Optimized scheduling of integrated energy systems for low carbon economy considering carbon transaction costs

With the introduction of the“dual carbon”goal and the continuous promotion of low-carbon development,the integrated energy system(IES)has gradually become an effective way to save energy and reduce emissions.This study proposes a low-carbon economic optimization scheduling model for an IES that considers carbon trading costs.With the goal of minimizing the total operating cost of the IES and considering the transferable and curtailable characteristics of the electric and thermal flexible loads,an optimal scheduling model of the IES that considers the cost of carbon trading and flexible loads on the user side was established.The role of flexible loads in improving the economy of an energy system was investigated using examples,and the rationality and effectiveness of the study were verified through a comparative analysis of different scenarios.The results showed that the total cost of the system in different scenarios was reduced by 18.04%,9.1%,3.35%,and 7.03%,respectively,whereas the total carbon emissions of the system were reduced by 65.28%,20.63%,3.85%,and 18.03%,respectively,when the carbon trading cost and demand-side flexible electric and thermal load responses were considered simultaneously.Flexible electrical and thermal loads did not have the same impact on the system performance.In the analyzed case,the total cost and carbon emissions of the system when only the flexible electrical load response was considered were lower than those when only the flexible thermal load response was taken into account.Photovoltaics have an excess of carbon trading credits and can profit from selling them,whereas other devices have an excess of carbon trading and need to buy carbon credits.

Allocation of fixed transmission cost based on power flow tracing algorithm

In the electricity market, charging based on the traditional spot electricity price often results in the payment imbalance of electric network, and goes against the development of the power system. So, it is necessary to modify the spot price. The key of the modification lies in how to calculate the fixed unit transmission cost of each node, that is how to allocate the fixed transmission cost to users.To solve this problem, we develop a power flow tracing algrithm to modify the spot price. We put forward a path searching method based on the graph theory after studying the fundamental principle of power flow tracing and apply the method to the downstream tracing algorithm and upstream tracing algorithm according to the proportional distribution principle. Furthermore, to improve the computational efficiency of the algorithm, we introduce the branch expunction method to optimize the node order. By using the result of power flow tracing to get fixed node transmission cost and introducing it to modify the spot price, we obtain the synthetical price.The application to a 5-bus system prove the algorithm feasible.

User Association and Power Allocation for UAV-Assisted Networks: A Distributed Reinforcement Learning Approach

Unmanned aerial vehicles(UAVs)can be employed as aerial base stations(BSs)due to their high mobility and flexible deployment.This paper focuses on a UAV-assisted wireless network,where users can be scheduled to get access to either an aerial BS or a terrestrial BS for uplink transmission.In contrast to state-of-the-art designs focusing on the instantaneous cost of the network,this paper aims at minimizing the long-term average transmit power consumed by the users by dynamically optimizing user association and power allocation in each time slot.Such a joint user association scheduling and power allocation problem can be formulated as a Markov decision process(MDP).Unfortunately,solving such an MDP problem with the conventional relative value iteration(RVI)can suffer from the curses of dimensionality,in the presence of a large number of users.As a countermeasure,we propose a distributed RVI algorithm to reduce the dimension of the MDP problem,such that the original problem can be decoupled into multiple solvable small-scale MDP problems.Simulation results reveal that the proposed algorithm can yield lower longterm average transmit power consumption than both the conventional RVI algorithm and a baseline algorithm with myopic policies.

Experimental Research of the Radiator Thermal Performance Test Equipment and Its Application in Heating System

Radiator thermal performance test equipment plays a key role in the processing of developing a new type of heat radiator and its application products.The precise of temperature controlling,temperature measuring andflow measuring are the vital factors for a radiator thermal performance test equipment.Based on the above back-ground,this paper improves the measurement and control system of radiator thermal performance test equip-ment,which improves the accuracy of the radiator thermal performance test equipment.This paper also optimizes the software and hardware system simultaneously so as to improve the precision of the auto-test system of test equipment.Theflow rate ranges from 175 kg/h to 178 kg/h under different conditions.The average is 176.5 kg/h and the deviation rates are from 1.62%to 1.97%.The heat produced under various conditions is different.The maximum is 4.3 kW and the minimum is 4.2 kW for condition 1,the maximum is 3.3 kW and the minimum is 3.2 kW for condition 2 and the maximum is 1.95 kW and the minimum is 1.89 kW for condition 3.However,the deviation rate is about 2.9%,which shows that the device has high stability and high precision.This paper studies a new electronic heat cost allocate meter test method by radiator thermal performance test equipment at the same time.This paper tests temperature changes through four measures points and gets a result appeared as a heat backup which should be avoided when using in the test of electronic heat cost allocate meter.Some experiences and references could be gained for further research in the heating system from this test and research.

