Combined hybrid energy storage system and transmission grid model for peak shaving based on time series operation simulation

This study proposes a combined hybrid energy storage system(HESS) and transmission grid(TG) model, and a corresponding time series operation simulation(TSOS) model is established to relieve the peak-shaving pressure of power systems under the integration of renewable energy. First, a linear model for the optimal operation of the HESS is established, which considers the different power-efficiency characteristics of the pumped storage system, electrochemical storage system, and a new type of liquid compressed air energy storage. Second, a TSOS simulation model for peak shaving is built to maximize the power entering the grid from the wind farms and HESS. Based on the proposed model, this study considers the transmission capacity of a TG. By adding the power-flow constraints of the TG, a TSOS-based HESS and TG combination model for peak shaving is established. Finally, the improved IEEE-39 and IEEE-118 bus systems were considered as examples to verify the effectiveness and feasibility of the proposed model.

Optimization dispatching strategy for an energy storage system considering its unused capacity sharing

In renewable energy systems,energy storage systems can reduce the power fluctuation of renewable energy sources and compensate for the prediction deviation.However,if the renewable energy prediction deviation is small,the energy storage system may work in an underutilized state.To efficiently utilize a renewable-energy-sided energy storage system(RES),this study proposed an optimization dispatching strategy for an energy storage system considering its unused capacity sharing.First,this study proposed an unused capacity-sharing strategy for the RES to fully utilize the storage’s unused capacity and elevate the storage’s service efficiency.Second,RES was divided into“deviation-compensating energy storage(DES)”and“sharing energy storage(SES)”to clarify the function of RES in the operation process.Third,this study established an optimized dispatching model to achieve the lowest system operating cost wherein the unused capacity-sharing strategy could be integrated.Finally,a case study was investigated,and the results indicated that the proposed model and algorithm effectively improved the utilization of renewable-energy-side energy storage systems,thereby reducing the total operation cost and pressure on peak shaving.

“Extreme utilization” theory and practice in gas storages with complex geological conditions

Based on more than 20-year operation of gas storages with complex geological conditions and a series of research findings, the pressure-bearing dynamics mechanism of geological body is revealed. With the discovery of gas-water flowing law of multi-cycle relative permeability hysteresis and differential utilization in zones, the extreme utilization theory targeting at the maximum amount of stored gas, maximum injection-production capacity and maximum efficiency in space utilization is proposed to support the three-in-one evaluation method of the maximum pressure-bearing capacity of geological body, maximum well production capacity and maximum peak shaving capacity of storage space. This study realizes the full potential of gas storage(storage capacity) at maximum pressure, maximum formation-wellbore coordinate production, optimum well spacing density match with finite-time unsteady flow, and peaking shaving capacity at minimum pressure, achieving perfect balance between security and capacity. Operation in gas storages, such as Hutubi in Xinjiang, Xiangguosi in Xinan, and Shuang6 in Liaohe, proves that extreme utilization theory has promoted high quality development of gas storages in China.

Applications of Lithium-Ion Batteries in Grid-Scale Energy Storage Systems

In the electrical energy transformation process,the grid-level energy storage system plays an essential role in balancing power generation and utilization.Batteries have considerable potential for application to grid-level energy storage systems because of their rapid response,modularization,and flexible installation.Among several battery technologies,lithium-ion batteries(LIBs)exhibit high energy efficiency,long cycle life,and relatively high energy density.In this perspective,the properties of LIBs,including their operation mechanism,battery design and construction,and advantages and disadvantages,have been analyzed in detail.Moreover,the performance of LIBs applied to grid-level energy storage systems is analyzed in terms of the following grid services:(1)frequency regulation;(2)peak shifting;(3)integration with renewable energy sources;and(4)power management.In addition,the challenges encountered in the application of LIBs are discussed and possible research directions aimed at overcoming these challenges are proposed to provide insight into the development of grid-level energy storage systems.

