光储联合系统中储能电站的能量管理

为提高储能设备利用率,实现储能电站能量的合理管理,以浙江地区某光伏电站配置的MW级储能电站示范工程为背景,针对现有单应用模式下储能装置容量和功率存在富余的特点,文章提出了一种平抑波动和分时电价相结合的储能装置控制方案。根据光伏出力特点,在光伏波动较强时进行光伏波动平抑,在光伏出力较弱时,根据储能装置剩余容量(state of charge,SOC)的实际情况,结合当地负荷变化曲线,实施分时电价策略。仿真实验表明,该控制方案维持储能设备SOC在合理范围的前提下,能及时平抑白天光伏的波动。同时在一定程度上实现了对负荷的削峰填谷,提高了储能设备利用率,实现了储能电站能量的合理管理,为项目后续示范应用提供了理论依据与技术支撑。     

Distributed photovoltaic generation and energy storage systems: A review

Currently, in the field of operation and planning of electrical power systems, a new challenge is growing which includes with the increase in the level of distributed generation from new energy sources, especially renewable sources. The question of load redistribution for better energetic usage is of vital importance since these new renewable energy sources are often intermittent. Therefore, new systems must be proposed which ally energy storage with renewable energy generators for reestablishment of grid reliability. This work presents a review of energy storage and redistribution associated with photovoltaic energy, proposing a distributed micro-generation complex connected to the electrical power grid using energy storage systems, with an emphasis placed on the use of NaS batteries. These systems aim to improve the load factor, considering supply side management, and the offer of backup energy, in the case of demand side management.     

某15MW太阳能屋顶光伏发电工程的应用分析

在对太阳能屋顶光伏发电系统构成及发展意义阐述的基础上,通过对某15MW屋顶光伏发电工程大量实际数据的分析,表明太阳能屋顶光伏发电工程具有良好的社会、经济效益和广阔的发展前景。     

独立光伏混合储能发电自治系统配置优化

发电自治系统是指零排放不间断运行的系统。根据负载特性和太阳光照强度时间分布曲线,结合典型储能器件,包括蓄电池、燃料电池与电解制氢,用穷尽搜索法对独立光伏混合储能发电自治系统进行了优化配置。以年为运行周期,按照蓄电池、燃料电池与电解制氢的充放电顺序,得到实现不间断供电的配置方案。根据各器件的安装和运行维护成本,计算各配置方案的年运行成本。为实现独立光伏混合储能发电自治系统的配置优化提供设计依据。     

Optimization of integrated photovoltaic–wind power generation systems with battery storage

In this paper, a new method for optimization of a wind–PV integrated hybrid system is presented. Based on deficiency of power supply probability (DPSP), relative excess power generated (REPG), unutilized energy probability (UEP), life cycle cost (LEC), levelized energy cost (LEC) and life cycle unit cost (LUC) of power generation with battery bank, the method addresses a specific location and employs an iterative scheme. A simulation software code has been developed to carryout the analysis for optimizing the size of the integrated system for a given location. Also, a case study using the software on the selection of optimal size of the integrated system for the site Pompuhar, Tamil Nadu state in India has been presented.     

Benefit allocation model of distributed photovoltaic power generation vehicle shed and energy storage charging pile based on integrated weighting-Shapley method

In this study, to develop a benefit-allocation model, in-depth analysis of a distributed photovoltaic-power-generation carport and energy-storage charging-pile project was performed; the model was developed using Shapley integrated-empowerment benefit-distribution method. First, through literature survey and expert interview to identify the risk factors at various stages of the project, a dynamic risk-factor indicator system is developed. Second, to obtain a more meaningful risk-calculation result, the subjective and objective weights are combined, the weights of the risk factors at each stage are determined by the expert scoring method and entropy weight method, and the interest distribution model based on multi-dimensional risk factors is established. Finally, an example is used to verify the rationality of the method for the benefit distribution of the charging-pile project. The results of the example indicate that the limitations of the Shapley method can be reasonably avoided, and the applicability of the model for the benefit distribution of the charging-pile project is verified.     

Review on combined wind power generation and energy storage systems

储能系统由于能够实现电能的时空平移,具有响应速度快,规模化等优点,是改善风电波动性,提高其并网能力的有效手段,构建风储联合发电系统成为目前研究重点.简单介绍了风电并网对电力系统的影响及不同类型电池储能技术的发展现状,给出了部分国内外风储联合发电系统的示范工程,并分析了平滑风电功率波动,跟踪计划出力曲线和削峰填谷3种主要运行方式,重点阐述了目前风储联合发电系统控制策略和储能容量配置研究现状,对进一步开展风储联合发电系统的研究进行了展望,指出经济性仍然是制约储能技术应用的关键问题之一,提高包含储能单元的风储联合发电系统的经济性是今后的研究重点.     