液态空气储能耦合综合能源系统热电联储联供优化配置研究

液态空气储能(LAES)在多能耦合的综合能源系统中极具应用前景,合理的储能容量配置更有利于综合能源系统低碳经济运行,但目前研究未充分考虑LAES热电联储联供强相关的特性和优势。因此,本文提出了一种LAES耦合综合能源系统的热电联储联供优化配置方法,针对综合能源系统的基本架构,构建了各组成单元的热电联储/供调度约束模型,并以设备初始投资成本、设备运维成本、购能成本、弃风弃光成本等为目标函数,考虑了系统能量平衡约束、设备容量约束、设备出力约束、外网交互功率约束以及储能约束,建立了相应的优化配置模型,并基于混合整数线性规划方法进行模型求解。以某实际园区为例,设置了5种场景进行优化结果对比分析,结果表明:考虑LAES热电联储联供特性的综合能源系统能实时有效地满足系统用能需求,同时能实现更好的经济效益和环境效益,相较于传统分供系统,系统总经济成本下降37.1%,实现碳减排71.50%,并在消纳可再生能源和减少弃光弃风方面更具潜力。本研究可为LAES耦合系统热电联储联供优化模型的有效性提供理论依据,有助于推动LAES在综合能源系统中的商业化应用。

电力市场环境下抽水蓄能电站容量电费定价与成本分摊方法

抽水蓄能电站作为一种有效的电力系统灵活性资源,将成为保障新型电力系统安全稳定运行的重要手段。制定合理的回收抽水蓄能电站建设固定成本方案是支撑系统运行、激励投资的关键问题。在抽水蓄能电站的市场化运行背景下,构建了抽水蓄能电站顺次参与现货-辅助服务市场的容量电费定价模型,实现以经营期内收支平衡为目标定期滚动核定抽水蓄能电站的待分摊成本。同时,考虑抽水蓄能电站容量电费的潜在分摊对象,提出采用效用比例VCG(Vickrey-Clarke-Groves)机制对抽水蓄能电站容量电费进行成本分摊,量化源荷侧分摊主体的替代效益,并将容量电费按比例分摊。实际系统算例的仿真分析验证了所提方法的有效性。

消纳弃风的风电混合储能供热系统容量配置优化

为解决“三北”地区冬季建筑能耗较高且弃风严重的问题,设计了由锂电池、固体蓄热装置和热泵设备组成的风电混合储能供热系统。首先基于BP神经网络预测了风电机组输出功率,采用k-means聚类分析得到了供热典型日负荷曲线;然后提出了一种基于粒子群优化算法的风电混合储能供热系统容量配置优化方法,以系统总成本最小和弃风量最低为约束条件构建了目标函数;最后比较了考虑和不考虑弃风条件下,风电混合储能供热系统的容量配置优化结果。研究表明,所提出的优化方法不但可以有效降低弃风率,场景适用性强,还能够满足严寒地区冬季清洁供热需求,为可再生能源高效利用提供参考。

Allocating Ex-post Deviation Cost of Virtual Power Plants in Distribution Networks

Virtual power plants(VPPs)including distributed generation,energy storage,and elastic load are emerging in distribution networks.Multiple VPPs can participate in electricity market as an aggregated entity and effective cost allocation mechanism among VPPs is a crucial issue.This paper focuses on allocating ex-post cost of VPPs incurred by deviation between actual power and ex-ante schedule in a two-settlement electricity market.We obtain approximate quadratic formulation of ex-post deviation cost considering network loss and develop an analytical cost allocation algorithm based on cooperative game theory.The allocated cost is consistent with cost causation principle and provides VPPs with incentive for aggregation.The proposed allocation method and relevant theoretical result are evaluated and verified by numerical tests.

考虑出力相关性的海上风电接入系统固定成本分摊方法

在海上风电规模化开发、集群化并网的背景下,如何回收海上风电接入系统的输电成本,公平合理地向各风电场分摊已成为目前海上风电行业亟待解决的问题。针对该问题,提出了一种考虑风电出力相关性的海上风电接入系统固定成本分摊方法。首先,利用藤Copula函数构建多个海上风电场的出力相关性模型,同时假定系统负荷需求模型服从正态分布,发电机服从0-1概率分布;然后,结合蒙特卡洛抽样和顺流概率潮流追踪法计算各海上风电场接入系统的固定成本分摊费用;最后,通过算例仿真分析,验证了所提方法的合理性和有效性。

