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

E. Blanc‐Betes, N. Gomez‐Casanovas, C. J. Bernacchi et al.

ABSTRACT The expansion of sugarcane onto land currently occupied by improved (IMP) and semi‐native (SN) pastures will reshape the U.S. bioenergy landscape. We combined biometric, ground‐based and eddy covariance methods to investigate the impact of sugarcane expansion across subtropical Florida on the carbon (C) budget over a 3‐year rotation. With 2.3‐ and 5.1‐fold increase in productivity over IMP and SN pastures, sugarcane displayed a C use efficiency (CUE; i.e., fraction of gross C uptake allocated to plant growth) of 0.59, well above that of pastures (0.31–0.23). Sugarcane also had greater C allocation to aboveground productivity and hence, harvestable biomass relative to IMP and SN. Cane heterotrophic respiration over the 3‐year rotation (903 ± 335 gC m−2 year−1) was 1% and 14% higher than IMP and SN pastures, respectively. These soil C losses responded largely to disturbance over the first year after conversion (1510 ± 227 gC m−2 year−1) but declined in subsequent years to an average 599 ± 90 gC m−2 year−1—well below those of IMP (933 ± 140 gC m−2 year−1) and SN (759 ± 114 gC m−2 year−1) pastures—despite a significant 40%–61% increase in soil C inputs. Soil C inputs, however, shifted from root‐dominated in pastures to litter‐dominated in sugarcane, with only 5% C allocation to roots. Reduced decomposition rates in sugarcane were likely driven by changes in the recalcitrance and distribution rather than the size of the newly incorporated soil C pool. As a result, we observed a rapid shift in the net ecosystem C balance (NECB) of sugarcane from a large source immediately following conversion to approaching the net C losses of IMP pastures only 2 years after conversion. The environmental cost of converting pasture to sugarcane underscores the importance of implementing management practices to harness the soil C storage potential of sugarcane in advancing a sustainable bioeconomy in Southeastern United States.

Aron Bell, Liam Anthony Mannion, Mark Kelly et al.

The life cycle carbon dioxide equivalent (CO2e) intensity of Power-to-Liquid (PtL) sustainable aviation fuel (SAF) scenarios in Spain are evaluated using a specific, granular, and transparent modelling approach. Post combustion CO2 capture and direct air CO2 capture are considered, in addition to grid and renewable electricity sources. The mass and energy requirements of the PtL system are determined from a mass and energy conserved reaction mechanism and a comprehensive literature review. The SAF yield is constrained by its molecular composition, formulated to meet the physical property specifications for Fischer-Tropsch synthetic paraffinic kerosene (FT-SPK) in ASTM D7566 Annex 1. The results of the life cycle assessment (LCA) show large ranges in CO2e intensity of PtL SAF scenarios, from 11 to 101 gCO2e/MJ. The electricity emission factors at which the CO2e intensity of PtL SAFs meet the 70% reduction required under the ReFuelEU Aviation legislation are 112 – 168 gCO2e/kWh for direct air capture and post combustion capture of biogenic CO2. As the average EU grid is approximately 300 gCO2e/kWh, the use of renewable electricity (onsite or power purchase agreement) is therefore essential to achieve the 70% reduction. The carbon intensity of the Madrid to Dublin commercial flight route is analysed, per revenue-passenger-kilometre (RPK), as a specific use case with actual data of Ryanair Boeing 737-800 and 737 MAX 8 aircraft. Compared to the Science Based Targets 1.5°C limit of 3.3 gCO2/RPK, it is shown that sustainable aviation is challenging using PtL SAF, with a best case of 9 gCO2/RPK.

Hussein A. Kazem, Miqdam T. Chaichan, Ali H.A. Al-Waeli et al.

