This work aims to address barriers and unknowns in green hydrogen energy storage modelling for remote northern communities. This hydrogen model exceeds the capabilities of existing models by providing detail, flexibility, and transparency. In addition to electrical energy tracking, this includes degradation modelling, water management, compression, and thermal energy accounting which considers local environmental temperature. The integration of these features within a fully developed microgrid electricity model is unique to this model and fills a critical gap in the field of microgrid energy storage modelling. To showcase these novel model capabilities, an arctic community case study was conducted to provide generally conclusive insight for the field of northern energy planning. In this case study, the baseline comparison of this model against industry standard software resulted in a difference of 10% in hydrogen utilization and 0.4% in renewable energy captivation due to differing dispatch protocol algorithms. Results also revealed wind as a superior renewable energy source for hydrogen energy storage integration and drawbacks surrounding seasonal green hydrogen storage. These outcomes successfully present novel insights on green hydrogen's potential role in decarbonizing remote communities in Canada, along with a valuable model for its exploration, by incorporating important practical systems aspects.

The maritime sector is under mounting pressure to decarbonize, with international shipping responsible for nearly 3% of global greenhouse gas (GHG) emissions. However, the industry faces substantial uncertainty regarding viable next-generation marine fuel pathways, and existing studies largely lack scenario-based assessments that reflect divergent policy and market priorities. In this context, this study applies a multi-criteria decision analysis (MCDA), operationalized through the TOPSIS method, across 19 decision attributes grouped into four categories (environmental, economic, technical readiness, and operability) under three policy-relevant scenarios: balanced, climate-led, and cost-led. The framework evaluates energy transition pathways for international shipping aligned with mid-century climate goals, focusing on leading alternative fuels (ammonia, methanol, hydrogen, and biodiesel). Fuel performance and attributes importance assumptions for the 2050 horizon are synthesized from a broad range of academic and industry sources and assessed within the defined scenarios. Ranking outcomes are further examined using Monte Carlo (MC) simulations that explicitly distinguish uncertainty in future fuel performance from uncertainty in policy and stakeholder priorities. The results show that fuel rankings are highly sensitive to both scenario framing and uncertainty structure, with no single fuel consistently dominating across perspectives. Hydrogen performs best under climate-led priorities, biodiesel dominates under cost-led conditions, and ammonia and methanol emerge as competitive options under balanced scenarios. The TOPSIS results reveal clear rank reversals across scenarios. In the balanced scenario, ammonia ranks first, followed by methanol and hydrogen, with biodiesel ranking last. Under the climate-led scenario, hydrogen emerges as the top-ranked fuel, followed by ammonia and methanol, while biodiesel consistently ranks lowest. In contrast, the cost-led scenario favors biodiesel as the leading option, followed by ammonia and methanol, with hydrogen ranking last. MC sensitivity analyses indicate that these rankings are robust but not deterministic. Rankings are relatively stable under weight-only uncertainty, more sensitive to uncertainty in fuel performance scores, and most variable when uncertainty in both scores and weights is combined. Category-level uncertainty analysis further shows that economic and operability attributes exert the greatest influence on ranking outcomes, while technical readiness and environmental attributes play a more limited role in differentiating fuels at the 2050 horizon.

Abstract This paper presents the hydrodynamic modelling and analysis of a hybrid Floating Offshore Wind Turbine (FOWT) platform integrating four Oscillating Water Columns (OWCs) into the ITI Energy barge. Three numerical modelling environments, namely MultiSurf–WAMIT, Rhino–ShipMo, and ANSYS AQWA, are compared to evaluate the added mass, radiation damping, and motion responses of the proposed system. A mesh convergence study is conducted to assess the numerical reliability of the simulations. Response Amplitude Operator (RAO) analysis shows that the integration of OWCs introduces additional hydrodynamic damping and slightly reduces the pitch resonance response while maintaining similar overall motion characteristics to the baseline barge. The results demonstrate the feasibility of OWC integration for combined wind–wave energy harvesting and passive motion mitigation in floating offshore platforms.

