Resilience of gas interchangeability in hydrogen-blended integrated electricity and gas systems:A transient approach with dynamic gas composition tracking

Green hydrogen can be produced by consuming surplus renewable generations.It can be injected into the natural gas networks,accelerating the decarbonization of energy systems.However,with the fluctuation of renewable energies,the gas composition in the gas network may change dramatically as the hydrogen injection fluctuates.The gas interchangeability may be adversely affected.To investigate the ability to defend the fluctuated hydrogen injection,this paper proposes a gas interchangeability resilience evaluation method for hydrogen-blended integrated electricity and gas systems(H-IEGS).First,gas interchangeability resilience is defined by proposing several novel metrics.Then,A two-stage gas interchangeability management scheme is proposed to accommodate the hydrogen injections.The steady-state optimal electricity and hydrogen-gas energy flow technique is performed first to obtain the desired operating state of the H-IEGS.Then,the dynamic gas composition tracking is implemented to calculate the real-time traveling of hydrogen contents in the gas network,and evaluate the time-varying gas interchangeability metrics.Moreover,to improve the computation efficiency,a self-adaptive linearization technique is proposed and embedded in the solution process of discretized partial derivative equations.Finally,an IEEE 24 bus reliability test system and Belgium natural gas system are used to validate the proposed method.

Optimal Operation of Integrated Energy Systems Subject to Coupled Demand Constraints of Electricity and Natural Gas

This paper proposes a hybrid multi-objective optimization and game-theoretic approach(HMOGTA)to achieve the optimal operation of integrated energy systems(IESs)consisting of electricity and natural gas(E&G)utility networks,multiple distributed energy stations(DESs),and multiple energy users(EUs).The HMOGTA aims to solve the coordinated operation strategy of the electricity and natural gas networks considering the demand characteristics of DESs and EUs.In the HMOGTA,a hierarchical Stackelberg game model is developed for generating equilibrium strategies of DESs and EUs in each district energy network(DEN).Based on the game results,we obtain the coupling demand constraints of electricity and natural gas(CDCENs)which reflect the relationship between the amounts and prices of electricity and cooling(E&C)that DESs purchase from utility networks.Furthermore,the minimization of conflicting costs of E&G networks considering the CDCENs are solved by a multi-objective optimization method.A case study is conducted on a test IES composed of a 20-node natural gas network,a modified IEEE 30-bus system,and 3 DENs,which verifies the effectiveness of the proposed HMOGTA to realize fair treatment for all participants in the IES.

Optimal Energy Reserve Scheduling in Integrated Electricity and Gas Systems Considering Reliability Requirements

With the growing interdependence between the electricity system and the natural gas system,the operation uncertainties in either subsystem,such as wind fluctuations or component failures,could have a magnified impact on the reliability of the whole system due to energy interactions.A joint reserve scheduling model considering the cross-sectorial impacts of operation uncertainties is essential but still insufficient to guarantee the reliable operation of the integrated electricity and natural gas system(IEGS).Therefore,this paper proposes a day-ahead security-constrained unit commitment(SCUC)model for the IEGS to schedule the operation and reserve simultaneously considering reliability requirements.Firstly,the multi-state models for generating units and gas wells are established.Based on the multi-state models,the expected unserved energy cost(EUEC)and the expected wind curtailment cost(EWC)criteria are proposed based on probabilistic methods considering wind fluctuation and random failures of components in IEGS.Furthermore,the EUEC and EWC criteria are incorporated into the day-ahead SCUC model,which is nonconvex and mathematically reformulated into a solvable mixed-integer second-order cone programming(MISOCP)problem.The proposed model is validated using an IEEE 30-bus system and Belgium 20-node natural gas system.Numerical results demonstrate that the proposed model can effectively schedule the energy reserve to guarantee the reliable operation of the IEGS considering the multiple uncertainties in different subsystems and the cross-sectorial failure propagation.

Integrated operational planning of hydrothermal power and natural gas systems with large scale storages

The growing installation of natural gas fired power plants has increased the integration of natural gas and electricity sectors. This has driven the need investigate the interactions among them and to optimize energy resources management from a centralized planning perspective. Thus, a combined modeling of the reservoirs involved in electric power and gas systems and their locations on both networks are essential features to be considered in the operational planning of energy resources.This paper presents a modeling and optimization approach to the operational planning of electric power and natural gas systems, taking into account different energy storage facilities, such as water reservoirs, natural gas storages and line packs of pipelines. The proposed model takes advantage of captures both energy systems synergy and their associated networks. This approach identifies the interactions between the energy storage facilities and their economic impact over their optimal scheduling. The results show the benefits of an integrated operational planning of electric power and natural gas systems, the close interdependency between the energy resources stored in both systems, and the effects of a combined scheduling.

