By increasing the penetration of renewable resources in power systems, which are mostly inverter-based, voltage and frequency control has faced many challenges. Unlike the synchronous generators in large power systems, these sources have no resistance against load changes due to their low inertia, therefore, controlling the voltage and frequency of inverter-based microgrids requires new approaches. In this article, by taking feedback from the output voltage and current of the inverter and using the Proportional Integral controller, the desired control signal to be applied to the inverter is obtained in a way that initially creates a phase and voltage difference between the DGs in the microgrid, the power flow is established in a way that without the need for any communication link, the balance of energy production and consumption is established in an island mode, and at the end, the voltage and frequency of Distributed Generations are restored to their nominal values. The presented control logic is also implemented in Simulink MATLAB software and its results are measured and evaluated.
Energy industries. Energy policy. Fuel trade, Renewable energy sources
In the pursuit of Net Zero, the rapid adoption of electric vehicles, heat pumps, and distributed generation is placing unprecedented pressure on low-voltage electrical distribution networks. Can these networks adapt and evolve without facing gridlock? Our study proposes an innovative peer-to-peer coordinated flexibility strategy that has the potential to significantly transform the landscape. By aggregating individual flexibility through peer-to-peer coordination, this approach enhances local power balance, mitigates gridlock, and safeguards individual benefits. Through a novel large-scale network analysis method based on statistically similar networks, we have quantified the maximal potential of peer-to-peer coordinated flexibility in alleviating gridlock and deferring network expansion. Using real-world UK low-voltage electrical distribution network data and authoritative distributed energy resources roadmaps, our findings reveal that peer-to-peer coordinated flexibility can reduce peak power flows by up to 20 % and enable as much as 91 % of UK residential low-voltage electrical distribution networks to meet peak demand without gridlock by 2050, significantly reducing the need for network expansion. Furthermore, with the adoption of peer-to-peer coordinated flexibility, the network's peak is projected to occur between 2045–2050, postponing it by 8–10 years compared to scenarios without it. These results underscore the critical role of peer-to-peer coordinated flexibility and serve as a benchmark for the co-development of future grids and flexible resources when addressing associated implementation challenges such as technological infrastructure and consumer engagement.
China's iron and steel industry, significant for national economic development, is notable for high energy consumption and carbon emissions. To balance industry growth with carbon neutrality goals, it is crucial to analyze emissions throughout production processes. This study begins with an industry overview, followed by an analysis of the ‘Energy-Material-Carbon Nexus’ (EMC Nexus) in steel production. Referencing the National Key Low-Carbon Technology Promotion Catalogue and considering hydrogen replacement and process substitution technologies, 52 potential energy-saving and emission-reduction technologies are identified. By integrating these technologies with production steps, a comprehensive carbon reduction model is established under the framework of the energy-process chain, providing standardized methods for calculating abatement potential and abatement costs. Subsequently, employing the Analytic Hierarchy Process (AHP), the feasibility of each technology is ranked based on five dimensions: policy support, technological complexity, abatement cost, abatement potential and payback period. Finally, based on the Marginal Abatement Cost Function, this study proposes a method for fitting the cost curve of carbon abatement. To analyze the medium and long-term trends in carbon reduction potential and comprehensive ranking of energy-saving and emission-reduction technologies in China's steel production, empirical analysis is conducted for four target years: 2030, 2040, 2050, and 2060. The results demonstrate significant abatement potential in China's iron and steel industry. Taking the target year 2030 as an example, the average unit abatement cost is 287.29 ¥/ton, with an annual abatement potential of 3.755 million ton, accounting for 18.1 % of the industry's total emissions. Using the proposed multi-dimensional approach for comprehensive evaluation of energy-saving and emission-reduction technologies, comparative analysis of ranking results across different target years confirms the substantial carbon abatement potential of Scrap-based electric arc furnace steelmaking technology and two hydrogen-based technologies in the medium and long-term. Furthermore, the fitted relationship between total abatement costs and abatement volumes under different target years for China's iron and steel industry provides mathematical tools for macro policy-making and industry-level carbon simulation. While the proposed research methodology demonstrates general applicability, some conclusions are dependent on scenario parameter settings and questionnaire implementation in the empirical analysis. This study aims to provide valuable insights for the design and implementation of decarbonization processes in China's iron and steel industry.
