A Distributionally Robust Optimization Scheduling Model for Regional Integrated Energy Systems Considering Hot Dry Rock Co-Generation

Hot dry rock(HDR)is rich in reserve,widely distributed,green,low-carbon,and has broad development potential and prospects.In this paper,a distributionally robust optimization(DRO)scheduling model for a regionally integrated energy system(RIES)considering HDR co-generation is proposed.First,the HDR-enhanced geothermal system(HDR-EGS)is introduced into the RIES.HDR-EGS realizes the thermoelectric decoupling of combined heat and power(CHP)through coordinated operation with the regional power grid and the regional heat grid,which enhances the system wind power(WP)feed-in space.Secondly,peak-hour loads are shifted using price demand response guidance in the context of time-of-day pricing.Finally,the optimization objective is established to minimize the total cost in the RIES scheduling cycle and construct a DRO scheduling model for RIES with HDR-EGS.By simulating a real small-scale RIES,the results show that HDR-EGS can effectively promote WP consumption and reduce the operating cost of the system.

Research on the bi-layer low carbon optimization strategy of integrated energy system based on Stackelberg master slave game

With increasing reforms related to integrated energy systems(IESs),each energy subsystem,as a participant based on bounded rationality,significantly influences the optimal scheduling of the entire IES through mutual learning and imitation.A reasonable multiagent joint operation strategy can help this system meet its low-carbon objectives.This paper proposes a bilayer low-carbon optimal operational strategy for an IES based on the Stackelberg master-slave game and multiagent joint operation.The studied IES includes cogeneration,power-to-gas,and carbon capture systems.Based on the Stackelberg master-slave game theory,sellers are used as leaders in the upper layer to set the prices of electricity and heat,while energy producers,energy storage providers,and load aggregators are used as followers in the lower layer to adjust the operational strategy of the system.An IES bilayer optimization model based on the Stackelberg master-slave game was developed.Finally,the Karush-Kuhn-Tucker(KKT)condition and linear relaxation technology are used to convert the bilayer game model to a single layer.CPLEX,which is a mathematical program solver,is used to solve the equilibrium problem and the carbon emission trading cost of the system when the benefits of each subject reach maximum and to analyze the impact of different carbon emission trading prices and growth rates on the operational strategy of the system.As an experimental demonstration,we simulated an IES coupled with an IEEE 39-node electrical grid system,a six-node heat network system,and a six-node gas network system.The simulation results confirm the effectiveness and feasibility of the proposed model.

Identification of time-varying system and energy-based optimization of adaptive control in seismically excited structure

The combination of structural health monitoring and vibration control is of great importance to provide components of smart structures.While synthetic algorithms have been proposed,adaptive control that is compatible with changing conditions still needs to be used,and time-varying systems are required to be simultaneously estimated with the application of adaptive control.In this research,the identification of structural time-varying dynamic characteristics and optimized simple adaptive control are integrated.First,reduced variations of physical parameters are estimated online using the multiple forgetting factor recursive least squares(MFRLS)method.Then,the energy from the structural vibration is simultaneously specified to optimize the control force with the identified parameters to be operational.Optimization is also performed based on the probability density function of the energy under the seismic excitation at any time.Finally,the optimal control force is obtained by the simple adaptive control(SAC)algorithm and energy coefficient.A numerical example and benchmark structure are employed to investigate the efficiency of the proposed approach.The simulation results revealed the effectiveness of the integrated online identification and optimal adaptive control in systems.

Prospects for key technologies of new-type urban integrated energy system

In recent years,primary energy consumption in China’s urban areas has increased rapidly,facing the problems of extensive use of energy,high energy consumption and insufficient intensified use of energy resources.Improving multienergy supply,increasing the proportion of clean energy and integrated energy efficiency are the main goals of urban development.The integrated energy system with multi-functional synergy and open trading will become one of the new directions for the development of new urban energy systems.This paper summarizes the main problems faced by the current towns and the characteristics of the new urban energy system,analyzes the development of new urban energy system from three aspects including energy interconnection hub infrastructure construction,energy management platform construction and energy value sharing,and forecasts the future development direction of new urban energy systems.

Symplectic-energy-first integrators of discrete mechanico-electrical dynamical systems

A discrete total variation calculus with variable time steps is presented for mechanico-electrical systems where there exist non-potential and dissipative forces. By using this discrete variation calculus, the symplectic-energy-first integrators for mechanico-electrical systems are derived. To do this, the time step adaptation is employed. The discrete variational principle and the Euler-Lagrange equation are derived for the systems. By using this discrete algorithm it is shown that mechanico-electrical systems are not symplectic and their energies are not conserved unless they are Lagrange mechanico-electrical systems. A practical example is presented to illustrate these results.