Power management in co-phase traction power supply system with super capacitor energy storage for electrified railways

Increasing railway traffic and energy utilization issues prompt electrified railway systems to be more economical,efficient and sustainable.As regenerative braking energy in railway systems has huge potential for optimized utilization,a lot of research has been focusing on how to use the energy efficiently and gain sustainable benefits.The energy storage system is an alternative because it not only deals with regenerative braking energy but also smooths drastic fluctuation of load power profile and optimizes energy management.In this work,we propose a co-phase traction power supply system with super capacitor(CSS_SC)for the purpose of realizing the function of energy management and power quality management in electrified railways.Besides,the coordinated control strategy is presented to match four working modes,including traction,regenerative braking,peak shaving and valley filling.A corresponding simulation model is built in MATLAB/Simulink to verify the feasibility of the proposed system under dynamic working conditions.The results demonstrate that CSS_SC is flexible to deal with four different working conditions and can realize energy saving within the allowable voltage unbalance of 0.008%in simulation in contrast to 1.3%of the standard limit.With such a control strategy,the performance of super capacitor is controlled to comply with efficiency and safety constraints.Finally,a case study demonstrates the improvement in power fluctuation with the valley-to-peak ratio reduced by 20.3%and the daily load factor increased by 17.9%.

Forecast of natural gas supply and demand in China under the background of “Dual Carbon Targets”

As a kind of clean energy which creates little carbon dioxide, natural gas will play a key role in the process of achieving “Peak Carbon Dioxide Emission” and “Carbon Neutrality”. The Long-range Energy Alternatives Planning System(LEAP) model was improved by using new parameters including comprehensive energy efficiency and terminal effective energy consumption. The Back Propagation(BP) Neural Network–LEAP model was proposed to predict key data such as total primary energy consumption, energy mix, carbon emissions from energy consumption, and natural gas consumption in China. Moreover, natural gas production in China was forecasted by the production composition method. Finally, based on the forecast results of natural gas supply and demand, suggestions were put forward on the development of China’s natural gas industry under the background of “Dual Carbon Targets”. The research results indicate that under the background of carbon peak and carbon neutrality, China’s primary energy consumption will peak(59.4×10^(8)tce) around 2035, carbon emissions from energy consumption will peak(103.4×10^(8)t) by 2025, and natural gas consumption will peak(6100×10^(8)m^(3)) around 2040, of which the largest increase will be contributed by the power sector and industrial sector. China’s peak natural gas production is about(2800–3400)×10^(8)m^(3), including(2100–2300)×10^(8)m^(3)conventional gas(including tight gas),(600–1050)×10^(8)m^(3)shale gas, and(150–220)×10^(8)m^(3)coalbed methane. Under the background of carbon peak and carbon neutrality, the natural gas consumption and production of China will further increase, showing a great potential of the natural gas industry.

Battery Technologies for Grid-Level Large-Scale Electrical Energy Storage

Grid-level large-scale electrical energy storage(GLEES) is an essential approach for balancing the supply–demand of electricity generation, distribution, and usage. Compared with conventional energy storage methods, battery technologies are desirable energy storage devices for GLEES due to their easy modularization, rapid response, flexible installation, and short construction cycles. In general, battery energy storage technologies are expected to meet the requirements of GLEES such as peak shaving and load leveling, voltage and frequency regulation, and emergency response, which are highlighted in this perspective. Furthermore, several types of battery technologies, including lead–acid, nickel–cadmium, nickel–metal hydride, sodium–sulfur, lithium-ion, and flow batteries, are discussed in detail for the application of GLEES. Moreover, some possible developing directions to facilitate efforts in this area are presented to establish a perspective on battery technology, provide a road map for guiding future studies, and promote the commercial application of batteries for GLEES.

Optimization of Urban Multi-energy Flow Systems Considering Seasonal Peak Shaving of Natural Gas

In order to alleviate the shortage of natural gas supply in winter,relevant policies have been issued to promote the construction of gas peak-shaving and storage facilities.Largescale gas storage can transfer the supply-demand relationship of natural gas in time sequence,which has great potential in improving the economy and reliabillity of urban multi-energy flow systems.Addressing this issue,this paper proposes a mid-and long-term energy optimization method for urban multi-energy flow system that considers seasonal peak shaving of natural gas.First,the energy supply and demand features of different energy subsystems are analyzed.Then,a network model of the electricity-gas-heat multi-energy flow system is established.Considering the time-of-use electricity price mechanism and the seasonal fluctuations of the natural gas price,a mid-and long-term energy optimization model maximizing the annual economic revenue is established.The alternative direction multiplier method with Gaussian back substitution(ADMM-GBS)algorithm is used to solve the optimal dispatch model.Finally,the proposed method is verified by employing the actual data of the demonstration zone in Yangzhong City,China.The simulation results show that the proposed method is effective.