The strong coupling $α_s$ is extracted with high precision through fits to lattice-QCD data for the static energy. Our theoretical framework is based on R-improving the three-loop fixed-order prediction for the static energy: we remove the $u=1/2$ renormalon and resum the associated large infrared logarithms. Combined with radius-dependent renormalization scales (the so-called profile functions), this procedure extends the range of validity of perturbation theory to distances as large as $\sim 0.5\,$fm. In addition, we resum large ultrasoft logarithms to N$^3$LL accuracy using renormalization-group evolution. Since the standard four-loop R-evolution treats N$^4$LL and higher-order contributions asymmetrically, we also incorporate this potential source of bias in our analysis. Our estimate of the perturbative uncertainty is obtained through a random scan over the parameters controlling the profile functions and the implementation of R-evolution. We analyze how the extracted value of $α_s$ depends on the shortest and longest distances included in the fit, on the details of the R-evolution procedure, on the fitting strategy itself, and on the accuracy of ultrasoft resummation. From our final analysis, and after evolution to the $Z$ pole, we obtain $α^{(n_f=5)}_s(m_Z)=0.1170\pm 0.0009$, a result fully compatible with the world average and with a comparable uncertainty.
Due to the high photosensitivity, quantum dots (QDs) offer promise in establishing heterojunctions to improve the photoelectrochemical (PEC) water oxidation process and enhance the solar-to-hydrogen conversion efficiency. However, apart from their catalytic capacity, additional protection strategies should be considered to eliminate the destruction of QDs from electrolytes and photo-corrosion. Here, we present a facile strategy to fabricate heterojunction by employing graphitic carbon nitride QDs (g-C3N4 QDs) coupled with BiVO4, referred to CNQDs/BiVO4. With the help of CNQDs, a gradient energy band alignment has been established in CNQDs/BiVO4, leading to facilitated hole migration driven by an upward force. The optimal CNQDs/BiVO4 sample shows significantly enhanced PEC performance for water oxidation, with a photocurrent of 2.2 mA/cm2 at 1.23 V vs. RHE (reversible hydrogen electrode), which is about 2.26 times better than that of BiVO4 (0.97 mA/cm2). The enhanced PEC performance could be attributed to the increased surface-active area and facilitated surface oxidation kinetics.
Energy industries. Energy policy. Fuel trade, Renewable energy sources
Abstract The trend of global energy systems towards carbon neutrality has led to an escalating interdependency between electricity, hydrogen fuel, and transportation networks. However, the means of surmounting the many challenges confronting the optimal coupling and coordination of electric power, hydrogen fuel, and transportation systems are not sufficiently understood to guide modern infrastructure planning operations. The present work addresses this issue by surveying the extant literature, relevant government policies, and future development trends to evaluate the present state of technology available for coordinating these systems and then determine the most pressing issues that remain to be addressed to facilitate future trends. On the one hand, the users of transportation networks represent flexible consumers of electric power and hydrogen fuel for those connected via devices such as electric vehicles and hydrogen fuel cell vehicles through charging stations and hydrogen refuelling stations. On the other hand, power grids can mitigate the negative effect of random charging behaviours on grid security through time‐of‐use electricity pricing, while excess renewable energy outputs can be applied to generate hydrogen fuel. The findings of this overview offer support for infrastructure planning and operations. Finally, the most urgent issues requiring further research are summarised.
Production of electric energy or power. Powerplants. Central stations, Energy industries. Energy policy. Fuel trade
This article aims to quantify the impact of different energy consumption sources on greenhouse gas (GHG) emissions for three major economies: the United States of America (USA), China, and the European Union (EU). To achieve this, energy consumption and GHG emissions data were obtained from “Our World in Data” for the period 1965–2021. Then, two machine learning techniques were utilized. Gradient Boosting (GB) was used to identify the major energy consumption sources contributing to GHG. While Artificial Neural Network (ANN) was used to quantify the effects of these major energy consumption sources on GHG emissions. The findings have significant implications for policymakers, as they suggest that effective strategies to reduce GHG emissions must be tailored based on the energy utilization sources of each country. Specifically, for the USA it was found that reducing coal consumption could be the most effective strategy to reduce GHG emissions, as increasing coal consumption by 25% would result in a 13% increase in GHG emissions. In contrast, increasing nuclear consumption by 25% in China would result in an 11% decrease in GHG emissions due to the displacement of fossil fuel-based energy sources. Increasing wind energy consumption by 25% in China would result in a 3% decrease in GHG emissions. In the EU, the study found that increasing oil consumption has a minor effect on GHG emissions while increasing coal consumption by 25% would result in an 11% increase in GHG emissions, highlighting the importance of reducing coal consumption. This study's originality lies in the use of machine learning techniques to identify the key energy consumption sources driving GHG emissions in the three major economies, as well as its specific recommendations for reducing emissions.