A study of novel real-time power balance strategy with virtual asynchronous machine control for regional integrated electric-thermal energy systems

The development of regional integrated electric-thermal energy systems(RIETES) is considered a promising direction for modern energy supply systems. These systems provide a significant potential to enhance the comprehensive utilization and efficient management of energy resources. Therein, the real-time power balance between supply and demand has emerged as one pressing concern for system stability operation. However, current methods focus more on minute-level and hour-level power optimal scheduling methods applied in RIETES. To achieve real-time power balance, this paper proposes one virtual asynchronous machine(VAM) control using heat with large inertia and electricity with fast response speed. First, the coupling timescale model is developed that considers the dynamic response time scales of both electric and thermal energy systems. Second, a real-time power balance strategy based on VAM control can be adopted to the load power variation and enhance the dynamic frequency response. Then, an adaptive inertia control method based on temperature variation is proposed, and the unified expression is further established. In addition, the small-signal stability of the proposed control strategy is validated. Finally, the effectiveness of this control strategy is confirmed through MATLAB/Simulink and HIL(Hardware-in-the-Loop) experiments.

Enhancing Wind Power Integration through Optimal Use of Flexibility in Multi-Carrier Energy Systems from the Danish Perspective

Denmark’ goal of being independent of fossil energy sources in 2050 puts forward great demands on all energy subsystems (electricity, heat, gas and transport, etc.) to be operated in a holistic manner. The Danish experience and challenges of wind power integration and the development of district heating systems are summarized in this paper. How to optimally use the cross-sectoral flexibility by intelligent control (model predictive control-based) of the key coupling components in an integrated heat and power system including electrical heat pumps in the demand side, and thermal storage applications in buildings is investigated.

Building Integrated Photovoltaic Systems for Single Family Dwellings: Innovation Concepts

Growing consumer interest in distributed Building Integrated Photovoltaic (BIPV) Systems and industry competition to reduce installation costs are stimulating the development of deploying these materials to the residential sector of the building industry. This emerging market continues to attract the attention of many stakeholders, yet cohesive opportunities to deploy in residential sectors, specifically detached single-family dwellings, is scattered. As a result, this study of literature and implementation strategies through simple examples looks to identify several characteristics related to BIPV. Characteristics that were studied in this initial pilot study were design considerations for system selection, applicability to residential construction, and system and material options and enhancements. A case-study home was analyzed demonstrating opportunity for implementation of BIPV on an existing residence. Strategies for maximizing the energy-generating capacity of the system to achieve net-zero energy performance, including all building surfaces and landscaping were also explored. This body of work provides a state-of-the-art review on common materials as well as the more customizable types.

Optimal Multi-Timescale Scheduling of Integrated Energy Systems with Hybrid Energy Storage System Based on Lyapunov Optimization

The economic operation of integrated energy system(IES)faces new challenges such as multi-timescale characteristics of heterogeneous energy sources,and cooperative operation of hybrid energy storage system(HESS).To this end,this paper investigates the multi-timescale rolling opti-mization problem for IES integrated with HESS.Firstly,the architecture of IES with HESS is established,a comparative analysis is conducted to evaluate the advantages of the HESS over a single energy storage system(SESS)in stabilizing power fluctuations.Secondly,the dayahead and real-time scheduling cost functions of IES are established,the day-ahead scheduling mainly depends on operation costs of the components in IES,the real-time optimal scheduling adopts the Lya-punov optimization method to schedule the battery and hydrogen energy storage in each time slot,so as to minimize the real-time average scheduling operation cost,and the problem of day-ahead and real-time scheduling error,which caused by the uncertainty of the energy storage is solved by online optimization.Finally,the proposed model is verified to reduce the scheduling operation cost and the dispatching error by performing an arithmetic example analysis of the IES in Shanghai,which provides a reference for the safe and stable operation of the IES.

ENERGY SYSTEM INTEGRATION OF CHEMICAL PROCESSES

A combined approach of thermodynamic analysis and mixed-integer linear programming is presented for performing structural and parameter optimization in the integration of energy system of chemical processes. Tnermodynamic analysis is used to set up a superstructure configuration of energy system in order to reduce the space of search. The application of the combined approach is illustrated by a revamping integration of a large existing energy system in a refinery complex.

