Hasil untuk "Energy industries. Energy policy. Fuel trade"

Teerapat Suteerapongpun, Poonnut Thaeviriyakul, Watanyoo Phairote et al.

This study investigated the effects of blending weight ratio of 5% and 10% ethanol (B7E5 and B7E10) with standard B7-diesel on the performance, combustion, and emission characteristics of a light-duty common-rail diesel engine. The engine was tested on a dynamometer across various speeds (1600–2000 rpm) and loads (84 and 112 Nm) to analyze in-cylinder pressure, thermal efficiencies, and exhaust emissions. Results indicated significant emission benefits, especially at high loads. The B7E10 blend reduced smoke intensity by approximately 75% and carbon dioxide emissions by 34% compared to the baseline B7. The performance analysis revealed a critical trade-off associated with the ethanol blends: while the inherent oxygen content in ethanol significantly improved the indicated thermal efficiency (ITE) through enhanced combustion, its lower viscosity simultaneously led to increased frictional losses. Consequently, these competing effects resulted in only a modest improvement in brake thermal efficiency (BTE) and comparable brake-specific energy consumption (BSEC) compared to the baseline B7. The primary objective is to identify the benefits and trade-offs associated with ethanol blending in biodiesel-based diesel fuels that are compatible with existing diesel vehicles.

Francesco Cenvinzo, Alberto Procacci, Alessandro Parente et al.

Despite advances in computing power, a major limitation in the simulation of turbulent flame stems from the need to track all chemical species involved in the thin reaction zones throughout the flow field. This paper investigates how Reduced Order Models (ROMs), combining data-driven analysis and neural network training, can significantly reduce computational cost. Specifically, neural networks are employed to assist in solving ϕ(x̲,t), a thermochemical scalar representing species mass fractions, energy, or temperature. The evolution of ϕ(x̲,t) over no time steps is used as input to a ROM framework, in which dimensionality reduction is achieved using Proper Orthogonal Decomposition (POD), while temporal dynamics are modeled using a Long Short-Term Memory (LSTM) network, with ANN trained for each of the retained POD modes. The scalar field for the nrom subsequent time steps is then predicted by the network, bypassing the need to solve the transport equation for these iterations. In this work the pair of values (no=10,nrom=1) and (no=20,nrom=5) are implemented. This approach is first validated on a non-reactive Large Eddy Simulation (LES) of a cavity flow, where air and H2 are injected separately and mix downstream. The methodology is then extended to a reactive Unsteady Reynolds-Averaged Navier–Stokes (URANS) simulation of a non-premixed H2-air flame stabilized downstream of the same cavity geometry, assuming infinitely fast chemistry. When skipping CFD iterations, the network can also predict the flow evolution over a time step that is ten times larger than the standard CFD time step. This leads to a reduction in computational cost to reach a given physical time. Results demonstrate that the ROM is capable of accurately predicting the unsteady dynamics of the turbulent system across testing sequences unseen during training. The approach yields a CPU time saving of the order of 27%.

Lindsay Shade, Karen Rignall, Lyndsay Tarus et al.

Scholars from a wide range of disciplines have grappled with defining and assessing the limitations and opportunities for ‘just’ low carbon energy transitions. Here, we offer an alternative approach to developing a framework for just transition that is grounded in long-term participatory action research with environmental justice communities in Appalachia. We ground our discussion in literature from both scholars and social movements, as well as experiences of the authors through collective autoethnography. Specifically, our work seeks to bring land ownership to the forefront of conversations about economic development in Appalachia and about energy transition more broadly, and to expand the perspectives of directly impacted communities in the scholarly literature. For the past 7 years, the contributors to this article have worked to build a broad-based ‘land study collective’ to support public knowledge, action, and policy focused on the role of land ownership in both incumbent energy systems and transition dynamics. We discuss our shared goals, our process of building the collective and defining and studying research questions across geographically dispersed stakeholders, and vignettes from empirical research of collective members. We conclude with challenges and considerations for others who may want to integrate participatory research on land ownership into their just transition frameworks. We pay special attention to the ethics and empirical benefits of collective autoethnography for developing just transition frameworks that incorporate the lived experiences of those most impacted by energy extraction regimes.

