Applications & Pathways

In the context of green aviation as an internationally recognized solution hydrogen energy is lauded as the “ultimate energy source of the 21st century” with zero emissions at the source. Developed economies with aviation industries such as Europe and the United States have announced hydrogen energy aviation development plans successively. The study and development of high-energy hydrogen fuel cells and hydrogen energy power systems have become some of the future aviation research focal points. As a crucial component of hydrogen energy storage and delivery the design and development of a safe lightweight and efficient hydrogen storage structure have drawn increasing consideration. Using a hydrogen-powered Unmanned Aerial Vehicle (UAV) as the subject of this article the crash characteristics of the UAV’s hydrogen storage structure are investigated in detail. The main research findings are summarized as follows: (1) A series of crash characteristics analyses of the hydrogen storage structure of a hydrogen-powered UAV were conducted and the Finite Element Analysis (FEA) response of the structure under different impact angles internal pressures and impact speeds was obtained and analyzed. (2) When the deformation of the hydrogen storage structure exceeds 50 mm and the strain exceeds 0.8 an initial crack will appear at this part of the hydrogen storage structure. The emergency release valve should respond immediately to release the gas inside the tank to avoid further damage. (3) Impact angle and initial internal pressure are the main factors affecting the formation of initial cracks.

Hydrogen energy plays an important role in the transformation of low-carbon energy and electric–hydrogen coupling will become a typical energy scenario. Aiming at the operation flexibility of a low-carbon electricity–hydrogen coupling system with high proportion of wind power and photovoltaic this work studies the flexibility margin of an electricity–hydrogen coupling energy block based on model predictive control. By analyzing the power exchange characteristics of heterogeneous energy the homogenization models of various heterogeneous energy sources are established. According to the analysis of power system flexibility margin three dimensions of flexibility margin evaluation indexes are defined from the dimension of system operation and an electricity–hydrogen coupling energy block scheduling model is established. The model predictive control algorithm is used to optimize the power balance operation of the electro–hydrogen coupling energy block and the flexibility margin of the energy block is quantitatively analyzed and calculated. Through the example analysis it is verified that the calculation method proposed in this article can not only realize the online power balance optimization of the electric–hydrogen coupling energy block but also effectively quantify the operation flexibility margin of the electric–hydrogen coupling energy block.

Aviation is the backbone of our modern society. In 2019 around 4.5 billion passengers travelled through the air. However at the same time aviation was also responsible for around 5% of anthropogenic causes of global warming. The impact of the COVID-19 pandemic on the aviation sector in the short term is clearly very high but the long-term effects are still unknown. However with the increase in global GDP the number of travelers is expected to increase between three- to four-fold by the middle of this century. While other sectors of transportation are making steady progress in decarbonizing aviation is falling behind. This paper explores some of the various options for energy carriers in aviation and particularly highlights the possibilities and challenges of using cryogenic fuels/energy carriers such as liquid hydrogen (LH2) and liquefied natural gas (LNG).

Hydrogen is one of the main alternative fuels with the greatest potential to replace fossil fuels due to its renewable and environmentally friendly nature. Due to this the present investigation aims to evaluate the combustion characteristics performance parameters emissions and variations in the characteristics of the lubricating oil. The investigation was conducted in a spark-ignition engine fueled by gasoline and hydrogen gas. Four engine load conditions (25% 50% 75% and 100%) and three hydrogen gas mass concentration conditions (3% 6% and 9%) were defined for the study. The investigation results allowed to demonstrate that the injection of hydrogen gas in the gasoline engine causes an increase of 3.2% and 4.0% in the maximum values of combustion pressure and heat release rates. Additionally hydrogen causes a 2.9% increase in engine BTE. Hydrogen's more efficient combustion process allowed for reducing CO HC and smoke opacity emissions. However hydrogen gas causes an additional increase of 14.5% and 30.4% in reducing the kinematic viscosity and the total base number of the lubricating oil. In addition there was evidence of an increase in the concentration of wear debris such as Fe and Cu which implies higher rates of wear in the engine's internal components.

The transformation of hydrogen metallurgy is a principal means of promoting the iron and steel industry (ISI) in reaching peak and deep emissions reduction. However the environmental impact of different hydrogen production paths on hydrogen metallurgy has not been systemically discussed. To address this gap based on Long-range Energy Alternatives Planning System (LEAP) this paper constructs a bottom-up energy system model that includes hydrogen production iron and steel (IS) production and power generation. By setting three hydrogen production structure development paths namely the baseline scenario business-as-usual (BAU) scenario and clean power (CP) scenario the carbon dioxide (CO2) emissions impact of different hydrogen production paths on hydrogen metallurgy is carefully evaluated from the perspective of the whole industry and each IS production process. The results show that under the baseline scenario the hydrogen metallurgy transition will help the CO2 emissions of ISI peak at 2.19 billion tons in 2024 compared to 2.08 billion tons in 2020 and then gradually decrease to 0.78 billion tons in 2050. However different hydrogen production paths will contribute to the reduction or inhibit the reduction. In 2050 the development of electrolysis hydrogen production with renewable electricity will reduce CO2 emissions by an additional 48.76 million tons (under the CP scenario) while the hydrogen production mainly based on coal gasification and methane reforming will increase the additional 50.04 million tons CO2 emissions (under the BAU scenario). Moreover under the hydrogen production structure relying mainly on fossil and industrial by-products the technological transformation of blast furnace ironmaking with hydrogen injections will leak carbon emissions to the upstream energy processing and conversion process. Furthermore except for the 100% scrap based electric arc furnace (EAF) process the IS production process on hydrogen-rich shaft furnace direct reduced iron (hydrogen-rich DRI) have lower CO2 emissions than other processes. Therefore developing hydrogen-rich DRI will help the EAF steelmaking development to efficiently reduce CO2 emissions under scrap constraints.

