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The utilization of saline aquifer for solar energy storage is recognized as a promising solution to address the spatial and temporal mismatch between energy demand and supply. This approach holds significant potential for future renewable energy storage and conversion. Thermal energy storage in saline aquifer can effectively transform intermittent solar energy into stable geothermal energy at...
Geothermal energy can provide clean and sustainable baseload energy for heating, cooling, and power. The injected working fluid undergoes flow and heat transfer within the surrounding porous rocks during the geothermal reservoir extraction. The geological complexity and lack of data require digital technology like computer simulation to assist in the optimization and decision-making of...
The extent of interactions between clay surfaces and water molecules and their impact on hydrate stability in clay reservoirs have been a source of debate. This uncertainty arises from the inherent challenges associated with the nanoscale temporal and spatial detection of bound water molecule distribution characteristics. This study employs molecular dynamics simulations to investigate the...
Gas hydrates are crystalline solids in which guest molecules are trapped within cages formed by water molecules at high pressure and low temperature. These solids have important applications in natural gas hydrate exploration, CO2 or H2 storage, water desalination, gas separation, and gas/oil transportation. Natural methane (CH4) hydrates are abundant in the seabed sediments and are potential...
The imperative to achieve net zero carbon emissions by 2050, aligned with global efforts to limit temperature rise, emphasizes the urgent shift to low-carbon energy sources. Hydrogen is identified as a key player in global decarbonisation however, concerns about the efficiency of hydrogen storage accompany its expanding production. This study investigates underground geological hydrogen...
Depleted gas reservoirs have large storage capacity, pre-proved containment security, in-place depleted gas, and well-established surface infrastructures, thus are viewed as the most feasible hydrogen storage space. However, the impacts of depletion time, volume ratio ($VR_{H_{2}:CH_{4}/CO_{2}}$) of hydrogen ($H_2$), depleted gas (mainly $CH_4$) and cushion gas (e.g., $CO_2$), and...
The increasing demand for green hydrogen in Europe, particularly in Germany, requires extensive storage capacities to compensate the imbalance between production and consumption. Although salt caverns are known as safe and reliable medium for large scale hydrogen storage, however, these are geographically limited. Therefore, porous reservoirs - such as saline aquifers and depleted hydrocarbon...
To address seasonal fluctuations in supply and demand for renewable energy, hydrogen (H$_2$) can be produced using excess electricity and temporarily stored in geological formations [1]. Due to their large volumes, widespread occurrence and distribution in sedimentary basins, saline aquifers have significant potential for underground hydrogen storage (UHS). However, large-scale UHS of pure...
Carbon capture, utilization, and storage (CCUS) is an attractive approach to help decarbonization from point sources, like energy supply and other industries, as well as for pulling CO2 out of the atmosphere (i.e., direct air capture, DAC). Among several approaches at differing technology readiness levels, solid sorbents are promising as they generally combine high uptakes and selectivity with...
Storage of carbon in the form of compressed CO2 in the subsurface represents a potentially viable and cost-effective way to reduce emission of heat-trapping CO2 to the atmosphere. The feasibility of a CO2 storage scheme depends on many factors, including CO2-induced corrosion and scale; availability of inexpensive CO2 sources, available pipeline, pipeline integrity, temperature and pressure...
In this study, with the utilization of quasi-dynamic X-ray micro-computed tomographic (MCT) imaging, pore-scale fluid configurations were tracked for CO$_{2}$ injected into two different brine-saturated Bentheimer sandstone cores under conditions relevant to geologic carbon sequestration. CO$_{2}$ injection was performed at low capillary number (Ca = 10$^{-9}$) into cores saturated with live-...
Subsurface carbon dioxide (CO2) storage is one of the most critical strategies in combatting climate change. One of the principal challenges encountered by the Carbon Capture and Storage (CCS) industry is the accurate understanding, representation, and upscaling of fluid flow dynamics within targeted reservoir formations. This problem is rather complex in carbonate formations due to their...
A crucial aspect of maximizing hydrogen storage and recovery in aquifers is understanding the flow dynamics of hydrogen-water. By gaining insights into these interactions at the pore scale, researchers can develop more efficient strategies for optimizing storage capacity and extending the production life span in aquifers. This progress ultimately contributes to advancing underground hydrogen...
