Current Issue

  • A demand response system for wind power integration: greenhouse gas mitigation and reduction of generator cycling

    Abstract

      2018-6-18

    A smart grid power system for a small region consisting of 1,000 residential homes with electric heating appliances from the demand side, and a generic generation mix of nuclear, hydro, coal, gas and oil-based generators representing the supply side, is investigated using agent-based simulations. The simulation includes a transactive load control in a real-time pricing electricity market. The study investigates the impacts of adding wind power and demand response (DR) on both greenhouse gas (GHG) emissions and generator cycling requirements. The results demonstrate and quantify the effectiveness of DR in mitigating the variability of renewable generation. The extent to which greenhouse gas emissions can be mitigated is found to be highly dependent on the mix of generators and their operational capacity factors. It is expected that the effects of demand response on electricity use can reduce dependency on fossil fuel-based electricity generation. However, the anticipated mitigation of GHG emissions is found to dependent on the number and efficiency of fossil fuel generators, and especially on the capacity factor at which they operate. Therefore, if a generator (the marginal seller) is forced to use less efficient fossil fuel power generation schemes, it will result in higher GHG emissions. The simulations show that DR can yield a small reduction in GHG emissions, but also lead to a smaller increase in emissions in circumstances when, for example, a generator (the marginal seller) is forced to use less efficient fossil fuel power generation schemes. Nonetheless, DR is shown to enhance overall system operation, particularly by facilitating increased penetration of variable renewable electricity generation without jeopardizing grid operation reliability. DR reduces the amount of generator cycling by an increased order of magnitude, thereby reducing wear and tear, improving generator efficiency, and avoiding the need for additional operating reserves. The effectiveness of DR for these uses depends on the participation of responsive loads, and this study highlights the need to maintain a certain degree of diversity of loads to ensure they can provide adequate responsiveness to the changing grid conditions.

  • Review of key problems related to integrated energy distribution systems

    Abstract

      2018-6-18

    Integrated energy distribution system (IEDS) is one of the integrated energy and power system forms, which involves electricity/gas/cold/heat and other various energy forms. The energy coupling relationship is close and complex. IEDS is the focus of regional energy internet research and development at home and abroad. Compared with the traditional power distribution system, IEDS through the multi-energy coupling link comprehensive utilization, effectively improve the distribution system economy, safety, reliability, flexibility and toughness, but also to ease the regional energy system environmental pressure. IEDS is an important direction for the future development of energy systems, and its related research and practice on China’s energy system development also has important practical and strategic significance. This paper summarizes the related researches of the IEDS and explores the energy operation characteristics and coupling mechanisms. What’s more, the integrated model of IEDS is summarized. On these bases, this paper discusses and prospects some key issues such as joint planning, optimization control and security analysis, state estimation and situational awareness and generalized demand side management.

  • A virtual energy storage system for voltage control of distribution networks

    Abstract

      2018-6-18

    Increasing amounts of distributed generation (DG) connected to distribution networks may lead to the violation of voltage and thermal limits. This paper proposes a virtual energy storage system (VESS) to provide voltage control in distribution networks in order to accommodate more DG. A VESS control scheme coordinating the demand response and the energy storage system was developed. The demand response control measures the voltage of the connected bus and changes the power consumption of the demand to eliminate voltage violations. The response of energy storage systems was used to compensate for the uncertainty of demand response. The voltage control of the energy storage system is a droop control with droop gain values determined by applying voltage sensitivity factors. The control strategy of the VESS was applied to a medium-voltage network and the results show that the control of the VESS not only facilitates the accommodation of higher DG capacity in the distribution network without voltage violations or network reinforcements but also prolongs the lifetime of the transformer’s on-load tap changer.

  • Bi-level planning for integrated energy systems incorporating demand response and energy storage under uncertain environments using novel metamodel

    Abstract

      2018-6-18

    The optimal planning and design of an integrated energy system (IES) is of great significance to facilitate distributed renewable energy (DRE) technology and improve the overall energy efficiency of the energy system. With the increased penetration of distributed generation (DG), the power supply and load sides of an IES present more increased levels of uncertainties. Demand response (DR) and the energy storage system (ESS) serve as important means to shift energy supply and use across time to counter the indeterminate variations. However, the current IES planning methods are unable to effectively deal with the uncertainties of DREs and loads, and to optimize the operations of DG-DR-ESS due to the enormous possible combinations. In this paper, a new method for the optimal planning and design of an integrated energy system has been introduced and verified. The new method consists of three integrated elements. First, the method of the probability scenario has been used to model the uncertainties of the DREs and loads so as to better characterize the impact of uncertainty on the planning and design of the IES. Secondly, the optimal operation of the IES under different probability scenarios is ensured using the second-order cone optimization for quick solutions due to the simplicity of this sub-problem, serving as the bottom-level optimization. Thirdly, the optimal planning and design of IES through optimal sizing of the power generating components and ESS are performed using a special meta-model based global optimization method due to the complex, black-box, and computation intensive nature of this top-level optimization in a nested, bi-level global optimization problem. The combined approach takes full account of the interrelated operations of DG-DR-ESS under different design configurations to support a better optimal planning and design of the IES. The simulation has been carried out on an IES system modified from the IEEE 33-node distribution system. The simulation results show that the proposed method and model are effective.

  • Modeling and operation of the power-to-gas system for renewables integration: a review

    Abstract

      2018-6-18

    Power-to-Gas (P2G) plays an important role in enhancing large-scale renewable energy integration in power systems. As an emerging inter-disciplinary subject, P2G technology requires knowledge in electrochemistry, electrical engineering, thermodynamic engineering, chemical engineering and system engineering. Aiming at P2G modeling and operational problems concerning the research field of power systems and the energy internet, this paper briefly reviews the main technologies and application potentials of the P2G system, and makes systematic summaries of major progresses related to P2G’s integration into the power grid in a bottom-top manner, including the modeling of high/room-temperature electrolysis cells, steady-state/dynamic optimization control of the P2G system, P2G’s integrated model and operational strategies at the grid level. In the final part of this paper, suggestions are put forward on future research directions of P2G systems from the aspects of modeling and operational optimization.

Introduction

CSEEJPESThe articles published in this journal will focus on advanced concepts, technologies, methodologies and practices associated with all aspects concerning power and energy systems...
more...

CSEEJPES WeixinWelcome to follow our Wechat Official Account (CSEEJPES2015)