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

Zhaodong Shi, Rui-zhi Yang

The Westerlund 1 (Wd 1) is the most massive known young star cluster in the Galaxy, and an extended $γ$-ray source HESS J1646-458 surrounding it has been detected up to 80 TeV in the very high energy, implying that cosmic rays (CRs) are accelerated effectively in the region. However, the dominant radiation process contributing to the $γ$-ray emission is not well constrained. In the present work, we develop a model of CR acceleration at the termination shock in the superbubble inflated by the interaction of the cluster wind from the Wd 1 with the surrounding interstellar medium. We then calculate the flux and radial profile of $γ$ rays produced by the inelastic collisions of the hadronic CRs with the ambient gas. Our results with reasonable parameters can explain well the spectrum and radial profile of the $γ$-ray emission of HESS J1646-458, and consequently the $γ$-ray emission of HESS J1646-458 is likely to be of hadronic origin.

Ellis R. Owen, Kinwah Wu, Yoshiyuki Inoue et al.

Cosmological filaments, galaxy clusters, and galaxies are magnetized reservoirs of cosmic rays (CRs). The exchange of CRs across these structures is usually modeled assuming that they remain charged and magnetically confined. At high energies, hadronic interactions can convert CR protons to neutrons. This physics is routinely included in air-shower and ultra-high-energy (UHE) CR propagation Monte Carlo simulations used for composition studies but is rarely treated explicitly in propagation models of CR transport and exchange between magnetized reservoirs. CR neutrons are not affected by magnetic fields and can propagate ballistically over kpc-Mpc distances before decaying back into protons, with relativistic time dilation extending their effective decay length. We show how such charged-neutral switching modifies CR confinement and escape in four representative environments: a Milky Way-like galaxy, a starburst galaxy, a galaxy cluster, and a cosmological filament. By solving the transport of a confined CR proton population in each structure using a diffusion/streaming propagation approach with hadronic pp and p$γ$ interactions, and treating neutron production and decay as a stochastic Poisson ''jump'' process, we find that neutron-mediated steps can allow additional CR escape from large-scale cosmological structures at energies where charged-particle transport alone would predict strong CR confinement and attenuation in ambient radiation fields. These effects imply a qualitative shift in how ultra-high-energy CRs are transferred from embedded sources into filaments and voids once intermediate neutron propagation is considered, with consequences for the partitioning of CRs across the large-scale structure of the Universe.

Nianru Chen, Haoran Zhang, Hongbin Xie et al.

Hydrogen-Integrated Energy Systems have emerged as a critical architecture for deep decarbonization, yet their operational complexity — characterized by nonlinear electrochemical dynamics, profound stochasticity, and rigid physical safety constraints — renders traditional model-based optimization increasingly insufficient. This paper presents a comprehensive review of Reinforcement Learning applications in H-IES scheduling, underpinned by a novel lifecycle-oriented framework. This framework systematically aligns the hydrogen value chain from production and storage to multi-energy coordination with RL research. As the study’s primary contribution, it serves as a unifying architecture that maps fragmented literature to specific operational stages and engineering mandates, establishing a coherent roadmap for researchers and practitioners. We systematically evaluate the performance of various RL algorithms, distinguishing between model-free approaches for economic optimization and hybrid frameworks designed to enforce physical safety constraints. Notably, while deep reinforcement learning algorithms evolve rapidly, the Markov Decision Process formulation and the lifecycle-stage requirements they encode are more durable than any specific algorithmic choice, especially given the slower implementation cycle of real H-IES assets. Furthermore, this review critically identifies the key engineering barriers hindering real-world deployment, including data scarcity, the simulation-to-reality gap, and the lack of interpretability. Finally, this review articulates prospective research directions, highlighting the potential of emerging technologies such as Large Language Models, Meta-Reinforcement Learning, and Digital Twins to evolve RL from a theoretical tool into a robust engine for the intelligent management of the next-generation hydrogen economy.

Choon-Jie Wong, Adam A. Larkin, Jie Bao et al.