Underground Hydrogen Storage (UHS) plays a pivotal role in the shift towards renewable energy resources, necessitating paramount attention to safety and efficiency. To maximize the recovery of stored hydrogen and ensure a reliable seal against leakage, it is crucial to comprehend the propensity for hydrogen migration through caprock. The migration may occur within the pore solution, where...
Utilising depleted hydrocarbon reservoirs or aquifers for hydrogen storage shows promise due to their substantial storage capacity. Efficiently managing hydrogen storage requires careful consideration of hysteresis across multiple cycles. Hydrogen experiences both injection and production, usually on a seasonal basis, impacting both hydrogen recovery and pore space entrapment. Our study...
The global climate change crisis has heightened the current focus on sustainable energy solutions, where hydrogen has emerged as a promising candidate for clean and efficient energy storage. However, effective and scalable storage of hydrogen remains a major challenge. Underground rock formations, including fractured reservoirs, offer a potentially impactful solution for hydrogen storage. This...
Energy storage is becoming an increasing concern as the world transitions towards unpredictable renewable energy production. Hydrogen is expected be a key player as it can be produced through electrolysis of water using renewable electricity and used as a clean energy carrier to decarbonise industry, hence hydrogen storage is energy storage. Its small molecule size and low density means...
Underground hydrogen storage (UHS) is recognized as a viable solution for storing significant amounts of hydrogen (H2) in the advancement of a low carbon energy system. The diffusive mixing between H2 and cushion gas, which leads to a reduction in the purity of produced H2, persists through the entire storage period. Therefore, it is crucial to understand the diffusive mass transfer and its...
The process of CO2 enhanced shale gas recovery CO2-ESGR seeks to recover the maximum amount of shale gas while simultaneously injecting and trapping CO2 to reduce greenhouse gases. CO2-ESGR has been studied in the laboratory and tested in small field prototypes, however, its commercial feasibility remains questionable. Therefore, more fundamental and experimental research need to be conducted...
The search for suitable sites for the safe disposal of radioactive waste, a prerequisite for phasing out nuclear energy, is a major scientific, technical and political challenge on which intensive work is being done worldwide. Numerical models for safety investigations for site selection will also play an important role in the endeavour. The OpenWorkFlow project, which was initiated by the...
Amid intensified global efforts to mitigate climate change, carbon mineralization in basaltic formations has emerged as a more prominent, secure, and permanent storage solution for anthropogenic CO2. When CO2 is injected into basaltic rocks, displacing the in-situ pore fluid, the volume of displaced fluid and, consequently, the injected gas depends on the interplay between relative...
CO2 geo-sequestration is a practical approach to achieve net-zero carbon target. Coal has become an optimal geological storage option due to its large adsorptive capability for CO2. However, one of the main challenges for successful CO2 geo-sequestration is the reduced injectivity that are caused by adsorption-induced swelling of coal matrix. In addition, its complex and heterogenous internal...
Abstract: The emission of greenhouse gasses, especially carbon dioxide (CO2) is a major contributor to the global climate and the ecological environment. Geological storage of CO2 in deep saline aquifers is currently a widely recognized method with its stable storage and strong feasibility. However, researchers focus on the CO2 storage in saline aquifers, and there are few studies on the...
The mechanical analysis and stability assessment of reservoir-caprock systems are critical considerations for the successful industrial implementation of CO2 geological storage. Injecting CO2 into the formation can cause fluid pressure accumulation, altering the effective stress field and subsequently leading to potential geological risks. Stress changes due to CO2 injection can activate...
Natural gas resources in tight sandstone are huge, but the gas production rate decreases rapidly and the gas recovery rate is low due to poor reservoir physical properties. Injecting CO2 when the gas reservoir is depleted can enhance gas recovery and simultaneously sequestering a large amount of greenhouse gases, which has significant economic and environmental benefits. To fully understand...
Carbon capture and storage (CCS) holds immense promise for mitigating climate change, but its full potential remains largely untapped due to challenges in sourcing CO2 and constructing an extensive infrastructure across Europe. To address these limitations, we present a workflow and an open-source Python package that assesses the material, energy, environmental, financial, and operational...
Underground hydrogen (H2) storage in saline aquifers is a viable solution for large-scale H2 storage. Due to its remarkably low viscosity and density, the flow of H2 within saline aquifers exhibits strong instability. Therefore, it is crucial to understand the flow processes of H2 and brine at the pore-scale, which can be translated into constitutive relations at continuum-scale to guide...