Optimizing Power Plant Thermal System Design Using "Process Energy Integration" Method

The paper presents a renovation of thermal system design of a power and heat cogeneration device by utilizing the "Process Energy Integration Method". The new alternative obtains prominent energy saving result.

Economic Feasibility Assessment of Motorized PV Louver System Considering the Near Shading Parameter, Array Incidence Losses and Other Environmental Factors

Seoul has good weather settings for incorporating renewable energies, hence, given its small land area living mode was mostly set in an apartment condition it is an ideal place for building applied photovoltaic (BAPV) for solar energy harvesting. On the other hand, the BAPV energy self-consumption hasn’t been thoroughly examined considering the overall energy consumption requirement. Therefore, presented in this communication are the viability of PVL to produce electricity from solar energy and insights on modulating and improving energy harvesting efficiency. To accomplish this objective, three major factors were considered: 1) the photovoltaic (PV) positioning;2) the solar tracking scenario;and 3) the mechanistic system energy consumption. The overall louver energy generation was thoroughly scrutinized from the net energy conception of the BAPV up to the mechanistic module energy expenditure. This work intends to provide insights into the economic feasibility of BAPV assessing its technological profitability in the specified location and building size.

Reliability Assessment for Integrated Power-gas Systems Considering Renewable Energy Uncertainty and Cascading Effects

Integrated power-gas systems(IPGSs)make the power system and natural gas system(NGS)as a whole,and strengthen interdependence between the two systems.Due to bidirectional energy conversion in IPGS,a disturbance may turn into a catastrophic outage.Meanwhile,increasing proportion of renewable energy brings challenges to reliability of IPGS.Moreover,partial failure or degradation of system performance leads IPGS operate at multiple performance levels.Therefore,this paper proposes a reliability assessment model of IPGSs which represents multiple performance of components and considers cascading effects,as well as renewable energy uncertainty.First,a framework of IPGS reliability assessment is proposed:multistate models for main elements in the IPGS are represented.Especially a gas-power-generation calculation operator and a power-to-gas calculation operator are utilized to bi-directionally convert a multi-state model between NGS and power systems.Furthermore,nodal reliability indices for IPGS are given to display impacts of cascading effects and renewable energy uncertainty on reliabilities of IPGSs.Numerical results on IPGS test system demonstrate the proposed methods.

Research on Solar Water Heating System and Architectural Integration Design—A Case Study of Anqing Children Welfare Home

Taking the planning and major architectural design projects of Anqing Children Welfare Home for example,through the research on categories and each component of solar water heating system,the paper discussed strategies and methods to realize solar energy and architectural integration design in the climate condition and location environment of Anhui Province.

Intelligent Energy Management Strategy and Sizing Methodology for Hybrid Systems in Isolated Regions

In this study,a comprehensive approach is presented for the sizing and management of hybrid renewable energy systems(HRESs)that incorporate a variety of energy sources,while emphasizing the role of artificial neural networks(ANNs)in system management.For optimal sizing of an HRES,the monthly average method wherein historical weather data are used to calculate the monthly averages of solar irradiance and wind speed,offering a well-balanced strategy for system sizing.This ensures that the HRES is appropriately scaled to meet the actual energy requirements of the specified location,avoiding the pitfalls of over-and under-sizing,and thereby enhancing the operational efficiency.Furthermore,the study details a cutting-edge strategy that employs ANNs for managing the inherent complexities of HRESs.It elaborates on the design,modeling,and control strategies for the HRES components by utilizing Matlab/Simulink for implementation.The findings demonstrate the proficiency of the ANN-based power manager in determining the operational modes guided by a specifically designed flowchart.By integrating ANN-driven energy management strategies into an HRES,the proposed approach marks a significant advancement in system adaptability,precision control,and efficiency,thereby maximizing the effective utilization of renewable resources.

Methods of reduction for Lagrange systems on time scales with nabla derivatives

The Routh and Whittaker methods of reduction for Lagrange system on time scales with nabla derivatives are studied.The equations of motion for Lagrange system on time scales are established, and their cyclic integrals and generalized energy integrals are given. The Routh functions and Whittaker functions of Lagrange system are constructed, and the order of differential equations of motion for the system are reduced by using the cyclic integrals or the generalized energy integrals with nabla derivatives. The results show that the reduced Routh equations and Whittaker equations hold the form of Lagrnage equations with nabla derivatives. Finally, two examples are given to illustrate the application of the results.