Rong ZHANG, Ti DU, Pengjie SUN

[Objective] To analyze the critical meteorological conditions for conductor icing and melting, accurately predict the start and end times of conductor icing, and provide a basis for power departments to prevent icing disasters. [Method] This study used the complete conductor icing records of eight winters from an icing observation station in Southwest China, and the simultaneous meteorological observation data from adjacent surface meteorological stations. Fisher discriminant analysis theory was applied to study the frequency distribution characteristics of meteorological factors of temperature, wind speed, relative humidity, water vapor transport, cloud cover at the start and melting moments of conductor icing. [Result] The results show that conductor icing is most likely to occur when the temperature ranges from −3 to 0 ℃, the water vapor transport rate is 15～30 (g·m2·s−1), and the relative humidity is ≥90%. During the melting stage of conductor icing, the temperature increases significantly and the wind speed strengthens. Based on the characteristics of meteorological factors in different stages. Fisher discriminant functions for icing occurrence and melting are established respectively. The effect test shows that the fitting accuracy of the discriminant equation for the icing start moment is 77.3%, and that for the icing melting moment is 68.99%, indicating the equations can reflect the actual icing situation. [Conclusion] This method can provide ideas for line icing prediction, help improve the technical level of line design for icing, innovate and enrich the icing data analysis technology, and provide support for scientifically solving the problem of line design for icing.

Rongrong Li, Qiang Wang, Sailan Hu

As the global demand for sustainable energy intensifies, achieving economic growth without carbon emissions has become both a critical challenge and an opportunity. This study investigates the potential of five major clean energy sources—solar, wind, hydroelectric, nuclear, and geothermal energy—in fostering economic growth while reducing carbon emissions. Despite the growing interest in clean energy, the comparative effectiveness of these energy sources in different economic and environmental contexts remains underexplored, particularly concerning their nonlinear relationships with economic development and emissions. To address this gap, this study uses a robust panel dataset covering 24 countries from 2005 to 2020, and employs fixed-effect and panel threshold models to uncover the nuanced relationships between clean energy consumption, GDP, and CO2 emissions. The results indicate a positive impact of clean energy consumption on economic growth across all five energy types, with solar and wind contributing to steady development. However, the relationship with CO2 emissions varies: solar, wind, and geothermal significantly reduce emissions, while hydroelectric and nuclear energy are associated with higher emissions due to infrastructure complexities. Threshold regression analysis further identifies nonlinear effects moderated by geopolitical risk. For solar and wind energy, the carbon-reducing impact becomes more pronounced when risk levels exceed the threshold, while hydroelectric and nuclear energy show escalating emissions in high-risk environments. This study highlights solar and wind energy as the most effective solutions for achieving carbon-free economic growth, while hydroelectric and nuclear energy require improved governance and risk management frameworks to minimize their environmental trade-offs.

Max Langtry, Ruchi Choudhary

Energy storage is needed to match renewable generation to industrial loads in energy parks. However, the future performance of bulk storage technologies is currently highly uncertain. Due to the urgency of decarbonization targets, energy park projects must be designed and begun now. But, as uncertainty in storage performance reduces, a different technology than identified during initial design may turn out cheaper. Enabling flexibility so that design adaptations can be made as better information becomes available would lower the cost of decarbonizing industry. But having this flexibility is itself costly. This raises the question, "Is it worth it?" This study quantifies the benefit of retaining flexibility to adapt energy park designs and optionality over storage technology choice as uncertainty reduces, to determine whether it is economically worthwhile. It applies the Value of Information analysis framework to the sizing of wind, solar, and storage in an illustrative energy park model based on a real-world proposal near Rotterdam, considering uncertainty in storage efficiency, lifetime, and capital cost. Updating asset sizings after storage uncertainty reduced is found to reduce total costs by 18% on average. Having the option to switch storage technology choice as well reduces costs by a further 13%, which is substantially greater than the cost of providing storage optionality. Using two storage technologies in the energy park reduces costs by 14%, and in this case storage optionality is not worthwhile. These results are robust to the level of uncertainty reduction in storage performance, and the risk aversion of the system designer.

