Authors: Khalid Alanazi, Robert Steinberger-Wilckens, Mahbod Moein Jahromi, Ahmad El-kharouf
Abstract: This paper presents a comprehensive evaluation of metal foam flow field application within polymer electrolyte fuel cells (PEFCs) and compares it with conventional serpentine channels from both computational fluid dynamics simulation and experimental viewpoints. The experiments are designed to investigate the effects of material, area density, compression ratio, and final thickness of metal foam. Additionally, the influence of housing plate material and relative humidity (RH) is tested here. The results reveal that at RH = 75%–100%, the best flow field design is nickel foam with a compression ratio of 70%, a final thickness of 0.5 mm, and an SS-304 housing plate, which delivers a great limiting current density. In comparison with the serpentine channel case, the PEFC with this foam flow field shows a 10% improvement in maximum power density (901 vs 989 mW cm−2) and a 45% improvement in limiting current density (2140 vs 3110 mA cm−2). While at RH = 30%, the same foam flow field with a final thickness of 1 mm is a superior option. The experiments also indicate that maximum power density increases by 23% (from 684 to 841 mW cm−2) as the compression ratio rises from 0% to 70% while reducing final thickness from 1 to 0.5 mm causes a 5.8% enhancement in (from 935 to 989 mW cm−2) cell performance. Simulation results reveal that metal foam is more effective in evenly distributing reactants, resulting in an average oxygen mass fraction at the cathode catalyst layer that is 38% higher than the serpentine channel case.
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Authors: Hadi Heidary, Michele de Lisi, Moataz M. Attallah, Sophie C. Cox, Ahmad El-kharouf, Robert Steinberger-Wilckens
Abstract: Polymer electrolyte fuel cells (PEFCs) are key in sustainable energy solutions, particularly in transportation, maritime, and aviation. However, the weight and volume of conventional bipolar plates remain significant barriers to high power densities and widespread adoption. Through simulation and experiments, the nickel foam bipolar plates improve oxygen concentration by 35 % across active area and increase the limiting current by 50 %. Despite these benefits, the high density of nickel limits improvements in gravimetric power density. This study presents the first demonstration of lightweight porous titanium bipolar plates for PEFCs, fabricated via Laser Powder Bed Fusion (LPBF) using an engineered Kelvin cell lattice. A parametric study evaluates the effects of key structural parameters, including cell size, ligament, and sample thickness on PEFC performance. The optimised titanium lattice, with 1 mm cell size, 125 μm ligament, and 1 mm thickness, demonstrated significant improvements. Experimental results showed a 30 % increase in power density and a 60 % enhancement in limiting current compared to a conventional serpentine flow-field. Furthermore, it achieved 25 % higher power than nickel foam bipolar plates while offering a significantly lighter design. These findings highlight the potential of LPBF-fabricated titanium lattices as high-performance, lightweight alternatives for next-generation PEFCs and electrolysers.
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Authors: Daniel Davids, Neil Grant, Shivika Mittal, Adam Hawkes, Gbemi Oluleye
Abstract: Fossil fuels dominate the production of hydrogen and will continue to contribute in a decarbonised future. Blue hydrogen production from natural gas with carbon capture and storage technology applied is seen as the major route for natural gas in a future Hydrogen Economy. Methane leakage rate in natural gas supply chains and carbon capture rate are two critical parameters for the success of blue hydrogen. Despite this, the linked effect of the variables are difficult to identify, especially in terms of their impacts on decarbonisation metrics within the energy system. We formulate a new Combined Warming Index (CWI) measure and develop a framework for analysing the influence of methane leakage rate and carbon capture rate on blue hydrogen viability and other relevant energy system characteristics.
Framework outline: • Investigate energy system scenarios within a range of methane leakage rates and carbon capture rates (varying Combined Warming Indices [CWI]) on blue hydrogen. • Analyse important energy system dynamic parameter indicators versus the Combined Warming Index (CWI). • Resultant energy system trends for methane leakage rates and carbon capture rates analysed against Combined Warming Index (CWI) establish unique property envelopes that reveal the state of the energy system at conditions and periods of interest.