混合式抽水蓄能电站群容量计算研究Ⅰ:短期调峰特征与梯级开发增益

依托常规梯级水电站修建混合式抽水蓄能电站(简称混蓄电站)成为提升电力系统调峰能力的重要途径。混蓄电站即可抽水又可发电的典型运行方式增加了水电基地的灵活性调节能力,为此亟需研究其运行方式以及与原有梯级水电站运行方式间的互馈关系。研究以黄河上游待开发龙羊峡-拉西瓦、拉西瓦-尼那混蓄电站为对象,建立含混蓄电站的梯级水电站短期联合调峰优化模型,分析混蓄电站对原有梯级水电站运行方式的影响,基于理论推导与数值计算两种方法揭示混蓄电站调峰效果的变化特征。主要结论如下:(1)混蓄电站抽水水量经由原有梯级水电站机组下泄,使得非填谷时段原有水电站出力增加,水电站上旋备容量降低;(2)龙羊峡水电站满发流量相对较小、拉西瓦水库调节库容较小以及日综合利用供水流量过大是制约混蓄电站调峰效果的主要因素,发现了综合利用流量影响混蓄电站调峰效果的临界特性,并提出了临界综合利用流量的计算公式;(3)发现并量化了混蓄电站梯级开发模式较单一开发模式所带来的梯级抽水调峰增益现象,并揭示了梯级抽水调峰增益背后所蕴含的“河流梯级反向再造”内在机理。

2023年中国天然气调峰特性及2024年市场供需展望

为了助推天然气在中国新型能源体系建设中发挥更大的作用,回顾了2023年中国天然气市场调峰需求的主要特点,展望了2024年中国天然气市场的发展趋势。研究结果表明:(1)2023年,中国天然气供需总体宽松,天然气季节性调峰量为212×10^(8)m^(3),占该年全国天然气消费总量的5.4%,较2022年有所下滑;(2)2023年中国高月天然气不均匀系数为1.34,低月不均匀系数为0.85,月峰谷比为1.57,消费量月度波动幅度在年初市场异常和淡季需求量增长的影响下有所收窄;(3)2023年中国高峰天然气日消费量在历史性寒潮的刺激下直线攀升,峰值达到15.7×10^(8)m^(3)/d,同比增长18.9%;(4)城市燃气和发电用气成为2023年中国天然气调峰需求的主力,工业燃料和化工原料用气在一定程度上平抑了天然气消费量的季节性波动;(5)2023年中国储气设施顶峰能力再上新台阶,经营品种更加丰富;(6)在诸多有利条件叠加的情景下,预计2024年中国天然气需求量将有望达到4264×10^(8)m^(3),同比增长8.8%,新增需求量以工业燃料和发电用气为主;(7)2024年中国天然气调峰需求量预计为227×10^(8)m^(3),同比增长7.0%;(8)预计2024年中国天然气供应能力增长将超过需求量增长,整体上继续保持供应宽松的格局,并且在积极情景下LNG现货需求将保持旺盛;(9)建议国内天然气进口企业高度关注国际市场供应侧风险,销售企业提前做好冬季资源储备,城市燃气企业利用改革红利及时补齐相关短板,设施经营企业积极拓展市场化经营模式。

计及深度调峰的风-光-水-火-抽蓄多能源联网系统优化调度研究

多种能源联网运行逐步成为未来电力系统发展的方向,多能源联网系统的优化调度是应对规模化新能源并网消纳的重要手段。文中建立了计及火电机组深度调峰成本的风-光-水-火-抽蓄联网系统成本模型和考虑调峰主动性的风-光-水-火-抽蓄联网系统日前优化调度模型。针对多能源耦合系统结构复杂的情况,提出了分层优化调度的模型求解策略。上层模型以净负荷波动最小为优化目标,得到等效负荷曲线;下层模型根据上层模型的调度结果,以调峰运行的经济性最优和新能源弃电率最低为目标函数,计及调峰主动性,求解考虑火电机组深度调峰煤耗特性的含新能源系统的经济调度问题。仿真算例表明所建模型实现了多能源联网系统的互补运行,提升了火电机组的深度调峰能力,降低新能源弃电率和系统运行成本。