Muhammad Ghulam Khuwajah Khan

We propose a phenomenological framework in which the observed late-time dark-energy sector is interpreted as the intrinsic tension of space itself. Motivated by recent observational hints that the dark-energy equation of state may exhibit mild low-redshift evolution, we begin from an intrinsic membrane description of spacetime and show that a uniform space tension contributes to the gravitational field equations with precisely the tensor structure of vacuum energy. We then consider its Dirac--Born--Infeld completion, which naturally introduces a hidden Abelian $U(1)$ gauge sector on the membrane of space. Within this setting, we study a late-time hidden symmetry-breaking transition $U(1)_h \to \mathbb{Z}_n$, which reorganizes hidden magnetic energy into a coarse-grained flux-tube reservoir. If this reservoir exchanges energy with the dynamical part of the space-tension sector, the effective dark-energy density becomes time dependent and acquires a nontrivial equation of state. At the background level, the model yields a simple proof-of-concept realization of mild running dark energy and admits a transient crossing of the phantom divide. We compare the resulting evolution with a compressed observational benchmark in the effective Chevallier--Polarski--Linder plane. Although the minimal single-reservoir realization does not exactly reproduce the benchmark target, it generates a phenomenologically relevant low-redshift evolution and points toward a late hidden-sector transition together with a substantial hidden defect population. The construction should therefore be viewed not as a complete theory of dark energy, but as a physically transparent proof of concept.

Abdulfatai Olatunji Yakub, Misbaudeen Aderemi Adesanya, Noel Ngando Same et al.

Greenhouses offer controlled microclimates that enable year-round cultivation, improving food security and agricultural productivity. However, greenhouses are energy-intensive, with heating accounting for a significant portion of the associated costs. This study explores optimal microgrid configurations, economic viability, and policy recommendations for sustainable greenhouse agriculture in Nigeria. An in-depth energy assessment of a reference greenhouse in a South Korean facility is conducted. Distinct climatic differences between South Korea and Nigeria are highlighted, emphasizing the need for tailored greenhouse designs and energy solutions. Shifting focus to Nigeria, this study investigates the feasibility of hybrid renewable energy systems with a focus on wind and solar power across six geopolitical zones in Nigeria. The analysis encompasses technical, economic, and policy aspects, providing a holistic perspective on renewable energy adoption. Notably, the study uses an advanced optimization model, Teaching and Learning–Based Optimization algorithm, to assess the net present cost and baseload supply reliability, offering valuable insights for investors and policymakers. The result indicates diverse energy requirements across Nigeria, with total monthly peak energy demands ranging from 5374.80 kWh in the Southeast to 17,115.76 kWh in the Northwest, and a notable variation in the Levelized Cost of Electricity (LCOE), with the lowest at $0.07327 in Kano. Specifically, in Ogun, the net present cost for the WT-PV-ESS system stood at $520,935.45, while the PV-ESS system cost was substantially lower at $500,444.41. This confirms the effectiveness of location-specific analysis and shows the suitability of photovoltaic–battery energy storage systems for Nigeria's diverse regions, with unique considerations for specific areas. Policy recommendations, including feed-in tariffs, renewable portfolio standards, net metering, research support, and market development, provide a holistic framework for the adoption of renewable energy and sustainable agriculture. Improving infrastructure, market access, and financing for smallholder farmers is integral for improving food security and standards of living in rural Nigeria. In conclusion, Nigeria can leverage renewable resources to revolutionize its energy and agriculture sectors, setting an example for a sustainable and resilient future.

Hounaida Daly, Badreldin Mohamed Ahmed Abdulrahman, Sumaya Awad Khader Ahmed et al.