Prime Energy Challenges for Operating Power Plants in the GCC

There is a false notion of existing available, abundant, and long lasting fuel energy in the Gulf Cooperation Council (GCC) Countries;with continual income return from its exports. This is not true as the sustainability of this income is questionable. Energy problems started to appear, and can be intensified in coming years due to continuous growth of energy demands and consumptions. The demands already consume all produced Natural Gas (NG) in all GCC, except Qatar;and the NG is the needed fuel for Electric Power (EP) production. These countries have to import NG to run their EP plants. Fuel oil production can be locally consumed within two to three decades if the current rate of consumed energy prevails. The returns from selling the oil and natural gas are the main income to most of the GCC. While NG and oil can be used in EP plants, NG is cheaper, cleaner, and has less negative effects on the environment than fuel oil. Moreover, oil has much better usage than being burned in steam generators of steam power plants or combustion chambers of gas turbines. Introducing renewable energy or nuclear energy may be a necessity for the GCC to keep the flow of their main income from exporting oil. This paper reviews the GCC productions and consumptions of the prime energy (fuel oil and NG) and their role in electric power production. The paper shows that, NG should be the only fossil fuel used to run the power plants in the GCC. It also shows that the all GCC except Qatar, have to import NG. They should diversify the prime energy used in power plants;and consider alternative energy such as nuclear and renewable energy, (solar and wind) energy.

电动汽车与清洁能源融合发展技术研究与展望

以光电、风电为代表的清洁能源发电技术可为电动汽车提供清洁的电力供给,减少全生命周期碳排放,助力交通领域“双碳”战略目标的实现,因此近年来得到迅猛发展。为了推动交能融合技术的应用,明确相关研究中的关键问题,该文综述了国内外学者过去10年在电动汽车与清洁能源融合技术方面的研究进展。首先,介绍了二者融合发展的必要性与现实意义;其次,将已有研究成果分为公路环境与城市道路环境两类,分别从电网、充电站、车辆3个层面归纳了当前电动汽车与清洁能源融合技术的研究成果;最后,考虑到清洁能源发电以及电动汽车充电存在较强的随机波动,对未来发展提出了加强公共领域交能融合发展、构建多种互补型清洁能源发电策略、建立“源—网—荷—储”集成优化技术、强化分布式微电网能源自洽调度、加强无线光伏充电公路运营管理等建议。

考虑电-热储能协同的综合能源系统规划优化研究

针对传统电化学储能造价高导致我国可再生能源消纳困难问题,提出一种考虑电-热储能协同的综合能源系统最优化规划方法。分析铅酸电池和蓄热罐的物理特性,建立其状态表征模型;设计电-热储能系统融合平抑可再生能源出力波动、保障供需平衡、峰谷套利三种功能场景的协同运行策略,建立考虑电-热协同的规划优化策略;基于最优化理论,以年总成本最小为优化目标,提出一种考虑电-热储能协同的综合能源系统规划优化模型,并以改进粒子群算法对模型进行求解。算例结果表明,所提出的模型能够有效提升能源系统的可再生能源消费占比。

计及电-气双向耦合的综合能源配电网优化重构

综合能源系统是实现电网、气网以及热网等多种能源系统深度融合,利用能量耦合互补等优势提升整个系统能源利用效率的有效形式。为提升综合能源系统优化运行能力,文章首先基于电转气技术与天然气发电技术,构建了的电-气双向耦合综合能源系统总体模型。进而考虑配电网重构技术(Distribution Network Reconfiguration Technology,DNR)中拓扑结构灵活可控这一特性,在配电子系统中引入开关变量、系统运行总费用最低这一目标函数及网络辐射状拓扑结构等约束,建立了配电子系统重构模型。从降低模型求解复杂性的角度,应用二阶锥松弛、乘积变量线性化及分段线性化等方法,将原始综合能源配电网重构非凸非线性模型转化为混合整数二阶锥规划(Mixed Integer Second-Order Cone Programming,MISOCP)问题求解。仿真结果表明,在电-气双向耦合的综合能源系统中应用配电网重构技术,能够降低综合能源系统运行费用,同时有效支撑了配电子系统电压与配气子系统气压。