超临界煤电供热机组经营成本决策系统研发

随着越来越多的亚临界、超临界、超超临界纯凝机组改供热,发电企业如何分配发电负荷与供热负荷,如何实时计算供热煤电的发电、供热、调峰边界成本,已成为重要的研究课题。以某电厂2台600MW超临界工业供热抽凝机组为研究对象,预测机组发电煤耗和供热煤耗,针对不同煤价、电价、汽价、电网辅助交易价格等市场外部环境,计算出机组盈利边界成本,给出不同边界条件下的生产策略。在企业经营成本辨识与预测、生产决策分析的基础上,研发供热煤电机组生产经营成本决策系统,可自动计算发电、供热、调峰边界成本,整合各底层系统生产成本维度数据,形成公司级大数据库,通过正平衡法和回归分析法对各管理数据、生产数据进行深层次分析,并通过以往大量数据进行专业化分析,使系统具有更强的决策力,进而预测企业在不同生产条件下应做出的最优决策。

多机组、多供热模式热电负荷优化分配算法的研发

为了解决热电厂机组间负荷均衡不合理的问题,提出一种基于模型预测的多供热模式热电厂多机组间实时负荷均衡方法。以国能长源汉川发电工业原有的依靠冷、热再蒸汽低压供热的6台机组为例,给出经改造后不同热电负荷组合情况下的厂内加热分配工况。结果表明,该算法的研发可有效依据热电负荷的实时指示,在线获得全厂机组间经济优化的负荷分配方案。

Optimal Operation and Size for an Energy Hub with CCHP

The interest in distributed generation has been increasing in recent years, especially due to technical devel- opment on generation systems that meet environmental and energy policy concerns. One of the most impor- tant distributed energy technologies is Combined Cooling, Heat and Power (CCHP) systems. CCHP is a small and self-contained electric, heating and cooling generation plant that can provide power for households, commercial or industrial facilities. It can reduce power loss and enhance service reliability in distribution systems. The proposed method in this paper determines the optimal size and operation of CCHP, auxiliary boiler and also heat storage unit as elements of an energy hub, for users by an integrated view of electricity and natural gas network. Authors apply cost and benefit analysis in the optimization. To confirm the proposed method, the optimum sizes of these elements are determined for a hotel in Tehran as a case study.

Energetic, economic, and environmental analysis of solid oxide fuel cell-based combined cooling, heating, and power system for cancer care hospital

In this study,energetic,economic,and environmental analysis of solid oxide fuel cell-based combined cooling,heating,and power(SOFC-CCHP)system is proposed for a cancer care hospital building.The energy required for the hospital power,cooling,and heating demands was obtained based on real and detailed field data,which could serve as a reference for future works in the field.These data with a 3D model for the hospital building are constructed and created in eQUEST software to precisely calculate the energy demands of the existing system(baseline case).Then,energetic,economic,and environmental models were developed to compare and assess the performance of the proposed SOFC-CCHP system.The results show that the proposed system can cover about 49% to 77% of the power demand of the hospital with an overall efficiency of 78.3%.Also,the results show that the levelized cost of electricity of the system and its payback period at the designed capacity of the SOFC is 0.087S/kWh and 10 years,respectively.Furthermore,compared to the baseline system of the hospital,the SOFC-CCHP reduces the CO_(2) emission by 89% over the year.The sensitivity analysis showed that a maximum SOFC efficiency of 52%and overall efficiency of 80%are achieved at cell operating temperature of 1027℃ and fuel utilization factor of 0.85.

Two new methods for power flow tracing using bus power balance equations

Two new methods were presented for power flow tracing(PFT).These two methods were compared and the results were discussed in detail.Both methods use the active and reactive power balance equations at each bus in order to solve the tracing problem.The first method considers the proportional sharing assumption while the second one uses the circuit laws to find the relationship between power inflows and outflows through each line,generator and load connected to each bus of the network.Both methods are able to handle loop flow and loss issues in tracing problem.A formulation is also proposed to find the share of each unit in provision of each load.These methods are applied to find the producer and consumer's shares on the cost of transmission for each line in different case studies.As the results of these studies show,both methods can effectively solve the PFT problem.

Dynamic Simulation and Performance Analysis on Multi-Energy Coupled CCHP System

Although the Combined Cooing,Heating and Power System(hereinafter referred to as“CCHP”)improves the capacity utilization rate and energy utilization efficiency,single use of CCHP system cannot realize dynamic matching between supply and demand loads due to the unbalance features of the user’s cooling and heating loads.On the basis of user convenience and wide applicability of clean air energy,this paper tries to put forward a coupled CCHP system with combustion gas turbine and ASHP ordered power by heat,analyze trends of such parameters as gas consumption and power consumption of heat pump in line with adjustment of heating load proportion of combustion gas turbine,and optimize the system ratio in the method of annual costs and energy environmental benefit assessment.Based on the analysis of the hourly simulation and matching characteristics of the cold and hot load of the 100 thousand square meter building,it is found that the annual cost of the air source heat pump is low,but the energy and environmental benefits are poor.It will lead to 6.35%shortage of cooling load in summer.Combined with the evaluation method of primary energy consumption and zero carbon dioxide emission,the coupling system of CHHP and air source heat pump with 41%gas turbine load ratio is the best configuration.This system structure and optimization method can provide some reference for the development of CCHP coupling system.

