Jemal Worku Fentaw, Elvin Hajiyev, Abdul Rehman Baig
et al.
CO2-based enhanced geothermal system (CO2-EGS), also known as CO2 plume geothermal, has emerged as a promising avenue to address the growing global energy demand and mitigate global climate concerns by exploiting renewable energy from geothermal reservoirs while concurrently sequestering CO2. In this method, CO2, in a supercritical state or dissolved in brine, is used as a working fluid to harness the geothermal energy held in hot reservoir rocks, with part of the CO2 being trapped in the reservoir. Despite their rapidly growing popularity, the integration assessment of CO2-EGS studies, fragmented into various subjects such as thermodynamics, heat transfer, multiphase flow, reservoir hydraulics, geomechanics, and geochemistry, remains insufficiently explored. Thus, a critical review that consolidates conducted studies, identifies gaps, and directs future research in this coupled technology is crucial. This review aims to provide a comprehensive assessment of CO2-EGS, emphasizing its significance, the major challenges affecting its performance and mitigation strategies, the thermophysical properties of CO2 as a working fluid, and CO2 storage while extracting geothermal energy. The study revealed the key benefits of CO2-EGS, including reducing corrosion and scaling effects in the wellbore, maintaining reservoir pressure, storing CO2, increasing sweep efficiency of the reservoir, lowering pumping power, and addressing water scarcity for geothermal systems. Despite its significance, CO2-EGS encounters major challenges, such as cost, drilling and operating wells in harsh geological conditions, CO2 leakage, lost circulation, premature thermal breakthrough, lower specific enthalpy, and incomplete heating. Key factors influencing its performance include properties of the reservoir, natural fractures and faults, geochemical and geomechanical factors, well design, type of thermodynamic cycle used, and CO2-related factors such as injection rate, injection pressure, temperature, and impurities. Overall, this review provides insights into significant advancements achieved and highlights future research to leverage CO2-EGS for reducing CO2 emissions while extracting geothermal energy.
Energy industries. Energy policy. Fuel trade, Renewable energy sources
Ruiqi Chang, Ali Vafaei-Zadeh, Haniruzila Hanifah
et al.
This research seeks to explore the determinants influencing private vehicle owners’ readiness to adopt Mobility as a Service (MaaS) through the lens of the Value-based Adoption Model (VAM). Additionally, it examines the moderating role of attitude in shaping the relationship between attitude and the intention to use MaaS. The study employs partial least squares structural equation modeling (PLS-SEM) to validate the proposed model. Data were collected through a survey of 355 private vehicle owners, focusing on their travel habits and openness to adopting MaaS. The findings indicate that perceived value, shaped by MaaS digital platform expectations, social influence, and perceived enjoyment, plays a central role in driving adoption. Conversely, perceived sacrifices, including privacy risk and perceived fees, significantly hinder adoption intentions. Trust, influenced by structural assurance and reputation, emerged as a critical determinant of both attitude and behavioral intention, while environmental consciousness moderates the relationship between attitude and intention, highlighting the importance of sustainability in user decisions. The study contributes to theoretical advancements by integrating socio-psychological and structural factors into VAM and offers practical insights for policymakers and MaaS providers to enhance adoption through trust-building, affordability, sustainability, and user-friendly platform design. These findings provide a roadmap for addressing the challenges of MaaS adoption and promoting sustainable urban transportation systems.
Antoine Larbanois, Victor Dachet, Antoine Dubois
et al.
Remote renewable energy hubs (RREHs) for synthetic fuel production are engineering systems harvesting renewable energy where it is particularly abundant. They produce transportable synthetic fuels for export to distant load centers. This article aims to evaluate the production costs of different energy carriers, and includes a discussion on advantages and disadvantages in terms of technical performance. To do so, we extend the study of Berger et al., (2021) which focuses on methane (CH4) as energy carrier and introduce three new carriers: ammonia (NH3), hydrogen (H2) and methanol (CH3OH). The four different RREHs are located in the Algerian Sahara desert and must serve to the load center, Belgium, a constant electro-fuel demand of 10 TWh per year. The modelling and optimisation of these systems are performed using the modelling language GBOML (Graph-Based Optimisation Modelling Language). Our findings reveal that the three new RREHs, each with its respective carrier (ammonia, hydrogen, and methanol), are all more cost-effective than the methane-based system. Ammonia demonstrates the most favourable cost-to-energy exported ratio.