Remote Arctic communities in Canada face significant challenges in transitioning from diesel reliance towards renewable energy. While wind, solar, and battery technologies have proven to enable renewable energy penetration up to approximately 60%, achieving higher levels requires long-duration energy storage. This study evaluates the potential of green hydrogen energy storage to support Arctic microgrids on the pathway to 100% renewable energy using an optimization model and a community case study. This evaluated the least-cost designs for renewable energy penetration targets from 50% to 100%, comparing scenarios with and without hydrogen energy storage. The analysis incorporated operational constraints, including minimum load ratio, ramping limitations, and compression requirements, as well as a cost sensitivity analysis. Results demonstrate that hydrogen energy storage becomes economically attractive above 65% renewable energy, providing cost savings at high renewable energy penetration by reducing renewable generation over-sizing requirements. However, cost-effective achievement of 100% renewable energy requires predictive controls and flexible dispatch to coordinate smart dispatch of storage assets. Beyond economic benefits, the study identifies practical implementation challenges related to environmental conditions, project logistics, and human capacity. This work provides novel insights into hydrogen’s potential role in Arctic microgrid decarbonization and identifies key technological and practical barriers that must be addressed for its successful implementation.

Merging Floating Offshore Wind Turbines (FOWTs) with integrated Oscillating Water Columns (OWCs) offers a compelling hybrid mechanism for simultaneous wind and wave energy capture. Accurately capturing the hydrodynamic behavior of such coupled systems is crucial for evaluating their performance and guiding design optimization. This investigation evaluates two distinct numerical models: the standard ITI Energy barge and a modified variant featuring four integrated OWCs. Utilizing a computational suite comprising MultiSurf, WAMIT, and OpenFAST, we established the hydrodynamic characterization for both systems, with particular emphasis on metrics such as added mass, radiation damping, and Response Amplitude Operators (RAOs). The comparative results provide valuable insights into the dynamic performance, stability, and energy potential of each platform, emphasizing the trade-offs between system complexity and overall efficiency.

The Pacific Northwest to Alaska Green Shipping Corridor (GSC) represents a crucial step toward decarbonizing maritime transportation along one of the world's most active cruise routes. This study conducts a comprehensive assessment of sustainability efforts at four key ports - Vancouver, Seattle, Prince Rupert, and Juneau - analyzing their emission reduction strategies, shore power adoption, alternative fuel initiatives, and regional collaboration efforts. A mixed-methods approach is employed, integrating qualitative analysis of port sustainability reports, policies, and industry frameworks with quantitative data on Greenhouse Gas (GHG) emissions and shore power utilization. The findings indicate that Vancouver and Seattle ports lead in shore power deployment and policy alignment, whereas Prince Rupert and Juneau ports face infrastructural and regulatory challenges that hinder full decarbonization. While GSCs provide valuable case studies, the Pacific Northwest GSC requires enhanced cross-border coordination, financial incentives, and infrastructure expansion to accelerate the transition to low-carbon maritime operations. This research identifies key technological, economic, and policy barriers while providing strategic recommendations to stakeholders, including policymakers, port authorities, and industry leaders. The study highlights the potential for alternative fuels, the role of shore power, and the necessity for harmonized regulatory frameworks to achieve a viable green corridor. Ultimately, this paper contributes to the broader discourse on sustainable maritime transportation, emphasizing the need for a multi-stakeholder approach to achieve net-zero emissions goals in the shipping industry.

The Solid Carbon initiative aims to inject carbon dioxide (CO2) into the upper ocean crust, utilizing mineralization as a means for permanent carbon dioxide removal to mitigate climate change. After seven years of pre-feasibility and feasibility studies, we have demonstrated that the Cascadia Basin, located in the Northeast Pacific offshore Vancouver Island, is an ideal site for a deep-ocean CO2 injection test. This site has been the focus of decades of intensive scientific investigations, including a hydrogeological injection test. Additionally, the presence of Ocean Networks Canada's NEPTUNE cabled observatory, which provides power and communication to seafloor sensors and instrumented boreholes, further supports its suitability for this demonstration. Our efforts confirm that conducting a CO2 injection test at this location is both viable and promising, warranting field demonstration. We also investigated regulatory, public, and engineering aspects for taking Solid Carbon to a full-scale negative emissions technology and identified the legislative needs, public concerns, benefits, and realistic implementation scenarios that would involve floating platforms to generate wind power for direct air or ocean capture of CO2 and facilitate injection for decades to come. Advantages of deep ocean settings for basalt injection are the massive capacities (up to 750 Gt in the Cascadia Basin alone, and over 30,000 Gt of CO2 globally), huge unused wind energy resources far away from human activities, short injection holes that can be drilled robotically, and several natural safety mechanisms that prevent accidentally lost CO2 to escape back into the atmosphere including a CO2-depleted deep ocean.