Hydrogen energy has been a subject of increasing interest over the past decade. The use of hydrogen for energy storage allows for a clean energy carrier that produces only water and heat after oxidation. Focus has been hydrogen storage, which demands abundant and safe storage volumes. Similar to the carbon dioxide storage campaign, subsurface formations offer large pore volumes for gas...
Hydrogen is poised to become one of the most promising alternative clean sources of. energy for climate mitigation. The development of a sustainable hydrogen economy depends on the global implementation of safe and economically feasible inter-seasonal hydrogen storage and recovery. However, the current body of literature lacks a comprehensive numerical characterization of the multiphase flow...
Understanding the pore-scale displacement and trapping mechanisms for hydrogen-brine systems in porous rocks is pivotal as efforts increase to develop subsurface hydrogen storage facilities. Pore-scale flow visualization experiments serve as an important tool to comprehend the pore-scale mechanisms during hydrogen (H2) injection and withdrawal. However, conducting such experiments,...
In the construction and operation of depleted gas reservoirs underground gas storage, the block pressure, effective storage capacity, injection and production capacity, and operating cycle are key issues that reflect the storage efficiency of gas storage facilities. This article is based on the geological and structural characteristics, geometric characteristics, and physical properties of a...
Carbon capture, utilization, and storage (CCUS) is expected to play an essential role in global decarbonization. Safe and efficient storage of CO2 in saline aquifers requires mobility control to prevent CO2 from exposure and accumulation at the formation top. An effective agent for CO2 mobility control should be carefully tailored with low adsorption in rock surfaces, low injection pressure,...
Long-distance propagation of foam is one key to deep gas mobility control for CO2 sequestration (Rossen et al., 2022). It depends on two processes: convection of bubbles and foam generation at the displacement front. Prior studies with N2 foam show the existence of a critical threshold for foam generation in terms of a minimum pressure gradient (∇pmin) or minimum velocity (vt,min), beyond...
In wells designed for carbon capture and storage (CCS), leakage pathways may develop due to thermal cycling when injecting cold CO2 into the warm subsurface, for example, debonding between cement and casing, or fractures in the cement itself. These leakage pathways can impede the permanent geological storage of CO2. In this study, we investigate how thermal cycling affects the sealing ability...
Geological carbon sequestration (GCS) in subsurface media is one of promising approaches to alleviate excessive CO2 emission [1], while saline aquifers are ideal GCS sites [2, 3]. Generally, four trapping mechanisms including: structural/stratigraphic trapping, residual trapping, solubility trapping and mineral trapping are proposed for GCS in saline aquifers [4, 5]. Among them, structural...
In recent years, tight and shale reservoirs have become increasingly significant in global oil and gas production. However, the recovery efficiency from these reservoirs remains low, with a substantial portion of shale oil left unrecovered. CO2 flooding has emerged as a leading method for enhanced oil recovery (EOR) in these environments, offering both improved oil extraction and opportunities...
An efficient management of a CO2 storage site requires an uncertainty assessment for storage capacity and injectivity. For the case of a saline aquifer onshore Denmark, an unsteady-state core-flooding experiment was conducted in order to assess a potential risk of CO2 injectivity impairment. The experimental results indicate that the rock mineralogy, samples permeability, and samples...
Optimization of the porous structure is essential to achieve high solar-to-fuel efficiency in solar thermochemical fuel production. The porous structure directly converts concentrated solar radiation into heat and facilitates heat and mass transfer, as well as provides sites for chemical reactions. An ideal porous structure is expected to have a large surface area to provide reactive sites, a...
A manufacturing process derived from paper technology can be used to produce a flat porous metallic material. To this end, organic fibers, fillers and additives are mixed with metal powder and the pulp is subsequently processed on a paper making machine. The so-called green paper is then subjected to a heat treatment where the organic components are removed. After that, the remaining sheets...
Due to the rising atmospheric concentration of CO2 from human activities, the separation of CO2 from N2, commonly referred to as flue gas, has become a crucial priority.[1] There are four prevalent technologies used for CO2 capture: (i) adsorption with amine-based solvents, (ii) adsorption by nanoporous solids, (iii) cryogenic distillation, and (iv) membrane separation. Zeolites, among the...