The purpose of this study is to investigate the short-run and long-run relationship between liquefied petroleum gas Consumption (LPGC), natural gas consumption (NGC), other refined products consumption (ORPC), carbon dioxide emissions (CO2), and gross domestic product (GDP) in Saudi Arabia, from 1970 to 2021. To study the link between energy consumption and economic growth and its role in this relationship, we use an autoregressive distributed lag (ARDL) bounds-testing technique of cointegration. The research findings revealed the development of a cointegrating association among all the variables. The anticipated results provide more evidence that a long-run link exists between the drivers of economic development and its regressors. The empirical estimation suggests an LPGC effect that is both beneficial and statistically significant on economic growth. A positive correlation exists between energy consumption and GDP growth. Using the Toda-Yamamoto Granger Causality approach, the causality test reveals a unidirectional causal relationship between the consumption of liquified petroleum and GDP, and between the consumption of natural gas and other refined products. In addition, there is bidirectional causality between GDP and other refined products. Consumption of natural gas and carbon dioxide emissions both have a neutral causal effect on economic growth. In the short run, NGC, ORPC, and CO2 have a positive effect on GDP. The KSA energy policy, actively engaged in slowing CO2 while preserving energy consumption, will significantly benefit from the conclusions of this research. Thus, policymakers should consider how to make LPGC, NGC, and ORPC more prudent and effective, particularly in the energy sector. The government of Saudi Arabia also needs to centralize the renewable energy sector.

Wenkui Zhang, Hongyi Xu, Wei Liu et al.

Abstract On-line monitoring of flow rate is rather important to evaluate the water consumption of the pump-turbine and the overall efficiency of the pumped storage station. Flow rate can be worked out based on the flow differential pressure measured in the flow passage and coefficients determined on model test. But the coefficients must be calibrated to obtain the reliable flow rate. As thermodynamic method is a common way to measure the discharge of prototype pump-turbine, site test is carried out on a vertical pump-turbine with 600 m rated head to calibrated the coefficients in this paper. Measuring devices are designed to satisfy both the turbine and pump operating conditions, and test results of flow rate at both turbine and pump operating conditions are presented and show that the calibrated coefficients are different to the predicted values. The calibrated results indicate the importance of site calibration on prototype turbine to ensure the monitoring validity on real-time flow rate.

Walter Winter

We discuss recent results in neutrino astronomy and their implications for the cosmic-ray acceleration in relativistic outflows, such as in Active Galactic Nuclei (AGN) jets, Gamma-Ray Bursts (GRBs), and Tidal Disruption Events (TDEs). We especially focus on challenges at the interface to particle acceleration which can be inferred from the multi-messenger context, such as the paradigm that the sources power the Ultra-High-Energy Cosmic Rays (UHECRs). We demonstrate that both AGN blazars (in the context of neutrino observations) and GRBs (as UHECR sources in the context of neutrino-non-observations) point towards acceleration spectra harder than $E^{-2}$, or relatively high minimal cosmic-ray injection energies, to meet the respective energy budget requirements. We furthermore speculate that neutrino flares in blazars may be related to super-Eddington accretion flares, or that GRBs are powered by significantly higher kinetic energies than typically assumed in electromagnetic models. For internal shock models, the UHECR paradigm for GRBs can only be maintained in the light of neutrino stacking limits in multi-zone models. While relativistic outflows in TDEs have become recently interesting per se and models for the neutrino emission from jetted TDEs exist, a direct connection between TDE jets pointing in our direction and astrophysical neutrinos has not been identified yet.

IceCube Collaboration, R. Abbasi, M. Ackermann et al.

This Letter presents the result of a 3+1 sterile neutrino search using 10.7 years of IceCube data. We analyze atmospheric muon neutrinos that traverse the Earth with energies ranging from 0.5 to 100 TeV, incorporating significant improvements in modeling neutrino flux and detector response compared to earlier studies. Notably, for the first time, we categorize data into starting and through-going events, distinguishing neutrino interactions with vertices inside or outside the instrumented volume, to improve energy resolution. The best-fit point for a 3+1 model is found to be at $\sin^2(2θ_{24}) = 0.16$ and $Δm^{2}_{41} = 3.5$ eV$^2$, which agrees with previous iterations of this study. The result is consistent with the null hypothesis of no sterile neutrinos with a p-value of 3.1\%.