Dynamic modeling of hybrid energy storage systems coupled to photovoltaic generation in residential applications

A model of a photovoltaic (PV) powered residence in stand-alone configuration was developed and evaluated. The model assesses the sizing, capital costs, control strategies, and efficiencies of reversible fuel cells (RFC), batteries, and ultra-capacitors (UC) both individually, and in combination, as hybrid energy storage devices. The choice of control strategy for a hybrid energy storage system is found to have a significant impact on system efficiency, hydrogen production and component utilization. A hybrid energy storage system comprised of batteries and RFC has the advantage of reduced cost (compared to using a RFC as the sole energy storage device), high system efficiency and hydrogen energy production capacity. A control strategy that preferentially used the RFC before the battery in meeting load demand allows both grid independent operation and better RFC utilization compared to a system that preferentially used the battery before the RFC. Ultra-capacitors coupled with a RFC in a hybrid energy storage system contain insufficient energy density to meet dynamic power demands typical of residential applications.     

面向废弃能量收集的风电-压缩空气储能耦合发电系统

目前,风电与压缩空气储能耦合发电系统是发电后再与压缩空气储能系统连接,对于风电场一些不能发电工况的能量无法利用。通过风力发电功率特性和运行状态分析,找出产生废弃能量的2种工况:起动风速到切入风速期间的低风速工况和电网原因弃风工况,设计了一套新型的风电-压缩空气储能耦合发电系统,通过啮合切换装置可以进行风机和压缩机、发电机的切换运行。通过工况的效率分析,系统在2种工况时,可以回收废弃能量,实现电能输出,有效提高风电场的能量利用率。     

A stand-alone photovoltaic power system for remote villages using pumped water energy storage

The present paper regards the implementation of a stand-alone photovoltaic plant in which battery storage is partially replaced by a micro-hydraulic system. The plant was installed on Donoussa Island in the Aegean Sea, Greece to cover basic electricity needs of the remote village of Merssini (13 houses). Lighting, TV set and refrigerator were considered basic electricity needs for each house. The photovoltaic array consists of 300 photovoltaic modules of 60 W_p each, for a combined 18 kW_p total installed power. The micro-hydraulic system consists of a water pump of 6 kV A and a water turbine coupled with a DC generator of 7.5 kW and two identical water reservoirs of 150 m³ capacity each. During the day, the load is satisfied directly form the photovoltaic generator through an inverter (UPS unit of 25 kV A, 380 V-3 phases alternative current), while any energy surplus is directed to the pump for pumping water from the low level reservoir (at about 100 m altitude from sea level), to the high level reservoir (at about 200 m altitude from sea level). During the night, water is turbined to the low level reservoir providing energy to the load. There is also a battery bank of 186 cells of 2 V nominal voltage in series, with a total capacity of 100 A h. The batteries cover primarily load peaks. The paper presents first results and experience gained from the system performance.     

Experimental results for hybrid energy storage systems coupled to photovoltaic generation in residential applications

An experimental solar-hydrogen powered residence simulator was built and tested. The system consisted of a solar photovoltaic array connected to an electrolyzer which produced hydrogen as a means of energy storage. The hydrogen was used to produce electricity in a fuel cell that operated in parallel with a battery to meet dynamic power demand similar to that found in residential applications. The study demonstrated the technical feasibility of operating such a system under the simultaneous dynamics of solar input and load. Limitations of current fuel cell and electrolyzer designs, as they pertain to both power delivery and energy storage, were identified. The study also established the need to understand and address dynamic performance in the design and application of solar-hydrogen reversible fuel cell hybrid systems. An economic analysis found that major cost reductions would need to be achieved for such systems to compete with conventional energy storage devices.     

光伏发电发展趋势分析

回顾了光伏发电的发展历程,通过对光伏发电度电成本与煤电度电成本的变化趋势对比,将未来光伏发展模式分为3个阶段,即政策补贴发展阶段、大规模分布式并网应用阶段和大规模分散式并网就地消纳阶段,并提出了光伏发电各阶段的发展建议。     

Comparative impacts of wind and photovoltaic generation on energy storage for small islanded electricity systems

This paper addresses the annual energy storage requirements of small islanded electricity systems with wind and photovoltaic (PV) generation, using hourly demand and resource data for a range of locations in New Zealand. Normalised storage capacities with respect to annual demand for six locations with winter-peaking demand profiles were lower for wind generation than for PV generation, with an average PV:wind storage ratio of 1.768:1. For two summer-peaking demand profiles, normalised storage capacities were lower for PV generation, with storage ratios of 0.613:1 and 0.455:1. When the sensitivity of storage was modelled for winter-peaking demand profiles, average storage ratios were reduced. Hybrid wind/PV systems had lower storage capacity requirements than for wind generation alone for two locations. Peak power for storage charging was generally greater with PV generation than with wind generation, and peak charging power increased for the hybrid systems. The results are compared with those for country-scale electricity systems, and measures for minimising storage capacity are discussed. It is proposed that modelling of storage capacity requirements should be included in the design process at the earliest possible stage, and that new policy settings may be required to facilitate a transition to energy storage in fully renewable electricity systems.     