Integrating the photovoltaic/thermal (PV/T) system in green hydrogen production is an improvement in sustainable energy technologies. In PV/T systems, solar energy is converted into electricity and thermal energy simultaneously using hot water or air together with electricity. This dual use saves a significant amount of energy and officially fights greenhouse gases. Different cooling techniques have been proposed in the literature for improving the overall performance of the PV/T systems; employing different types of agents including nanofluids and phase change materials. Hydrogen is the lightest and most abundant element in the universe and has later turned into a flexible energy carrier for transportation and other industrial applications. Issues, including the processes of Hydrogen manufacturing, preservation as well as some risks act as barriers. This paper provides an analysis of several recent publications on the efficiency of using PV/T technology in the process of green hydrogen production and indicates the potential for its increased efficiency as compared to conventional systems that rely on fossil fuels. Due to the effective integration of solar energy, the PV/T system can play an important role in the reduction of the levelized cost of hydrogen (LCOH) and hence play an important part in reducing the economic calculations of the decarbonized energy system.

Karl Magnus Møller

杜婉琳*, 梅桂华, 马明 et al.

海上风电经长距离高压交流海底电缆接入电网，海底电缆容升效应显著，容易引起工频过电压，同时电力电子器件和线路电容引起的谐波谐振问题也严重影响着电网电能质量，因此进行海上风电场无功配置时应充分考虑过电压和谐波谐振问题。针对上述问题，建立了海上风电场谐波模型，对海上风电场的谐波模态阻抗进行扫描，继而分析海上风电场的谐振特性；然后研究了海上风电场无功特性，计算各种发电出力水平和并网点电压下的风电场无功缺额；接着以降低综合成本为目标，以静态电压稳定裕度、最小补偿容量、谐波谐振及过电压为约束，进行海上风电场无功优化配置；最后通过Matlab/Simulink仿真验证所提方法的有效性。

Qili LIN, Chengye MEI, Zhen CHEN et al.

[Introduction] With the development of energy storage technology, technical schemes and application scenarios become more and more complex. For energy storage research, the conventional classification method based on technical route has certain limitations in some cases. [Method] A classification method of energy storage research based on object hierarchy was proposed: according to the hierarchy order of objects from micro to macro, energy storage researches were divided into material-level, device-level, system & power plant-level and power system-level. This method was applied to the quantitative analysis of 5 397 articles published in journals of energy storage research retrieved by CNKI. [Result] The results show that the number of power system-level research literatures in 2022 is obviously more than other types of literatures, and the number and cumulative citation times of power system-level research literatures in the top 200 literatures cited from 2001 to 2022 are absolutely superior. Before 2010, material-level and device-level research literatures account for a relatively high proportion. Since 2010, the proportion of system & power plant-level and power system-level research literatures has gradually increased, and the growth rate of power system-level research literatures is more obvious. The newly installed capacity of new energy storage from 2011 to 2022 is positively correlated with the number of literatures. Since the system & power plant-level research often directly focuses on actual projects, the number of such literatures is most closely related to the newly installed capacity. [Conclusion] A new way to summarize the research results of energy storage is provided, which could provide support for industrial policy formulation, industrial chain layout and other work.

Meng Tang, Shiwei Ma, Jianzheng Xu et al.

Chemical looping gasification (CLG) of biomass produces high contents of syngas, which would have inhibition effect on the gasification of its biomass char. Experiments using a rice husk char as fuel and a low-cost red mud as oxygen carrier for CLG investigation were performed, and effects of temperature, concentrations of steam and H2 on gasification rate were evaluated. Meanwhile, the mathematical models coupling with reaction and diffusion were established focusing on the H2 inhibition on syngas distributions inside and surrounding a single char particle. The results indicated that H2 in the reaction atmosphere has an inhibition effect on its char conversion, and at a high temperature the inhibition effect tends to be stronger. The shrinking core model (spherical symmetry) was found to be suitable to describe the char conversion under the present conditions with the reaction kinetic parameters of E = 128.8 kJ mol−1 and A = 451.2 s−1. In the internal diffusion of a single char particle, the concentrations of CO and H2 both decrease with the increase of dimensionless radius due to the consumption of carbon. In the external diffusion of the char particle, the concentrations of CO and H2 decrease with the increase of the dimensionless radius. The accumulation of H2 inside the char particle prevents CO production, thus inhibiting char gasification.