Two-stage distributionally robust optimization-based coordinated scheduling of integrated energy system with electricity-hydrogen hybrid energy storage

A coordinated scheduling model based on two-stage distributionally robust optimization(TSDRO)is proposed for integrated energy systems(IESs)with electricity-hydrogen hybrid energy storage.The scheduling problem of the IES is divided into two stages in the TSDRO-based coordinated scheduling model.The first stage addresses the day-ahead optimal scheduling problem of the IES under deterministic forecasting information,while the sec-ond stage uses a distributionally robust optimization method to determine the intraday rescheduling problem under high-order uncertainties,building upon the results of the first stage.The scheduling model also considers col-laboration among the electricity,thermal,and gas networks,focusing on economic operation and carbon emissions.The flexibility of these networks and the energy gradient utilization of hydrogen units during operation are also incor-porated into the model.To improve computational efficiency,the nonlinear formulations in the TSDRO-based coordinated scheduling model are properly linearized to obtain a Mixed-Integer Linear Programming model.The Column-Constraint Generation(C&CG)algorithm is then employed to decompose the scheduling model into a mas-ter problem and subproblems.Through the iterative solution of the master problem and subproblems,an efficient analysis of the coordinated scheduling model is achieved.Finally,the effectiveness of the proposed TSDRO-based coordinated scheduling model is verified through case studies.The simulation results demonstrate that the proposed TSDRO-based coordinated scheduling model can effectively accomplish the optimal scheduling task while consider-ing the uncertainty and flexibility of the system.Compared with traditional methods,the proposed TSDRO-based coordinated scheduling model can better balance conservativeness and robustness.

Improvement potential analysis for integrated fractionating and heat exchange processes in delayed coking units

A novel diagram-based representation approach is developed to analyze the thermodynamic efficiency and identify quickly the promising energy-use improvement for integrated fractionating and heat exchange processes in delayed coking units. For considering temperature dependence of heat capacity and integrating fractionating and heat exchange processes, an advanced energy level composite curve is constructed by using the simulation results and a stepwise procedure. More accurate results of exergy analysis are obtained and the interaction between different components of the integrated system can be properly revealed in an integrated figure. Then the exergy calculation is performed to validate the performance of processes and to define the targets for improvement. The avoidable exergy destruction is also analyzed by applying the concepts of avoidable and unavoidable exergy destructions for the integrated system. In a case study for a Chinese refinery, the results reveal that the heat exchange between gas oil and deethanization gasoline is the most inefficient process with the highest retrofitting potential, and the lowest exergy efficiency of component in the integration system is only29.4%. The improvement potential and exergy efficiency for the fractionator are 38.1% and 97.3%, respectively.It is obvious that the fractionator is not the most promising component for improvement.

电-气-氢-热-风-光耦合综合能源系统分层级Energy Hub建模方法

随着多能融合的不断深入,综合能源系统可实现大规模可再生能源消纳。由于综合能源系统广泛涉及电、气、氢、热、风、光等多种能源形式,经典Energy Hub方法与图论Energy Hub方法在建模效率与复杂度等方面均存在局限性。文章提出了分层级Energy Hub建模方法,将综合能源系统从能量输入到输出的耦合过程建模为分配层、转换层、集成层、储能层、网络层5个环节,全面涵盖了综合能源系统复杂多元的多能耦合关系,为输入与输出搭建桥梁,确保能量供需平衡。最后,通过算例分析论证了所提方法的优势与可行性,以及与传统方法在可再生能源消纳量上的提升。

基于改进模拟退火遗传算法的高速公路服务区自洽能源系统高能效优化

针对高速公路自洽能源系统高能效优化的问题,基于改进模拟退火遗传算法(SA-GA),提出了一种综合考虑经济目标和环保目标的自洽能源系统高能效优化运行策略。首先根据高速公路服务区自洽能源系统中各电力单元特性,建立一种综合考虑系统经济性和环保性的能效目标函数;其次根据高速公路服务区自洽能源系统的分类,建立了不同类型系统对应的约束条件;为避免遗传算法易陷入局部最优的缺陷,引入模拟退火算法,对改进后的SA-GA算法采用降温函数,寻找全局最优解;利用新疆某高速公路服务区自洽能源系统发电和负荷数据,并在传统服务区负荷的基础上进一步考虑新能源汽车充电站的影响。测试函数测试结果表明:SA-GA算法在求解速度和稳定性方面有明显提升,改进SA-GA算法对夏季、冬季典型日能效优化的结果,相较于遗传算法,在寻优精度提升约为20.33%。