Multi-energy systems (MES) area key concept for developing more sustainable energy systems, but optimizing their design is computationally burdensome. This paper explores the development of machine-learning (ML) based surrogate models for the optimal design of MES. Surrogates are simple models, often ML-based, used to approximate detailed simulations, in this case MES design optimizations. These models provide instant responses, enabling fast comparisons and explorations of trade-offs between design variables. No related work proposes an ML procedure tailored to properties of the MES design application. Most related works use surrogates to predict system cost and other objectives. However, few works have used them to directly predict the optimal system design, and those that do show poor performance. This paper provides an extensive methodology tailored to properties of MES design problems to improve surrogate performance on small datasets. Four components were found to significantly improve surrogate performance: a careful and objective-oriented selection of samples, the use of upsampling to balance datasets, the use of non-linear rescaling methods, and a specific neural-network architecture called Mixture-of-Experts. These work together to turn the original design variable distribution (i.e., of the output) into a Gaussian-like data distribution, that can be more easily learned by the neural-network. The resulting surrogate model almost instantly predicts optimal energy system designs with high precision. This was tested across a wide variety of different climates, building types and decarbonization goals. Such surrogate models will make it much easier to explore different MES design options.

Flow characteristics in a river or open channel, including mean flow velocities and turbulence intensity profiles, are essential information for the marine and hydrokinetic energy industry in site selection, engineering design, commissioning, and operation phases. Using an acoustic Doppler velocimeter (ADV), a precise velocity measurement from the free surface to the boundary layer region of a rapid current channel is performed for the first time. In this paper, we introduce a novel technique to deploy and control an ADV from the free surface to the boundary layer of a fast-current channel to improve the accuracy of the flow data obtained from traditional techniques such as acoustic Doppler current profiler (ADCP) or single point ADV (e.g., near-surface or near channel bed). The knowledge of true flow characteristics and turbulence properties at different depths in a fastcurrent river or channel can lead to better performance evaluation, lifetime estimation, and power output prediction. This investigation is conducted at the Canadian Hydro Kinetic Turbine Test Centre (CHTTC) on Winnipeg River. Results indicate that the maximum mean velocity occurs at about 3 m below the free surface, independent of channel depth and mean velocity, and drops by 34 % at 0.8 m above the channel bed, in the boundary layer region. Therefore, flow in this region carries only 29 % of the energy that the flow has in the maximum velocity point. Turbulence intensity has a reversed pattern and increases near the channel bed. The free surface to half depth changes is gradual, both in mean velocity and turbulence intensity. After mid-depth, the mean velocity drops rapidly while the turbulence intensity increases quickly.

Carbon storage in basaltic aquifers has demonstrated enormous potential for securely and permanently storing carbon dioxide (CO2) through basalt carbonation. Recent experimental and pilot-scale studies investigating CO2 injection as either a supercritical or dissolved phase have shown that dissolved phase injection results in faster mineralization than the supercritical phase scenario because it bypasses the rate-limiting CO2 dissolution step. However, to meet the magnitude of the climate crisis, dissolved CO2 injection schemes will likely need considerable improvements in efficiency to be implemented at gigaton-per-year levels. Here, we consider whether water-alternating-gas (WAG) injection, long been used in the hydrocarbon industry to enhance extraction efficiencies, can increase injection volumes and reduce energy requirements, while promoting CO2 dissolution and improving mineralization efficiency. We performed a series of reactive transport simulations of WAG injection (alternating supercritical CO2 and water) into a submarine basaltic aquifer in the Cascadia basin, an area under active investigation for basalt carbonation demonstration. The findings indicate that implementing WAG and optimizing the injection parameters improves mineralization up to 20% by increasing the quantity of CO2 in the dissolved phase, which, in turn, allows for greater extents of reaction between dissolved CO2 and basalt. Our results indicate that, in lieu of implementing fully dissolved CO2 injection at the field scale, implementing and optimizing WAG schemes for CO2 mineralization in the basaltic oceanic crust can offer significant advantages over supercritical CO2 injection. However, the economics of WAG injection are heavily impacted by WAG frequency and water handling capacity, particularly in offshore environments, as considered in this study. Nevertheless, our results indicate WAG injection schemes should be strongly considered when developing a site-specific injection strategy capable of achieving large-scale carbon mineralization in basaltic aquifers. Our findings also stress the importance of conducting appropriate assessments, such as quantifying a workable WAG slug ratio and injection period, along with economic analyses, to develop feasible site-specific large-scale carbon dioxide mineralization strategies in basalts.