Shruthi Dasappa, Joaquin Camacho

The work examines the unique nanostructure of carbon nanoparticles deposited from sooting premixed flames with flame temperatures exceeding 2200 K. This flame temperature regime has previously been shown to transition from typical soot formation conditions to a regime whereby the flame-form carbon adopts a nanostructure considerably more ordered than soot. Graphenic carbon deposits observed by High-resolution TEM (HRTEM) are reported here corroborating previous Raman spectroscopy evidence. The use of premixed stretch-stabilized flames enables particle production in the high-temperature regime under a flow field amenable to low-dimensional flame modeling. Although the flame flow configuration is relatively simple, three sample preparation methods are used to assess the representation of true carbon properties as they exist in the flame. HRTEM imaging is carried out on carbon particle samples prepared by rapid-insertion deposition, aerosol dilution probe deposition and carbon particle film deposition. Images from rapid-insertion samples show amorphous particles in the lightly sooting flame and turbostratic particles in the heavy sooting flame. There is trace evidence of graphenic structure in rapid-insertion samples but the most striking particles on the TEM grid are graphite nanocrystals presumably formed by a new artificial crystallization process. HRTEM images of particles collected over time by diluted aerosol deposition and film deposition show clear graphenic structures. Overall, the carbon nanostructure observed by HRTEM is a mixture of amorphous, turbostratic and graphenic carbon lattices depending on the flame condition and sampling method. The current work highlights potential impacts of higher flame temperatures and higher equivalence ratio on deposited flame-formed carbon. Namely, graphenic particle structure is observed in rapid-insertion deposition samples but graphene portions are most abundant in aerosol dilution and carbon particle film deposition samples. This may indicate that graphene structures grow on the deposition surface over time.

Yang Yu, Jiali Li, Dongyang Chen

Effective source–load prediction and reasonable dispatching are crucial to realize the economic and reliable operations of integrated energy systems (IESs). They can overcome the challenges introduced by the uncertainties of new energies and various types of loads in the IES. Accordingly, a robust optimal dispatching method for the IES based on a robust economic model predictive control (REMPC) strategy considering source–load power interval prediction is proposed. First, an operation model of the IES is established, and an interval prediction model based on the bidirectional long short-term memory network optimized by beetle antenna search and bootstrap is formulated and applied to predict the photovoltaic power and the cooling, heating, and electrical loads. Then, an optimal dispatching scheme based on REMPC is devised for the IES. The source–load interval prediction results are used to improve the robustness of the REPMC and reduce the influence of source–load uncertainties on dispatching. An actual IES case is selected to conduct simulations; the results show that compared with other prediction techniques, the proposed method has higher prediction interval coverage probability and prediction interval normalized averaged width. Moreover, the operational cost of the IES is decreased by the REMPC strategy. With the devised dispatching scheme, the ability of the IES to handle the dispatching risk caused by prediction errors is enhanced. Improved dispatching robustness and operational economy are also achieved.

Yanhui Xu, Tianchu Gao

The equivalent simplification of large wind farms is essential for evaluating the safety of power systems. However, sub-synchronous oscillations can significantly affect the stability of power systems. Although detailed mathematical models of wind farms can help accurately analyze the oscillation mechanism, the solution process is complicated and may lead to problems such as the “dimensional disaster.” Therefore, this paper proposes a sub-synchronous frequency domain- equivalent modeling method for wind farms based on the nature of the equivalent resistance of the rotor, in order to analyze sub-synchronous oscillations accurately. To this end, Matlab/Simulink is used to simulate a detailed model, a single-unit model, and an equivalent model, considering a wind farm as an example. A simulation analysis is then performed under the sub-synchronous frequency to prove that the model is effective and that the wind farm equivalence model method is valid.

Jingwen Wu, I. Daniel Posen, Heather L. MacLean

Mahesh Bashyal, Michael J. Mulvaney, Dewey Lee et al.