Aluminium is manufactured through the Hall-Héroult process, which is very energy intensive. Power modulation, as an industrial-scale demand-side power management approach, allows aluminium smelters to operate with variable power consumption rates and as such be powered by renewable energy sources. In this way, aluminium smelting cells can be used as a large virtual energy storage to balance power demand-supply and stabilise electrical grids. This paper studies the potential optimal power modulation operating conditions, including time-varying line current and anode-cathode distance (ACD) profiles to maximise the aluminium reduction cell profitability subject to constraints on the cell thermal balance. To deal with the complex cell dynamics which are spatially distributed and multi-timescale, a novel optimisation approach that utilises both reduced-order and detailed models is developed. The results yield insight into the optimal line current and ACD profiles for different power modulation scenarios including the time of use electricity tariff and spot price. These results can form the foundation for further studies into online control policies of aluminium reduction cells.

Philipp Danner, Hermann de Meer

The global energy transition towards distributed, smaller-scale resources, such as decentralized generation and flexible assets like storage and shiftable loads, demands novel control structures aligned with the emerging network architectures. These architectures consist of interconnected, self-contained clusters, commonly called microgrids or energy communities. These clusters aim to optimize collective self-sufficiency by prioritizing local energy use or operating independently during wide-area blackouts. This study addresses the challenge of defining optimal clusters, framed as a community detection problem. A novel metric, termed energy modularity, is proposed to evaluate community partitions by quantifying energy self-sufficiency within clusters while incorporating the influence of flexible resources. Furthermore, a highly scalable community detection algorithm to maximize energy modularity based on the Louvain method is presented. Therefore, energy modularity is calculated using linear programming or a more efficient simulation-based approach. The algorithm is validated on an exemplary benchmark grid, demonstrating its effectiveness in identifying optimal energy clusters for modern decentralized energy systems.

Xiaodong Zhang, Kang Yu, Jingwei Zhu et al.

Abstract Under the large-scale integration of wind turbine and photovoltaic into the grid, the power system faces the challenge of insufficient flexibility for regulation. Coordinated planning of hydro-wind-solar-storage systems can effectively mitigate the output volatility of renewable energy sources. This paper proposes a distributionally robust planning method for hydro-wind-solar-storage systems based on the Wasserstein distance. First, taking into account the spatiotemporal correlations of factors such as wind speed and solar irradiance, an auxiliary classifier generative adversarial network (AC-GAN) is employed to generate a set of wind turbine and photovoltaic output scenarios. Then, a bilevel capacity planning model is constructed for the integrated system. The upper level aims to minimize investment costs by determining the optimal energy storage capacity, while the lower level focuses on minimizing operational costs through optimizing storage operation states and the output of various devices. Subsequently, an improved proximal policy optimization (PPO) algorithm, grounded in the Markov decision process framework, is used to solve the model. Finally, an actual case study based on a hydro-wind-solar system in Qinghai China is conducted to validate the effectiveness of the proposed method.

Subhankar Chakraborty, Santanu Sharma, Rupam Goswami

In the world of electric vehicles energy recovery is a major concern for improving the mileage. One way of doing this can be recovery of road vibrations through regenerative damping. In this article, we propose a comparative analysis of 2 different types of regenerative dampers. One is Ball-screw damper and the other is Dual clutch rack and pinion damper on the basis of 2 characteristics. Firstly, analysis of impulse response to study the stability and filtration capability. Secondly, power optimization has been done to analyse the energy recovery and dissipation along with riding comfortability for different operational frequencies. The main identification parameter is the internal impedance of energy harvesting circuit. Mathematical analysis followed by simulation suggests that, in case of Dual clutch rack and pinion damper the average bandwidth to impedance ratio is 3.41 hertz-Ω−1 whereas for Ball-screw dampers is 0.22 hertz-Ω−1. This makes Dual clutch rack and pinion damper a good energy harvester at wider frequency ranges. However, magnitude of energy recovery is higher for Ball-screw damper dampers. The results obtained in this work would motivate other researchers to improve the functionality of both the dampers to enhance the dynamic stability and energy recovery of the vehicle.

Mark Sanctuary, Anton Fagerström, Roozbeh Feiz et al.

