Publications

This paper assesses the techno-economic feasibility of a green hydrogen-based microgrid for a remote Australian island. Hydrogen can be used to provide clean energy in areas where large-scale renewable energy sources are not feasible owing to geography government regulations or regulatory difficulties. This study not only identifies the appropriate component size for a hydrogen-based microgrid but also provides an economic perspective of decarbonising Thursday Island in Torres Straits Queensland Australia. Due to geographical constraints the green hydrogen production system needs to be distinct from the electrical network. This research shows how to produce green hydrogen transport it and generate power at a low cost. The study was performed utilising the HOMER simulation platform to find the least cost solution. The simulation results demonstrate an AU$0.01 reduction in Levelised Cost of Energy compared to the present electricity generation cost which is AU$0.56. The inclusion of a green hydrogen system will potentially minimise CO2 emissions by 99.6% while ensuring almost 100% renewable penetration. The results of this study will also serve as a guide for the placement of hydrogen-based microgrids in similar remote locations around the world where numerous remote energy systems are located close to each other.

Steam methane reforming (SMR) using natural gas is the most commonly used technology for hydrogen production. Industrial hydrogen production contributes to pollutant emissions which may differ from the theoretical estimates due to process conditions type and state of installed pollution control equipment. The aim of this study was to estimate the impacts of hydrogen production using facilitylevel real emissions data collected from multiple US EPA databases. The study applied the ReCiPe2016 impact assessment method and considered 12 midpoint and 14 endpoint impacts for 33 US SMR hydrogen production facilities. Global warming impacts were mostly driven by CO2 emissions and contributed to 94.6% of the endpoint impacts on human health while global warming impact on terrestrial ecosystems contributed to 98.3% of the total endpoint impacts on ecosystems. The impacts estimated by direct emissions from the 33 facilities were 9.35 kg CO2e/kg H2 which increased to 11.2 kg CO2e/kg H2 when the full life cycle of hydrogen production including upstream emissions was included. The average global warming impact could be reduced by 5.9% and 11.1% with increases in hydrogen production efficiency by 5% and 10% respectively. Potential impact reductions are also found when natural gas hydrogen production feedstock is replaced by renewable sources with the greatest reduction of 78.1% found in hydrogen production via biomass gasification followed by 68.2% reduction in landfill gas and 53.7% reduction in biomethane-derived hydrogen production.

Development of hydrogen facilities such as hydrogen refuelling stations (HRS) at scale is a fine balance between economy and safety where an optimal solution would both prevent showstoppers due to cost of increased safety measures and prevent showstoppers due to hydrogen accidents. A detailed Quantitative Risk Analysis (QRA) methodology is presented where the aim is to establish the total risk of the facility and use it to find the right level of safety features such as blast walls and layout. With upscaled hydrogen facilities comes larger area footprints and more potential leak points. These effects will cause increased possible consequence in terms of vapour cloud explosions and increased leak frequencies. Both effects contributing negative to the total risk of the hydrogen facility. At the same time as the number of such facilities is increasing rapidly the frequency of incidents can also increase. A risk-based approach is employed where inherently safe solutions is investigated and cost efficient and acceptable solutions can be established. The present QRA uses well established tools such as SAFETI FLACS and Express which are fitted for hydrogen risks. By using the established Explosion Risk Analysis tool Express the explosion risk inside the station can be found. By using CFD tools actively one can point at physical risk drivers such as equipment layout that can minimize gas cloud build-up on the station. The explosion simulations are further used to find the effects of e.g. blast wall on the pressures affecting on people on the other side of the wall. This is used together with the results from the SAFETI analysis to develop risk contours around the facility. Current standardized safety distances are discussed by considering the effects of scaling and risk drivers on the safety distances. The methodology can be used to develop certain requirement for how hydrogen facilities should be built inherently safe and in cost-efficient ways.

