Publications

This study introduces a machine learning approach to predict the effect of alloying elements and test conditions on the hydrogen environment embrittlement (HEE) index of austenitic steels for the first time. The correlation between input features and the HEE index was analyzed with Pearson's correlation coefficient (PCC) and Maximum Information Coefficient (MIC) algorithms. The correlation analysis results identified Ni and Mo as dominant features influencing the HEE index of austenitic steels. Based on the analysis results the performance of the four representative machine learning models as a function of the number of top-ranked features was evaluated: random forest (RF) linear regression (LR) Bayesian ridge (BR) and support vector machine (SVM). Regardless of the type and the number of top-ranking features the RF model had the highest accuracy among various models. The machine learning-based approach is expected to be useful in designing new steels having mechanical properties required for hydrogen applications.

We spend a lot of time on the show talking about the interesting use cases and potential applications of hydrogen technologies as a means to decarbonize high-emissions sectors and that is the point! However moving hydrogen around the world (e.g. to remote areas without the capacity to produce it locally) presents a number of complexities and challenges that are unique to hydrogen itself or for which there are no traditionally established technologies to do so. On this episode the EAH team has a fascinating chat with Dr. Daniel Teichmann CEO and founder of Hydrogenious to learn more about liquid organic hydrogen carriers (LOHCs) and how they can help companies overcome some of the major hurdles that moving hydrogen around the globe presents.

The podcast can be found on their website

Type IV hydrogen storage tanks play an important role in hydrogen fuel cell vehicles (HFCVs) due to their superiority of lightweight good corrosion and fatigue resistance. It is planned to be used between -40℃ and 85℃ at which the polymer liner may have a degradation of mechanical properties and buckling collapse. This demand a good performance of liner materials in that temperature range. In this article the temperature effect on mechanical properties of polyamide 6 (PA6) liner material including specimens with weld seam was investigated via the stress-strain curve (S-S curve) macroscopic and microscopic morphology. Considering that the mechanical properties will change after the liner molding process this test takes samples directly from the liner. Results show that the tensile strength and tensile modulus increased by 2.46 times and 10.6 times respectively with the decrease of temperature especially in the range from 50℃ to -90℃. For the elongation at break and work of fracture they do not monotonously increase with the temperature up. Both of them reduce when the temperature rises from 20°C to 50°C especially for the work of fracture decreasing by 63%. The weld seam weakens the mechanical properties and the elongation at break and work of fracture are more obvious which are greater than 40% at each temperature. In addition the SEM images indicate that the morphology of fracture surface at -90°C is different from that at other temperatures which is a sufficient evidence of toughness reducing in low temperature.

Introducing CO2 electrochemical conversion technology to the iron-making blast furnace not only reduces CO2 emissions but also produces H2 as a byproduct that can be used as an auxiliary reductant to further decrease carbon consumption and emissions. With adequate H2 supply to the blast furnace the injection of H2 is limited because of the disadvantageous thermodynamic characteristics of the H2 reduction reaction in the blast furnace. This paper presents thermodynamic analysis of H2 behaviour at different stages with the thermal requirement consideration of an iron-making blast furnace. The effect of injecting CO2 lean top gas and CO2 conversion products H2–CO gas through the raceway and/or shaft tuyeres are investigated under different operating conditions. H2 utilisation efficiency and corresponding injection volume are studied by considering different reduction stages. The relationship between H2 injection and coke rate is established. Injecting 7.9–10.9 m3/tHM of H2 saved 1 kg/tHM coke rate depending on injection position. Compared with the traditional blast furnace injecting 80 m3/tHM of H2 with a medium oxygen enrichment rate (9%) and integrating CO2 capture and conversion reduces CO2 emissions from 534 to 278 m3/tHM. However increasing the hydrogen injection amount causes this iron-making process to consume more energy than a traditional blast furnace does.

The independent cross-party report highlights a ‘sensible middle ground’ in the renewables debate and calls for more effort in building cross-party consensus. It finds that the UK has only just begun to harness low carbon renewable resources bigger than North Sea oil and gas and argues that the Government could do more to narrow the scope of debate about the technology mix beyond 2020. It argues that it should work with industry and academia first to establish ‘low regrets’ levels of technology deployment and second to ensure that policies are in place to incentivise investments such as supply chain investment needed to deliver these low regrets actions.

This approach would help provide the longer term clarity that could secure supply chain investments giving the UK a head-start in the global race. The report finds that these investments could be missed delayed or more expensive if there is insufficient confidence about long term demand for key technologies such as offshore wind. Work by Government to help incentivise these investments would increase the likelihood that technology cost reductions are achieved and help mitigate against high costs if new nuclear or carbon capture and storage development fail or are delayed.

On affordability the report finds that there are ‘hidden’ benefits that the UK could see from investing more in renewables through electricity bills between now and 2020. These include: avoiding bill increases driven by fossil fuels; making electricity bills more predictable; and providing an economic boost. The extra money paid to support renewables and other low carbon generation such as nuclear power could be more than offset by energy efficiency savings although Government needs to do more to show how these savings will arise.

On sustainability the report tackles myths about the carbon emitted in manufacturing renewable technologies or in backing up varying technologies such as wind solar wave and tidal. It finds that even when considering these factors renewables are still amongst the most low carbon options. The report also looks at the sustainability of electricity from biomass. Bioenergy overall could provide up to ten per cent of energy and reduce the cost of cutting carbon by £44 billion per year in 2050. The Government’s new biomass policies are a pragmatic response to concerns about the sustainability of biomass power which balances protecting the environment building public confidence and enabling the sector to grow.