综合能源系统低碳规划与运行研究述评

为提高综合能源系统(integrated energy system, IES)低碳规划及优化运行的技术水平,推进能源结构低碳转型及新型电力系统建设,梳理和总结研究学者在IES的模型构建、系统规划、运行调度等方面的研究成果,该文开展了相关领域的综述研究。首先,阐述了综合能源系统的典型架构、典型设备及其能流特性。其次,针对IES低碳规划和运行策略及其相关支撑技术,分别论述了多态不确定性模型及功率预测、柔性负荷调控策略、IES参与电力辅助服务及其低碳运营机制、优化模型及其求解算法等方面的技术路线及研究成果;研究表明,规划与运行策略是支撑IES低碳、高效、经济运行水平的关键技术,计及不确定性的高维、非线性、多目标、非凸问题的精确建模和快速求解等难点问题亟待深入研究。最后,展望了人工智能、大数据、电力物联网等新技术在IES低碳规划和运行方面的应用前景,归纳了该领域亟待应对的技术挑战和关键问题。

Many-objective optimization for coordinated operation of integrated electricity and gas network

This paper develops a many-objective optimization model, which contains objectives representing the interests of the electricity and gas networks, as well as the distributed district heating and cooling units, to coordinate the benefits of all parties participated in the integrated energy system(IES). In order to solve the many-objective optimization model efficiently, an improved objective reduction(IOR) approach is proposed, aiming at acquiring the smallest set of objectives. The IOR approach utilizes the Spearman’s rank correlation coefficient to measure the relationship between objectives based on the Pareto-optimal front captured by the multi-objective group search optimizer with adaptive covariance and Lévy flights algorithm, and adopts various strategies to reduce the number of objectives gradually. Simulation studies are conducted on an IES consisting of a modified IEEE 30-bus electricity network and a 15-node gas network. The results show that the many-objective optimization problem is transformed into a bi-objective formulation by the IOR. Furthermore,our approach improves the overall quality of dispatch solutions and alleviates the decision making burden.

Bi-Level Bidding and Multi-Energy Retail Packages for Integrated Energy Service Providers Considering Multi-Energy Demand Elasticity

How to effectively use the multi-energy demand elasticity of users to bid in the multi-energy market and formulate multi-energy retail packages is an urgent problem which needs to be solved by integrated energy service providers(IESPs)to attract more users and reduce operating costs.This paper presents a unified clearing of electricity and natural gas based on a bi-level bidding and multi-energy retail price formulation method for IESPs considering multi-energy demand elasticity.First,we propose an operating structure of IESPs in the wholesale and retail energy markets.The multi-energy demand elasticity model of retail-side users and a retail price model for electricity,gas,heat and cooling are established.Secondly,a bi-level bidding model for IESPs considering multi-energy demand elasticity is established to provide IESPs with wholesale-side bidding decisions and retail-side energy retail price decisions.Finally,an example is given to verify the proposed method.The results show that the method improves the total social welfare of the electricity and natural gas markets by 7.99%and the profit of IESPs by 1.40%.It can reduce the variance of the electricity,gas,and cooling load curves,especially the reduction of the variance of the electricity load curve can which reach 79.90%.It can be seen that the research in this paper has a positive effect on repairing the limitations of integrated energy trading research and improving the economics of the operation of IESPs.

电热氢综合能源系统建模及容量规划研究

在“双碳”目标下,电热氢综合能源系统的应用将成为能源高效利用、多能耦合发展以及清洁低碳转型的重点战略方向。结合当前电热氢综合能源系统的国内外研究现状,首先对系统建模部分进了归纳与总结,并建立了考虑系统电热特性、自身寿命衰减特性等特点的各设备数学模型,为后续相关方向的深入研究提供一定的参考。其次,对电热氢综合能源系统的容量规划问题展开研究,并分别从系统运行策略、目标函数与求解以及当前存在问题与创新方面展开详细分析。最后,对电热氢综合能源系统的未来创新与发展进行了展望。

中国电动汽车发展及车网互动对新型储能配置的影响

电力系统新型储能发展预期高,但存在与其他灵活调节资源统筹考虑不足的问题。随着电动汽车持续快速发展,未来电动汽车车网互动必将影响新型储能需求,新型储能规划必须与电动汽车发展统筹考虑。通过分析影响电动汽车发展与车网互动调节能力的关键因素,研判中国电动汽车的发展规模,结合电动汽车用能习惯与电力系统调节需求,构建了中国电动汽车灵活性潜力研究模型,并从系统全局优化角度,评估车网互动灵活调节能力,分析了对中国及其7个区域新型储能配置的影响。

