Publications

A low pressure superheated hydrogen-steam system has been used to accelerate the oxidation kinetics while keeping the electrochemical conditions similar to those of the primary water in a pressurized water reactor. The initiation has been investigated using a Constant Extension Rate Tensile (CERT) test. Tests were performed on flat tapered specimens made from Type 316L austenitic stainless steel with strain rates of 2×10^-6 and 2×10^-8 ms^-1 at room temperature and at an elevated temperature of 350 °C. R = 1/6 was chosen as a more oxidizing environment and R = 6 was selected as a more reducing environment where the parameter R represents the ratio between the oxygen partial pressure at the Ni/NiO transition and the oxygen partial pressure. Different exposures (1 day and 5 days) prior to loading were investigated post-test evaluation by scanning electron microscopy.

In this work the design of the hardware architecture to implement an algorithm for optimizing the Hydrogen Productivity Rate (HPR) in a Microbial Electrolysis Cell (MEC) is presented. The HPR in the MEC is maximized by the golden section search algorithm in conjunction with a super-twisting controller. The development of the digital architecture in the implementation step of the optimization algorithm was developed in the Very High Description Language (VHDL) and synthesized in a Field Programmable Gate Array (FPGA). Numerical simulations demonstrated the feasibility of the proposed optimization strategy embedded in an FPGA Cyclone II. Results showed that only.

Using electricity for heating can contribute to decarbonization and provide flexibility to integrate variable renewable energy. We analyze the case of electric storage heaters in German 2030 scenarios with an open-source electricity sector model. We find that flexible electric heaters generally increase the use of generation technologies with low variable costs which are not necessarily renewables. Yet making customary night-time storage heaters temporally more flexible offers only moderate benefits because renewable availability during daytime is limited in the heating season. Respective investment costs accordingly have to be very low in order to realize total system cost benefits. As storage heaters feature only short-term heat storage they also cannot reconcile the seasonal mismatch of heat demand in winter and high renewable availability in summer. Future research should evaluate the benefits of longer-term heat storage.

Detailed analysis of pathways to future sustainable energy systems is important in order to identify and overcome potential constraints and negative impacts and to increase the utility and speed of this transition. A key aspect of a shift to renewable energy technologies is their relatively higher metal intensities. In this study a bottom-up cost-minimizing energy model is used to calculate aggregate metal requirements in different energy technology including hydrogen and climate policy scenarios and under a range of assumptions reflecting uncertainty in future metal intensities recycling rate and life time of energy technologies. Metal requirements are then compared to current production rates and resource estimates to identify potentially “critical” metals. Three technology pathways are investigated: 100 percent renewables coal & nuclear and gas & renewables each under the two different climate policies: net zero emissions satisfying the well-below 2 °C target and business as usual without carbon constraints resulting together in six scenarios. The results suggest that the three different technology pathways lead to an almost identical degree of warming without any climate policy while emissions peaks within a few decades with a 2 °C policy. The amount of metals required varies significantly in the different scenarios and under the various uncertainty assumptions. However some can be deemed “critical” in all outcomes including Vanadium. The originality of this study lies in the specific findings and in the employment of an energy model for the energy-mineral nexus study to provide better understanding for decision making and policy development.

Microwave heating offers a number of advantages over conventional heating methods such as rapid and volumetric heating precise temperature control energy efficiency and lower temperature gradient. In this article we demonstrate the use of 2450 MHz microwave traveling wave reactor to heat the catalyst bed for thermo-catalytic upgrading of pyrolysis vapors. HZSM-5 catalyst was tested at three different temperatures (290 330  and 370°C) at a catalyst to biomass ratio of 2. Results were compared with conventional heating and induction heating method of catalyst bed. The yields of aromatic compounds and coke deposition were dependent on temperature and method of heating. Microwave heating yielded higher aromatic compounds and lower coke deposition. Microwave heating was also energy efficient compared to conventional reactors. The rate of catalyst deterioration was lower for catalyst heated in microwave system.