Guoying Zhao, WeiKang Zheng, Rong-Feng Shen
et al.
Stellar flares are an intense stellar activity that can significantly impact the atmospheric composition of the surrounding planets and even the possible existence of life. During such events, the radiative energy of the star is primarily concentrated in the optical and X-ray bands, with the X-ray flux potentially increasing by tens or even hundreds of times. Einstein Probe (EP) detected a new X-ray transient EP J2322.1-0301 on 27 September 2024. Its spatial localization shows a high positional coincidence with the nearby high proper motion K-type star PM J23221-0301. Follow-up X-ray observations confirmed the flux enhancement of the source, while optical spectroscopic monitoring revealed time-variable features, particularly the disappearance of the H-alpha emission line. This X-ray flare is consistent with a characteristic fast-rise-exponential-decay (FRED) light curve, with a rise timescale of 1.4 ks, a decay timescale of 5.7 ks, and a total duration of about 7.1 ks. The peak luminosity in the 0.5-4.0 keV energy band reached about 1.3 x 10^31 erg s^-1, with a total energy release of about 9.1 x 10^34 erg, consistent with the empirical energy correlations observed in magnetic-reconnection-driven stellar flares, as inferred from the multitemperature plasma structure and H-alpha-X-ray energy correlation. This discovery underscores EP's capability in understanding stellar magnetic activity via observing stellar transients.
Saudi Arabia, as part of its Saudi Green Initiative, has announced its goal to achieve net zero green-house gas emissions by 2060. This ambitious target underscores the nation's dedication to addressing climate change. However, there is a significant gap in comprehensive analysis regarding the long-term effects of Saudi Arabia's climate policies and their collective contribution towards the net-zero objective. This study endeavors to bridge this gap through a detailed examination using the GCAM-KSA, a specialized version of the Global Change Analysis Model tailored for Saudi Arabia, employing a multi-sectoral methodology that integrates economic, energy, and land use systems within a coherent framework to assess the impact of climate policies on GHG emissions. Our analysis reveals that reaching net-zero GHG emissions by 2060 is a complex challenge requiring concerted efforts across all sectors of the economy. While transitioning to low-carbon electricity and improving energy efficiency offer considerable emission reductions, fully decarbonizing the industrial and transportation sectors poses a significant hurdle. Our findings suggest that Saudi Arabia must triple its emission reduction commitments in its next Nationally Determined Contributions (NDCs) update to align with its 2060 net-zero goal. Early action and increased ambition could avoid the chances of getting locked into the high emission assets and give enough time to transform the energy system. Furthermore, the adoption and integration of Carbon Dioxide Removal (CDR) technologies are identified as crucial for offsetting residual emissions, especially in sectors that might continue to rely on fossil fuels.
Sustainable development (SD) is the foremost requirement for the environmental sustainability and this aspect needs the attention of recent studies and policymakers. Hence, the present study examines the impact of green technology adoption (GTA), green dynamic capabilities (GDC) on the green competitive advantage (GCA) and SD of manufacturing companies in China. The study also investigates the mediating role of GCA among GTA, dynamic capabilities and SD and also checks the moderating role of organizational commitment among GCA and SD. The study gets the primary data from the employees of manufacturing companies in China using survey questionnaires. The study also used the smart-PLS to check the nexus among the variables. The outcomes indicated that the GTA and dynamic capabilities has a positive association with GCA and SD. The outcomes also exposed that the GCA significantly mediates and organizational commitment significantly moderates among variables. The study provides the guidelines to the policymakers in making the policies related to enhance the SD using GTA and dynamic capabilities.
