scholarly journals An Energy Optimal Dispatching Model of an Integrated Energy System Based on Uncertain Bilevel Programming

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 477 ◽  
Author(s):  
Xueying Song ◽  
Hongyu Lin ◽  
Gejirifu De ◽  
Hanfang Li ◽  
Xiaoxu Fu ◽  
...  

An integrated energy system (IES) involving a large number of decision-makers causes problems of bad coordination between energy sub-networks and the IES and it is not able to fully consider the multi-energy complementarity among multiple decision-makers. In this context, firstly, this paper constructs an energy optimal dispatching model of an IES based on uncertain bilevel programming. The upper model takes the transformation matrix of energy hubs as the upper decision-maker, taking the minimum operation cost of the IES in the form of confidence as the objective function; the lower model takes each optimal operation plan of the electric power sub-network, the thermal energy sub-network, and the gas energy sub-network as the lower decision-makers, aiming at the operation economy of each sub-network and considering their operation as necessary constraints. Secondly, a firefly algorithm with chaotic search and an improved light intensity coefficient is designed to improve the proposed model. An empirical analysis was conducted on a pilot area of an integrated energy system in Hebei Province. The results show the following: (1) The typical daily operating cost of the integrated energy system in winter is lower than that in summer; (2) under the same load level, the typical winter and summer running costs of the integrated energy system are lower than that of the traditional microgrid; (3) compared with the particle swarm optimization algorithm, the improved firefly algorithm proposed in the paper has obvious advantages both in terms of running cost and solution time; and (4) when the confidence of the objective function and the constraints increases, the operating cost of various schemes also increase. The above results validate the effectiveness of the energy optimal dispatching model of the IES and the economy of the system operation under the multiple decision-maker hierarchy.

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-23 ◽  
Author(s):  
Thang Trung Nguyen ◽  
Nguyen Vu Quynh ◽  
Le Van Dai

This paper presents a novel improved firefly algorithm (IFA) to deal the problem of the optimal operation of thermal generating units (OOTGU) with the purpose of reducing the total electricity generation fuel cost. The proposed IFA is developed based on combining three improvements. The first is to be based on the radius between two solutions, the second is updated step size for each considered solution based on different new equations, and the third is to slightly modify a formula producing new solutions by using normally distributed random numbers and canceling uniform random numbers of conventional firefly algorithm (FA). The effect of each proposed improvement on IFA is investigated by executing five benchmark functions and two different systems. The performance of IFA is investigated on six other study cases consisting of different types of objective function and complex level of constraints. The objective function considers single fuel with quadratic form and nonconvex form, and multifuels with the sum of several quadratic and nonconvex functions while a set of constraints taken into account are power loss, prohibited zone, ramp rate limit, spinning reserve, and all constraints in transmission power networks. The obtained results indicate the proposed improvements in terms of high optimal solution quality, stabilization of search ability, and fast convergence compared with FA. In addition, the comparisons with other methods also lead to a conclusion that the proposed method is a very promising optimization tool for systems with quadratic fuel cost function and with complicated constraints.


2020 ◽  
Vol 213 ◽  
pp. 02005
Author(s):  
Peng Fang ◽  
Cui Mao ◽  
Yuping Chen ◽  
Shan Zhou ◽  
Rui You ◽  
...  

The integrated energy system (IES) has the advantage of improving energy utilization and promoting energy flexibility. From the perspective of demand-side load response, this paper establishes demand-side power, thermal load response, and natural gas demand response models, and then constructs the objective function of the lowest operating cost of the regional IES for combined electric heating and gas supply, using Cplex to perform optimization. Finally, a typical northern park is taken as an example to analyze and verify the feasibility of the model and algorithm. The analysis of the case shows that considering the electric heating gas demand side response will be better than not considering or considering only the single and both responses, not only can reduce operating costs, achieve peak reduction and valley filling, but also reduce abandonment of wind and energy, and increase energy utilization rate.


2021 ◽  
Vol 2087 (1) ◽  
pp. 012017
Author(s):  
Yan Liang ◽  
Yao Wang ◽  
Hongli Liu ◽  
Peng Wang ◽  
Yongming Jing ◽  
...  

Abstract Due to the high cost of energy storage part in traditional integrated energy systems, the demand response effect is poor. The paper proposes electrolytic water hydrogen production technology and applies it to the optimal operation of integrated energy system. By optimizing the operating cost of the system through adaptive genetic algorithm, we show that when the load matching degree was increased from 50% to 70%, the system operating cost was reduced by about 15.8%, and the carbon displacement was decreased by about 35%. System operating costs, carbon emissions, and the amount of electrolytic water systems involved in the demand response have all decreased.


Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2765 ◽  
Author(s):  
Yongjie Zhong ◽  
Dongliang Xie ◽  
Suwei Zhai ◽  
Yonghui Sun

The integrated energy system (IES) has the characteristic of energy system integrated/multi-energy coupling that involves heat, cooling, electricity, natural gas, and various other energy forms, which can maximize the synergistic effects and complementary benefits among various energy forms and their comprehensive utilization. In this paper, based on energy hub (EH), the day-ahead hierarchical steady state optimal operation for IES is discussed, in which the coupling natural gas system, electricity transmission system, and district heating system are all considered. Firstly, the model architecture of EH with diverse storage devices, renewable energy, and different energy conversion equipment is proposed and the steady state mathematical model of different energy networks in IES is developed, respectively. Secondly, the day-ahead operating cost of EH is minimized by an optimizing strategy to maximize the benefits of all kinds of energy demand users, where different types of energy power input into EH can be obtained. Then, the day-ahead optimal operation mode for IES considering minimization of operating fuel cost index is proposed via an energy management system, which provides various energy power data that are uploaded from EH. Finally, numerical results are presented to verify the effectiveness and usefulness of the day-ahead hierarchical optimal operation and steady state calculation analysis for IES, which could further illustrate that the proposed optimal operation can meet the requirements of practical engineering applications.


Author(s):  
Sai Liu ◽  
Cheng Zhou ◽  
Haomin Guo ◽  
Qingxin Shi ◽  
Tiancheng E. Song ◽  
...  

AbstractAs a key component of an integrated energy system (IES), energy storage can effectively alleviate the problem of the times between energy production and consumption. Exploiting the benefits of energy storage can improve the competitiveness of multi-energy systems. This paper proposes a method for day-ahead operation optimization of a building-level integrated energy system (BIES) considering additional potential benefits of energy storage. Based on the characteristics of peak-shaving and valley-filling of energy storage, and further consideration of the changes in the system’s load and real-time electricity price, a model of additional potential benefits of energy storage is developed. Aiming at the lowest total operating cost, a bi-level optimal operational model for day-ahead operation of BIES is developed. A case analysis of different dispatch strategies verifies that the addition of the proposed battery scheduling strategy improves economic operation. The results demonstrate that the model can exploit energy storage’s potential, further optimize the power output of BIES and reduce the economic cost.


2021 ◽  
Vol 289 ◽  
pp. 116698
Author(s):  
Peng Li ◽  
Zixuan Wang ◽  
Jiahao Wang ◽  
Tianyu Guo ◽  
Yunxing Yin

Author(s):  
Xinwei Zhou ◽  
Junqi Yu ◽  
Wanhu Zhang ◽  
Anjun Zhao ◽  
Min Zhou

Reasonable distribution of cooling load between chiller and ice tank is the key to realize the economical and energy-saving operation of ice-storage air-conditioning (ISAC) system. A multi-objective optimization model based on improved firefly algorithm (IFA) was established in this study to fully exploit the energy-saving potential and economic benefit of the ISAC system. The proposed model took the partial load rate of each chiller and the cooling ratio of the ice tank as optimization variables, and the lowest energy consumption loss rate and the lowest operating cost of the ISAC system were calculated. Chaotic logic self-mapping was used to initialize population to avoid falling into local optimum, and Cauchy mutation was used to increase the population’s diversity to improve the algorithm’s global search ability. The experimental results show that compared with the operation strategy based on constant proportion, particle swarm optimization (PSO) algorithm, and firefly algorithm (FA), the optimal operation strategy based on IFA can achieve more significant energy-saving and economic benefits. Meanwhile, the convergence accuracy and stability of the algorithm are significantly improved. Practical application: The optimized operation strategy of the ice-storage air-conditioning system can reduce energy loss and operating costs. The traditional operation strategies have the problems of low optimization precision and poor optimization effect. Therefore, this study presents an optimal operation strategy based on IFA. The convergence accuracy and stability of the algorithm are increased after the algorithm is improved. The operation strategy can get the maximum energy-saving effect and economic benefit of the ISAC system.


2020 ◽  
Vol 165 ◽  
pp. 01013
Author(s):  
Linfeng Wang ◽  
Kai Zhang ◽  
Nan Xu ◽  
Jingyan Wang ◽  
Danyang Zhang ◽  
...  

With the depletion of fossil energy and the popularity of renewable energy, a comprehensive energy system with the goal of improving system energy efficiency and consuming renewable energy is booming. Based on the combined heat, power, and heat generation, this paper builds a comprehensive energy system operation optimization model in conjunction with ground source heat pumps. It aims to find the optimal operation strategy based on the actual situation of the park’s load, equipment capacity, and energy prices. Using the linear programming method, a mathematical model with the best economic efficiency of the integrated energy system is established, the optimal operation strategy for a typical day is analyzed, and the annual operation is simulated. Finally, it compares with conventional energy supply methods and analyzes the contribution to the consumption of renewable energy.


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