Ammonia a chemical that contains high hydrogen quantities has been presented as a candidate for the production of clean power generation and aerospace propulsion. Although ammonia can deliver more hydrogen per unit volume than liquid hydrogen itself the use of ammonia in combustion systems comes with the detrimental production of nitrogen oxides which are emissions that have up to 300 times the greenhouse potential of carbon dioxide. This factor combined with the lower energy density of ammonia makes new studies crucial to enable the use of the molecule through methods that reduce emissions whilst ensuring that enough power is produced to support high-energy intensive applications. Thus this paper presents a numerical study based on the use of novel reaction models employed to characterize ammonia combustion systems. The models are used to obtain Reynolds Averaged Navier-Stokes (RANS) simulations via Star-CCM+ with complex chemistry of a 70%–30% (mol) ammonia–hydrogen blend that is currently under investigations elsewhere. A fixed equivalence ratio (1.2) medium swirl (0.8) and confined conditions are employed to determine the flame and species propagation at various operating atmospheres and temperature inlet values. The study is then expanded to high inlet temperatures high pressures and high flowrates at different confinement boundary conditions. The results denote how the production of NOx emissions remains stable and under 400 ppm whilst higher concentrations of both hydrogen and unreacted ammonia are found in the flue gases under high power conditions. The reduction of heat losses (thus higher temperature boundary conditions) has a crucial impact on further destruction of ammonia post-flame with a raise in hydrogen water and nitrogen through the system thus presenting an opportunity of combustion efficiency improvement of this blend by reducing heat losses. Final discussions are presented as a method to raise power whilst employing ammonia for gas turbine systems.

To meet the target of reducing greenhouse gas emissions hydrogen as a carbon-free fuel is expected to play a major role in future energy supplies. A challenge with hydrogen is its low density and volumetric energy value meaning that large tanks are needed to store and transport it. By injecting hydrogen into the natural gas network the transportation issue could be solved if the hydrogen–natural gas mixture satisfies the grid gas quality requirements set by legislation and standards. The end consumers usually have stricter limitations on the gas quality than the grid where Euromot the European association of internal combustion engine manufacturers has specific requirements on the parameters: the methane number and Wobbe index. This paper analyses how much hydrogen can be added into the natural gas grid to fulfil Euromot’s requirements. An average gas composition was calculated based on the most common ones in Europe in 2021 and the results show that 13.4% hydrogen can be mixed with a gas consisting of 95.1% methane 3.2% ethane 0.7% propane 0.3% butane 0.3% carbon dioxide and 0.5% nitrogen. The suggested gas composition indicates for engine manufacturers how much hydrogen can be added into the gas to be suitable for their engines.

One of the major advantages of SOFCs is their high fuel flexibility. Next to natural gas and hydrogen which are today’s most common fuels for SOFC-systems and cell-/stack-testing respectively various other fuels are applicable as well. In the literature a number of promising results show that available fuels as propane butane ammonia gasoline diesel etc. can be applied. Here the performance of an anode supported cell operated in specialized single cell test benches with different gaseous and liquid fuels and reformates thereof is presented. Fuels as ammonia dissolved urea (AddBlueTM) methane/steam and ethanol/water mixtures can directly be fed to the cell whereas propane and diesel require external reforming. It is shown that in case of a stable fuel supply the cell performance with such fuels is similar to that of appropriate mixtures of H2 N2 CO CO2 and steam if the impact of endothermic reforming or decomposition reactions is considered. Even though a stable fuel cell operation with such fuels is possible in a single cell test bench it should be pointed out that an appropriate fuel processing will be mandatory on the system level.

Water electrolysis (WE) is a highly promising approach to producing clean hydrogen. Medium-temperature WE (100–350 ◦C) can improve the energy efficiency and utilize the low-grade water vapor. Therefore a high-temperature proton-conductive membrane is desirable to realize the medium-temperature WE. Here we present a polyvinyl chloride (PVC)-poly(4vinylpyridine) (P4VP) hybrid membrane by a simple cross-linking of PVC and P4VP. The pyridine groups of P4VP promote the loading rate of phosphoric acid which delivers the proton conductivity of the PVC-P4VP membrane. The optimized PVC-P4VP membrane with a 1:2 content ratio offers the maximum proton conductivity of 4.3 × 10−2 S cm−1 at 180 ◦C and a reliable conductivity stability in 200 h at 160 ◦C. The PVC-P4VP membrane electrode is covered by an IrO2 anode and a Pt/C cathode delivers not only the high water electrolytic reactivity at 100–180 ◦C but also the stable WE stability at 180 ◦C.

