基于调峰能力分析的电网弃风评估方法及风电弃风影响因素研究

  [目的]  由于风电出力的间歇性、随机性和反调峰特性,大规模可再生能源风电并网造成京津唐地区冬季供热季弃风现象愈加严重。  [方法]  为了能够定量研究电源调峰、联络线外送等弃风因素变化时对电网弃风的影响情况,从而准确衡量不同情形下电网对风电的接纳能力,文章从系统调峰的角度,以电热负荷平衡约束、机组出力约束为条件建立风电弃风评估模型。  [结果]  对京津唐电网弃风情况的模拟结果表明,常规电源调峰越深、联络线外送深度越小,系统接纳风电出力的空间越大;而过快的风电装机容量增长速度和较高的热电机组供热比率,会抑制风电出力,从而导致弃风。  [结论]  因此,可通过激励系统中常规电源积极主动进行调峰、控制联络线外送峰谷差和热电机组出力范围来提高系统接纳风电的能力;而根据未来规划水平,选取某一比例的风电装机容量增长速度,即可确定最佳的风电并网规模,控制弃风电量在一定水平内。     

Optimization modeling method for coal-to-electricity heating load considering differential decisions

Heating by electricity rather than coal is considered one effective way to reduce environmental problems. Thus, the electric heating load is growing rapidly, which may cause undesired problems in distribution grids because of the randomness and dispersed integration of the load. However, the electric heating load may also function as an energy storage system with optimal operational control. Therefore, the optimal modeling of electric heating load characteristics, considering its randomness, is important for grid planning and construction. In this study, the heating loads of distributed residential users in a certain area are modeled based on the Fanger thermal comfort equation and the predicted mean vote thermal comfort index calculation method. Different temperatures are considered while modeling the users’ heating loads. The heat load demand curve is estimated according to the time-varying equation of interior temperature. A multi-objective optimization model for the electric heating load with heat energy storage is then studied considering the demand response (DR), which optimizes economy and the comfort index. A fuzzy decision method is proposed, considering the factors influencing DR behavior. Finally, the validity of the proposed model is verified by simulations. The results show that the proposed model performs better than the traditional method.     

Primary energy savings through thermal storage in district heating networks

District heating is an efficient way to provide heat to residential, tertiary and industrial users. Heat is often produced by CHP (combined heat and power) plants, usually designed to provide the base thermal load (40-50% of the maximum load) while the rest is provided by boilers. The use of storage tanks would permit to increase the annual operating hours of CHP: heat can be produced when the request is low (for instance during the night), stored and then used when the request is high. The use of boilers results partially reduced and the thermal load diagram is flattered. Depending on the type of CHP plant this may also affect the electricity generation. All these considerations are crucial in the free electricity market.In this paper, a multi-scale model of storage tanks is proposed. This model is particularly suitable to analyze the operation of storage systems during the heating season and to predict their effects on the primary energy consumption and cash flows. The analysis is conducted considering the Turin district heating system as case study. Results show that primary energy consumption can be reduced up to 12%, while total costs can be reduced up to about 5%.     

基于旁路系统提升热电机组风电消纳能力研究

针对中国三北地区冬季供热期弃风现象严重的问题,提出利用高低压旁路供热解耦传统热电机组的电热强耦合关系,并基于旁路系统供热的热电机组电热特性,建立风电消纳能力数学模型,根据电网调峰需求,给出热电机组的运行策略。结果表明:高低压旁路系统参与供热可大幅提升热电机组的风电消纳能力和供热能力。为了保证高低压旁路供热安全,要注意高低压旁路蒸汽流量的匹配关系。采用"传统抽汽+高低压旁路"切换方式供热,风电消纳能力最强。以某330 MW热电机组为例,采用高低压旁路供热可进一步提升供热能力90.56%;在满足额定供热量的前提下,采用"传统抽汽+高低压旁路"切换方式供热可进一步提升热电机组风电消纳能力324.46%。     

Economic analysis of electrical heating with heat storage using grid integrated wind power

针对冬季供热期我国北方地区因电网风电接纳能力不足导致的严重弃风问题,研究了电力市场背景下采用蓄热式电采暖提高电网风电消纳规模的经济性评估问题,考虑弃风电量、弃风电价等因素影响,建立了弃风蓄热式电采暖系统的经济性评估模型,分析了影响蓄热式电采暖系统经济性的关键因素。结合某清洁供暖示范工程进行算例分析,分析了协定弃风电价对系统经济性的影响,对所提出的经济性评估模型的有效性进行验证,为蓄热式电采暖可行性分析奠定了理论基础。     