Superconducting magnetic energy storage

Superconducting magnetic energy storage (SMES) is an energy storage technology that stores energy in the form of DC electricity that is the source of a DC magnetic field. The conductor for carrying the current operates at cryogenic temperatures where it is a superconductor and thus has virtually no resistive losses as it produces the magnetic field. The overall technology of cryogenics and superconductivity today is such that the components of a SMES device are defined and can be constructed. The integrated unit appears to be feasible for some utility applications at a cost that is competitive with other technologies. SMES is the only technology based on superconductivity that is applicable to the electric utilities and is commercially available today. In addition to today's power quality application, the historical development of SMES starting with the concept of very large plants that would store hundreds of megawatt hours of energy and were intended for diurnal load leveling are described.     

Dynamic modeling and sizing optimization of stand-alone photovoltaic power systems using hybrid energy storage technology

Economic and environmental concerns over fossil fuels encourage the development of photovoltaic (PV) energy systems. Due to the intermittent nature of solar energy, energy storage is needed in a stand-alone PV system for the purpose of ensuring continuous power flow. Three stand-alone photovoltaic power systems using different energy storage technologies are studied in this paper. Key components including PV modules, fuel cells, electrolyzers, compressors, hydrogen tanks and batteries are modeled in a clear way so as to facilitate the evaluation of the power systems. Based on energy storage technology, a method of ascertaining minimal system configuration is designed to perform the sizing optimization and reveal the correlations between the system cost and the system efficiency. The three hybrid power systems, i.e., photovoltaic/battery (PV/Battery) system, photovoltaic/fuel cell (PV/FC) system, and photovoltaic/fuel cell/battery (PV/FC/Battery) system, are optimized, analyzed and compared. The obtained results indicate that maximizing the system efficiency while minimizing system cost is a multi-objective optimization problem. As a trade-off solution to the problem, the proposed PV/FC/Battery hybrid system is found to be the configuration with lower cost, higher efficiency and less PV modules as compared with either single storage system.     

Superconductive magnetic energy storage

Technical and economic aspects of large scale superconductive magnetic energy storage are discussed. This paper is a review of a program which has been under way at the University of Wisconsin since 1970. Early work between 1970 and 1976 was primarily involved in proving economic and technical feasibility of the concept The present program deals with component development and detailed design ultimately leading to construction of a large superconducting magnet capable of storing 1000–10,000 MWh. The magnet is a single-layered segmented solenoid of approx. 100 m radius. Energy containment is achieved economically by burying the magnet underground in bedrock tunnels. Magnetic loads are transmitted from the conductor to bedrock through glass fiber reinforced composite struts. The conductor consists of a composite of aluminum and NbTi and is designed for full cryogenic stability in 1.8 K superfluid helium. The dewar-conductor assembly will be rippled in a l m radius of curvature to reduce the hoop stress tension. A Graetz bridge is required to convert the d.c. superconducting current into a.c. current in the three-phase power system. Economic analysis indicates that superconductive magnetic energy storage is competitive with alternative large scale storage schemes for units greater than 1000 MWh size.     

Life cycle assessment and evaluation of energy payback time on high-concentration photovoltaic power generation system

In this study, the environmental load of photovoltaic power generation system (PV) during its life cycle and energy payback time (EPT) are evaluated by LCA scheme. Two hypothetical case studies in Toyohashi, Japan and Gobi dessert in China have been carried out to investigate the influence of installation location and PV type on environmental load and EPT. The environmental load and EPT of a high-concentration photovoltaic power generation system (hcpV) and a multi-crystalline silicon photovoltaic power generation system (mc-Si PV) are studied. The study shows for a PV of 100 MW size, the total impacts of the hcpV installed in Toyohashi is larger than that of the hcpV installed in Gobi desert by 5% without consideration of recycling stage. The EPT of the hcpV assumed to be installed in Gobi desert is shorter than EPT of the hcpV assumed to be installed in Toyohashi by 0.64 year. From these results, the superiority to install PV in Gobi desert is certificated. Comparing with hcpV and mc-Si PV, the ratio of the total impacts of mc-Si PV to that of hcpV is 0.34 without consideration of recycling stage. The EPT of hcpV is longer than EPT of mc-Si PV by 0.27 year. The amount of global solar radiation contributing to the amount of power generation of mc-Si PV is larger than the amount of direct solar radiation contributing to the amount of power generation of hcpV by about 188 kW h/(m² year) in Gobi desert. Consequently, it appears that using mc-Si PV in Gobi desert is the best option.     

Sampled data automatic generation control with superconductingmagnetic energy storage in power systems

A discrete state-space model of a two-area interconnected power system with reheat steam turbine, governor deadband nonlinearity and superconducting magnetic energy storage is developed in this paper. The effect of a small-capacity superconducting magnetic energy storage (SMES) system is studied in relation to supplying sudden power requirements of real power load. The feasibility of using an IGBT power converter instead of a thyristor converter as a power conditioning system with the SMES is studied. Time domain simulation results are also presented which show the improvement of transient response with SMES