The spinning process will lead to changes in the micro-structure and mechanical properties of the materials in different positions of the high-pressure hydrogen storage cylinder which will show different hydrogen embrittlement resistance in the high-pressure hydrogen environment. In order to fully study the safety of hydrogen storage in large-volume seamless steel cylinders this chapter associates the influence of the forming process with the deterioration of a high-pressure hydrogen cylinder (≥100 MPa). The anti-hydrogen embrittlement of SA-372 grade J steel at different locations of the formed cylinders was studied experimentally in three cylinders. The hydrogen embrittlement experiments were carried out according to method A of ISO 11114-4:2005. The relationship between tensile strength microstructure and hydrogen embrittlement is analyzed which provides comprehensive and reliable data for the safety of hydrogen storage and transmission.

Decarbonizing the planet is one of the major goals that countries around the world have set for 2050 to mitigate the effects of climate change. To achieve these goals green hydrogen that can be produced from the electrolysis of water is an important key solution to tackle global decarbonization. Consequently in recent years there is an increase in interest towards green hydrogen production through the electrolysis process for large-scale implementation of renewable energy based power plants and other industrial and transportation applications. The main objective of this study was to provide a comprehensive review of various green hydrogen production technologies especially on water electrolysis. In this review various water electrolysis technologies and their techno-commercial prospects including hydrogen production cost along with recent developments in electrode materials and their challenges were summarized. Further some of the most successful results also were described. Moreover this review aims to identify the gaps in water electrolysis research and development towards the techno-commercial perspective. In addition some of the commercial electrolyzer performances and their limitations also were described along with possible solutions for cost-effective hydrogen production Finally we outlined our ideas and possible solutions for driving cost-effective green hydrogen production for commercial applications. This information will provide future research directions and a road map for the development/implementation of commercially viable green hydrogen projects.

Background: Sustainable development requires access to afordable reliable and efcient energy to lift billions of people out of poverty and improve their standard of living. The development of new and renewable forms of energy that emit less CO2 may not materialize quickly enough or at a price point that allows people to attain the standard of living they desire and deserve. As a result a parallel path to sustainability must be developed that uses both renewable and clean carbon-based methods. Hybrid microgrids are promoted to solve various electrical and energy-related issues that incorporate renewable energy sources such as photovoltaics wind diesel generation or a combination of these sources. Utilizing microgrids in electric power generation has several benefts including clean energy increased grid stability and reduced congestion. Despite these advantages microgrids are not frequently deployed because of economic concerns. To address these fnancial concerns it is necessary to explore the ideal confguration of micro-grids based on the quantity quality and availability of sustainable energy sources used to install the microgrid and the optimal design of microgrid components. These considerations are refected in net present value and levelized energy cost. Methods: HOMER was used to simulate numerous system confgurations and select the most feasible solution according to the net present value levelizied cost of energy and hydrogen operating cost and renewable fraction. HOMER performed a repeated algorithm process to determine the most feasible system configuration and parameters with the least economic costs and highest benefits to achieve a practically feasible system configuration. Results: This article aimed to construct a cost-effective microgrid system for Saudi Arabia’s Yanbu city using five configurations using excess energy to generate hydrogen. The obtained results indicate that the optimal configuration for the specified area is a hybrid photovoltaic/wind/battery/generator/fuel cell/hydrogen electrolyzer microgrid with a net present value and levelized energy cost of $10.6 billion and $0.15/kWh. Conclusion: With solar photovoltaic and wind generation costs declining building electrolyzers in locations with excellent renewable resource conditions such as Saudi Arabia could become a low-cost hydrogen supply option even when accounting for the transmission and distribution costs of transporting hydrogen from renewable resource locations to end-users. The optimum confguration can generate up to 32132 tons of hydrogen per year (tH2/year) and 380824 tons per year of CO2 emissions can be avoided.