Preventing humanity from serious impact of climate crisis requires carbon neutrality across all economic sectors including steel industry. Although fossil-free steelmaking routes receiving increasing attention fundamental process aspects especially approaches towards the improvement of efficiency and flexibility are so far not comprehensively studied. In this paper optimized process concepts allowing for a gradual transition towards fossil-free steelmaking based on the coupling of direct reduction process electric arc furnace and electrolysis are presented. Both a high-temperature and low-temperature electrolysis were modeled and possibilities for the integration into existing infrastructure are discussed. Various schemes for heat integration especially when using high-temperature electrolysis are highlighted and quantified. It is demonstrated that the considered direct reduction-based process concepts allow for a high degree of flexibility in terms of feed gas composition when partially using natural gas as a bridge technology. This allows for an implementation in the near future as well as the possibility of supplying power grid services in a renewable energy system. Furthermore it is shown that an emission reduction potential of up to 97.8% can be achieved with a hydrogen-based process route and 99% with a syngas-based process route respectively provided that renewable electricity is used.

The EU has set a goal of achieving climate neutrality by 2050 and decided to raise its 2030 climate target to 55%. For this the EU needs to transform its energy system. It is of paramount importance that it will become more efficient affordable and interconnected. Hydrogen can play a pivotal role in the EU’s decarbonisation efforts and be at the centre of the energy system integration supporting transport of renewable energy over very long distances and facilitating renewables storage from one season to another.<br/><br/>ENTSOG GIE and Hydrogen Europe have joined forces on a factsheet that answers a number of fundamental questions about gaseous and liquid hydrogen transport and storage titled “How to transport and store hydrogen? Facts and figures”. This factsheet provides an objective and informative analysis on key concepts terminology and facts and figures from different public sources.<br/><br/>The factsheet illustrates the EU’s potential to enable a global hydrogen economy and to become a global technology leader due to its extensive gas infrastructure that can be used to transport blends of hydrogen or be converted to transport pure hydrogen.

Grand Canonical Monte Carlo GCMC simulations are used to study the gravimetric and volumetric hydrogen storage capacities of different carbon nanopores shapes: Slit-shaped nanotubes and torusenes at room temperature 298.15 K and at pressures between 0.1 and 35 MPa and for pore diameter or width between 4 and 15 A. The influence of the pore shape or curvature on the storage capacities as a function of pressure temperature and pore diameter is investigated and analyzed. A large curvature of the pores means in general an increase of the storage capacities of the pores. While torusenes and nanotubes have surfaces with more curvature than the slit-shaped planar pores their capacities are lower than those of the slit-shaped pores according to the present GCMC simulations. Torusene a less studied carbon nanostructure has two radii or curvatures but their storage capacities are similar or lower than those of nanotubes which have only one radius or curvature. The goal is to obtain qualitative and quantitative relationships between the structure of porous materials and the hydrogen storage capacities in particular or especially the relationship between shape and width of the pores and the hydrogen storage capacities of carbon-based porous materials.

This paper discusses the performance improvement of a green building by optimization procedures and the influences of load characteristics on optimization. The green building is equipped with a self-sustained hybrid power system consisting of solar cells wind turbines batteries proton exchange membrane fuel cell (PEMFC) electrolyzer and power electronic devices. We develop a simulation model using the Matlab/SimPowerSystemTM and tune the model parameters based on experimental responses so that we can predict and analyze system responses without conducting extensive experiments. Three performance indexes are then defined to optimize the design of the hybrid system for three typical load profiles: the household the laboratory and the office loads. The results indicate that the total system cost was reduced by 38.9% 40% and 28.6% for the household laboratory and office loads respectively while the system reliability was improved by 4.89% 24.42% and 5.08%. That is the component sizes and power management strategies could greatly improve system cost and reliability while the performance improvement can be greatly influenced by the characteristics of the load profiles. A safety index is applied to evaluate the sustainability of the hybrid power system under extreme weather conditions. We further discuss two methods for improving the system safety: the use of sub-optimal settings or the additional chemical hydride. Adding 20 kg of NaBH4 can provide 63 kWh and increase system safety by 3.33 2.10 and 2.90 days for the household laboratory and office loads respectively. In future the proposed method can be applied to explore the potential benefits when constructing customized hybrid power systems.

