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Robustness-Based Evaluation of GHG Emissions and Energy Use at Neighborhood Level
Get PDFEvaluating neighborhood performance is crucial for achieving long-term zero-carbon goals, enabling efficient energy, cost, and resource sharing among buildings. This task requires balancing multiple criteria and managing uncertainties, emphasizing the importance of performance robustness alongside high performance. This article introduces a flexible multi-criteria approach for evaluating neighborhood performance, focusing on greenhouse gas (GHG) emissions and energy use across different life cycle stages. Flytårnet, a Norwegian neighborhood with zero-emission ambitions, serves as a case study. The methodology incorporates the T-robust method, an established robustness-based approach, to select high-performance, resilient neighborhood designs under various uncertainties. Results indicate that when assessing buildings as key components and considering energy delivered during the operational phase, including photovoltaic generation, the supplied energy ranges from 25 to 80 kWh/m2/year. Over a 60-year period, life cycle GHG emissions span from 4 to 12 kg CO2-eq./m2/year, accounting for uncertainties and encompassing material production and replacement, as well as energy consumption and generation. However, the optimal design choice varies based on whether life cycle stages beyond the use stage are considered. This research provides valuable insights for decision-makers and designers seeking effective neighborhood designs in early-stage planning, considering diverse and conflicting performance criteria to achieve zero-emission goalspublishedVersio
Methodology for activation of flexible resources and BESSs for optimal voltage support in medium voltage distribution grid
Get PDFThis paper introduces an innovative approach for the optimal utilization of flexible resources in voltage control, thereby mitigating the need for immediate power system upgrades in distribution grids facing voltage challenges. The proposed methodology focuses on pre-planning the activation of the most cost-effective flexible resources 24 hours in advance, based on load and generation predictions and a market for flexible resources. An Optimal Power Flow (OPF) problem is designed to minimize the overall cost incurred by flexible resources, Battery Energy Storage Systems (BESSs) managed by the Distribution System Operator (DSO), and distribution grid losses, all while adhering to voltage and current constraints. The costs associated with the degradation of BESSs due to cycling are accounted for using a nonlinear and adaptable function. Additionally, the paper elucidates a method for real-time updating of the OPF results, triggered by instances such as exceeding voltage or current limits or updates in load predictions. The methodology has been validated across various 24-hour scenarios on a reference grid and has demonstrated a significant reduction in costs for flexible resources incurred by DSOs.Methodology for activation of flexible resources and BESSs for optimal voltage support in medium voltage distribution gridacceptedVersio
Assessing Hydrate Formation Risk in Infill CCS Wells
Get PDFCarbon capture and storage (CCS) has been identified as a part of the solution to the climate crisis, but to play a major role, a massive scale-up is required. This will inevitably lead to a need for drilling wells into existing CO2 storage formations, and with that comes the risk of well control incidents where the influx from the formation into the well is dominated by CO2. A major concern regarding such incidents is the potential formation of hydrates caused by Joule-Thomson cooling when the CO2 loaded drilling fluid is forced through flow restrictions while being circulated out of the wellbore or when flowing through topside valves. Software tools incorporating mathematical models for hydraulics and flow in the well play an important role in risk assessment related to drilling operations. To evaluate the risk of hydrate formation and subsequent plugging of valves and flow restrictions, a tool that sufficiently well captures the relevant thermodynamics and flow physics may be of crucial importance. By combining existing hydraulic flow models for drilling and well control operations developed for petroleum wells with new sub-models describing Joule-Thomson cooling and hydrate formation risk in the presence of CO2, such a tool can be built. To achieve accurate models, laboratory experiments of hydrate formation in drilling muds loaded with CO2 are required. In order to enable a software tool for evaluating and handling risks related to hydrate formation during CO2 well control incidents, researchers and industry actors here work together to close knowledge gaps and provide the understanding of the physics involved that is required. We present experimental methods and lab results on hydrate formation in drilling fluids loaded with CO2 along with considerations on modelling aspects. This includes thermodynamical sub-models, integrated hydraulic models and the development of a software tool for use in operations planning and execution. Finally, the impact from such a tool for contributing to reducing the risk for hydrate formation related to drilling of CO2 infill wells is discussed.acceptedVersio
The Rule of Three: the third session of negotiations (INC-3) on the global treaty to end plastic pollution
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Konseptbeskrivelse for bærekrafts-rapportering i FiskInfoPlattformen
Get PDFDenne rapporten utreder konseptet FiskInfoPlattformen: en digital plattform for fangst og bærekraftsrapportering basert på operasjonell datafangst under fiske. Arbeidet har tatt utgangspunkt i grunnstammen i veikartet for databaserte fiskeritjenester som ble etablert i FHF prosjekt 901803 og er første steg i å utvide dette med nødvendig dataflyt for å støtte bærekraftsrapportering.