Energy industries. Energy policy. Fuel trade, Energy conservation
The recent and brightest GRB 221009A observed by LHAASO marked the first detection of the onset of TeV afterglow, with a total of 7 GRBs exhibiting very high energy (VHE) afterglow radiation. However, consensus on VHE radiation of GRBs is still lacking. Multi-wavelength studies are currently a primary research method for investigating high-energy $γ$-ray astronomy. The limited sample of VHE GRBs, combined with their transient nature, hinders the progress of physical studies of GRBs. This paper aims to obtain useful information for GRB research through the properties of blazars, which share significant similarities with GRBs. By fitting high-quality and simultaneous multiwavelength spectral energy distributions with a one-zone leptonic model, the study explores the similarity of radiation properties of blazars and GRBs. A tight correlation between synchrotron and synchrotron self-Compton (SSC) emission luminosities suggests that blazars and GRBs share similar radiation mechanisms, to be specific, synchrotron radiation produces the observed X-ray photons, which also serve as targets for electrons in the SSC process. We hope that ground-based experiments can observe more GRBs in sub-TeV to confirm these findings.
در اسناد بالادستی کشور از جمله سیاستهای کلی اقتصاد مقاومتی، یکی از راههای افزایش تابآوری اقتصادی، انجام سرمایهگذاریهای بلندمدت در صنعت نفت و گاز بهمنظور حفظ سطوح تولیدی فعلی و افزایش ظرفیت آن است. این درحالی است که طی سالهای اخیر تحریمهای شدیدی علیه کشور بهویژه در حوزه انرژی اعمال شده است. باتوجه به نیاز بالای سرمایهگذاری در پروژههای صنعت نفت و گاز، عدم امکان پوشش کامل نیازهای سرمایهگذاری این صنعت از منابع داخلی و چالش در ارتباطات مؤثر با نهادهای پولی و مالی بینالمللی، اهمیت استفاده از خطوط اعتباری تخصیصی کشور چین برای تأمین مالی این پروژهها آشکار میگردد. با این وجود، بررسیهای انجامگرفته حاکی از چالشهایی جدی در استفاده از ظرفیت خطوط اعتباری است. به همین منظور این پژوهش درصدد بررسی چندجانبه این چالشها است. در این مقاله با استفاده از روش تحلیل مضمون و گروه کانونی، چالشهای استفاده از خطوط اعتباری استخراج و در چهار دسته مالی و اقتصادی، اجرایی و عملیاتی، ساختاری و نهادی و حقوقی و قانونی دستهبندی شدند. به منظور اعتبارسنجی یافتهها، چالشهای استخراجشده در معرض نظر خبرگان قرار گرفت. در پایان با تشکیل گروه کانونی راهکارهای اصلاحی استفاده از خطوط اعتباری با هدف تأمین مالی پروژههای صنعت نفت و گاز ارائه شدند
Social Sciences, Energy industries. Energy policy. Fuel trade
To realize the efficient transient simulation of a grid-connected power generation system based on multiple inverters, this paper proposes a hybrid simulation method integrating the models of electromagnetic transient and dynamic phasors. Based on a demonstration of the concepts and properties of dynamic phasors, the models of single-phase and three-phase inverters described by dynamic phasors are established first. Considering the numerical compatibility problem between dynamic phasors and instantaneous values, an interface scheme between dynamic phasors and instantaneous values is designed, and the efficiency and precision differences of various transformation methods are compared in detail. Finally, by utilizing MATLAB/Simulink, a hybrid simulation platform of a multi-inverter grid-connected system is built, and the efficiency and accuracy of the hybrid simulation are validated via comparison with the full electromagnetic transient simulation.