Thorsten Winkelmann, Julia Zimmermann, Erik Vollmann

Abstract Background Traffic and transport infrastructure is a vital prerequisite for social and economic development as well as the socio-spatial integration of countries and regions’ societal strata. It sets the course for the future of mobility and transport-related social and economic development and is thus inherently political. Deficiencies in traffic infrastructure provision, such as delays in project deployment and exceeding costs, increase the potential for public discontent. It is the mission of public audits to identify, diminish and remedy infrastructure deployment problems—and to encourage best practice models and policy learning. Despite their importance, shortcomings that audit offices identify as well as the reactions and follow-up measures of the addressees to official problem statements remain vastly under-researched. As the transport area is one of the core emitters of CO2 and at the heart of many transition policies to tackle climate change, lack of knowledge regarding transformative change opportunities in the mobility sector is detrimental to the success of these adaptations. One major policy issue in this respect are reform strategies regarding transport and traffic infrastructure planning and project implementation. Our systematic analysis of public audit reports in Germany on traffic and transport infrastructure project deployment contributes to a better understanding of this issue. Results We detect patterns of compliance and resistance to audit office assessments by the executing administrations in traffic infrastructure project deployment. While we witness at least the partial compliance and announcement of corrections in 51% of the cases, in about 19% of the cases, the responsible authorities acknowledge the audit’s critique (partially), but do not signal concrete willingness for further corrections. In more than 20% of the identified audit statements, the audit’s assessments are even rejected without corrections to the further projects’ execution. Conclusion We analyze the extents and limits of organizational learning and institutional adaptation of public control strategies in mobility and transport-related infrastructure provision. Our contribution discusses possible reasons for sustainable transport and traffic infrastructure development deficits as well as shortcomings in infrastructure planning and project deployment. We thus try to open new avenues for debate on improved sustainable infrastructure policy and planning.

Toyese Oyewusi, Gabriel Alebiowu, Elizabeth Aransiola et al.

Briquettes from agro-residues have been promoted as a better replacement to firewood and charcoals for heating and cooking in the rural communities. In view of this, a study was carried out to investigate the effect of pretreatment methods on physical properties and heating values of briquettes produced from corncob. To accomplish this work, the experiment was designed as a 2×3×3×3 completely randomized with three replicates. The parameters are pretreatment methods (carbonized and uncarbonized), binder types (cassava, corn and gelatine), binder concentrations (10, 20, 30%) and compacting pressure (50, 100 and 150 kPa). A charcoal kiln was fabricated to obtain the pretreatment through pyrolysis and a punch and die was also fabricated to enable the briquette densification. The physical properties tested were limited to moisture content (MC), density and compressive strength and were determined using a conventional method. The heating value of the briquettes produced was determined using bomb calorimeter. The results showed that average moisture content ranged between 5.29-6.58% and 12.75-13.72%, mean relaxed density varied from 813-925 kgm-3 and 963-1166 kgm-3, compressive strength ranged between 2.27-5.07 MPa and 5.97-10.12 MPa and heating value ranged between 28.85-32.36 MJkg-1 and 27.58-28.80 MJkg-1 for carbonized and uncarbonized briquettes, respectively. Briquettes produced from carbonized corncob had a better moisture content and heating value, while briquettes produced from uncarbonized corncob had higher density and compressive strength. The study shows that pretreatment methods under different binder types and concentrations and the compacting pressure significantly affected briquette’s physical properties and heating values.

Xiaohui Zhang, Liang Wang, Bo Zhang et al.

Abstract The rapid development of photovoltaics (PVs) and load caused a significant increase in peak loads and peak‐valley differences in rural distribution networks, which require load peak shifting and line upgrading. Large peak‐valley differences also bring challenges on the safe operation of the utility power grid. Considering the integration of a high proportion of PVs, this study establishes a bilevel comprehensive configuration model for energy storage allocation and line upgrading in distribution networks, which can reduce peak loads and peak‐valley differences. In the upper level, a minimum annual planning cost is obtained by developing the installation capacity of centralised energy storage in transformer stations, the installation location and capacity of decentralised energy storage on lines and a scheme of line upgrading. In the lower level, the minimum total annual operation cost of the distribution network is obtained by developing an optimal scheduling for the centralised energy storage in transformer stations and decentralised energy storage on lines. Simulation results show that compared with the conventional energy storage planning strategy, the configuration investment can be reduced by 467.66 million yuan at least with the proposed strategy.

LAO Yongzhao, WU Renbo, XIAO Jian et al.