This research activity aims at investigating the hydrogen embrittlement of Maraging steels in connection to real sudden failures of some of the suspension blades of the Virgo Project experimental apparatus. Some of them failed after 15 years of service in working conditions. Typically in the Virgo detector blades are loaded up to 50-60% of the material yield strength. For a deeper understanding of the failure the relationship between hydrogen concentration and mechanical properties of the material have been investigated with specimens prepared in order to simulate blade working conditions. A mechanical characterization of the material has been carried out by standard tensile testing in order to establish the effect of hydrogen content on the material strength. Further experimental activity was executed in order to characterize the fracture surface and to measure the hydrogen content. Finally some of the failed blades have been analyzed in DICI-UNIPI laboratory. The experimental results show that the blades failure can be related with the hydrogen embrittlement phenomenon.

Biochar (BCH) is a carbon‐based bio‐material produced from thermochemical conversion of biomass. Several activation or functionalization methods are usually used to improve physicochemical and functional properties of BCHs. In the context of green and sustainable future development activated and functionalized biochars with abundant surface functional groups and large surface area can act as effective catalysts or catalyst supports for chemical transformation of a range of bioproducts in biorefineries. Above the well‐known BCH applications their use as adsorbents to remove pollutants are the mostly discussed although their potential as catalysts or catalyst supports for advanced (electro)catalytic processes has not been comprehensively explored. In this review the production/activation/functionalization of metal‐supported biochar (M‐BCH) are scrutinized giving special emphasis to the metal‐functionalized biochar‐based (electro)catalysts as promising catalysts for bioenergy and bioproducts production. Their performance in the fields of biorefinery processes and energy storage and conversion as electrode materials for oxygen and hydrogen evolutions oxygen reduction and supercapacitors are also reviewed and discussed.

Understanding hydrogen embrittlement phenomenon that leads to deterioration of mechanical properties of metallic components is vital for applications involving hydrogen environment. Among these understanding the influence of hydrogen on the fatigue behaviour of metals is of great interest. Total fatigue life of a material can be divided into fatigue crack initiation and fatigue crack growth phase. While fatigue crack initiation can be linked with the propagation of short fatigue cracks the size of which is of the order of grain size (few tens of microns) that are generally not detectable by conventional crack detection techniques applicable for the long fatigue crack growth behaviour using conventional CT specimens. Extensive literature is available on hydrogen effect on long fatigue crack growth behaviour of metals that leads to the change in crack growth rate and the threshold stress intensity factor range (ΔKth). However it is the short fatigue crack growth behaviour that provides the fundamental understanding and correlation of the metallic microstructure with hydrogen embrittlement phenomenon. Short fatigue crack growth behaviour is characteristically different from long crack growth behaviour showing high propagation rate at much lower values than threshold stress intensity factor range as well as a strong dependency on the microstructural features such as grain boundaries phase boundaries and inclusions. To this end a novel experimental framework is developed to investigate the short fatigue crack behaviour of hydrogen charged materials involving in-situ observation of propagating short cracks coupled with image processing to obtain their da/dN vs a curves. Various metallic materials ranging from austenitic stainless steel (AISI 316L) to reactor pressure vessel steel (SA508 Grade 3 Class I low alloy steel) and line pipe steels (API 5L X65 & X80) are studied in this work.

Hydrogen gas has tremendous potential as an environmentally acceptable energy carrier for vehicles. A cutting edge technology called a microbial electrolysis cell (MEC) can achieve sustainable and clean hydrogen production from a wide range of renewable biomass and wastewaters. Enhancing the hydrogen production rate and lowering the energy input are the main challenges of MEC technology. MEC reactor design is one of the crucial factors which directly influence on hydrogen and current production rate in MECs. The rector design is also a key factor to upscaling. Traditional MEC designs incorporated membranes but it was recently shown that membrane-free designs can lead to both high hydrogen recoveries and production rates. Since then multiple studies have developed reactors that operate without membranes. This review provides a brief overview of recent advances in research on scalable MEC reactor design and configurations.