On security of supply the inquiry argues that debate should focus on the whole electricity system and that individual technologies should be considered in the context of how they add to or reduce system risks. Considered like this renewables reduce some risks such as fuel supply risks which caused concern last winter and add to others such as system balancing risks. System balancing risks from varying renewables (wind solar wave and tidal technologies) are manageable using a number of existing and developing technologies.

The independent report chaired by former Energy Minister Charles Hendry MP and Shadow Energy Minister Baroness Worthington was compiled between May and September 2013 and was sponsored by Siemens and DONG Energy. It is part of a year-long independent and cross party inquiry into the UK power sector the Future Electricity Series sponsored by the Institution of Gas Engineers and Managers.

Link to Launch Video

This study has developed traceable standards for evaluating impurities in hydrogen fuel according to ISO 14687. Impurities in raw H2 including sub mmol/mol levels of CO CO2 and CH4 were analyzed using multiple detectors while avoiding contamination. The gravimetric standards prepared included mixtures of the following nominal concentrations: 1 2 3e5 8e11 17e23 and 47e65 mmol/mol for CO2 CH4 and CO O2 N2 Ar and He respectively. The expanded uncertainty ranges were 0.8% for Ar N2 and He 1% for CH4 and CO and 2% for CO2 and O2. These standards were stable while that for CO varied by only 0.5% during a time span of three years. The prepared standards are useful for evaluating the compliance of H2 fuel in service stations with ISO 14687 quality requirements.

This study investigates the production of green hydrogen for use in oil refining as specified in the draft of European union delegated act published in May 2022. The European union plans to set strict requirements of additionality and reporting regarding the criteria of renewable electricity used in hydrogen production. Alkaline electrolyzer proton exchange membrane electrolyzer and solid oxide electrolyzer are evaluated in various scenarios supplied by wind power: power purchase agreement-based scenarios and wind power investment-based scenarios. In power purchase agreement-based scenarios baseload and pay as produced power purchase agreements (with and without electricity storage) are assessed. According to results the use of 600 MW compressed air energy storage could reduce the dependency on the grid by 7% but increase the cost of green hydrogen significantly. Investment-based scenarios produce green hydrogen with a lower operation cost but higher break-even price compared to power purchase agreement-based scenarios. The cheapest green hydrogen can be achieved by alkaline electrolyzer with baseload power purchase agreement. Direct ownership of wind power is outside the operation of oil refining industry thus power purchase agreements contracting is more likely to realize.

This paper discloses the architecture and related performance of an environment control system designed to be integrated within a complex multi-functional thermal and energy management system that manages the heat loads and generation of electric power in a hypersonic vehicle by benefitting from the presence of cryogenic liquid hydrogen onboard. A bleed-less architecture implementing an open-loop cycle with a boot-strap sub-freezing air cycle machine is suggested. Hydrogen boil-off reveals to be a viable cold source for the heat exchangers of the system as well as for the convective insulation layer designed around the cabin walls. Including a 2 mm boil-off convective layer into the cabin cross-section proves to be far more effective than a more traditional air convective layer of approximately 60 mm. The application to STRATOFLY MR3 a Mach 8 waverider cruiser using liquid hydrogen as propellant confirmed that presence of cryogenic tanks provides up to a 70% reduction in heat fluxes entering the cabin generated outside of it but inside the vehicle by the propulsive system and other onboard systems. The effectiveness of the architecture was confirmed for all Mach numbers (from 0.3 to 8) and all flight altitudes (from sea level to 35 km).

Recently smart energy hubs with hydrogen conversion and storage have received increased attention in the Netherlands. The hydrogen is to be used for vehicle filling stations industrial processes and heating. The scientific problem addressed in this paper is the proper sizing of capacities for renewable energy generation hydrogen conversion and storage in relation to a feasible business case for the energy hub while achieving security of supply. Scenario analysis is often used during the early stages of the energy planning process and for this an easy-to-use analysis model is required. This paper investigates available modelling approaches and develops an algorithmic modelling method which is worked out in Microsoft Excel and offers ease of use for scenario analysis purposes. The model is applied to case study which leads to important insights such as the expected price of hydrogen and the proper sizing of electrolyser and hydrogen storage for that case. The model is made available open-source. Future work is proposed in the direction of application of the model for other project cases and comparison of results with other available modelling tools.

This paper deals with two main issues regarding the specific energy consumption in an electrolyzer (i.e. the Faraday efficiency and the converter topology). The first aspect is addressed using a multistack configuration of proton exchange membrane (PEM) electrolyzers supplied by a wind turbine conversion system (WTCS). This approach is based on the modeling of the wind turbine and the electrolyzers. The WTCS and the electrolyzers are interfaced through a stacked interleaved DC–DC buck converter (SIBC) due to its benefits for this application in terms of the output current ripple and reliability. This converter is controlled so that it can offer dynamic behavior that is faster than the wind turbine avoiding overvoltage during transients which could damage the PEM electrolyzers. The SIBC is designed to be connected in array configuration (i.e. parallel architecture) so that each converter operates at its maximum efficiency. To assess the performance of the power management strategy experimental tests were carried out. The reported results demonstrate the correct behavior of the system during transient operation.