Abstract Brassica carinata (carinata), a non‐food oilseed feedstock mainly used for biofuel, is a relatively new alternative winter crop in the southeastern (SE) United States (US). However, there are limited N rate and N application timing data available at the regional scale. These data are needed to expand production in the SE US. An N rate study was conducted during the winter–spring growing seasons during 2017–2018 and 2018–2019 in Florida, US, and at three locations during 2018–2019 in Georgia, US, to quantify the effects of N rate (0, 45, 90, 134, and 179 kg N ha−1) on carinata nutrient uptake, biomass, seed yield, and seed chemical composition. Seed yield showed a linear response up to 134 kg N ha−1. Seed protein and glucosinolate concentrations decreased from 0 to 90 kg N ha−1, then increased from 90 to 179 kg N ha−1. Seed oil concentration was inversely related to seed protein concentration. A two‐factor N application timing study (4 N application timing: at‐plant, pre‐bolting, at‐plant + pre‐bolting, at‐plant + pre‐bolting + bolting × 4 N rates: 0, 45, 90, and 134 kg N ha−1) was conducted in Georgia, US, over three site‐years to quantify the effect of N application timing on yield and agronomic and economic optimum N rates (AONR and EONR, respectively). All split applications increased AONR by at least 10 kg N ha−1 compared to a single at‐plant application. A two‐split N application was more profitable than either a single N application or a three‐split N application based on marginal return. A two‐way split application (at‐plant + pre‐bolting) at 134 kg N ha−1 is recommended to optimize yield and economical production. Based on uncertainty analyses, the 50% credible interval of EONR occurred between 116 and 152 kg N ha−1, with a median estimate at 130 kg N ha−1.

Maame Esi Eshun, Joe Amoako-Tuffour

An amendment to this paper has been published and can be accessed via the original article.

王尼娜, 陆艳艳, 刘树洁 et al.

准确评估风电场发电量水平对项目开发至关重要。针对海岸线附近的近海风电场，结合已建项目的测风塔数据和风电机组运行资料，得出WAsP计算模型主要参数取值。近海地区的风资源及发电量呈现一定的衰减规律，通过不同粗糙度和尾流衰减系数的设置，验证各方案模型电量与实际电量的拟合水平。结果表明，风电场的粗糙度取值要结合地形地貌、海洋水文条件等因素，海岸线附近近海风电场的粗糙度取值略高于软件推荐值，粗糙度水平为0～0.005 m；Park模型尾流衰减系数越小，发电量越小，不同的尾流衰减系数对发电量计算结果影响高达4.9%，采用0.04更接近实测值。

Oussama Moussa, Rachid Abdessemed, Said Benaggoune et al.

Brushless doubly fed induction generators (BDFIG) show commercial promise for wind-power generation due to their lower capital and operational costs and higher reliability as compared with doubly fed induction generators. This paper proposes a robust sliding mode control of grid-connected brushless doubly fed induction generator (BDFIG). The developed algorithm is based on the decoupling control by using oriented grid flux vector control strategy. The decoupling of the active and the reactive stator powers insures an optimal performance of the BDFIG at the sub-synchronous region. The stator of this machine incorporates two sets of three phase windings with different number of poles, power winding (PW) and control winding (CW). The proposed method is tested with the Matlab/Simulink software. Simulation results illustrate the performances and the feasibility of the designed control.

Luo Erhui, Hu Yongle, Wang Jianjun et al.

The CO2 displacement is one of the gasflooding Enhanced Oil Recovery (EOR) methods. The application from volatile oil to black oil is popular mainly because CO2 requires a relatively low miscibility pressure, which is suitable to most reservoir conditions. However, CO2 always contains some impurity, such as CH4, H2S and N2, leading to the change of phase behavior and flooding efficiency. Whether the gasflooding achieves successfully miscible displacement depends on the reservoir pressure and temperature, injected solvent and crude oil compositions. So three different types of oil samples from the real field are selected and mixtures of CH4, H2S and N2 with various CO2 concentrations as the solvent are considered. After a series of experimental data are excellently matched, three nine-pseudocomponent models are generated based on the thermodynamic Equation-of-State (EoS), which are capable of accurately predicting the complicated phase behavior. Three common tools of pressure–temperature (P–T), pressure–composition (P–X) and pseudoternary diagrams are used to display and analyze the alteration of phase behavior and types of displacement mechanism. Simulation results show that H2S is favorable to attain miscibility while CH4 and N2 are adverse, and the former can reduce the Multiple Contact Miscibility (MCM) pressure by the maximum level of 1.675 MPa per 0.1 mol. In addition, the phase envelope of the mixtures CO2/H2S displacing the reservoir oil on the pseudoternary diagram behaves a triangle shape, indicating the condensing-dominated process. While most phase envelopes of CO2/CH4 and CO2/N2 exhibit the trump and bell shapes, revealing the MCM of vaporization.