Numerical experiments are performed to understand different regimes of hydrogen non-premixed combustion in an enclosure with passive ventilation through one horizontal or vertical vent located at the top of a wall. The Reynolds averaged Navier–Stokes (RANS) computational fluid dynamics (CFD) model with a reduced chemical reaction mechanism is described in detail. The model is based on the renormalization group (RNG) k-ε turbulence model the eddy dissipation concept (EDC) model for simulation of combustion coupled with the 18-step reduced chemical mechanism (8 species) and the in-situ adaptive tabulation (ISAT) algorithm that accelerates the reacting flow calculations by two to three orders of magnitude. The analysis of temperature and species (hydroxyl hydrogen oxygen water) concentrations in time as well as the velocity through the vent shed a light on regimes and dynamics of indoor hydrogen fires. A well-ventilated fire is simulated in the enclosure at a lower release flow rate and complete combustion of hydrogen within the enclosure. Fire becomes under-ventilated at higher release flow rates with two different modes observed. The first mode is the external flame stabilised at the enclosure vent at moderate release rates and the second mode is the self-extinction of combustion inside and outside the enclosure at higher hydrogen release rates. The simulations demonstrated a complex reacting flow dynamics in the enclosure that leads to formation of the external flame or the self-extinction. The air intake into the enclosure at later stages of the process through the whole vent area is a characteristic feature of the self-extinction regime. This air intake is due to faster cooling of hot combustion products by sustained colder hydrogen leak compared to the generation of hot products by the ceasing chemical reactions inside the enclosure and hydrogen supply. In general an increase of hydrogen sustained release flow rate will change fire regime from the well-ventilated combustion within the enclosure through the external flame stabilised at the vent and finally to the self-extinction of combustion throughout the domain.

Rod-like molybdenum carbide (Mo₂C) microcrystals were obtained from the pyrolysis of Mo-containing organic-inorganic hybrid composite. We investigated the photocatalytic H₂ evolution activity of Mo₂C by constructing a Mo₂C-dye sensitizer photocatalyst system. A high quantum efficiency of 29.7% was obtained at 480 nm. Moreover Mo₂C catalyst can be easily recycled by simple filtration.

Hydrogen produced from renewables works as an energy carrier and as energy storage medium and thus hydrogen can help to overcome the intermittency of typical renewable energy sources. However there is no comprehensive environmental performance study of hydrogen production and consumption. In this study detailed cradle to grave life cycle analyses are performed in an isolated territory. The hydrogen is produced on-site by Polymer Electrolyte Membrane (PEM) water electrolysis based on electricity from wind turbines that would otherwise have been curtailed and subsequently transported with gas cylinder by road and ferry. The hydrogen is used to provide electricity and heat through fuel cell stacks as well as hydrogen fuel for fuel cell vehicles. In order to evaluate the environmental impacts related to the hydrogen production and utilisation this work conducts an investigation of the entire life cycle of the described hydrogen production transportation and utilisation. All the processes related to the equipment manufacture operation maintenance and disposal are considered in this study.

The Flexibility in Great Britain project analysed the system-level value of deploying flexibility across the heat transport industry and power sectors in Great Britain to provide a robust evidence-base on the role and value of flexibility in a net zero system.

Overview

Findings from this groundbreaking analysis of the future net zero energy system in Great Britain are expected to have profound implications for policymakers households and the wider energy sector across Great Britain.

Key findings include:

• Embedding greater flexibility across the entire energy system will reduce the cost of achieving net zero for all consumers while assuring energy security.
• Investing in flexibility is a no-regrets decision as it has the potential to deliver material net savings of up to £16.7bn per annum across all scenarios analysed in 2050.
• A more flexible system will accelerate the benefits of decarbonisation supported by decentralisation and digitalisation.
• To maximise the benefits of flexibility households and businesses should play an active role in the development and operation of the country’s future energy system as energy use for transport heat and appliances becomes more integrated.
• Policymakers should preserve existing flexibility options and act now to maximise future flexibility such as by building it into ‘smart’ appliances or building standards.