Hydrogen is regarded as a flexible energy carrier with multiple applications across several sectors. For instance it can be used in industrial processes transports heating and electrical power generation. Green hydrogen produced from renewable sources can have a crucial role in the pathway towards global decarbonization. However the success of green hydrogen production ultimately depends on its economic sustainability. In this context this work evaluates the economic performance of a hydrogen power plant participating in the electricity market and supplying multiple hydrogen consumers. The analysis includes technical and economical details of the main components of the hydrogen power plant. Its operation is simulated using six different scenarios which admit the production of either grey or green hydrogen. The scenarios used for the analysis include data from the Iberian electricity market for the Portuguese hub. An important conclusion is that the combination of multiple services in a hydrogen power plant has a positive effect on its economic performance. However as of today consumers who would wish to acquire green hydrogen would have to be willing to pay higher prices to compensate for the shorter periods of operation of hydrogen power plants and for their intrinsic losses. Nonetheless an increase in green hydrogen demand based on a greater environmental awareness can lead to the need to not only build more of these facilities but also to integrate more services into them. This could promote the investment in hydrogen-related technologies and result in changes in capital and operating costs of key components of these plants which are necessary to bring down production costs.

This paper introduces the concept of a thermal management system (TMS) with integrated on-board power generation capabilities for a Mach 8 hypersonic aircraft powered by liquid hydrogen (LH2). This work developed within the EU-funded STRATOFLY Project aims to demonstrate an opportunity for facing the challenges of hypersonic flight for civil applications mainly dealing with thermal and environmental control as well as propellant distribution and on-board power generation adopting a highly integrated plant characterized by a multi-functional architecture. The TMS concept described in this paper makes benefit of the connection between the propellant storage and distribution subsystems of the aircraft to exploit hydrogen vapors and liquid flow as the means to drive a thermodynamic cycle able on one hand to ensure engine feed and thermal control of the cabin environment while providing on the other hand the necessary power for other on-board systems and utilities especially during the operation of high-speed propulsion plants which cannot host traditional generators. The system layout inspired by concepts studied within precursor EU-funded projects is detailed and modified in order to suggest an operable solution that can be installed on-board the reference aircraft with focus on those interfaces impacting its performance requirements and integration features as part of the overall systems architecture of the plane. Analysis and modeling of the system is performed and the main results in terms of performance along the reference mission profile are discussed.

Globally iron and steel production is responsible for approximately 6.3% of global man-made carbon dioxide emissions because coal is used as both the combustion fuel and chemical reductant. Hydrogen reduction of iron ore offers a potential alternative ‘near-zero-CO2’ route if renewable electrical power is used for both hydrogen electrolysis and reactor heating. This paper discusses key technoeconomic considerations for establishing a hydrogen direct reduced iron (H2-DRI) plant in New Zealand. The location and availability of firm renewable electricity generation is described the experimental feasibility of reducing locally-sourced titanomagnetite irons and in hydrogen is shown and a high-level process flow diagram for a counter-flow electrically heated H2-DRI process is developed. The minimum hydrogen composition of the reactor off-gas is 46% necessitating the inclusion of a hydrogen recycle loop to maximise chemical utilisation of hydrogen and minimize costs. A total electrical energy requirement of 3.24 MWh per tonne of H2-DRI is obtained for the base-case process considered here. Overall a maximum input electricity cost of no more than US$80 per MWh at the plant is required to be cost-competitive with existing carbothermic DRI processes. Production cost savings could be achieved through realistic future improvements in electrolyser efficiency (∼ US$5 per tonne of H2-DRI) and heat exchanger (∼US$3 per tonne). We conclude that commercial H2-DRI production in New Zealand is entirely feasible but will ultimately depend upon the price paid for firm electrical power at the plant.

The European Commission recently proposed requirements for the production of renewable fuels as these are required to decarbonize the hard-to-electrify parts of the industrial and heavy transport sectors. Power-to-X (P2X) energy hubs enable efficient synergies between energy infrastructures production facilities and storage options. In this study we explore the optimal operation of an energy hub by leveraging the flexibility of P2X including hydrogen methanol and ammonia synthesizers by analyzing potential revenue streams such as the day-ahead and ancillary services markets. We propose EnerHub2X a mixed-integer linear program that maximizes the hub’s profit based on current market prices considering the technical constraints of P2X such as unit commitment and non-linear efficiencies. We investigate a representative Danish energy hub and find that without price incentives it mainly sells renewable electricity and produces compressed hydrogen. A sufficient amount of renewable ammonia and methanol is only produced by adding a price premium of about 50% (0.16 e/kg) to the conventional fuel prices. To utilize production efficiently on-site renewable energy sources and P2X must be carefully aligned. We show that renewable power purchase agreements can provide flexibility while complying with the rules set by the European Commission.

The present research work deals with prediction of hydrogen consumption of a fuel cell in an energy storage system. Due to the fact that these kind of systems have a very nonlinear behaviour the use of traditional techniques based on parametric models and other more sophisticated techniques such as soft computing methods seems not to be accurate enough to generate good models of the system under study. Due to that a hybrid intelligent system based on clustering and regression techniques has been developed and implemented to predict the necessary variation of the hydrogen flow consumption to satisfy the variation of demanded power to the fuel cell. In this research a hybrid intelligent model was created and validated over a dataset from a fuel cell energy storage system. Obtained results validate the proposal achieving better performance than other well-known classical regression methods allowing us to predict the hydrogen consumption with a Mean Absolute Error (MAE) of 3.73 with the validation dataset.