Green hydrogen for heating and its impact on the power system

With a relatively high energy density, hydrogen is attracting increasing attention in research, commercial and political spheres, specifically as a fuel for residential heating, which is proving to be a difficult sector to decarbonise in some circumstances. Hydrogen production is dependent on the power system so any scale use of hydrogen for residential heating will impact various aspects of the power system, including electricity prices and renewable generation curtailment (i.e. wind, solar). Using a linearised optimal power flow model and the power infrastructure on the island of Ireland this paper examines least cost optimal investment in electrolysers in the presence of Ireland's 70% renewable electricity target by 2030. The introduction of electrolysers in the power system leads to an increase in emissions from power generation, which is inconsistent with some definitions of green hydrogen. Electricity prices are marginally higher with electrolysers whereas the optimal location of electrolysers is driven by a combination of residential heating demand and potential surplus power supplies at electricity nodes.     

计及用户响应成本的电采暖负荷群参与风电备用研究

分布式电采暖具有调度灵活、反应迅速的优点,可用于时序变化的可再生能源辅助服务中,但其响应成本和用户使用价格较高。文章通过负荷聚合商聚合用户群调节能力,并激励用户参与风电场备用,提高用户-负荷聚合商-电网综合收益。首先,负荷聚合商将用户群按建筑参数、初始状态和用户响应成本分组,应用二阶等效热力学模型模拟建筑物的储热过程;其次,提出含温差补贴的价格激励方法,负荷聚合商通过该方法激励用户参与响应以满足风电场的备用需求;最后,通过算例证明该方法降低了电采暖负荷参与风电备用的成本,提高了风电备用。     

Comparison of carbon monoxide emissions and electricity consumption of modulating and non‐modulating pellet and solar heating systems

Emission and electricity consumption are important aspects of a pellet heating system. Low noxious emissions, particularly carbon monoxide, are a measure of a well‐performing system. High carbon monoxide emissions are often caused by unnecessary cycling of the burner, poor adjustment of the combustion air and insufficient maintenance. The carbon monoxide output, the thermal performance and the electricity consumption for modulating and non‐modulating operation mode have been investigated by simulations of four stoves/boilers as part of combined solar and pellet heating systems. The systems have been modelled with the simulation programme TRNSYS and simulated with the boundary conditions for space heating demand, hot water load and climate data as used in earlier research projects. The results from the simulations show that operating the pellet units with modulating combustion power reduces the number of starts and stops but does not necessarily reduce the carbon monoxide output. Whether the carbon monoxide output can be reduced or not depends very strongly on the reduction of starts and stops and how much the carbon monoxide emissions increase with decreased combustion power, which are in turn dependent on the particular settings of each pellet burner and how the heat is transferred to the building. However, for most systems the modulating operation mode has a positive impact on carbon monoxide emissions. Considering the total auxiliary energy demand, including the electricity demand of the pellet units, the modulating combustion control is advantageous for systems 1 and 4 for the used boundary conditions. The study also shows that an appropriate sizing of the stove or boiler has a huge potential for energy saving and carbon monoxide emission reduction. Copyright © 2006 John Wiley & Sons, Ltd.     

风电供暖提升可再生能源电力系统消纳能力的概率评价方法

文章基于随机生产模拟方法,在中长期时间尺度下,建立了多环节概率模型。深入分析了风电供暖的运行机理及其对电力、热力系统的影响作用,建立了消纳效果评估模型。仿真结果表明,该模型能够计算不同热力站功率和运行时间下的消纳提升电量,验证了方法的有效性。     

Economic and climate impacts of reducing China's renewable electricity curtailment: A comparison between CGE models with alternative nesting structures of electricity

To mitigate climate change impacts and achieve low-carbon transformation, China has accelerated the development of renewable energy, which is severely challenged by the curtailment of renewable electricity. This study uses a dynamic multi-sectoral CGE model with alternative nesting structures and substitution elasticities for electricity with different power sources to capture the economic and environmental feasibility of reducing renewable electricity curtailment across all economic sectors in China. The reduction of renewable electricity curtailment is simulated during 2021–2030 from the curtailment rates of 2015–2017. We found that the reduction of renewable electricity curtailment would lead to a significant expansion in the output of renewable electricity and a moderate decrease in non-renewable electricity production. Among the renewable electricity, wind power has the most significant output gain (over 9%), with solar power and hydropower outputs rising by over 5% and 1.5%, respectively. However, without the cost-neutrality assumption, the impacts of reducing electricity curtailment would be largely over-estimated with CGE models simulated by improved technology. The disparity between results from the models with alternative nesting constant elasticity of substitution (CES) functions for electricity sectors is highly dependent on the difference between their substitution elasticities. Accompanying the changes in electricity generation, the reduction of renewable electricity curtailment would bring multiple green co-benefits like significantly reducing CO2 and air pollutants emitted from electricity sectors, and improvements in real GDP and employment.     