This study investigates the interaction between fuel security and climate policy in Sweden, a small economy with no domestic oil production and one of the highest shares of fossil-free alternative fuels in the transport sector within Europe accounting for approximately 20% (by energy content) of total transportation fuel demand in 2019, excluding electricity. Using a Structural Vector Autoregression (SVAR) model estimated on monthly data from 2010 to 2023, the analysis quantifies the elasticity of Swedish GDP to global oil supply shocks and computes the associated fuel security premium. Results indicate that Sweden’s short-run GDP response to oil shocks is modest—approximately one-third the magnitude of the U.S.—but the longer-run response is comparatively stronger, reflecting the importance of international economic spillovers. The estimated fuel security premium reaches up to 0.065 EURO/liter diesel equivalent (or USD 12.6 USD/barrel of oil), underscoring persistent macroeconomic exposure despite high adoption of alternative fuels. A qualitative assessment of Sweden’s fuel market shows that while biodiesels are widely used, their reliance on imported feedstocks, exportability, and high cost limits their contribution to fuel security. Electricity and biomethane offer more promising pathways for enhancing fuel security due to their domestic production potential, barriers to international trade, and price competitiveness. The findings help define the scope to which unilateral fuel security policies can reinforce climate policy goals in small economies, emphasizing the importance of diversified energy systems and international coordination. These insights provide guidance for the strategic planning and implementation of energy policy in small, oil-import-dependent countries seeking to balance energy security and climate objectives in a globally integrated fuel market.

Erdal Tekin, Annika Gillich, Kai Hufendiek

In energy system transformation studies, the assumption of linearly rising CO2 prices is common and based on the decreasing issued European allowances (EUA). The actual auction price for allowances is influenced by market dynamics, resulting in non-linear variations in CO2 prices due to the possibility of banking allowances. This study explores the impact of non-linear CO2 price trajectories on the European electricity market. Various scenarios, such as increasing prices with the market interest rate, early price peaks, collapse, or fluctuations, are examined until 2030. The study quantifies the effects on power plant investments, profitability, consumer costs, and government revenues. The findings reveal that early and high price signals lead to an earlier transition with 7 % more wind power plants but at 4 % higher costs. Conversely, lower initial prices delay power plant investments in wind power plants by 6 % and result in 21 % higher emissions. Compensation for climate impact costs can yield a positive cost-benefit analysis in scenarios with early and high price signals when emissions are avoided through mechanisms like the Market Stability Reserve (MSR).

Yoel R. Cortés‐Peña, William Woodruff, Shivali Banerjee et al.

Abstract Oilcane—an oil‐accumulating crop engineered from sugarcane—and microbial oil have the potential to improve renewable oil production and help meet the expected demand for bioderived oleochemicals and fuels. To assess the potential synergies of processing both plant and microbial oils, the economic and environmental implications of integrating microbial oil production at oilcane and sugarcane biorefineries were characterized. Due to decreased crop yields that lead to higher simulated feedstock prices and lower biorefinery capacities, current oilcane prototypes result in higher costs and carbon intensities than microbial oil from sugarcane. To inform oilcane feedstock development, we calculated the required biomass yields (as a function of oil content) for oilcane to achieve financial parity with sugarcane. At 10 dw% oil, oilcane can sustain up to 30% less yield than sugarcane and still be more profitable in all simulated scenarios. Assuming continued improvements in microbial oil production from cane juice, achieving this target results in a minimum biodiesel selling price of 1.34 [0.90, 1.85] USD∙L−1 (presented as median [5th, 95th] percentiles), a carbon intensity of 0.51 [0.47, 0.55] kg CO2e L−1, and a total biodiesel yield of 2140 [1870, 2410] L ha−1 year−1. Compared to biofuel production from soybean, this outcome is equivalent to 3.0–3.9 as much biofuel per hectare of land and a 57%–63% reduction in carbon intensity. While only 20% of simulated scenarios fell within the market price range of biodiesel (0.45–1.11 USD∙L−1), if the oilcane biomass yield would improve to 25.6 DMT∙ha−1∙y−1 (an equivalent yield to sugarcane) 87% of evaluated scenarios would have a minimum biodiesel selling price within or below the market price range.