Energy conservation, Energy industries. Energy policy. Fuel trade
[Introduction] The rapid development of VSC-HVDC provides practical support for MMC (Modular Multi-Level Converter) topology. Takes a half bridge MMC converter as an example, the relationship between steady-state capacitor voltage fluctuation, harmonic interaction, and bridge arm switching function of MMC is studied in order to provide theoretical support for MMC system design and control strategy. [Method] By establishing analytical expressions for the sub module capacitor voltage and bridge arm switch function, the mathematical approximate expressions for the energy fluctuation and capacitor voltage fluctuation of the upper and lower bridge arms of the MMC converter were obtained. Furthermore, the distribution law of harmonics in the upper and lower bridge arms current, AC (Alternating Current ) valve side, and DC (Direct Current) side, as well as the positive and negative sequence relationship of inter phase circulation were studied. Based on the harmonic formula, an estimation method for the secondary circulation was obtained; Furthermore, the variable comparison method was used to study the relationship between the switching function of the bridge arm and the voltage of the submodule capacitance with the valve side power factor and the size of the submodule capacitance. Finally, a detailed PSCAD/EMTDC model was built based on actual engineering parameters, and a consistency comparison between theoretical analysis and offline simulation was conducted. [Result] The research has shown that the inter phase circulating current of MMC only contains even harmonics, with 6k+2 circulating currents exhibiting negative sequence, 6k+4 circulating currents exhibiting positive sequence, and 6k circulating currents exhibiting zero sequence characteristics. At the same time, under steady-state conditions, the AC voltage and current flow at the outlet of MMC valve side only contains odd harmonics, while the DC voltage and current flow at MMC DC side only contains even harmonics, and at the power factor angle φ<0, the peak value of the bridge arm switch function will be greater than 1, and the peak voltage fluctuation of the module capacitor at low power factor is greater than that at high power factor. [Conclusion] Based on this, we can select and design capacitor for MMC inverters and carry out the transient stability strategies, also, master the operational characteristics of MMC topology through theoretical analysis.
The development of new energy sources is imminent for solving the crucial problems in resources and environment fields. Due to national resource endowment, the consumption of energy in developing countries is inevitably increasing. This paper predicts new energy electricity generation for representatives of developing countries—Brazil, Russia, India, China and South Africa (BRICS). A new compound accumulation grey model is proposed by introducing two adjusting factors. The parameters of the model are obtained by using particle swarm optimization algorithm. The accuracy and applicability of the model are verified by four cases. The new energy electricity generation of these countries from 2023 to 2030 is predicted based on the new energy generation data from 2014 to 2022 released by British Petroleum. The results show that these countries have a certain degree of growth in new energy generation. Among them, China has the largest amount of new energy generation. By 2030, the wind power in China will reach 1560 TW-hours, solar power generation will reach 1240 TW -hours. The results of prediction can provide reference for related departments.
Jet substructure is a powerful tool to probe the time evolution of a parton shower. However, many of the analysis methods used to extract splitting formation times from jet substructure, such as Soft Drop grooming and the Lund plane, focus on the hardest radiation of the jet. A complementary observable with growing theoretical and experimental interest, the 2-point Energy Correlator (EEC), re-contextualizes jet substructure study by using the distribution of angular distance of all combinations of two final state particles within a jet. This distribution is weighted by the product of the fractions of jet energy that each of the constituents carry, and thus is infrared-and-collinear safe. The EEC can reveal the separation between two distinct regimes: effects originating from free hadrons at small opening angles and from perturbative fragmentation of quarks and gluons at large opening angles. In these proceedings, the first measurement of the EEC at RHIC is presented, using the data taken at $\sqrt{s}$ = 200 GeV $pp$ collisions by STAR. The EEC will be shown for several full jet transverse momentum selections and compared to predictions from the PYTHIA-8 Detroit tune. This study is useful as a baseline for comparisons to future studies in heavy-ion collisions, which will provide information about how the quark-gluon plasma interacts with the jet across different angular scales.
Huang Huang, Satvik Sharma, Antonio Loquercio
et al.
This paper focuses on the problem of detecting and reacting to changes in the distribution of a sensorimotor controller's observables. The key idea is the design of switching policies that can take conformal quantiles as input, which we define as conformal policy learning, that allows robots to detect distribution shifts with formal statistical guarantees. We show how to design such policies by using conformal quantiles to switch between base policies with different characteristics, e.g. safety or speed, or directly augmenting a policy observation with a quantile and training it with reinforcement learning. Theoretically, we show that such policies achieve the formal convergence guarantees in finite time. In addition, we thoroughly evaluate their advantages and limitations on two compelling use cases: simulated autonomous driving and active perception with a physical quadruped. Empirical results demonstrate that our approach outperforms five baselines. It is also the simplest of the baseline strategies besides one ablation. Being easy to use, flexible, and with formal guarantees, our work demonstrates how conformal prediction can be an effective tool for sensorimotor learning under uncertainty.