As hydrogen emerges as a key enabler in the global transition to sustainable energy, blue hydrogen production technologies are gaining increased attention. While existing studies have evaluated the environmental and economic feasibility of blue hydrogen, a comprehensive and innovative assessment remains essential. This study introduces a novel integration of three natural gas reforming techniques: Steam Methane Reforming (SMR), CO2- based Autothermal Reforming (ATR), and Steam-based ATR, where the CO2-concentrated stream from SMR is utilized as feedstock for ATR-an approach not widely explored. A detailed thermodynamic analysis and process simulation are conducted for a 1 Mt/year hydrogen production plant, integrating a point-source CO2 capture system. The high-CO2 concentration stream from the reforming system is directed to an MEA-based capture unit for carbon capture, utilization, and storage (CCUS), significantly reducing greenhouse gas (GHG) emissions. A heat exchanger network is designed to minimize energy consumption, offering operational savings and enhanced process efficiency. Results indicate that at a 50 % CO2 capture rate, the carbon intensity is 3.13 kg CO2-eq/kg H2, which reduces to 1.25 kg CO2-eq/kg H2 at a 80 % CO2 capture rate. The benchmarked cost of hydrogen production ranges from US$1.0/kg H2 for carbon intensities of 0.45-1.5 kg CO2-eq/kg H2, decreasing with higher carbon intensity. Gas composition analysis across reforming techniques maximizes hydrogen yield while minimizing byproducts. Additionally, thermal management, pinch analysis, and sensitivity analyses provide valuable insights into system dynamics, identifying inefficiencies and opportunities to further enhance performance.

This paper designs a flexible riser for transporting carbon dioxide (CO2) off a floating offshore wind turbine (FOWT)-powered CO2 capture platform, and analyzes the internal flow-induced effects caused by the CO2 on the flexible riser. Internal effects on flexible risers due to the pressurized and internal dynamic flow are a well- studied problem in offshore oil and gas (O&G) applications, which typically requires the use of tools capable of representing their pressurized contents and flows. However, because the flow rates and pressure conditions expected from individual FOWT-CO2 capture platforms are much lower than those used in O&G installations, we studied the importance of internal flow effects on riser dynamics. To determine their relevance, we designed and modelled the flexible riser in OrcaFlexTM with different design pressure and flow conditions under normal and extreme environmental events. The results indicate that the riser's effective tension and curvature are not significantly affected by internal flow effects, but differences were observed in the von Mises stress arising from the shear stress, which is a purely hydrostatic term. As such, as long as the shear term is properly accounted for, these results enable future work to utilize simplified models for the flexible riser system, similar to models for dynamic power cables employed in FOWT farms. This simplification allows us to design and analyze the whole FOWT-CO2 system alternatively with lower fidelity and open-source offshore wind turbine simulation tools, like OpenFAST, without overlooking relevant riser-dynamics phenomena.

Negative Emission Technologies (NETs) can play a pivotal role in mitigating climate change by removing CO2 from the atmosphere, complementing emission reduction efforts especially as 1.5 °C Paris Agreement targets are exceeded and historical emissions removals are required. This review systematically evaluates the current landscape, technical performance, and scalability of key NETs, including Bioenergy with Carbon Capture and Storage (BECCS), Direct Air Carbon Capture and Storage (DACCS), afforestation, soil carbon sequestration and biochar, enhanced weathering, and ocean-based methods. Technological advancements required are analyzed to highlight and enhance the efficiency, scalability, resource requirements (land, water, and minerals), and economic viability of these solutions. The interplay between NETs and existing emissions reduction strategies is critically examined, emphasizing the need for synergies that maximize overall climate benefits while minimizing resource competition. Comparative analyses highlight differences in technological readiness, energy use, and environmental impacts, offering insights into the practical and theoretical limits of CO2 sequestration for each approach. The review also explores energy balances, cost structures, and life-cycle assessments (LCA), identifying bottlenecks in deployment and potential areas for innovation to enhance efficiency and reduce costs. Additionally, we evaluate the current policy frameworks that support NET development, identifying key challenges in both governance and measurement/reporting/verification (MRV) that must be addressed to facilitate widespread deployment. The review underscores the necessity for robust international cooperation and financing mechanisms tailored to NETs, particularly for capacity building in developing regions. As we pursue a net-zero future, addressing the research gaps and promoting effective integration of NETs into comprehensive climate strategies will be crucial for mitigating the long-term impacts of anthropogenic CO2 emissions.