Samuel Adu Fosu, Sarah C. Davis

Abstract Miscanthus × giganteus (miscanthus) is considered a beneficial biomass energy crop because of its carbon (C) sequestration potential and low fertilizer requirements, but few studies in the United States have measured long‐term C sequestration of miscanthus on suboptimal agricultural lands over a decadal scale, and none have been conducted in southeast Ohio. The objective of this study was to measure the soil C sequestration on abandoned agricultural land with a miscanthus crop that is harvested annually, the long‐term changes in plant and soil nitrogen (N), and the photosynthetic capacity in the tenth year of growth. This study was conducted over a 10‐year period from 2013 through 2023. A significant amount of C was accumulated in the soil (p < 0.05) and the mean C sequestration rates were 0.83 and 1.37 Mg C ha−1 year−1 at two different sites. The amount of C accumulated in the miscanthus plots by the tenth year was also greater than soil C in unmanaged grassland soils, but the difference was not statistically significant (p > 0.05). There was no statistically significant change in the amount of N found in soil and plants over 10 years (p > 0.05), but the variability in plant N was greater in some years relative to others. Even though miscanthus was grown without N fertilizers in this study, soil N at 0–30 cm depth was not depleted over 10 years of crop management. The photosynthetic capacity of miscanthus measured in this study indicated that the plants were thriving after 10 years, and C assimilation for growth was consistent with the findings of prior work that evaluated the maximum photosynthetic rates of this species. The combination of significant soil C sequestration, sustained soil N, and high photosynthetic rates has important implications for the sustainability of miscanthus as a biomass crop.

Ying Li, Weiquan Wang, Liang Zhang et al.

The reliability analysis of vertically integrated protection devices is crucial for designing International Electrotechnical Commission (IEC) 61850-based substations. This paper presents the hardware architecture of a four-in- one vertically integrated device and the information transmission path of each function based on the functional information transmission chain of protection devices, measurement and control devices, merging units, and intelligent terminals. Additionally, a reliability analysis model of the protection device and its protection system is constructed using the fault tree analysis method while considering the characteristics of each module of the vertically integrated device. The stability probability of the protection system in each state is analyzed by combining the state-transfer equations of line and busbar protection with a Markov chain. Finally, the failure rate and availability of the protection device and its protection system are calculated under different ambient temperatures using a 110 kV intelligent substation as an example. The sensitivity of each device module is analyzed.

Lingyun Zhao, Zhuoyu Wang, Tingxi Chen et al.

Randomness and fluctuations in wind power output may cause changes in important parameters (e.g., grid frequency and voltage), which in turn affect the stable operation of a power system. However, owing to external factors (such as weather), there are often various anomalies in wind power data, such as missing numerical values and unreasonable data. This significantly affects the accuracy of wind power generation predictions and operational decisions. Therefore, developing and applying reliable wind power interpolation methods is important for promoting the sustainable development of the wind power industry. In this study, the causes of abnormal data in wind power generation were first analyzed from a practical perspective. Second, an improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMDAN) method with a generative adversarial interpolation network (GAIN) network was proposed to preprocess wind power generation and interpolate missing wind power generation sub-components. Finally, a complete wind power generation time series was reconstructed. Compared to traditional methods, the proposed ICEEMDAN-GAIN combination interpolation model has a higher interpolation accuracy and can effectively reduce the error impact caused by wind power generation sequence fluctuations

Ponnuthurai Gokulakrishnan, Jiankun Shao, Michael S. Klassen et al.

NOx formation from ammonia impurities and its effects on fuel oxidation is not well understood for high-pressure supercritical CO2 oxy-combustion conditions. This effect is investigated computationally and experimentally in the present work. A chemical kinetic analysis revealed that the reaction between NH radical and CO2 plays an important role in determining the rate of NOx formation at these conditions. It was also found that a significant reduction in the NOx formation from ammonia oxidation occurs with sCO2 oxy-combustion at 300 atm when compared to traditional gas turbine conditions. A chemical reactor network simulation of realistic sCO2 cycle conditions confirmed the reduced NOx emissions. Monte Carlo simulations used to study the sensitivity of model input variables on the emissions showed that CO2 cooling impacts the CO emissions while most of the NOx are generated in the flame zone. Uncertainty analysis showed that the reaction between NH and CO2 to form HNO radical is an important contributor to the model uncertainty under sCO2 oxy-combustion conditions.The presence of combustion-generated NOx in the recycled-CO2 can impact the fuel oxidation in the primary zone of the combustor. Hence, to understand the effect of NOx on ignition, high-pressure shock tube ignition delay time experiments were performed at conditions relevant to sCO2 oxy-combustion. The ignition delay time measurements were made for syngas and CH4 fuels with and without NO addition under supercritical conditions using CO2 as the bulk diluent at nominal pressures around 100 atm. Experimental data showed that the presence of NO promotes ignition at these conditions. The effect is more pronounced for CH4 compared to syngas. Nitric oxide acts as a chemical catalyst to promote ignition by increasing the combustion radical pool. The catalytic cycle involves the conversion of NO to NO2 which also contributes to CH4 oxidation by H-atom abstraction to generate CH3 radical.