考虑供热系统热储能特性的电-热综合系统随机优化调度模型研究

热电联产机组、热泵等装置的应用促进了电-热综合系统间的耦合关系,为风电的消纳提供了新途径。文章考虑了供热系统热储能动态特性,采用多场景法模拟风电出力不确定性,搭建了电-热综合能源系统随机优化调度模型。首先,针对供热管道传输时延动态特性,研究分析了其储热能力;其次,以电-热综合能源系统购能费用最低为目标函数,以热网约束、电网约束为约束条件,提出了综合系统能量最优化调度方案;最后,在IEEE33节点和6节点热网上进行算例分析,验证了模型的有效性。     

基于EEMD-ACS-SELM的弃风电量组合预测模型

风电已在电力系统中得到了有效利用,因此,弃风电量的准确预测对于电网的安全、经济运行至关重要。文章提出了一种基于集合经验模态分解(EEMD)和t分布自适应变异布谷鸟算法(ACS)优化改进极限学习机(SELM)的弃风电量组合预测方法(EEMD-ACS-SELM)。该方法先采用集合经验模态分解,将原始弃风电量序列分解为一系列不同频率的分量,基于模糊熵理论计算各分量的熵值,并将熵值相似序列重构为新的子序列。然后,将新序列分别建立改进极限学习机预测模型,利用ACS优化算法对SELM算法的输入权值和阈值进行优化。最后,将各序列预测值叠加求和得到原始弃风电量序列的预测值。以新疆某风电场实际运行数据进行算例分析,结果表明,文章所提方法对弃风电量的预测具有较高的精度。     

Analysis of solar photovoltaic and wind power potential in Afghanistan

Afghanistan has a need for increased access to energy to enable development. In this paper we analyze the potential for large-scale grid-connected solar photovoltaic (PV) and wind power plants in two of Afghanistan's most populous provinces (Balkh and Herat) to meet a large fraction of growing electricity demand. The results presented here represent the first quantitative analysis of potential capacity factors and energy yields of power plants in the country using measured wind speed and typical solar radiation data. Variability of resources is also investigated by comparing temporal profiles with those of electricity demand, using residual load duration curves to determine penetration and curtailment levels for various demand scenarios. We show that solar PV and wind power plants in two provinces could achieve penetration levels of 65%–70% without significant curtailment, which in turn would mean less reliance on unpredictable and unstable power purchase agreements with neighboring countries, longer life of limited domestic fossil fuel resources, and lower imports of diesel fuel, thus avoiding rising costs and detrimental environmental impacts. Our results point to an alternative development pathway from that of previous recommendations for conventional thermal power plants, controversial hydroelectric projects, and a significant dependence on imported power.     

The impact of wind power on electricity prices

This paper investigates the impact of wind power on electricity prices using a production cost model of the Independent System Operator – New England power system. Different scenarios in terms of wind penetration, wind forecasts, and wind curtailment are modeled in order to analyze the impact of wind power on electricity prices for different wind penetration levels and for different levels of wind power visibility and controllability. The analysis concludes that electricity price volatility increases even as electricity prices decrease with increasing wind penetration levels. The impact of wind power on price volatility is larger in the shorter term (5-min compared to hour-to-hour). The results presented show that over-forecasting wind power increases electricity prices while under-forecasting wind power reduces them. The modeling results also show that controlling wind power by allowing curtailment increases electricity prices, and for higher wind penetrations it also reduces their volatility.     

基于电锅炉的火电机组灵活性改造技术研究

为有效解决东北电力产能过剩,促进风电、核电等清洁能源消纳问题,提升燃煤供热机组的灵活性,针对东北地区某热电厂,通过对热电解耦时间、电锅炉型式以及不同电锅炉容量配置对机组实际发电负荷的影响等灵活性改造关键技术进行研究,确定了最佳电锅炉容量,提出了电锅炉装设方案,并对改造前后机组的调峰能力和性能指标进行对比分析。研究表明:随着电锅炉容量增长,抵减电锅炉用电后机组实际发电负荷率显著降低,提升火电机组灵活性改造后,电厂调峰能力显著提升,考虑以全厂172 MW发电负荷运行,电厂调峰能力在采暖初末期增加了368 MW,采暖中期增加了528 MW;全厂供热标煤耗由39.7 kg/GJ降低至34.3 kg/GJ,降低了5.4 kg/GJ;经济效益显著,扣除电锅炉用电成本后1个采暖季的调峰辅助服务补贴收益为1.47亿元;同时,电锅炉投运后可实现电厂的上网电量接近零,为清洁能源就地消纳做出贡献。     