The following theses are claimed, several contrasting current climate policies and taxonomies. Analysis, based on solely carbon dioxide emission and energy budget, concludes a set of concrete solutions for mitigating climate change effects. Some of the theses violate more orthodox policy which is thus protested against in order to move forward. • Our long-term goal must be to stop using all carbon-containing fuels, including natural gas and other fossil products as well as biofuels. • We must electrify society and industry, with electricity from only non-carbon-based power including nuclear power, hydro-electric, wind and solar power. • We must prepare ourselves for changes. Even if the present emission volumes of carbon dioxide were possible to stop immediately, various lag effects are inevitable and negative development will therefore continue for considerable time. • We must count with continued melting of land ice, the complete liquifying of the Antarctica ice expected to lead to a global sea level rise by some 60 m, flooding most capitals. Among various solutions to mitigate the effects of ice melting, including lowered global temperatures, the following is proposed. • To mitigate sea level rise, stationary water reservoirs should be built around the world. With estimated melting rates it would require ca 1 million reservoirs be deployed or expanded during the next 20-40 years. • Such reservoirs could also solve the emergent problem of lack of fresh water in many places. They could also be used for local storage of hydroelectric energy by using pump storage hydroelectric (PSH) technology. • All energy production sources should be analyzed according to a Total Balanced Energy Budget (TBEB) with the main objective of minimizing the emissions of greenhouse gases. • For each region/country, a table of available or conceivable complementary electric energy sources should be made and ranked according to TBEB—the sources given priority weights depending on feasibility, significance, and environmental friendliness. Tables are presented for Sweden, Norway, Denmark, Germany, France, Ukraine, California, Massachusetts, Maine, Peru, Australia, China and Japan. Generally, we find the following rank of priority applicable. • Solar energy from desert arid areas is given highest priority in replacing carbon-based forms of energy. Submarine electric cables may be deployed along the Australia-Singapore model, if the available power grids are insufficient for the energy transport. • Electrolysis of water producing clean hydrogen gas is given very high priorityboth for using hydrogen as fuel as well as for energy storage. Improved efficiency should be achieved by the development of electrolysis catalysts. • Hydroelectric power in combination with PSH is given high priority to mitigate both grid power fluctuations as well as source (solar and wind) intermittence. • False hope should not be seeded among society and politicians by inflating projects that are less realistic or suboptimal for technological, economic or other reasons. Here, probably most forms of “biofuels” (which although being “carbon neutral” do produce carbon dioxide) and “carbon capture” (catching carbon dioxide gas at the combustion site, compressing it to liquid and depositing it in salt mines or empty oil fields) are considered less significant compared to other more direct solutions. Both biofuels and carbon capture may be associated with social and environmental issues. • Political legislation and instruments (“taxonomy”) invented with the original objective of mitigating negative climate change effects should be reanalyzed and changed if not functional. The EU Emissions Trading System (EU ETS)—a market for outlet rights, for example, is a local initiative which despite its valuable ambition might be suboptimal with respect to goal of efficient decrease of carbon dioxide emission globally. Similarly, “climate taxonomy” can create loopholes bypassing a sound TBEB. • Science-based targets (SBT) to decarbonize the private sector as part of global efforts to achieve the temperature goal of the Paris Agreement should be further encouraged. • Solve economic and political challenges allowing and promoting establishment of required international energy collaborations (e.g., for solar energy cross-continental transport programs).
In recent years, digital object management practices to support findability, accessibility, interoperability, and reusability (FAIR) have begun to be adopted across a number of data-intensive scientific disciplines. These digital objects include datasets, AI models, software, notebooks, workflows, documentation, etc. With the collective dataset at the Large Hadron Collider scheduled to reach the zettabyte scale by the end of 2032, the experimental particle physics community is looking at unprecedented data management challenges. It is expected that these grand challenges may be addressed by creating end-to-end AI frameworks that combine FAIR and AI-ready datasets, advances in AI, modern computing environments, and scientific data infrastructure. In this work, the FAIR4HEP collaboration explores the interpretation of FAIR principles in the context of data and AI models for experimental high energy physics research. We investigate metrics to quantify the FAIRness of experimental datasets and AI models, and provide open source notebooks to guide new users on the use of FAIR principles in practice.