser power and renewable peak power for off-grid hydrogen production considering location and energy source dependencies. Key findings include easy estimation of Levelized Costs of Hydrogen (LCOH) and optimal plant sizing based on the regional energy yield and source. Regional investment risks influence the LCOH by 7.9 % per 1 % change of the Weighted Average Cost of Capital. In Central Europe (Austria) hydrogen production costs range from 7.4 €/kg to 8.6 €/kg whereas regions like Chile exhibit cheaper costs at 5.1 €/kg to 6.8 €/kg. Despite the favourable energy yields in regions like Chile or the UAE domestically produced hydrogen can be cost-competitive when location-specific risks and transport costs are taken into account. This underlines the critical role of domestic hydrogen production and cost-effective hydrogen transport for Europe’s future hydrogen supply.

Solar hydrogen and electricity are promising high energy-density renewable sources. Although photochemistry or photovoltaics are attractive routes special challenge arises in sunlight conversion efficiency. To improve efficiency various semiconductor materials have been proposed with selective sunlight absorption. Here we reported a hybrid system synergizing photo-thermochemical hydrogen and photovoltaics harvesting full-spectrum sunlight in a cascade manner. A simple suspension of Au-TiO2 in water/methanol serves as a spectrum selector absorbing ultraviolet-visible and infrared energy for rapid photo-thermochemical hydrogen production. The transmitted visible and near-infrared energy fits the photovoltaic bandgap and retains the high efficiency of a commercial photovoltaic cell under different solar concentration values. The experimental design achieved an overall efficiency of 4.2% under 12 suns solar concentration. Furthermore the results demonstrated a reduced energy loss in full-spectrum energy conversion into hydrogen and electricity. Such simple integration of photo-thermochemical hydrogen and photovoltaics would create a pathway toward cascading use of sunlight energy.

Green hydrogen will play a key role in the transition to a carbon-neutral energy system. This study addresses the challenge of supplying baseload green hydrogen through an integrated off-grid alkaline water electrolyzer (AWE) plant wind and solar photovoltaic (PV) power a battery energy storage system (BESS) and a hydrogen storage system based on salt and rock cavern geologies. The capacities of the components and the hydrogen storage size are optimized simultaneously with the control of the AWE plant to minimize the levelized cost of hydrogen (LCOH2) of the gas supplied. The operation of the system is simulated over 30 years with a 15 min time resolution considering degradation operating expenses and component replacements. Power generation data collected from a wind farm and a solar PV installation both located in southeastern Finland are used for system simulation. A sensitivity analysis exploring different hydrogen demand rates discount rates and installation years is conducted for both systems considering rock and salt caverns providing the optimal configuration for each case. It is found that for the price scenario of the year 2025 for a combined 100 MW AWE and compressor the optimal hydrogen demand rate is 12 kg/min with an LCOH2 of 3.14 e/kg and 2.77 e/kg in systems including rock and salt caverns respectively.