Abir Hmida, Abdelghafour Lamrani, Mamdouh El Haj Assad
et al.
Around the globe, a 60 % increase in energy demand is predicted to occur by the end of the year 2030 due to the ever-increasing population and development. With a registered temperature up to 50 °C in August 2020, which is classified as one of the hottest regions in the world, the demand for cool temperatures in Gabes-Tunisia to achieve the thermal comfort of people ensuring the product storage has become more and more intense. Removing heat from buildings represents the most extensive energy consumption process. In this paper, an absorption-refrigeration system driven by solar energy is proposed. A parametric simulation model is developed based on the TRNSYS platform. A comparison between different models for global radiation calculation and experimental meteorological data was carried out. It has been proven that the Brinchambaut model seems to be the most convenient in describing the real global radiation, with an error of up to 3.16 %. An area of 22 m² of evacuated tube solar collector ensures the proper functioning of the generator and achieves a temperature up to 2 °C in the cold room.
Jarvin Mestra-Páez, Álvaro Restuccia, Francisco Tello-Ortiz
We analyze the dispersion relation for an anisotropic gravity-electromagnetic theory at very high energies. In particular for photons of very high energy. We start by introducing the anisotropic gravity-gauge vector field model. It is invariant under spacelike diffeomorphisms, time parametrization, and U(1) gauge transformations. It includes high-order spacelike derivatives as well as polynomial expressions of the Riemann and field strength tensor fields. It is based on the Hořava-Lifshitz anisotropic proposal. We show its consistency, and the stability of the Minkowski ground state. Finally, we determine the exact zone at which the physical degrees of freedom, i.e. the transverse-traceless tensorial degrees of freedom and the transverse vectorial degrees of freedom propagate according to a linear wave equation. This is so, in spite of the fact that there exists in the zone a non-trivial Newtonian background of the same order. The wave equation contains spatial derivatives up to the sixth order, in the lowest order it exactly matches the relativistic wave equation. We then analyze the dispersion relation at very high energies in the context of recent experimental data. The qualitative predictions of the proposed model, concerning the propagation of highly energetic photons, are different from the ones obtained from the modified dispersion relation of the LIV models.
Paul Schwarzmayr, Felix Birkelbach, Heimo Walter
et al.
The waste heat potential from industrial processes is huge and if it can be utilized it may contribute significantly to the mitigation of climate change. A packed bed thermal energy storage system is a low-cost storage technology that can be employed to enable the utilization of waste heat from industrial processes. This system can be used to store excess heat and release this energy when it is needed at a later time. To ensure the efficient operation of a packed bed thermal energy storage its characteristics in standby mode need to be studied in great detail. In the present study, the standby efficiency and thermocline degradation of a lab-scale packed bed thermal energy storage in standby mode is experimentally investigated for different flow directions of the heat transfer fluid during the preceding charging period. Results show that, for long standby periods, the standby efficiency is significantly affected by the flow direction. The maximum entropy generation rate for a 22-hour standby process with the flow direction of the heat transfer fluid from bottom to top in the preceding charging process is twice as high as for the same process with the reverse flow direction. Energy and exergy efficiencies are lower for the process with reverse flow direction by 5% and 18% respectively.
Saudi Arabia sets an ambitious plan to install 58.7 GW renewable capacity along with several mitigation measures. For the smooth accomplishment of undertaken projects, the role of the financial market is crucial. This paper investigates the role of financial development in explaining the low carbon economy (LCE), incorporating the role of innovation in the context of Saudi Arabia, where fossil fuel contributes almost 100% share of the total energy mix. We apply the standard, asymmetric, and quantile Autoregressive Distributed Lag (ARDL) Approaches to analyse our time-series data from 1981 to 2016 (both yearly and monthly forms). Our empirical analysis demonstrates that finance asymmetrically fosters the carbon economy, but it helps to achieve a low carbon economy through the channel of innovation under different economic circumstances. Our empirical evidence reinforces the role of the financial market in overcoming the financial constraints for launching green projects.