Read the Full Report here on the Carbon Trust Website

View the interactive analysis here at the Carbon Trust Website

Watch an accompanying video here at the Carbon Trust Youtube channel

Thermal gas meters represent a promising technology for billing customers for gaseous fuels however it is essential to ensure that measurement accuracy is maintained in the long term and in a broad range of operating conditions. The effect of hydrogen addition to natural gas will change the physicochemical properties of the mixture of natural gas and hydrogen. Such a mixture will be supplied through the gas system to consumers including households where the amounts of received gas will be metered. The physicochemical properties of hydrogen including the specific density or viscosity differ significantly from those of the natural gas components such as methane ethane propane nitrogen etc. Therefore it is of utmost importance to establish the impact of the changes in the gas composition caused by the addition of hydrogen to natural gas on the metrological properties of household gas meters including thermal gas meters. Furthermore since household gas meters can be installed outdoors and taking into account the fact that household gas meters are good heat exchangers the influence of ambient and gas temperature on the metrological properties of those meters should be investigated. This article reviews a test bench and a testing method concerning errors of thermal gas meter indicators using air and natural gas including the type containing hydrogen. The indication errors for thermal gas meters using air natural gas and natural gas with an addition of 2% 4% 5% 10% and 15% hydrogen were determined and then subjected to metrological analysis. Moreover the test method and test bench are discussed and the results of tests on the impact of ambient and gas temperatures (-25 ◦C and 55 ◦C respectively) on the errors of indications of thermal gas meters are presented. Conclusions for distribution system operators in terms of gas meter selection were drawn based on the test results.

Because of differences in irradiation levels it could be more efficient to produce solar electricity and hydrogen in North Africa and import these energy carriers to Europe rather than generating them at higher costs domestically in Europe. From a global climate change mitigation point of view exploiting such efficiencies can be profitable since they reduce overall renewable electricity capacity requirements. Yet the construction of this capacity in North Africa would imply costs associated with the infrastructure needed to transport electricity and hydrogen. The ensuing geopolitical dependencies may also raise energy security concerns. With the integrated assessment model TIAM-ECN we quantify the trade-off between costs and benefits emanating from establishing import-export links between Europe and North Africa for electricity and hydrogen. We show that for Europe a net price may have to be paid for exploiting such interlinkages even while they reduce the domestic investments for renewable electricity capacity needed to implement the EU’s Green Deal. For North African countries the potential net benefits thanks to trade revenues may build up to 50 billion €/yr in 2050. Despite fears over costs and security Europe should seriously consider an energy partnership with North Africa because trade revenues are likely to lead to positive employment income and stability effects in North Africa. Europe can indirectly benefit from such impacts.

In this study the consequences of an accidental release of hydrogen within large scale (>15000 m3) facilities were modelled. To model the hydrogen release an LES Navier–Stokes CFD solver called fireFoam was used to calculate the dispersion and mixing of hydrogen within a large scale facility. The performance of the CFD modelling technique was evaluated through a validation study using experimental results from a 1/6 scale hydrogen release from the literature and a grid sensitivity study. Using the model a parametric study was performed varying release rates and enclosure sizes and examining the concentrations that develop. The hydrogen dispersion results were then used to calculate the corresponding pressure loads from hydrogen-air deflagrations in the facility.

Direct containment heating (DCH) is one of the potential factors leading to early containment failure. DCH is closely related to safety analysis and containment performance evaluation of nuclear power plants. In this study a DCH prediction program was developed to analyze the DCH loads of containment vessel. The phenomenological model of debris dispersal metal oxidation reaction debris-atmospheric heat transfer and hydrogen jet burn was established. Code assessment was performed by comparing with several separate effect tests and integral effect tests. The comparison between the predicted results and experimental data shows that the program can predict the key parameters such as peak pressure temperature and hydrogen production in containment well and for most comparisons the relative errors can be maintained within 20%. Among them the prediction uncertainty of hydrogen production is slightly larger. The analysis shows that the main sources of the error are the difference of time scale and the oxidation of cavity debris.