基于热网-电网综合潮流的用户侧微型能源站及接入网络优化规划

提出一种考虑热网-电网综合潮流的用户侧综合能源系统的规划方法。考虑经济、节能、环保等因素,建立含风机、光伏、储能、微型燃气轮机及燃气锅炉的微型能源站二层规划模型。上层规划目标函数为年费用最小,优化变量为微型能源站安装位置、容量及接入网络;下层规划考虑储能与微型燃气轮机的优化调度,规划目标包含一次能源节约率、可控分布式能源运行费及网损费用。基于热电耦合,提出热网-电网综合潮流计算方法与流程。采用改进遗传算法和粒子群优化算法对模型进行求解。某用户侧综合能源系统算例验证了所提模型和方法的有效性。

基于混合整数二阶锥的配电-气网联合规划

提出了一种考虑配电网重构及小时级潮流变化的配电-气网(EGDN)联合规划模型。一方面,融入配电网重构来优化系统的运行状态,两网协同规划能发挥不同能源间的互补共济作用,提升系统的可靠性和运行效率;另一方面,所提模型考虑小时级配电网和配气网的潮流方程,以精细化描述系统的运行状态。为了求解该非线性非凸模型,适当松弛原问题,将其转换为可直接求解的混合整数二阶锥规划(MISOCP)问题。仿真结果表明所提规划模型显著提升了系统的可靠性,降低了相关设备的配置容量,减少了能量传输损耗,降低了总体规划与运行费用,证明了MISOCP模型与简单的混合整数线性规划模型相比,更能获得满足实际工程需求的规划方案。

考虑风力发电接入的电网规划

考虑风力发电的特点,研究有风电接入的电网规划问题,提出含风电电源的电网规划模型,依据中国当前促进新能源发展和节能减排政策,建立相应的风电利用指标和节能指标,并对规划模型进行科学评价.通过算例验证了所提模型的有效性.

计及供能可靠性的电-气互联传输网络优化规划

现有电-气互联综合能源系统(IEGES)的传输网络规划仍侧重于考虑输电系统可靠性,对“电-气”双向联供的可靠性考虑不足;并且传统电、气子系统网络独立规划的模式将难以满足日益增长的综合负荷需求。针对上述问题,重点研究衡量IEGES供能可靠性,完善了“以电为主”的IEGES传输网络规划模型;将可靠性引入传输网络优化规划的目标函数和约束条件中,直接获得满足可靠性要求的规划方案,避免方案的反复校核与调整。建立了考虑可靠性的弃风成本、能量短缺成本、电-气耦合转换、供电供气平衡等因素的传输网络优化规划数学模型。为提高模型求解效率,采用增量分段线性化的方法对非线性约束进行线性化处理,将原混合整数非线性规划问题转化为混合整数线性规划问题进行求解。基于IEEE 39节点与比利时NGS 20节点联合系统的仿真结果表明:考虑供能可靠性的传输网络规划方案在提升系统经济性、可靠性和风电消纳能力等方面效果显著,可为IEGES优化规划提供技术手段。

中国电力系统发展运营面临的挑战和对策

"十三五"及未来一段时期,中国经济长期处于新常态阶段,能源供需格局深刻调整,市场化体制机制不断完善,电力发展面临新机遇新挑战。基于中国未来一段时期电力供需总体宽松、新能源占比持续提高、市场化改革取得突破等边界条件,从电力供需的不确定性、煤电功能定位、新能源并网消纳、系统安全稳定运行、市场化运营等方面分析了电力系统发展运营所面临的一些问题,剖析了原因,并提出有关对策建议。

提高我国电力产业能效的系统规划方法研究

电力产业作为国民经济的基础产业和社会公用事业,其不仅生产能源同时也在耗费着大量一次能源。由于电力生产耗费一次能源的比重最高,提高电力能效自然成为节约能源的重要手段。本文从系统规划的角度出发,研究了提高电力能效的各种方法,包括电源结构优化、电力与经济协调规划、电源与电网协调规划、电价规划、电力节能规划等。

中国特色的低碳经济、能源、电力之路初探

中国作为发展中大国,探索一条适合我国国情的低碳经济-能源-电力的发展路径是至关重要的。在过去30年中,我国在节能方面取得了巨大成就,可以概括为具有中国特色的能源使用管理,它是低碳能源的重要组成部分。综合资源战略规划与智能电网构成低碳电力。它们将在中国的低碳经济中发挥重要作用。本文结合中国国情,在低碳经济(低碳能源与低碳电力)的模型基础上,展望了未来20年我国经济发展前景、能源的需求、能源消费结构、非化石能源的比重、能耗-电耗水平、CO2排放强度,以及经济发展对电力的需求、电源的结构、清洁能源的发电比重,能效电厂及其发电量(终端电力用户节约的电量)等,分析了今后发展应关注的问题。