[Introduction] The steam parameters of sodium-cooled fast reactor is different from PWR nuclear power or conventional fossil-fuel power plant, so it's necessary to restudy the drain system. [Method] Specific to PWR nuclear power plant or conventional fossil-fuel power plant, the steam drain system was collated and discussed from aspects such as the components and control logic. [Result] Then an optimized system is developed for fast reactor power unit based on the above analysis result and the characteristics of the steam system. [Conclusion] The result shows that the optimized drain system can meet with the requirement of fast reactor power unit, and it also can be a reference for construction of future reactor units.
Secure and reliable operation of power systems with high wind and solar shares requires system flexibility. In this paper, an hourly-based market and grid simulation model is developed to assess security and reliability of a power system with high wind and solar energy share. The model is applied to Turkey as an emerging G20 country that aims to supply its rapidly growing electricity demand from local renewables and lignite as well as nuclear energy. The most ambitious scenario that covers the 2016–2026 period assumes half of all electricity demand is supplied from renewables (30% wind and solar and 20% other resources). This is achieved by ensuring system flexibility through system-friendly location of wind and solar capacity, energy storage, flexible thermal generators, and demand response. Without system flexibility, 3% of renewable power is curtailed and redispatch share required for system security and reliability doubles from current levels. Moreover, additional transmission grid investments are needed. Improving system flexibility ensures secure and reliable operation but increases system costs by 1%–5% with each flexibility option providing different scale benefits, indicating the need for system-wide planning. As gas-based generation declines below 10%, accounting for energy security benefits will be important. On the other hand, coal supply remains around 25% depending on nuclear energy development. At this crossroad, Turkey needs to make its choices to transition to a secure, clean and affordable energy system. The study addresses quantitatively how the flexibility options contribute to such a transition, providing learnings for countries with similar conditions.
Brian D. Titus, Kevin Brown, Heljä-Sisko Helmisaari
et al.
Abstract Forest biomass harvesting guidelines help ensure the ecological sustainability of forest residue harvesting for bioenergy and bioproducts, and hence contribute to social license for a growing bioeconomy. Guidelines, typically voluntary, provide a means to achieve outcomes often required by legislation, and must address needs related to local or regional context, jurisdictional compatibility with regulations, issues of temporal and spatial scale, and incorporation of appropriate scientific information. Given this complexity, comprehensive reviews of existing guidelines can aid in development of new guidelines or revision of existing ones. We reviewed 32 guidelines covering 43 jurisdictions in the USA, Canada, Europe and East Asia to expand upon information evaluated and recommendations provided in previous guideline reviews, and compiled a searchable spreadsheet of direct quotations from documents as a foundation for our review. Guidelines were considered in the context of sustainable forest management (SFM), focusing on guideline scope and objectives, environmental sustainability concerns (soils, site productivity, biodiversity, water and carbon) and social concerns (visual aesthetics, recreation, and preservation of cultural, historical and archaeological sites). We discuss the role of guidelines within the context of other governance mechanisms such as SFM policies, trade regulations and non-state market-driven (NSMD) standards, including certification systems. The review provides a comprehensive resource for those developing guidelines, or defining sustainability standards for market access or compliance with public regulations, and/or concerned about the sustainability of forest biomass harvesting. We recommend that those developing or updating guidelines consider (i) the importance of well-defined and understood terminology, consistent where possible with guidelines in other jurisdictions or regions; (ii) guidance based on locally relevant research, and periodically updated to incorporate current knowledge and operational experience; (iii) use of indicators of sensitive soils, sites, and stands which are relevant to ecological processes and can be applied operationally; and (iv) incorporation of climate impacts, long-term soil carbon storage, and general carbon balance considerations when defining sustainable forest biomass availability. Successful implementation of guidelines depends both on the relevance of the information and on the process used to develop and communicate it; hence, appropriate stakeholders should be involved early in guideline development.
Renewable energy sources, Energy industries. Energy policy. Fuel trade
This paper presents a multi-objective mathematical model to perform power restoration. It considers simultaneously the objective functions: restoration time, load shedding, and cost. New formulations are developed to improve the maneuverability of the system elements. This distinguishes the novel proposal from the rest of the one or two objective approaches. The linear nature of the formulation allows for obtaining feasible solutions within efficient times. The proposal includes in the main objective function the social view in terms of prioritize the restitution of the system for as many users as possible. It enables using this proposal to restore large scale systems. Results indicate that more equitable and faster restoration solutions can be obtained than the reported one in the mentioned case.
