Synergetic planning method for energy stations, pipeline networks, and demand response

Rational planning for energy stations and their lower-level energy supply pipeline networks is vital for improving the economy of the regional integrated energy system. Many studies have been focused on synergetic planning for energy stations and pipeline networks, but few have been oriented from the perspective of synergetic planning for energy stations, pipeline networks, and demand response, which may result in a redundant configuration of the regional integrated energy system. This paper proposes a synergetic planning method for energy stations, pipeline networks, and demand response. Initially, the impact of demand response on the traditional synergetic planning for energy stations and pipeline networks is analyzed. Subsequently, a synergetic planning method for energy stations, pipeline networks, and demand response is proposed to determine the optimal locations of energy stations, the optimal equipment capacity of energy stations, the optimal demand response configuration, and the optimal layout of pipeline networks. Finally, case studies are conducted to verify the effectiveness of the proposed method. Compared with the traditional synergetic planning method for energy stations and pipeline networks without considering demand response, the proposed method can reduce the construction cost of energy stations by approximately 4.8% and pipeline networks by around 8.5%. Thus, the proposed method can be applied for planning energy stations and pipeline networks.</p

Synergetic planning method for energy stations, pipeline networks, and demand response

Rational planning for energy stations and their lower-level energy supply pipeline networks is vital for improving the economy of the regional integrated energy system. Many studies have been focused on synergetic planning for energy stations and pipeline networks, but few have been oriented from the perspective of synergetic planning for energy stations, pipeline networks, and demand response, which may result in a redundant configuration of the regional integrated energy system. This paper proposes a synergetic planning method for energy stations, pipeline networks, and demand response. Initially, the impact of demand response on the traditional synergetic planning for energy stations and pipeline networks is analyzed. Subsequently, a synergetic planning method for energy stations, pipeline networks, and demand response is proposed to determine the optimal locations of energy stations, the optimal equipment capacity of energy stations, the optimal demand response configuration, and the optimal layout of pipeline networks. Finally, case studies are conducted to verify the effectiveness of the proposed method. Compared with the traditional synergetic planning method for energy stations and pipeline networks without considering demand response, the proposed method can reduce the construction cost of energy stations by approximately 4.8% and pipeline networks by around 8.5%. Thus, the proposed method can be applied for planning energy stations and pipeline networks.</p

Adjustable capability of the distributed energy system:Definition, framework, and evaluation model

The adjustable capability of distributed energy systems responding to the incentives of the upper energy supply system has been significantly improved by energy storage and renewable energy technologies. Most existing research focuses on evaluating the flexibility of distributed energy system itself or the demand response potential of end-users, but there is no specific model which takes the distributed energy system as an integrated load and evaluates its adjustable capability from the perspective of the upper energy supply system. To fill the research gap, this paper defines the adjustable capability of distributed energy systems, describes its characteristics, and proposes a unified evaluation model. Then, from the perspective of energy demand and supply sides, it quantifies the impact of each influential factor in different energy links on the adjustable capability and studies the interactive mechanism between devices within the system. Thereafter, the adjustable capability of distributed energy systems under typical scenarios at a single moment is evaluated, and the impact of economic constraints on the adjustable capability is also extensively analyzed. Accordingly, this paper proposes a sequential recurrence method to evaluate the adjustable capability of distributed energy systems against three different initial states: unknown initial state, fixed initial state, uncertain initial state. Finally, the adjustable capability concept is demonstrated on a practical industrial park to verify the effectiveness and practicability. This study deepens the connection between distributed energy systems and upper energy supply system in the Energy Internet at the energy information level. Which enables distributed energy system to quantize its energy demand range for the upper energy supply system and realize its own reliable operation and rolling optimization. In addition, this evaluation method allows upper energy supply system to plan, overhaul and dispatch more economically and reliably on the basis of understanding the energy demand of distributed energy system. Moreover, upper energy supply system can formulate the demand response strategy with the maximum revenue by balancing the size of adjustable capability interval of distributed energy system and the investment cost of demand response.</p

Adjustable capability of the distributed energy system:Definition, framework, and evaluation model

The adjustable capability of distributed energy systems responding to the incentives of the upper energy supply system has been significantly improved by energy storage and renewable energy technologies. Most existing research focuses on evaluating the flexibility of distributed energy system itself or the demand response potential of end-users, but there is no specific model which takes the distributed energy system as an integrated load and evaluates its adjustable capability from the perspective of the upper energy supply system. To fill the research gap, this paper defines the adjustable capability of distributed energy systems, describes its characteristics, and proposes a unified evaluation model. Then, from the perspective of energy demand and supply sides, it quantifies the impact of each influential factor in different energy links on the adjustable capability and studies the interactive mechanism between devices within the system. Thereafter, the adjustable capability of distributed energy systems under typical scenarios at a single moment is evaluated, and the impact of economic constraints on the adjustable capability is also extensively analyzed. Accordingly, this paper proposes a sequential recurrence method to evaluate the adjustable capability of distributed energy systems against three different initial states: unknown initial state, fixed initial state, uncertain initial state. Finally, the adjustable capability concept is demonstrated on a practical industrial park to verify the effectiveness and practicability. This study deepens the connection between distributed energy systems and upper energy supply system in the Energy Internet at the energy information level. Which enables distributed energy system to quantize its energy demand range for the upper energy supply system and realize its own reliable operation and rolling optimization. In addition, this evaluation method allows upper energy supply system to plan, overhaul and dispatch more economically and reliably on the basis of understanding the energy demand of distributed energy system. Moreover, upper energy supply system can formulate the demand response strategy with the maximum revenue by balancing the size of adjustable capability interval of distributed energy system and the investment cost of demand response.</p