含混合式抽蓄的梯级水电站短期临界调峰模式

利用梯级水库电站建设混合式抽蓄电站,在提高新型电力系统清洁灵活性调峰能力的同时,也使得原梯级电站的运行方式变得更为复杂,亟需开展梯级电站与混合式抽蓄电站的联合调度模式研究。本文首先剖析了混合式抽蓄电站与梯级水电站日内联合调峰运行特点,建立了短期含混合式抽蓄的梯级水电站调峰优化模型;其次,发现了日内联合调峰的临界特性,并从临界调峰方式、临界调峰流量、临界调峰能力三方面定量刻画了该临界调峰特性,推导了梯级水电站临界调峰流量、混合式抽蓄电站临界抽发流量等计算公式,提出了混合式抽蓄电站与梯级水电站的临界调峰模式;最后,将上述理论成果应用至依托安康与旬阳梯级水库修建的安康混合式抽蓄电站。结果表明:安康水电站额定水头下临界调峰流量为892 m^(3)/s,小于892 m^(3)/s时,抽蓄电站日内满抽满发,以最大化调峰方式运行;大于892 m^(3)/s后,混合式抽蓄电站可转为与常规水电站同抽同发运行模式以及部分抽蓄机组转常规水电站机组运行模式等;长系列计算结果表明,与常规水电站同抽同发运行模式提高了抽蓄电站运行小时数,但降低了联合调度主体调峰能力,部分抽蓄机组转常规水电站机组运行模式耗用了安康水电站的可用发电水量,但提高了联合调度主体调峰能力,实际调度过程中应根据电网运行情况、电站运营主体等灵活选择抽蓄电站运行模式。

火电耦合压缩空气储能技术研究进展及展望

火电耦合压缩空气储能技术作为一种提升传统火电机组灵活性和经济性的有效手段,近年来受到了广泛关注。该文从分析火电耦合压缩空气储能技术在提升电网调峰能力、促进可再生能源整合等方面的重要意义出发。首先,介绍典型耦合系统的结构组成与工作原理;然后,探讨耦合系统中关键设备的技术现状和面临的挑战;之后,梳理火-储耦合系统的集成方案设计、调峰运行优化以及经济性评估的研究现状;最后,针对当前技术难点,展望未来火电耦合压缩空气储能技术的研究方向与重点。该文旨在为今后相关领域研究提供参考与借鉴,推动其持续发展和创新。

计及需求响应的光热电站参与深度调峰的分层优化调度策略

从源、荷两侧挖掘系统调峰潜力,建立计及需求响应的光热电站参与深度调峰的分层优化调度模型。上层从负荷侧出发,提出一种基于负荷分类的价格需求响应模型,可有效缓解系统调峰压力;中层从电源侧出发,利用光热电站灵活的调节特性在深度调峰时段协调火电机组参与辅助调峰,构建以运行总成本最小为目标函数的日前调度模型;下层提出一种基于模型预测控制的日内动态调整模型,在滚动优化的同时,通过状态反馈环节实时调整光热电站储热装置充放热修正日前调度计划。仿真结果表明,所提调度策略在降低系统调峰成本的同时能有效抑制风光以及负荷的短时功率波动,在保证系统安全稳定运行的前提下提升风光消纳率。

用于工业供汽的大型储蒸汽罐技术及结构分析

为满足供汽单位在常规火电快速变负荷及深度调峰时工业供汽的需求,针对直接存储蒸汽的设备进行研究,以保证供汽的快速性、稳定性及连续性。以某项目实际需求为依据,进行大型储蒸汽罐的方案设计,就无法采用常规计算且易发生失效主要结构,即罐壁与罐底连接结构进行数值模拟计算,通过计算结果分析,验证了该设备结构的可靠性,以及大型储蒸汽罐用于工业供汽方案的可行性。

风-火-储耦合系统储能容量配置优化对比

为提升风电富集区域风电消纳水平及燃煤机组的灵活性,提出了基于热电共蓄式压缩空气储能的风-火-储耦合系统及系统调度策略,建立了系统的容量配置优化框架,并对7种布局方案进行了多目标优化。优化结果表明:电锅炉将弃风电量转化为热量时,燃煤机组的运行点向电力负荷下限更低的区域移动,风电上网空间增大,燃煤机组出力水平降低;加入热电共蓄式压缩空气储能子系统,使得燃煤机组电功率水平降低;换热器废热的回收进一步降低了燃煤机组产热水平;通过调整燃煤机组热出力,抽汽蓄热子系统能够实现抽汽热的时空平移,促使燃煤机组运行点向电力负荷下限更低的区域移动,可间接促进风电的消纳。综合来看,3种子系统相组合的最佳耦合方案可实现燃煤机组的热电解耦,从而提升了其深度调峰能力,在更大程度消纳风电能力的同时提升了系统的效率和环保性。