The differential cross-section in squared momentum transfer of $ρ$, $ρ^0$, $ω$, $φ$, $f_{0}(980)$, $f_{1}(1285)$, $f_{0}(1370)$, $f_{1}(1420)$, $f_{0}(1500)$, and $J/ψ$ produced in high energy virtual photon-proton ($γ$$^{*} p$), photon-proton ($γp$), and proton-proton ($pp$) collisions measured by the H1, ZEUS, and WA102 Collaborations are analyzed by the Monte Carlo calculations. In the calculations, the Erlang distribution, Tsallis distribution, and Hagedorn function are separately used to describe the transverse momentum spectra of the emitted particles. Our results show that the initial- and final-state temperatures increase from lower squared photon virtuality to higher one, and decrease with increasing of center-of-mass energy.
This work presents the design and implementation of a blockchain system that enables the trustable transactive energy management for distributed energy resources (DERs). We model the interactions among DERs, including energy trading and flexible appliance scheduling, as a cost minimization problem. Considering the dispersed nature and diverse ownership of DERs, we develop a distributed algorithm to solve the optimization problem using the alternating direction method of multipliers (ADMM) method. Furthermore, we develop a blockchain system, on which we implement the proposed algorithm with the smart contract, to guarantee the transparency and correctness of the energy management. We prototype the blockchain in a small-scale test network and evaluate it through experiments using real-world data. The experimental results validate the feasibility and effectiveness of our design.
A number of popular extensions of the Standard Model of particle physics predict the existence of doubly charged scalar particles $X^{\pm\pm}$. Such particles may be long-lived or even stable. If exist, $X^{--}$ could form atomic bound states with light nuclei and catalyze their fusion by essentially eliminating the Coulomb barrier between them. Such an $X$-catalyzed fusion ($X$CF) process does not require high temperatures or pressure and may have important applications for energy production. A similar process of muon-catalyzed fusion ($μ$CF) has been shown not to be a viable source of energy because of the sticking of negative muons to helium nuclei produced in the fusion of hydrogen isotopes, which stops the catalytic process. We analyze $X$CF in deuterium environments and show that the $X$-particles can only stick to $^6$Li nuclei, which are produced in the third-stage reactions downstream in the catalytic cycle. The corresponding sticking probability is very low, and, before getting bound to $^6$Li, each $X$-particle can catalyze $\sim 3.5\cdot 10^{9}$ fusion cycles, producing $\sim 7\cdot 10^{4}$ TeV of energy. We also discuss the ways of reactivating the $X$-particles from the Coulomb-bound (${\rm ^6Li}X$) states, which would allow re-using them in $X$CF reactions.
Various methods including photocatalysis have been used for degradation and removal of phenolic compounds, which classified as hazardous materials in the environment. Nanomaterials exhibited significant advantages for photocatalytic degradation of phenolic compounds compared to the conventional oxidation approaches such as traditional biological and physical methods. In this study, zirconia (ZrO2)/graphitic carbon nitride (g-C3N4) nanocomposites were successfully synthesized using ultrasonication method and used for photodegradation of 4-chlorophenol (4-CP) in water under visible light. The g-C3N4 nanosheets, ZrO2 nanoparticles (NPs), and ZrO2/g-C3N4 nanocomposite were characterized by N2 adsorption, X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), photoelectrochemical (PEC) measurements, and photoluminescence spectroscopy (PL). The incorporation of ZrO2 NPs enhanced the surface area and light absorption capacity of pristine g-C3N4. The photocatalytic activity of ZrO2/g-C3N4 nanocomposite sample was evaluated by the degradation of 4-CP in aqueous medium. Results exhibited an increase in photocatalytic activity of ZrO2/g-C3N4 nanocomposite compared to unmodified ZrO2 NPs and pristine g-C3N4. In addition, reusability experiment of ZrO2/g-C3N4 nanocomposite for photo-catalytic degradation, as well as for 4-CP adsorption showed the ZrO2/g-C3N4 nanocomposites can be effectively used for several cycles.
River, lake, and water-supply engineering (General), Water supply for domestic and industrial purposes