YIN Jiamin, WANG Lu, XIA Wenbo et al.

[Introduction] To supply energy for industrial users in an economical and efficient way, an energy supply unit model in distributed energy system (DES) is established based on coupling characteristics of electric and thermal loads, and optimal operation strategy is proposed. [Method] Taking an industrial park in Guangzhou as the research object, combined with the actual load data, the optimum parameters were reasonably determined, annual power generation, gas consumption and energy efficiency were calculated, and the impact of load increment was studied. [Result] The results show that the start-up thermal load of unit has a great influence on the annual power generation of DES. With the optimized operation strategy, the annual power generation can be increased by 18.7%, and the self-power supply ratio of the park can be increased. The energy efficiency is more than 85%. [Conclusion] The optimal operation strategy is correct and effective. It can be applied to the optimization of thermo-electric coupled DES, effectively enhance the energy supply of DES with high energy efficiency.

Boyer C., Gazarian J., Lecocq V. et al.

The process development by IFP Energies nouvelles (IFPEN)/ENI/Axens of a Fischer-Tropsch process is described. This development is based on upstream process studies to choose the process scheme, reactor technology and operating conditions, and downstream to summarize all development work in a process guide. A large amount of work was devoted to the catalyst performances on one hand and the scale-up of the slurry bubble reactor with dedicated complementary tools on the other hand. Finally, an original approach was implemented to validate both the process and catalyst on an industrial scale by combining a 20 bpd unit in ENI’s Sannazzaro refinery, with cold mock-ups equivalent to 20 and 1 000 bpd at IFPEN and a special “Large Validation Tool” (LVT) which reproduces the combined effect of chemical reaction condition stress and mechanical stress equivalent to a 15 000 bpd industrial unit. Dedicated analytical techniques and a dedicated model were developed to simulate the whole process (reactor and separation train), integrating a high level of complexity and phenomena coupling to scale-up the process in a robust reliable base on an industrial scale.