基于穷举搜索法的城市建筑CCHP系统优化配置

冷-热-电三联供系统可实现能量的高效梯级利用,有利于实现“碳达峰、碳中和”。基于穷举搜索法构建了一套包含燃气热电联产系统、燃气锅炉、电制冷机、吸收式制冷机和水-水换热器的楼宇级冷-热-电三联供系统,并以北京3种典型的楼宇建筑为研究对象,研究了冷-热-电三联供系统在不同类型负荷下的容量配置、系统运行参数、经济性和减排情况并进行相应敏感性分析。结果表明:与分产系统相比,商业建筑、办公建筑、居住建筑的成本节约率分别为21.76%、16.72%和9.17%,二氧化碳减排率分别为15.80%、10.42%和4.41%,系统能源价格分别下降39.85%、49.04%和41.29%;研究结果可为冷-热-电三联供系统优化提供参考。

计及碳交易和价格型需求响应的热电联合低碳经济调度

针对热电联产机组在冬季供暖期间的“热电冲突”和弃风消纳问题,文中提出了计及碳交易成本和价格型需求响应的热电联合低碳经济调度模型,同时引入了电锅炉和储热装置解耦热电耦合限制,研究了不同运行方式对优化调度的影响。在系统中考虑碳交易成本,限制碳排放,并通过用户侧需求响应来增强电网调峰能力,对负荷曲线进行优化,有效削减了负荷的峰谷差,为风电上网提供了空间。最后,采用CPLEX求解器进行求解,并基于改进的IEEE-30节点系统进行仿真分析。结果表明,在文中调度方法下风电消纳量提高了83.72%,碳排放量减少了2211 t,验证了该调度模型的可靠性。

高温复合相变储热在城市清洁能源改造中的应用

高温复合相变储热材料电热装置利用低谷电、弃风电、弃光电等电能,通过电热转换实现能量存储应用,主要用于北方地区清洁供热以及火电机组灵活性改造和深度调峰,由于高温复合相变储热材料电热装置利用低谷电进行供暖,使得供暖成本大幅降低。本文针对北京城区一个锅炉房“油改电”供热工程,综述了高温复合相变储热装置,着重介绍了该装置的储热材料及运行原理,并根据供热工程目标用户的热负荷,进行了高温复合相变储热系统的设计。对于改造的可行性,本团队在负荷计算的基础上重点分析了整个采暖季能源消耗和运行费用,并与改造前做了详细对比。研究结果表明基于高温复合相变储热装置的供暖系统,不仅可以满足用户的热需求,还减少了碳排放,经计算改造后一个供暖季可减少591.85吨碳排放。同时由于该系统充分利用了低谷电,降低了供暖成本,与直热式供暖系统相比运行费用降低了57.76%,与燃油锅炉相比,运行费用降低了84.23%,实现了清洁能源的高效利用,提高了系统的经济性,也证明了改造的可行性。

电力市场不同发展阶段下抽水蓄能电站电价机制研究

抽水蓄能电站对电网调峰、新能源消纳、“双碳”目标的实现具有积极作用。针对电力市场进程中的抽水蓄能电站成本疏导问题,首先系统梳理国家政策对抽水蓄能价格机制规定的历史沿革,并调研国外抽水蓄能电站的成本回收方式,在了解现有政策和做法的前提下,结合我国电力市场建设进程,分初期阶段、过渡阶段、成熟阶段3个时期,根据各市场在不同阶段的建设情况,明确给出不同市场阶段下抽水蓄能电站价格机制,建立电价解析数学模型,将抽水蓄能电站发生的成本有效疏导。考虑经济发展、物价水平、承受能力等因素,确定抽水蓄能电站成本疏导的3个原则,提出成本分摊的6种单一方式和组合方式,对我国抽水蓄能电站的发展具有一定的理论和实践参考意义。

基于可逆功比的热电联产系统[火用]成本分析方法

为了分析多联产系统的各种输出能量的单位[火用]成本,提出一种基于可逆功比的[火用]成本分析方法。此方法假设完成可逆过程的热力系统输出的各种形式能量的单位[火用]成本相等,且与输入能量的平均单位[火用]成本相等。通过此假设和可逆功比(即可逆过程的做功量与总能量的比值),构建成本平衡方程,分析了燃气轮机热电联产系统输出能量的[火用]成本,最后进行了天然气分布式能源系统算例的[火用]成本分析。结果表明:利用此方法可以得出与“质优价高”一致的结论。