Publications

This paper investigates the optimal planning of microgrids including the hydrogen energy system through mixed-integer linear programming model. A real case study is analyzed by extending the only microgrid lab facility in Austria. The case study considers the hydrogen production via electrolysis seasonal storage and fuelling station for meeting the hydrogen fuel demand of fuel cell vehicles busses and trucks. The optimization is performed relative to two different reference cases which satisfy the mobility demand by diesel fuel and utility electricity based hydrogen fuel production respectively. The key results indicate that the low emission hydrogen mobility framework is achieved by high share of renewable energy sources and seasonal hydrogen storage in the microgrid. The investment optimization scenarios provide at least 66% and at most 99% carbon emission savings at increased costs of 30% and 100% respectively relative to the costs of the diesel reference case (current situation)

Global maritime transportation is responsible for around 3% of total anthropogenic green‐ house gas emissions and significant proportions of SOx NOx and PM emissions. Considering the predicted growth in shipping volumes to 2050 greenhouse gas emissions from ships must be cut by 75–85% per ton‐mile to meet Paris Agreement goals. This study reviews the potential of a range of alternative fuels for decarbonisation in maritime. A systematic literature review and information synthesis method was applied to evaluate fuel characteristics production pathways utilization technologies energy efficiency lifecycle environmental performance economic viability and cur‐ rent applicable policies. Alternative fuels are essential to decarbonisation in international shipping. However findings suggest there is no single route to deliver the required greenhouse gas emissions reductions. Emissions reductions vary widely depending on the production pathways of the fuel. Alternative fuels utilising a carbon‐intensive production pathway will not provide decarbonisation instead shifting emissions elsewhere in the supply chain. Ultimately a system‐wide perspective to creating an effective policy framework is required in order to promote the adoption of alternative propulsion technologies.

This paper presents an analysis of Stress Corrosion Cracking (SCC) based on the Theory of Critical Distances (TCD). The research is based on an experimental program composed of fracture specimens with notch radius varying from 0 mm (crack-like defect) up to 1 mm and tensile specimens. A pipeline steel was used in this work (X80). It has been analysed in one hydrogen embrittlement situation. The study has been completed with Finite Elements Simulation analysis. The capacity of the TCD to analyse SCC processes has been proven.

A critical drawback of battery-powered eVTOL UAVs is their limited range and endurance and this drawback could be solved by using a combination of hydrogen fuel cells and batteries. The objective of this paper is to develop a sizing methodology for the lift+cruise-type eVTOL UAV powered by a hydrogen fuel cell and battery. This paper presents the constraints analysis method for forward flight/VTOL multi-mode UAV the regression model for electric propulsion system sizing a sizing method for an electric propulsion system and hydrogen fuel cell system and a transition analysis method. The total mass of the UAV is iteratively calculated until convergence and the optimization method is used to ensure that the sizing results satisfy the design requirements. The sizing results are the UAV’s geometry mass and power data. To verify the accuracy of the proposed sizing methodology the sizing and the conceptual design phase results of a 25 kg hydrogen fuel-cell-powered UAV are compared. All parameters had an error within 10% and satisfied the design requirements.

Hydrogen (H₂) shows great promise as zero-carbon emission fuel but there are several challenges to overcome in regards to storage and transportation to make it a more universal energy solution. Gaseous hydrogen requires high pressures and large volume tanks while storage of liquid hydrogen requires cryogenic temperatures; neither option is ideal due to cost and the hazards involved. Storage in the solid state presents an attractive alternative and can meet the U.S. Department of Energy (DOE) constraints to find materials containing > 7 % H₂ (gravimetric weight) with a maximum H₂ release under 125 °C.

While there are many candidate hydrogen storage materials the vast majority are metal hydrides. Of the hydrides this review focuses solely on sodium borohydride (NaBH4) which is often not covered in other hydride reviews. However as it contains 10.6% (by weight) H₂ that can release at 133 ± 3 JK−1mol⁻¹ this inexpensive material has received renewed attention. NaBH4 should decompose to H₂g) Na(s) and B(s) and could be recycled into its original form. Unfortunately metal to ligand charge transfer in NaBH4 induces high thermodynamic stability creating a high decomposition temperature of 530 °C. In an effort make H₂ more accessible at lower temperatures researchers have incorporated additives to destabilize the structure.

This review highlights metal additives that have successfully reduced the decomposition temperature of NaBH₄ with temperatures ranging from 522 °C (titanium (IV) fluoride) to 379 °C (niobium (V) fluoride). We describe synthetic methods employed chemical pathways taken and the challenges of boron derivative formation on H₂ cycling. Though no trends can be found across all additives it is our hope that compiling the data here will enable researchers to gain a better understanding of the additives’ influence and to determine how a new system might be designed to make NaBH4 a more viable H2 fuel source.