Load carrying capability of regional electricity-heat energy systems:Definitions, characteristics, and optimal value evaluation

Evaluating the load carrying capability of regional electricity-heat energy systems is of great significance to its planning and construction. Existing methods evaluate energy supply capability without considering load characteristics between various users. Besides, the impact of integrated demand response is not fully considered. To address these problems, this paper builds a load carrying capability interval model, which uses reliability as a security constraint and considers integrated demand response. An evaluation method for the optimal load carrying capability considering uncertainties of load growth is proposed. First, this paper defines energy supply capability, available capacity, and load carrying capability. Interval models are built to achieve the visualization display of these indices. Their characteristics are studied and the impact factors of interval boundary are analyzed. Secondly, a two-layer optimization model for the evaluation of optimal load carrying capability is constructed, considering the uncertainties of load growth. The upper-layer model aims at optimizing the sum of load carrying capability benefit, integrated demand response cost, and load curtailment penalty. The lower-layer model maximizes energy supply capability. Thereafter, the lower-layer model is linearized based on piecewise linearization and the least square method. The computation efficiency is greatly enhanced. In the case study, a real regional electricity-heat energy system is used to validate the proposed model and method.</p

Research on unit commitment optimization of high permeability wind power generation and P2G

As an important form of future energy utilization, the operation of combined electricity-gas energy systems is also threatened by high-level penetration intermittent renewable energy. The application of power to gas (P2G) technology has deepened the coupling between the concerned power system and the natural gas system, and hence, bidirectional energy flow between the power system and the natural gas system can be implemented. P2G technology provides an alternative solution for the optimal operation of the combined electricity-gas energy systems to accommodate intermittent renewable energy, particularly, wind power. In this new environment, the unit commitment optimization of high permeability wind power and P2G is addressed, where the objective is to minimize the total operating cost of combined electricity-gas energy systems. First, the P2G technology and the application and supportive policies are introduced. Second, considering the characteristics of P2G devices and the combined system, a two-level economic dispatch model of the combined system with security constraints is proposed. Third, based on the Karush Kuhn Tucker optimality condition, the two-level optimization model is transformed into a mixed integer linear programming. Finally, the case study shows that the proposed unit commitment model is effective and accurate in optimizing the combined energy systems with high penetration level wind power.</p

Impact of DG Configuration on Maximum Use of Load Supply Capability in Distribution Power Systems

Traditional distributed generators (DGs) planning methods take network loss minimization as the main objective to optimize DG sites in feeders. The use of load supply capability (LSC) in DG planning will precisely answer the questions how many DGs should be integrated, which transformer they should be connected to, and which type of DGs should be adopted. The main work of this paper is to analyze the impact of DGs on LSC so as to answer the three key questions. It resolves the planning problem through three steps: (i) two LSC models considering DGs’ access are developed, in which two different transfer strategies are considered: direct load transfer and indirect load transfer; (ii) the method of combined simple method and point estimate method is proposed. At last, based on a base case, when the configuration of DGs is changing, the impact of DGs on system LSC is studied. After the case study, the conclusion concerning the impact of load transfer strategy, DG capacities, and DG types on LSC is reached

Flexibility evaluation of active distribution networks considering probabilistic characteristics of uncertain variables

The flexibility evaluation of distribution networks has attracted significant research attention with the increasing penetration of renewable energy. One particular gap in existing studies is that little attention has been paid to the probabilistic characteristics of uncertain regions. In this study, a novel sequential flexibility evaluation method is proposed based on the feasibility analysis of the uncertain region of photovoltaic active power and load demand. The model features the uncertain region with probabilistic characteristics, which is essential for analysing the impact of probabilistic characteristics of uncertain variables (PCUVs) on flexibility evaluation. The sequential direction matrix is adopted to reflect the major factor of flexibility shortage. The evaluation procedure is modelled as a bi-level optimisation problem. Demonstrated by the simulation results, the flexibility index is larger by considering the PCUV. Furthermore, the elements in the sequential direction matrix indicate that the photovoltaic power during midday is the major cause of flexibility shortage.</p

Research on unit commitment optimization of high permeability wind power generation and P2G

As an important form of future energy utilization, the operation of combined electricity-gas energy systems is also threatened by high-level penetration intermittent renewable energy. The application of power to gas (P2G) technology has deepened the coupling between the concerned power system and the natural gas system, and hence, bidirectional energy flow between the power system and the natural gas system can be implemented. P2G technology provides an alternative solution for the optimal operation of the combined electricity-gas energy systems to accommodate intermittent renewable energy, particularly, wind power. In this new environment, the unit commitment optimization of high permeability wind power and P2G is addressed, where the objective is to minimize the total operating cost of combined electricity-gas energy systems. First, the P2G technology and the application and supportive policies are introduced. Second, considering the characteristics of P2G devices and the combined system, a two-level economic dispatch model of the combined system with security constraints is proposed. Third, based on the Karush Kuhn Tucker optimality condition, the two-level optimization model is transformed into a mixed integer linear programming. Finally, the case study shows that the proposed unit commitment model is effective and accurate in optimizing the combined energy systems with high penetration level wind power.</p