2020 has been a year for the history books! Some good most of it not so good; but 2020 has been a boom year for the future of hydrogen technologies. Patrick Chris and Andrew do their level best on this episode to talk about all the stories and the highlights of 2020 in under 50 minutes. Have a listen and let us know if we missed anything in our penultimate episode of 2020!

The podcast can be found on their website

Biomaterials attract a lot of attention as next-generation materials. Especially in the energy field fuel cells based on biomaterials can further develop clean next-generation energy and are focused on with great interest. In this study solid-state hydrogen fuel (PSII–chitin composite) composed of the photosystem II (PSII) and hydrated chitin composite was successfully created. Moreover a biofuel cell consisting of the electrolyte of chitin and the hydrogen fuel using the PSII– chitin composite was fabricated and its characteristic feature was investigated. We found that proton conductivity in the PSII–chitin composite increases by light irradiation. This result indicates that protons generate in the PSII–chitin composite by light irradiation. It was also found that the biofuel cell using the PSII–chitin composite hydrogen fuel and the chitin electrolyte exhibits the maximum power density of 0.19 mW/cm2 . In addition this biofuel cell can drive an LED lamp. These results indicate that the solid-state biofuel cell based on the bioelectrolyte “chitin” and biofuel “the PSII–chitin composite” can be realized. This novel solid-state fuel cell will be helpful to the fabrication of next-generation energy.

On this weeks episode the team are talking all things hydrogen with Mark Neller Director at Arup. On the show we discuss the UK’s Hydrogen4Heat program where Arup has been leading the UK government’s work on the safety and practical considerations that are necessary to examine whether hydrogen could be a serious solutions for decarbonising UK residential commercial and industry heat. We also discuss the Nikola Badger the need for system wide planning when considering decarbonisation pathways for heat. All this and more on the show!

The podcast can be found on their website

The concerns over food security and protein scarcity driven by population increase and higher standards of living have pushed scientists toward finding new protein sources. A considerable proportion of resources and agricultural lands are currently dedicated to proteinaceous feed production to raise livestock and poultry for human consumption. The 1st generation of microbial protein (MP) came into the market as land-independent proteinaceous feed for livestock and aquaculture. However MP may be a less sustainable alternative to conventional feeds such as soybean meal and fishmeal because this technology currently requires natural gas and synthetic chemicals. These challenges have directed researchers toward the production of 2nd generation MP by integrating renewable energies anaerobic digestion nutrient recovery biogas cleaning and upgrading carbon-capture technologies and fermentation. The fermentation of methane-oxidizing bacteria (MOB) and hydrogen-oxidizing bacteria (HOB) i.e. two protein rich microorganisms has shown a great potential on the one hand to upcycle effluents from anaerobic digestion into protein rich biomass and on the other hand to be coupled to renewable energy systems under the concept of Power-to-X. This work compares various production routes for 2nd generation MP by reviewing the latest studies conducted in this context and introducing the state-of-the-art technologies hoping that the findings can accelerate and facilitate upscaling of MP production. The results show that 2nd generation MP depends on the expansion of renewable energies. In countries with high penetration of renewable electricity such as Nordic countries off-peak surplus electricity can be used within MP-industry by supplying electrolytic H2 which is the driving factor for both MOB and HOB-based MP production. However nutrient recovery technologies are the heart of the 2nd generation MP industry as they determine the process costs and quality of the final product. Although huge attempts have been made to date in this context some bottlenecks such as immature nutrient recovery technologies less efficient fermenters with insufficient gas-to-liquid transfer and costly electrolytic hydrogen production and storage have hindered the scale up of MP production. Furthermore further research into techno-economic feasibility and life cycle assessment (LCA) of coupled technologies is still needed to identify key points for improvement and thereby secure a sustainable production system.