FNs bærekraftsmål utgjør en grunnleggende ramme for å sikre en mer bærekraftig fiskerinæring. Finansnæringen blir først berørt av reguleringer som pålegger bærekraftsrapportering, noe som igjen påvirker rederier og deres finansieringsmuligheter. I tillegg til aktører fra fiskeridomenet som rederi, skipper, fiskeselger og fiskekjøper er derfor bankene en viktig målgruppe for FiskInfoPlattformen. Rapporten identifiserer drivere, brukerhistorier og relevante KPIer for de ulike målgruppene. Videre beskrives grensesnitt til omliggende systemer for å levere eller motta data, og en første skisse av bærekraftsdashboard og systemarkitektur for plattformen presenteres.publishedVersio
Hydrogen and Cushion Gas Adsorption–Desorption Dynamics on Clay Minerals
Get PDFTransitioning toward a hydrogen (H2)-centric energy paradigm necessitates understanding the adsorption properties of clay minerals, essential constituents of reservoirs and caprocks, for efficient geological H2 storage. This study examines the adsorption characteristics of H2 on various clay minerals (montmorillonite, illite, chlorite, kaolinite, and sepiolite) at different temperatures and the adsorption of cushion gases (N2, CH4, and CO2) under reservoir conditions (313.15 K, up to 10 MPa). The results indicate that sepiolite demonstrates superior adsorption capacity under all tested conditions, surpassing montmorillonite by over 12 times at 313.15 K for H2. Illite, chlorite, and kaolinite exhibit negligible H2 adsorption. Thermodynamic analysis reveals that H2 adsorption on clay minerals is a nonspontaneous and exothermic physisorption process. H2 loss due to adsorption hysteresis in montmorillonite and sepiolite is 42.19 and 3.56%, respectively. Sepiolite may exhibit more predictable and stable sorption properties under repeated pressure variations. The H2 adsorption capacity of montmorillonite and sepiolite is merely 0.4 and 4.5% of that of CO2, respectively. This study provides valuable insights for selecting clay minerals and cushion gases for efficient geological H2 storage and natural hydrogen exploration.publishedVersio
Formation of dimethyldichlorosilane (M2) in the Müller-Rochow process at the molecular level
Get PDFIn the Müller-Rochow process or direct process, CH3Cl reacts with silicon, forming (CH3)2SiCl2 (M2) as the dominant species with copper as catalyst. This complex and highly heterogeneous process takes place in a gas-solid stirred fluidized bed reactor. In this study, the formation of (CH3)2SiCl2 on a Cu rich Cu-Si model has been investigated using density functional theory (DFT). The results show that the overall reaction is exoergic. Upon dissociation of CH3Cl, the reaction proceeds first by interaction of CH3 with Si followed by subsequent addition of Cl. The largest activation barrier is found for the second Si-Cl bond formation in which a weakly adsorbed (CH3)2SiCl2 is formed. Compared to dehydrogenation of adsorbed CH3 formed upon dissociation of CH3Cl, formation of M2 is energetically favoured on a Si modified Cu(111) model.publishedVersio
Steady State and Transient Modelling of A Three-Core Once-Through Steam Generator
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A Study on Usage of Formal Knowledge Sharing Systems in Project-Based Organizations
Get PDFProjects are one-time activities that have time and resource limitations. Projects are considered as arenas for learning. There are opportunities for creating new knowledge and utilizing existing knowledge in projects. Since projects are per definition unique, there is at least some degree of uniqueness associated with each project. This uniqueness provides opportunities to learn something new in each project. The known element in projects – such as existing solutions that have been proven to produce good results – can be shared and utilized to avoid using time and resources to create the same or similar solutions from scratch. Knowledge sharing and learning can play a notable role in improving the ability of project-based organizations to carry out their projects successfully and contributing to obtain higher productivity, profitability and sustainable competitive advantage. However, there are several challenges. This paper looks at one of the challenges, namely ineffective usage of formal knowledge sharing systems in project-based organizations. In this regard, the following two research questions are considered: (1) What are the challenges of using formal knowledge sharing systems? (2) How can the challenges be addressed? Formal knowledge sharing systems play an important role in supporting knowledge sharing and learning in organizations. Technological development has created many possibilities to enhance functions as well as benefits of such systems. However, there are several factors that are to be taken into consideration in order to make sure an effective usage of formal knowledge sharing systems in project-based organizations. This paper presents six factors in this regard and emphasizes the need to have a strategic view and a top management perspective of knowledge sharing and learning in project-based organizations. The study on which this paper is based, is of qualitative nature. In this regard, interviews have been conducted to gather information from five public project-based organizations in Norway.publishedVersio
Coordinated Voltage-Frequency Control for High-Efficiency Full-Range Operation of Inductive Battery Charging Systems with Large Coupling Variations
Get PDFThis paper presents a coordinated voltage-frequency control (CVFC) method for inductive battery charging systems that ensures full-range output power control at high efficiencies over large variations in coupling conditions. The method automatically switches between sub-resonant frequency control (SRFC) and voltage control at the resonant frequency (VC-ω0) based on changes in the coupling conditions and power flow, without depending on estimation of the coupling coefficient. The design basis for the method is the selection of an appropriate nominal coupling that will minimize the maximum resonant capacitor voltage and maintain high system efficiency. The coordinated control strategy allows for minimum component stress and high efficiency over the entire operating region. Moreover, pulse density modulation is employed to achieve soft switching during the VC-ω0 mode. A comparison with pure VC-ω0 and pure SRFC is presented to highlight the advantages of CVFC in terms of maintaining a higher efficiency and a wider controllable power range during large variations in coupling conditions. The effectiveness and feasibility of the proposed method are validated by simulations and laboratory measurements from a small-scale experimental prototype. With a peak efficiency exceeding 96.9%, the proposed control strategy maintains consistently high efficiency, surpassing 95.5% across the majority of its operating range.Coordinated Voltage-Frequency Control for High-Efficiency Full-Range Operation of Inductive Battery Charging Systems with Large Coupling VariationsacceptedVersio