A comprehensive methodology for estimating the technological strength of welded joints are developed based on parameters reflecting the welding technology weldability hydrogen force and deformation conditions for welding and other informative parameters that correlate with the characteristics of the welded joint as well as improving existing methods for estimating the technological strength of welded joints connections through the introduction of modern equipment and non-destructive testing systems. It has been established that the proposed comprehensive estimation methodology will allow reaching a new qualitative level in assessing the technological strength of a welded joint using modern equipment and measuring instruments. According to the results of the experimental work it was found that when welding at low temperatures the increase in the probability of the formation and development of cold cracks is mainly determined by the critical content of diffusible hydrogen in the weld metal depending on the structural and force parameters of the welded joints.

The combination of catalytic decomposition of ammonia and in situ separation of hydrogen holds great promise for the use of ammonia as a clean energy carrier. However finding the optimal catalyst – membrane pair and operation conditions have proved challenging. Here we demonstrate that cobalt-based catalysts for ammonia decomposition can be efficiently 2 used together with a Pd-Au based membrane to produce high purity hydrogen at elevated pressure. Compared to a conventional packed bed reactor the membrane reactor offers several operational advantages that result in energetic and economic benefits. The robustness and durability of the combined system has been demonstrated for more than 1000 h on stream yielding a very pure hydrogen stream (>99.97 % H2) and recovery (>90 %). When considering the required hydrogen compression for storage/utilization and environmental issues the combined system offers the additional advantage of production of hydrogen at moderate pressures along with full ammonia conversion. Altogether our results demonstrate the possibility of deploying high pressure (350 bar) hydrogen generators from ammonia with H2 efficiencies of circa 75% without any external energy input and/or derived CO2 emissions.

The assessment of appropriate operational procedures to govern the injection of a hydrogen/natural gas blend into Northern Gas Networks’ (NGN) Winlaton gas distribution network was a key requirement of the HyDeploy2 project. To perform this assessment the review was broken down into two areas procedures upstream of the emergency control valve (owned by NGN) and procedures downstream of the Emergency Control Valve (procedures which would be performed by Gas Safe registered individuals). Assessment of the upstream procedures was led by NGN (own and carry out all upstream procedures on NGN’s gas network) and assessment of the downstream procedures was led by Blue Flame Associates (an industry expert on downstream gas procedures).<br/>Methodologies were adopted to be able to highlight procedures that could potentially be used on the Winlaton trial network during the hydrogen blended gas injection period and if they were impacted by the changing of the gas within the network from natural gas to hydrogen blended gas. This method determined that for downstream gas procedures a total of 56 gas procedures required expert review resulting in 80 technical questions to be assessed and for the upstream gas procedures a total of 80 gas procedures required expert review resulting in 266 technical questions to be assessed.<br/>The operational procedures assessment has led to a determination as to whether a change is or is not required for relevant operational procedures where a basis of concern existed with respect to the injection of hydrogen blended gas. Any requirements to modify an existing procedure has been given in this report referencing the source as to where the detailed analysis for the change/no change recommendation has been given.<br/>The assessment took into account the associated experimental and research carried out as part of the HyDeploy and HyDeploy2 projects such as the assessment of gas characteristics materials impact appliance survey of assets on the Winlaton network and impact of hydrogen blended gas on gas detection equipment references to these studies have been given accordingly to associated impacted operational procedures.<br/>The conclusion of the assessment is that for upstream gas procedures there are some operational procedures that are unchanged some that require an increase in the frequency as to how often they are performed and some procedures which require a technical modification. For downstream domestic gas procedures all procedures applicable to a domestic gas installation were deemed to not be detrimentally affected by the introduction of a 20 mol% hydrogen blend.<br/>For upstream gas procedures an appropriate training package will be built off the back of the results presented in this report and disseminated accordingly to all relevant Operatives that will be responsible for the safety operation and maintenance of the Winlaton network during the hydrogen blend injection period. For downstream gas procedures the Gas Safe community have been fully engaged and informed about the trial.<br/>Click on the supplements tab to view the other documents from this report

The CCUS Advisory Group (CAG) established in March 2019 is an industry-led group considering the critical challenges facing the development of CCUS market frameworks and providing insight into potential solutions. The CAG brings together experts from across the CCUS industry finance and legal sectors.<br/>The CAG has examined a range of business models focusing on industrial CCUS power production CO? transport and storage and hydrogen production. It has considered how the proposed business models interact in order to minimise issues such as cross-chain risk and has considered issues such as delivery capability. The conclusions of the CAG can be found in this report.

The remaining useful life (RUL) prediction for hydrogen fuel cells is an important part of its prognostics and health management (PHM). Artificial neural networks (ANNs) are proven to be very effective in RUL prediction as they do not need to understand the failure mechanisms behind hydrogen fuel cells. A novel RUL prediction method for hydrogen fuel cells based on the gated recurrent unit ANN is proposed in this paper. Firstly the data were preprocessed to remove outliers and noises. Secondly the performance of different neural networks is compared including the back propagation neural network (BPNN) the long short-term memory (LSTM) network and the gated recurrent unit (GRU) network. According to our proposed method based on GRU the root mean square error was 0.0026 the mean absolute percentage error was 0.0038 and the coefficient of determination was 0.9891 for the data from the challenge datasets provided by FCLAB Research Federation when the prediction starting point was 650 h. Compared with the other RUL prediction methods based on the BPNN and the LSTM our prediction method is better in both prediction accuracy and convergence rate.