On the potential trade-offs between energy supply and end-use technologies for residential heating

In Sweden, where district heating accounts for a significant share of residential heating, it has been argued that improvements in end-use energy efficiency may be counter-productive since such measures reduce the potential of energy efficient combined heat and power production. In this paper we model how the potential trade-offs between energy supply and end-use technologies depend on climate policy and energy prices. The model optimizes a combination of energy efficiency measures, technologies and fuels for heat supply and district heating extensions over a 50 year period. We ask under what circumstances improved end-use efficiency may be cost-effective in buildings connected to district heating? The answer hinges on the available technologies for electricity production. In a scenario with no alternatives to basic condensing electricity production, high CO₂ prices result in very high electricity prices, high profitability of combined heat and power production, and little incentive to reduce heat demand in buildings with district heating. In contrast, in a scenario where electricity production alternatives with low CO₂ emissions are available, the electricity price will level out at high CO₂ prices. This gives heat prices that increase with the CO₂ price and make end-use efficiency cost-effective also in buildings with district heating.     

多时间尺度下计及光热—储热的主动配电网主辅联合优化调度

为解决可再生能源弃风、弃光现象与不平衡功率惩罚较重等问题,提出了一种多时间尺度下考虑光热—储热的主动配电网主辅联合调度策略.该策略在满足内部负荷前提下参与电能与备用日前市场,考虑含光热—储热的主动配电网协调调度风电、光伏、需求响应,在促进风光消纳、减少不平衡功率的同时提高主动配电网运行经济性.首先根据含储热的光热电站与...     

风火储氢碳多能耦合打捆送出模式研究

目的  为在通道建设空间受限的情况下坚实城市负荷中心能源供给保障并实现海上风电大规模送出与消纳,提出一种风火打捆、多元耦合的系统建设运行模式,并结合项目对该模式进行理论分析与仿真验证。 方法  在研究过程中,设置风火分别送出、风火打捆送出但运行不耦合、风火打捆送出且运行耦合、风火氢碳耦合送出4种仿真试验方案,并依托HOMER软件环境及粒子群算法对试验方案进行系统运行仿真与指标测算。 结果  测试结果表明：通道总规模在未采用风火打捆送出模式时比采用风火打捆送出模式时高2.2 GW,通道平均利用率59%,比采用风火打捆送出模式时低21%~23%;风电与火电共用送出通道但运行不协同产生弃风量合计164 GWh;风火建设打捆且运营协同时可实现零弃风,并减少单位供电碳排放下降30~33 g/MWh。 结论  风火打捆、多元耦合的绿电送出及系统运行方式可行且有效,对海上风电项目的规划建设具有指导意义。     

Optimal coordination of wind-hydro-thermal based on water complementing wind

The increasing integration of wind power into the existing power system demands for effective strategies to deal with wind intermittency and uncertainty. Relying solely on thermal power to cover wind uncertainty will sacrifice the operating efficiency and economy of thermal generators. In view of this, the adjustable hydropower is preferred for complementing wind fluctuation and uncertainty and the coordinated dispatch problem of wind-hydro-thermal power is established. Based on a newly designed water supplementing wind strategy, the original complex problem is decomposed into wind-hydro subproblem and thermal subproblem. A novel stochastic constraint related to wind power uncertainty is proposed and handled according to stochastic programming theory. By introducing the concept of expected breed rate and elitist preservation strategy, the particle swarm optimization (PSO) algorithm is improved and combined with the exterior penalty function method for solving the complete optimization problem. Optimal generation scheduling schemes that can make full use of wind energy and ensure efficient and economic operating of thermal generators are obtained by the proposed approach. Meanwhile the coordinating operation of wind, hydro and thermal power under different water resources and wind penetrations respectively are revealed and discussed.     

基于博弈论的电采暖系统应用经济性研究

使用清洁电力代替化石能源燃烧供暖是实现"碳中和"的一个重要方式.若无适宜的商业模式,在一些煤炭资源丰富的地区,将很难推广电采暖替代燃煤供暖系统.首先,本文提出一种清洁电能采暖的商业模式,分析了利益相关者政府、国家电网和热能用户三者之间关于电采暖推广的博弈关系.基于此,提出利益相关者的收益函数并以次作为各自的优化目标,以...