Direct air capture is a method for removing carbon dioxide (CO2) directly from atmospheric air. To date, only land based installations have been considered, but with growing competition for land and resources, offshore locations are beginning to be contemplated. Offshore locations offer close proximity to vast renewable energy potential, and robust CO2 storage locations, but come with a large degree of uncertainty on performance and cost. The current study explores considerations for offshore operation, and reviews parallel technologies that have undergone similar transitions to use in offshore environments. A baseline energy calculation is completed under the assumption that air would need to be pre-treated prior to entering conventional DAC units. A design is proposed using wire mesh demister pads to collect and remove liquid particles containing salt from the air prior to entering the air contactor and coming into contact with capture materials. The pressure loss, and additional fan power required to overcome this is computed. Demister pads increase overall pressure drop by 20%-28% for solid sorbents, and by 79% for aqueous based DAC solvents, resulting in an additional fan energy requirement of 38.1 kWh/t-CO2 and 194.44 kWh/t-CO2 respectively. Until further experimental studies are completed to better understand the impacts, this design serves as a worst-case scenario for comparison. Once further experimental data becomes available, it can be determined whether the additional components for pre-treatment of air are necessary.

The world is increasingly facing the direct effects of climate change triggering warnings of a crisis for the healthy existence of humankind. The dominant driver of the climate emergency is the historical and continued accumulation of atmospheric CO2 altering net radiative forcing on the planet. To address this global issue, understanding the core chemistry of CO2 manipulation in the atmosphere and proximally in the oceans is crucial, to offer a direct partial solution for emissions handling through negative emissions technologies. Many technologies have been proposed to develop a strategic and economic solution for carbon capture, storage, and utilization. In this paper, we review recent advances in technologies proposed for carbon capture and release via electrochemical process for point source/flue gas, direct air capture (DAC), and ocean/seawater capture. Electrochemical approaches to carbon capture are favorable in terms of reaction conditions, their ability to be incorporated into transformation processes, modularity, low relative carbon footprint, and compatibility with the availability of renewable electricity sources. We offer a critical comparative analysis of land- and ocean-based capture technologies to help guide future research and innovation.

As degraded lithium-ion batteries proliferate from ageing electric vehicles, we must develop methods of forecasting battery lifetime to increase profitability and safety in second-life applications. However, electric vehicle batteries are subjected to variable and generally unknown operating conditions that yield different degradation mechanisms, affecting their future health trajectory. We propose a data-driven method of classifying retired Lithium-ion batteries to determine whether they should be reused or recycled. This method only takes a few minutes of testing requiring one electrochemical impedance spectroscopy measurement. The model was tested across five different use cases where the classification boundary was adjusted accordingly, resulting in an average accuracy of 92%. The model was also trained and tested against another independent dataset, achieving 90% accuracy. This method shows promise as a tool for lithium-ion battery repurposing companies to identify batteries that will likely exhibit rapid capacity degradation if repurposed to avoid expending resources on full battery re-certification.