Roholla Mahdavi

With regard to the ever-increasing need for energy in current societies to satisfy various requirements, scientists and researchers from different countries, such as Iran, have a basic approach in their agenda to achieve renewable energies، The scientists believe that with regard to the limited fossil fuels and their environmental pollutions, renewable and clean energies can be the first alternative to generate energy، Our country, Iran, has numerous capabilities in the field of generating new and renewable energies، This fact emphasizes the need for an optimum model to develop the use of renewable energies، In line with this objective the costfunction is chosenas the objective function، Given the potential and limits ofrenewable energy (resources Limited), Consumptionof electricpowerin each of16regions (apply Limited) confidencelimits  of renewable energy (technical limitations), the model was designed and with use Robust optimization model was solved in LINGO software،The optimum of using renewable energies suggests the 36،71% generation of small hydropower energy, 18،22% wind energy, 17،19% biomass energy, 13،43% geothermal energy, 12،53% tidal energy, and 1% solar energy. 2- Ciaschini, M et al (2011), “The Effects of Environmental Taxation Through a Dynamic CGE Model, Environmental Federalism: The Political Economy of the Design of Local Taxation and Environmental Protection”, Ancona, Italy, December 9-10, 2011   3- Devarajan, S. (1988), “Lecture Notes on Computable General Equilibrium Models”, John F. Kennedy School of Government, Harvard University, Mimeo, Processed. 4- Hosoe.N and et al (2010), “Textbook of Computable General Equilibrium Modelling: Programming and Simulations, Printed and bound in Great Britain by CPI Antony Rowe”, Chippenham and Eastbourne. 5- IEA (2012), World Energy Outlook. 6- Kulmer Y (2011), “Directed Technological Change in a Bottom-Up/Top-Down CGE model: Analysis of Passenger Transport, "Wegener Center for Climate and Global Change”, University of Graz, Austria. 7- Lofgren.H and et.al (2002), “A Standard Computable General Equilibrium (CGE) Model in GAMs”, International Food Policy Research Institute. 8- Orlov. A, Grethe. H and McDonald S, (2011), “Energy Policy and Carbon Emission in Russia: A Short Run CGE Analysis”, Presented at the 14th Annual Conference on Global Economic Analysis”, Venice, Italy.Solaymani. 9- S and Kari. F (2014), “Impacts of Energy Subsidy Reform on the Malaysian Economy and Transportation Sector”, Energy Policy, pp. 115-125. 10- Zhengning Pu and Hayashiyama Y (2012), Energy Resource Tax Effects on China’s Regional Economy by SCGE Model, Environmental Economics, vol. 3, issue 1, pp. 41-52.       bidi13- Stern,  J. (2007), “Gas-OPEC: A Distraction from Important Issues of Russian Gas Supply to Europe”. Oxford Energy Comment.   14- J.F. Nash Jr. (1950), “The Bargaining Problem”, Econometrica, 15(2):155_162. 17- Avrachenkov, K., Elias, J.,  Martignon, F., Neglia, G. and L. Petrosyan (2011), “A Nash bargaining solution for Cooperative Network Formation Games”, Networking 2011, pages 307–318, 2011 16- Shapley ,L. (1953),  “A Value for n-person Games”, In H. Kuhn and A. Tucker, editors, Contribution to the Theory of Games II, page 307. Princeton University Press. 17-  Shapley, L., and Shubik, M. (1969), “On Market Games”, Journal of Economic Theory, 1, 9-25. 19- Maskin, Erik (2003), “Coalitional Bargaining with Externalities, Keynote Lecture for the European Economic Association Conference 2003, Stockholm. 20-OME. “Future Natural Gas Supply Options and Supply Costs for Europe”, Report to Madrid Forum, Observatoire M´editerran´een de l’ Energie, 2004 21- Egging, R. and Gabriel, S. A.(2006), “Examining Market Power in the European Natural Gas Market”, Energy Policy, 34:2762–2778.

Bagheri M.B., Kharrat R., Ghotby C.

This paper presents the results of asphaltene precipitation and deposition during lean gas injection, CO2 injection and natural depletion in reservoir conditions. In addition, the effect of variations in operating pressure, injection gas concentration and production rate on asphaltene precipitation and deposition were investigated. The severity of asphaltene deposition was found to be more pronounced in lean gas injection in comparison with CO2 injection and natural depletion. Increasing the flow rate in natural depletion experiments showed a considerable increase in asphaltene deposition, and consequently permeability reduction in the core matrix. Moreover, more asphaltene deposition was observed along the porous media in the gas injection experiments when the gas mol percent of the mixture was increased. <br> Cet article présente les résultats d’une étude de la précipitation et du dépôt d’asphaltènes qui peuvent se produire lors d’une injection de gaz pauvre, d’une injection de CO2 ou d’une déplétion naturelle en conditions de réservoir. En outre, les effets de la pression de fonctionnement, de la concentration en gaz injecté et du débit de production sur la précipitation et le dépôt d’asphaltènes ont été étudiés. Il a été constaté que l’importance du dépôt d’asphaltènes est plus prononcée dans le cas d’une injection de gaz pauvre comparativement à une injection de CO2 ou à une déplétion naturelle. Une augmentation du débit au cours d’expériences de déplétion naturelle a montré un accroissement considérable du dépôt d’asphaltènes et, en conséquence, une réduction de perméabilité au sein de la matrice poreuse. Par ailleurs, un dépôt d’asphaltènes plus important a été observé au cours des expériences d’injection de gaz lorsque la concentration molaire gazeuse dans le mélange était augmentée.