Canada

The world is endowed with a tremendous amount of coal resources which are unevenly distributed in a few nations. While sustainable energy resources are being developed and deployed fossil fuels dominate the current world energy consumption. Thus low-carbon clean technologies like underground coal gasification (UCG) ought to play a vital role in energy supply and ensuring energy security in the foreseeable future. This paper provides a state-of-the-art review of the world's development of UCG for enhanced hydrogen production. It is revealed that the world has an active interest in decarbonizing the coal industry for hydrogen-oriented research in the context of UCG. While research is ongoing in multiple coal-rich nations China dominates the world's efforts in both industrial-scale UCG pilots and laboratory experiments. A variety of coal ranks were tested in UCG for enhanced hydrogen output and the possibilities of linking UCG with other prospective technologies had been proposed and critically scrutinized. Moreover it is found that transborder collaborations are in dire need to propel a faster commercialization of UCG in an ever-more carbon-conscious world. Furthermore governmental and financial support is necessary to incentivize further UCG development for large-scale hydrogen production.

Compressed hydrogen storage is an energy-efficient alternative to liquefaction and in the absence of underground salt formations reservoirs like rock caverns mining shafts and cased boreholes are gaining traction. The limited reservoir volume constrained by excavation or drilling results in short high-pressure cycles. Thus effective temperature control is crucial to maintain integrity and maximize hydrogen density. This study presents a validated numerical model with open-access code for simulating heat exchange and predicting operating pressure and temperature for underground hydrogen storage in tanks or caverns. The validation encompasses analytical solutions and existing cylindrical models. Results highlight the heat transfer’s impact on hydrogen density and the limited penetration depth of the thermal perturbation underscoring the need for simulating heat transfer across multiple layers especially in restrictive media like cement. Managing injection and extraction flow rates is crucial to limit temperature peaks for larger radius reservoirs where heat transfer is less efficient.

Salt caverns produced by solution mining in Southern Ontario provide ideal spaces for gas storage due to their low permeability. Underground hydrogen storage (UHS) is an important part of the future renewable energy market in Ontario in order to achieve global carbon neutrality and to fill the gap left by retiring nuclear power plants. However large-scale hydrogen storage is still restricted by limited storage space on the ground’s surface. In this study hydrogen’s physical and chemical properties are first introduced and characterized by low molecular weight high diffusivity low solubility and low density. Then the geological conditions of the underground reservoirs are analyzed especially salt caverns. Salt caverns with their inert cavity environments and stable physical properties offer the most promising options for future hydrogen storage. The scales heights and thicknesses of the roof and floor salt layers and the internal temperatures and pressures conditions of salt caverns can affect stabilities and storage capacities. Finally several potential problems that may affect the safe storage of hydrogen in salt caverns are discussed. Through the comprehensive analysis of the influencing factors of hydrogen storage in salt caverns this study puts forward the most appropriate development strategy for salt caverns which provides theoretical guidance for UHS in the future and helps to reduce the risk of large-scale storage design.

Hydrogen is known to be the carbon-neutral alternative energy carrier with the highest energy density. Currently more than 95% of hydrogen production technologies rely on fossil fuels resulting in greenhouse gas emissions. Water electrolysis is one of the most widely used technologies for hydrogen generation. Nuclear power a renewable energy source can provide the heat needed for the process of steam electrolysis for clean hydrogen production. This review paper analyses the recent progress in hydrogen generation via high-temperature steam electrolysis through solid oxide electrolysis cells using nuclear thermal energy. Protons and oxygen-ions conducting solid oxide electrolysis processes are discussed in this paper. The scope of this review report covers a broad range including the recent advances in material development for each component (i.e. hydrogen electrode oxygen electrode electrolyte interconnect and sealant) degradation mechanisms and countermeasures to mitigate them.

The energy transition calls for natural hydrogen exploration with most occurrences discovered either inadvertently or more recently at the location of potentially diffusive circles observed from a change of vegetation cover at the surface. However some notable hydrogen occurrences are not directly associated with the presence of diffusive circles like the Bourakebougou field in Mali. Thus the objective of this work was to highlight geological areas that have some potential to find natural hydrogen in Quebec a Canadian province where no diffusive circles have yet been documented but which is rich in potential source rocks and where no exploration for natural hydrogen has been undertaken so far. A review of the different geological regions of Quebec was undertaken to highlight the relevant characteristics and geographical distribution of geological assemblages that may produce or have produced natural hydrogen in particular iron-rich rocks but also uranium-rich rocks supramature shales and zones where significant structural discontinuities are documented or suspected which may act as conduits for the migration of fluids of mantle origin. In addition to regional and local geological data an inventory of available geochemical data is also carried out to identify potential tracers or proxies to facilitate subsequent exploration efforts. A rating was then proposed based on the quality of the potential source rocks which also considers the presence of reservoir rocks and the proximity to end-users. This analysis allowed rating areas of interest for which fieldwork can be considered thus minimizing the exploratory risks and investments required to develop this resource. The size of the study area (over 1.5 million km2 ) the diversity of its geological environments (from metamorphic cratons to sedimentary basins) and their wide age range (from Archean to Paleozoic) make Quebec a promising territory for natural hydrogen exploration and to test the systematic rating method proposed here.