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Authors: Vignesh Sridharan, John Ward, Sounthisack Phommachanh, Khamphone Nanthavong, Lukas Schirren, Pietro Lubello, Adam Hawkes
Abstract: Laos, the world’s second-largest net electricity exporter, faces dual challenges in its energy and agricultural sectors. While the country exports significant hydroelectric power to neighbouring nations, it remains dependent on electricity imports during dry seasons at unfavourable prices. Concurrently, Laos imports all its chemical nitrogenous fertilisers, exposing its agricultural sector to global price volatility. This study explores the potential of redirecting surplus electricity towards green ammonia production to address both issues. Using an open-source capacity expansion model of the Lao power sector, we analyse scenarios considering different power expansion plans and climate-induced variations in hydropower generation. Our results indicate that Laos could produce ~1 Mt of green ammonia annually by 2030, potentially reaching ~2 Mt by 2050. This production could satisfy domestic fertiliser demand and create export opportunities. Climate variability could significantly impact production potential, with dry conditions reducing production by 26% and wet conditions increasing it by 50% relative to the base scenario. Additional scenarios incorporating non-hydro renewable energy sources like solar PV and Wind and the transfer of power capacity into the control of the Lao government, post the termination of concessionary agreements, show potential for doubled production. While the levelized cost of green ammonia production currently exceeds import prices, it may become competitive if an appropriate carbon price is applied to imported ammonia. The study emphasises the importance of climate-resilient infrastructure planning and regulatory frameworks for successful implementation. This research contributes to Laos’ ongoing efforts to develop its first national green hydrogen and ammonia roadmap, positioning it as a pioneer among Least Developed Countries in fossil-free hydrogen and ammonia production.
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Authors:Peihao Chen, Dawei Wu, Yiqing Yang, Athanasios Tsolakis
Abstract:The discretization modeling methodology is proposed for dynamic analysis of Hybrid Wave-Tidal Energy Converters (HWTEC). By integrating the Pseudo Real-Time Wave (PRTW) simulation method based on random wave theory, it effectively reflects the actual random ocean waves characteristics and addresses the nonlinear response, without relying on continuous inputs. The discretization modeling method precisely determines and calculates the nonlinear dynamic response during the overrunning phase, enabling direct numerical solutions for nonlinear input and output parameters in the time domain, and eliminating the need for complex manual judgments. Validation through re-simulation of previous work shows an acceptable error of approximately 5 % in input and 0.5 % in output, demonstrating reliability. The proposed hybrid wave-tidal energy converter, based on the Non-Linear Motions Rectification and Coupling Device (NLMRCD), converts reciprocating wave motion into one-way motion and couples it with tidal rotation to enhance power output. It leverages the complementary and asynchronous distribution of wave and tidal energies, resulting in more stable output. Simulations reveal the impact of key parameters on output power and efficiency, achieving an average output power of 206.2 W and an efficiency of 40.8 %. The overrunning phase increases output power by 54.0 %, significantly enhancing output stability.
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Authors: Shirani F, Thomas G, Pidgeon N, Henwood K
Journal: Sustainability: Science, Practice and Policy
Abstract: Abstract
To meet UK government targets and support the transition to net zero, the energy system will need to decarbonize. In particular, buildings, as one of the largest sources of UK emissions, will need to transition to clean heat. This will involve changes to the material infrastructure of homes, which may have implications for people’s everyday lives and relationships, with public acceptability critical to processes of energy-system transformation. Alongside decarbonization, UK energy-system transformation has been positioned as potentially able to deliver significant benefits to households. In this article, we present qualitative data from deliberative workshops with members of the public concerning perceptions of heat decarbonization. We explore how low-carbon heating is not necessarily seen as an improvement where changes to heating systems may result in perceived compromises to comfort and convenience. We contend that a temporally sensitive approach, which explores past energy-system transitions and experiences of current heating systems as well as anticipated future technologies, can offer important insights into the transition to low-carbon heating.
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Authors: Encapsulating” experts’ knowledge: An exploration of benefits, risks, barriers and future opportunities of PCMs
Name of Journal: Sustainable Energy Technologies and Assessments
Abstract: Phase change materials (PCMs) can store high densities of thermal energy and possess strong heat transmission qualities. Given their diverse properties, these materials are well-suited for managing thermal energy in various applications This study focuses on battery thermal management systems (BTMS), where PCMs can regulate temperature variations in BTMS without needing external energy input to operate. However, despite their unique applications, PCMs application in BTMS remains limited. This research seeks to answer four important questions considering net-zero targets. What are the main advantages of PCMS in BTMS, what are their main drawbacks, which are the best means to combat their disadvantages and which are the key barriers to commercialising PCMs? These questions are addressed through a mixed-method approach, including a targeted literature review and 16 expert interviews with stakeholders from the industrial and academic sectors. The key conclusions emerging from professional public opinions and the literature analysis suggest that commercial barriers to PCM deployment are dominated by a lack of research examining the performance of these materials in the long term and a pervasive lack of interest from the automotive industry and Tier 1 battery pack suppliers in adopting PCMs.