锂电池储能用于削峰填谷优化配置方法研究

针对用户用电负荷不断增长,电网峰谷差进一步加大的问题,论文综合考虑削峰填谷效果和系统经济性,提出一种锂电池储能系统容量优化配置方法。首先,以储能系统综合成本最少和负荷标准差最小为优化目标,建立储能优化配置模型。其次,通过改进粒子群优化算法对模型进行求解,并使用负荷率作为评价指标对削峰填谷效果进行评估,得到综合成本和负荷标准差最优下储能系统最优配置容量。最后,结合某地区典型日负荷数据进行实验分析,结果表明,该模型在获得良好的削峰填谷效果的情况下系统具有一定的经济性,并且能够有效减少弃风弃光现象,从而提高电网整体运行效率。

关于进一步完善LNG储气调峰成本疏导机制的探讨——以四川省雅安市为例

随着天然气用气高峰时期气源短缺问题的日益凸显,储气调峰技术已成为缓解用气高峰的通用措施,合理地选择储气调峰方式是保障供气安全平稳进行的首要前提。为了更好地对LNG储气调峰项目进行成本疏导,在分析国内外研究现状的基础上,以四川省雅安市某项目为案例,对项目进行了效益测算,并针对其经济指标不达标的问题对项目进行了优化与改进。通过燃气企业储气调峰服务定价问卷调查,分析燃气企业储气调峰服务价格的可承受能力,将问卷调查与实例计算结合,得出燃气企业LNG储气调峰成本的推荐分摊比例,最后根据计算结果对政府有关部门、燃气企业、终端用户针对性地提出三种成本疏导方案。研究结果表明:①对政府而言,需要合理区分基本与非基本需求,统筹兼顾上下游行业、企业发展和民生保障、经济效益和社会公平公正,做好民生兜底工作,完善困难群体补贴政策,确保其基本生活用气不因价格联动等政策的实施而受影响;②对燃气企业而言,通过与终端用户合理分配LNG储气调峰成本,能够保证其合理利润,也体现了其作为保供主体的责任与优先“保民生”的社会属性;③对终端用户而言,充分考虑困难家庭经济承受能力,在尽可能降低居民支出的同时能够满足其用气高峰时段、季节的正常生产,最终实现多方互赢。结论认为:本研究所得的燃气企业LNG储气调峰成本的推荐分摊比例可为类似项目提供参考。

基于水蓄热的热源厂蒸汽调峰技术

基于工业供汽负荷波动大、昼夜偏差显著的现状,将水蓄热技术与热源厂热力生产工艺相结合,提出采用蒸汽-除盐冷水的间接换热技术、环氧富锌漆防腐技术和硬质聚氨酯发泡保温技术,并对形状、容积和高径比等罐体结构优化设计,旨在开发一种适用于工业供热的蒸汽调峰技术。实践应用表明,基于水蓄热的热源厂蒸汽调峰技术具有稳定高效、简单易操和投资收益显著等优点。本技术还可应用于燃煤机组实现深度调峰、消纳新能源发电等场景,具有重要的现实意义。

考虑储热装置多级特斯拉阀性能优化的热电机组调峰能力分析

随着风电并网容量与日俱增,热电机组调峰难度不断增加,由此导致弃风问题日趋严重。为有效缓解上述问题,提出将传统储热装置用多级特斯拉阀进行性能优化,扩大热电机组电-热特性区间,通过提升调峰能力来提高风电的消纳水平。首先,对特斯拉阀端口特性进行了分析,创新性地提出了一种基于多级特斯拉阀的新型储热装置,并在其传热与流动特性分析基础上构建了储热装置的模型;其次,对新型储热装置两种运行策略进行建模分析,证明了热电机组装配新型储热装置后能够提升调峰能力;最后,对热电机组的电-热特性区间和调峰能力的变化进行对比,结果表明,热电厂中配置含多级特斯拉阀的新型储热装置,可有效扩大热电机组电-热特性区间,提高调峰能力,同时缓解弃风问题。