[Introduction] The line loss of 10 kV distribution network is an important indicator to measure the economic benefits of power grid enterprises. At present, due to some areas, data collection cannot be synchronized, and the line topology relationship cannot be updated in real time. As a result, power grid companies have greater management line losses when calculating line losses. Using the distribution network synchronous phasor measurement terminal with the distribution network line loss real-time analysis platform for line loss management is an effective way to solve the problem of abnormal line loss. [Method] Firstly, it analyzed the abnormal main causes of the line loss of the medium voltage distribution network, and put forward the idea of improving the accuracy of the line loss. Then, the synchronous phasor measurement technology was introduced, and the synchronous phasor measurement architecture was proposed. Finally, the functional requirements of the line loss real-time synchronization analysis platform were proposed. [Result] Based on the power grid of a demonstration project in a certain area of Guangzhou as the research basis, according to the actual situation and needs of the power grid, the basis A design scheme for real-time synchronous analysis of line loss in 10 kV distribution network based on synchronous phasor measurement. [Conclusion] The solution in this paper provides effective direction and engineering experience for line loss management and governance of distribution network.

Judy Da Zhu

The top three carbon emitters, the European Union (EU), China, and the United States (US), account for up to 50% of the global total, and actions of them are deterministic for the ambitious target of the Paris Agreement. Towards carbon neutrality, while the EU has been consistently leading and the US has been swinging, China features a drastic but firm change of stance from a passive responder to a proactive leader in the past decade. Drawing the literature comparing their policies and plans, this paper analyzes the behaviors of the three actors within a theoretical framework of rational choice and applies game theory to find the Nash equilibria of their strategy combinations. Considering the complex variations in socioeconomic and international relations criteria, our ternary game model shows that the Nash equilibria evolve with time and are different from that of the prevalent Prisoner's Dilemma. Importantly, we found the collective cooperation strategy combination forms the only Nash equilibrium in the 2010s and after. Our model provides an explanation for the historic behaviors of the three players and allows for the prediction of their future environmental policy directions.

Jixiang Zhang, Xiaolei Zhang, Athanasios Rentizelas et al.

Biofuel large-scale application was constrained due to cost control. In order to reduce biofuel production cost and increase profitability, long-term strategy (strategic) and medium-term strategy (tactical) combined logistic model were assessed in this study. Geographic information system has been integrated into logistic model to minimize the effect of uncertainty on logistic modelling accuracy, with aims of transferring uncertainty problem to be certain. Combined heat and power generation plant as a case study present in logistic model, which provide a method in plant location and capacity selection criteria; logistic model design; and interaction between logistic model and local conditions. The logistic plan with compression as a pre-treatment technology has the optimal profitability performance, their properties affect the selection of the transport route, especially optimal for a lower availability of agricultural residues. With increased availability, torrefaction turns to more efficiency biomass pre-treatment technology due to storage cost significant reduction. With geographic information system transportation route assistance, logistic model transportation cost and CO2 emission has a 0.02% and 0.01% reduction.

Francesco Lombardi, Bryn Pickering, Stefan Pfenninger

Given the urgent need to devise credible, deep strategies for carbon neutrality, approaches for `modelling to generate alternatives' (MGA) are gaining popularity in the energy sector. Yet, MGA faces limitations when applied to state-of-the-art energy system models: the number of alternatives that can be generated is virtually infinite; no realistic computational effort can discover the complete technology and spatial diversity. Here, based on our own SPORES method, a highly customisable and spatially-explicit advancement of MGA, we empirically test different search strategies - including some adapted from other MGA approaches - with the aim of identifying how to minimise redundant computation. With application to a model of the European power system, we show that, for a fixed number of generated alternatives, there is a clear trade-off in making use of the available computational power to unveil technology versus spatial diversity of system configurations. Moreover, we show that focussing on technology diversity may fail to identify system configurations that appeal to real-world stakeholders, such as those in which capacity is more spread out at the local scale. Based on this evidence that no feasible alternative can be deemed redundant a priori, we propose to initially search for options in a way that balances spatial and technology diversity; this can be achieved by combining the strengths of two different strategies. The resulting solution space can then be refined based on the feedback of stakeholders. More generally, we propose the adoption of ad-hoc MGA sensitivity analyses, targeted at testing a study's central claims, as a computationally inexpensive standard to improve the quality of energy modelling analyses.