To reduce greenhouse gas emissions from natural gas use utilities are investigating the potential of adding hydrogen to their distribution grids. This will reduce the carbon dioxide emissions from grid-connected engines used for stationary power generation and it may also impact their power output and efficiency. Promisingly hydrogen and natural gas mixtures have shown encouraging results regarding engine power output pollutant emissions and thermal efficiency in well-controlled on-road vehicle applications. This work investigates the effects of adding hydrogen to the natural gas fuel for a lean-burn spark-ignited four-stroke 8.9 liter eight-cylinder naturally aspirated engine used in a commercial stationary power generation application via an engine model developed in the GT-SUITETM modelling environment. The model was validated for fuel consumption air flow and exhaust temperature at two operating modes. The focus of the work was to assess the sensitivity of the engine’s power output brake thermal efficiency and pollutant emissions to blends of methane with 0–30% (by volume) hydrogen. Without adjusting for the change in fuel energy the engine power output dropped by approximately 23% when methane was mixed with 30% by volume hydrogen. It was found that increasing the fueling rate to maintain a constant equivalence ratio prevented this drop in power and reduced carbon dioxide emissions by almost 4.5%. In addition optimizing the spark timing could partially offset the increases in in-cylinder burned and unburned gas temperatures and in-cylinder pressures that resulted from the faster combustion rates when hydrogen was added to the natural gas. Understanding the effect of fuel change in existing systems can provide insight on utilizing hydrogen and natural gas mixtures as the primary fuel without the need for major changes in the engine.

The European Union is committed to a 55% reduction in greenhouse gas emissions by 2030 as outlined in the Green Deal and Climate Law initiatives. In response to geopolitical events the RePowerEU initiative aims to enhance energy self-sufficiency reduce reliance on Russian natural gas and promote hydrogen utilization. Hydrogen valleys localized ecosystems integrating various hydrogen supply chain elements play a key role in this transition particularly benefiting isolated regions like islands. This manuscript focuses on optimizing a Centralized Green Hydrogen Production Facility (CGHPF) on the island of Crete. A mixed-integer linear programming framework is proposed to optimize the CGHPF considering factors such as land area wind and solar potential costs and efficiency. Additionally an in-depth sensitivity analysis is conducted to explore the impact of key factors on the economic feasibility of hydrogen investments. The findings suggest that hydrogen can be sold in Crete at prices as low as 3.5 EUR/kg. Specifically it was found in the base scenario that selling hydrogen at 3.5 EUR/kg the net profit of the investment could be as high as EUR 6.19 million while the capacity of the solar and wind installation supplying the grid hydrogen facility would be 23.51 MW and 52.97 MW respectively. It is noted that the high profitability is justified by the extraordinary renewable potential of Crete. Finally based on our study a policy recommendation to allow a maximum of 20% direct penetration of renewable sources of green hydrogen facilities into the grid is suggested to encourage and accelerate green hydrogen expansion.

In this paper we propose an optimization model that considers two pathways for injecting renewable content into natural gas pipeline networks. The pathways include (1) power-to-hydrogen or PtH where off-peak electricity is converted to hydrogen via electrolysis and (2) power-to-methane or PtM where carbon dioxide from different source locations is converted into renewable methane (also known as synthetic natural gas SNG). The above pathways result in green hydrogen and methane which can be injected into an existing natural gas pipeline network. Based on these pathways a multi-period network optimization model that integrates the design and operation of hydrogen from PtH and renewable methane is proposed. The multi-period model is a mixed-integer non-linear programming (MINLP) model that determines (1) the optimal concentration of hydrogen and carbon dioxide in the natural gas pipelines (2) the optimal location of PtH and carbon dioxide units while minimizing the overall system cost. We show using a case study in Ontario the optimal network structure for injecting renewable hydrogen and methane within an integrated natural gas network system provides a $12M cost reduction. The optimal concentration of hydrogen ranges from 0.2 vol % to a maximum limit of 15.1 vol % across the network while reaching a 2.5 vol % at the distribution point. This is well below the maximum limit of 5 vol % specification. Furthermore the optimizer realized a CO2 concentration ranging from 0.2 vol % to 0.7 vol %. This is well below the target of 1% specified in the model. The study is essential to understanding the practical implication of hydrogen penetration in natural gas systems in terms of constraints on hydrogen concentration and network system costs.

Transportation is an economic sector that contributes significantly to global warming due to its high consumption of fossil fuels and sustainably produced hydrogen is a major contender for an alternative clean energy source. Public transit is vital for environmental sustainability via reducing individual vehicle usage and traffic congestion and the prospect of powering buses using hydrogen fuel has been extensively studied lately. This paper seeks to comprehensively review the current status of research on hydrogen-powered buses considering triple bottom line sustainability perspectives. A brief technical overview of prospective environmentally benign hydrogen production processes has been presented. Technological economic and environmental findings and research trends seen in recent analyses on hydrogen-powered buses have been summarized along with the status quo of global hydrogen refuelling stations. Identified focal points for future studies include performance enhancements refuelling infrastructure propagation and policy formulation. The conclusions derived from this review will benefit the accelerated deployment of hydrogen-fuelled public transit fleets.

Hydrogen as a clean zero-emission energy fuel will play a critical role in energy transition and achievement of the net-zero target in 2050. Hydrogen delivery is integral to the entire value chain of a full-scale hydrogen economy. This work conducted a systematic review and analysis of various hydrogen transportation methods including truck tankers for liquid hydrogen tube trailers for gaseous hydrogen and pipelines by identifying and ranking the main properties and affecting factors associated with each method. It is found that pipelines especially the existing natural gas pipelines provide a more efficient and cheaper means to transport hydrogen over long distances. Analysis was further conducted on Canadian natural gas pipeline network which has been operating for safe effective and efficient energy transport over six decades. The established infrastructure along with the developed operating and management experiences and skillful manpower makes the existing pipelines the best option for transport of hydrogen in either blended or pure form in the country. The technical challenges in repurposing the existing natural gas pipelines for hydrogen service were discussed and further work was analyzed.