宁可儿, 刘俊杉, 张超逸 et al.

大规模分布式光伏的接入将对配电网的安全经济运行带来重要影响，分布式光伏发电的时效性变化和光伏装机的区域性差异为有效进行新能源消纳带来挑战。为此，通过提出配电网储能与直流线路协同规划架构，针对光伏随时间波动的不平衡，使用储能装置进行电能存储，实现电力的削峰填谷。针对区域光伏分布不均，通过建设直流线路以实现区域间能量互济，消纳光伏溢出区域的发电量。进一步，以投资成本、维护成本和电能费用构成的年综合费用最小为目标，构建储能及直流线路选址定容的交直流配电网优化规划问题，实现区域内和区域间光伏溢出功率的高质量、高经济性消纳。最后，基于改进的IEEE 13节点算例及多种规划方案，对比验证了模型的有效性与合理性。

Xingguang HU, Zhiquan SONG, Ge GAO et al.

[Introduction] In order to realize controlled nuclear fusion and solve the future energy problems of mankind, International Thermonuclear Experimental Reactor (ITER) is planning to build a superconducting tokamak device for fusion reaction. [Method] This paper briefly described the significance and development of ITER program and introduced the composition and function of its power supply system, as well as the structure and technical parameters of converter power supply of main coils. [Result] Finally, the optimization design of ITER magnet power supply in China and related procurement task for magnet power supply that have been completed are proposed. [Conclusion] By participating in ITER research projects, China has made important contributions to the development of international fusion engineering technology.

Siniša Spremić, Dušan Obradović

U radu se razmatra mogućnost direktne korekcije greške kod određivanja položaja regulacione preklopke iz napona primara i sekundara pojedinačnih transformatora koji imaju veći broj snimljenih merenih vrednosti napona i struja u manjem ili većem opsegu opterećenja. Direktna korekcija se nadovezuje na prethodno izvršenu korekciju greške od pada napona na impedansi transformatora koja se koristi za proračun položaja regulacione preklopke korišćenjem napona. Direktna korekcija se vrši određivanjem srednje vrednosti svih tačaka i zatim oduzimanjem na taj način određene srednje vrednosti od vrednosti pojedinačnih tačaka.

Marija Lazarevikj, Valentino Stojkovski, Viktor Iliev

U tehničkoj praksi često je potrebno meriti ili kontrolisati protok fluida u cevovodima i kanalima. Metoda polja brzina zahteva merenja u određenim tačkama u odgovarajućem poprečnom preseku zatvorenih cevi. Istovremeno izmerene lokalne srednje brzine meračima integrišu se u mernom preseku kako bi se izračunao protok. U ovom radu, tri pristupa ove metode primenjuju se na pravougaonom zatvorenom cevovodu za određivanje protoka vazduha pomoću tehnika integracije koje se koriste za izračunavanje protoka pretpostavljajući raspodele brzina koje se blisko približavaju poznatim zakonima, posebno u blizini granica čvrstih tela. U tu svrhu, merači brzine su bili 7 Pitoovih cevi postavljenih vertikalno u unapred definisanim mernim tačkama koje pokrivaju visinu cevovoda, i pomerale su se horizontalno duž širine cevi. Položaj Pitotovih cevi duž preseka cevovoda praćen je i kontrolisan mernim pretvaračem pomeranja. Pritisak se meri digitalnim senzorima. Prva tehnika za određivanje protoka vazduha zasniva se na fiksnim mernim tačkama po preseku cevi u kojima se određuju prosečne vrednosti lokalne brzine, druga je polukontinualno merenje profila brzine primenom interpolacije između prosečne lokalne brzine u fiksnoj tački i izmerene brzine pri kretanju između dva položaja, a treća se zasniva na kontinuiranom pomeranju Pitotovih cevi bez zaustavljanja. Rezultati se izračunavaju i predstavljaju pomoću različitih vrsta softvera. Kod poslednje tehnike, upoređivani su rezultati dobijeni primenom različitih brzina kretanja Pitotovih cevi kako bi se ispitao njihov uticaj na profil brzine.

Thomas Holst, Senior Analyst, Kem C. Gardner

Boris M. Dolgonosov

The dependence of world GDP on current energy consumption and total energy produced over the previous period and materialized in the form of production infrastructure is studied. The dependence describes empirical data with high accuracy over the entire observation interval 1965-2018.