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Authors: Mohd Hasan, Wong F, Al Kez D, Del Rio D, Foley A, Rooney D, Abai M
Name of Journal: Energy
Abstract: The Sixth Intergovernmental Panel on Climate Change Assessment Report underscores incremental progress in climate mitigation policies since 2014. Despite these efforts, the report indicates that global temperatures are likely to surpass the critical 1.5 °C threshold within the 21st century. In this context, the aviation industry, responsible for 2.8 % of global carbon dioxide emissions, faces challenges in meeting its net-zero emissions target by 2050. Through a mixed methods approach that includes expert interviews with 12 executive staff from airlines and airports and a targeted literature review, our research provides original data on means and challenges to decarbonize the aviation industry in the SEAO region. The findings reveal that significant hurdles persist while the aviation sector is actively pursuing decarbonization strategies, such as enhancing operational efficiency, adopting effective carbon offsetting measures, and transitioning to sustainable aviation fuels. Notably, using sustainable aviation fuels holds promise, potentially reducing carbon emissions by up to 70 %. However, its current contribution to total consumed jet fuel remains below 1 %. The industry is taking steps to address this by optimizing flight paths, schedules, and making strategic investments to decrease the costs associated with sustainable aviation fuels. Our qualitative data also underscores the influence of external factors, including investor pressure, national and international regulations, and a growing demand from environmentally conscious travellers for cleaner transport alternatives. Failure from airline industries to adopt more sustainable and efficient practices could lead to increased operating costs and revenue loss as corporate clients and customers increasingly seek greener transportation options.
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Authors: Alipour Bonab S, Waite T, Song W, Flynn D, Yazdani-Asrami M
Name of Journal: Energy Reports
Abstract: Aviation is a major contributor to transportation carbon emissions but aims to reduce its carbon footprint. Sustainable and environmentally friendly green hydrogen fuel is essential for decarbonization of this industry. Using the extremely low temperature of liquid hydrogen in aviation sector unlocks the opportunity for cryo-electric aircraft concept, which exploits the advantageous properties of superconductors onboard. A significant barrier for green hydrogen adoption relates to its high cost and the immediate need for large-scale production, which Proton Exchange Membrane Water Electrolyzers (PEMWE) can address through optimal dynamic performance, high lifetimes, good efficiencies, and importantly, scalability. In PEMWE the cell is a crucial component that facilitates the electrolysis process and consists of a polymer membrane and electrodes. To control the required production rate of hydrogen, the output power of cell should be monitored which usually is done by measuring the cell’s potential and current density. In this paper, five different machine learning (ML) models based on different algorithms have been developed to predict this parameter. Findings of the work highlight that the model based on Cascade-Forward Neural Network (CFNN) is investigated to accurately predict the cell potential of PEMWE under different anodic material and working conditions with an accuracy of 99.998 % and 0.001884 in terms of R2 and root mean square error, respectively. It can predict the cell potential with a relative error of less than 0.65 % and an absolute error of below 0.01 V. The Standard deviation of 0.000061 for 50 iterations of stability analysis indicated that this model has less sensitivity to the random selection of training data. By accurately estimating different cell’s output with one model, and considering its ultra-fast response, CFNN model has the potential to be used for both monitoring and the designing purposes of green hydrogen production.
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Authors: Vargas-Ferrer P, Jalil-Vega F, Pozo D, Sauma E
Name of Journal: Vargas-Ferrer P, Jalil-Vega F, Pozo D, Sauma E
Abstract: Renewable hydrogen is a promising alternative to increase the presence of renewable energy in hard-to-decarbonize economic sectors. Renewable-fuel regulation standards have been formalizing to ensure that on-grid electrolytic production is primarily powered by renewable electricity. This work evaluates the mid- and long-term impact of integrating renewable hydrogen supply chains into the expansion and operation of the power system using a tailored modification of the open-source energy modeling system (OSeMOSYS). The model optimizes the joint expansion of the Chilean power system and a hydrogen supply chain for exports, between 2025 and 2060, under the European standard for renewable hydrogen. Results show that incorporating renewable hydrogen supply chains that comply with this standard impacts the infrastructure and operation of the power system during its transition towards decarbonization. Between 2025 and 2040, the off-grid hydrogen production scenario results in distributed production, requiring internal hydrogen transport and low grid reliance. Conversely, a scenario that assumes Power Purchase Agreements for renewable electricity results in centralized hydrogen production, with higher electricity transmission investments and grid reliance. For the scenarios studied, the average systemic cost of hydrogen production ranges from $2.9/kgH2 to $6.4/kgH2.
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