Negative emission technologies (NETs) are considered essential to keep global warming below 2 °C. Situating wind-powered carbon dioxide removal (CDR) devices offshore and injecting carbon dioxide (CO2) into deep-water sub-seafloor basalt aquifers has the potential to offer large CO2 removal capacity. It also avoids land and water-use competition and provides additional low-risk protections against post-injection leakage compared to terrestrial CO2 storage. This paper seeks to identify locations where offshore wind and potential basalt storage locations exist within close proximity to one another around the globe. A global mean wind power density map at 150 m height was computed using 30 years (1986–2016) of ERA5 hourly wind speed reanalysis data. Offshore regions with mean wind speed greater than 8 m/s were identified. Offshore regions with basalt aquifers along seismic or aseismic ridges which provide potential CO2 storage sites were identified and selected based on sediment thickness, age, and distance from plate boundaries. Four scenarios were constructed to capture a range of constraints with implications for technical, economic and regulatory difficulties. For each scenario, eligible regions for CO2 injection were filled by regularly spaced grid points and the distance to the nearest eligible wind resource was calculated for each point to identify the most promising configurations. Total available storage capacity within reach of wind resources was estimated to be between 4,300Gt and 196,000Gt depending on both uncertainties in porosity and other imposed constraints; even the most conservative estimates represent enormous capacity compared to global targets for negative emissions technologies. Typically, the best areas were found close to the poles due to the greater prevalence of good wind resources in those areas. Site-specific properties such as water depth and distance from shore are computed for the identified locations in order to characterize the conditions in which such locations are typically found.

Injecting CO2 into subsea basalt can provide permanent storage via multiple trapping mechanisms, including mineralization reactions which convert the CO2 into solid carbonates over time. Injecting CO2 together with water can accelerate the process of mineralization, but presents additional challenges, such as high energy and water requirements. A techno-economic model of CO2 transport and injection into ocean basalt was developed to compare injection strategies using pure supercritical CO2, pure liquid CO2, and CO2 dissolved in seawater. The model was applied to a representative injection site off the coast of British Columbia, Canada. Injection of CO2 dissolved into seawater was found to be more energy and cost intensive than injection of supercritical or liquid CO2; this is primarily due to the reduced quantities of CO2 that can be injected into each well, and additional pumping energy required for the accompanying seawater. For the base assumptions, transport and storage costs for supercritical, liquid, and dissolved injection were estimated as $43/t, $38/t, and $250/t respectively. Their energy requirements were estimated as 93 kWh/t, 90 kWh/t, and 213 kWh/t respectively. The current best estimates of geological parameters for ocean basalt suggest good injectivity and very large storage capacities per well. This may help to compensate for the additional project expenses incurred by deep water, allowing cost-effective liquid and supercritical injection. However, this result is sensitive to high uncertainties in both geological parameters and component cost data.

The transition from fossil fuels to renewable energy sources is imperative to mitigate climate change and achieve sustainable development goals (SGDs). Hydrogen, as a clean energy carrier, holds great potential for decarbonizing various sectors, yet its production remains predominantly reliant on fossil fuels. This study explores a novel approach to sustainable hydrogen production by integrating offshore wind energy with reverse osmosis (RO) desalination technology. The proposed configuration harnesses offshore wind power to energize both a RO desalination system and water electrolysis unit. Initially, the wind energy powers the RO desalination process, purifying seawater, and then desalinated water is directed to water electrolysis system for generating green hydrogen directly from seawater. The resulting renewable hydrogen holds potential for diverse applications, including marine industries, and can be transported onshore as needed. The RO system is configured to treat 20 kg s-1 of seawater with a salinity of 35 000 ppm, aiming for a high recovery ratio and reduced freshwater salinity. A pressure exchanger (PX) is integrated to recover energy from high-pressure brine stream and transfer it to the low-pressure feed water, thus reducing the overall energy consumption of the RO process. The concentrated brine extracted from RO desalination is proposed to be utilized for the production of sodium hydroxide that can further pretreat incoming seawater and enhance the effectiveness of the filtration process by mitigating membrane fouling. This pressure exchanger increases the energy efficiency of the RO system from 63.1% to 64.0% and exergetic efficiency from 13.9% to 18.2% increasing the overall first and second law efficiencies to 37.9% and 33.5%. By leveraging offshore wind power to drive RO desalination systems, this research not only addresses freshwater scarcity but also facilitates green hydrogen generation, contributing to the advancement of renewable energy solutions and fostering environmental sustainability. This work aims to use offshore wind power for reverse osmosis (RO) desalination and water electrolysis, producing green hydrogen. By incorporating a pressure exchanger (PX) to enhance energy recovery, improved efficiency and reduced operational costs are targeted. The designed system is optimized to employ seawater for water electrolysis through RO desalination, addressing water scarcity sustainably. image