双碳背景下应急备用电源的定位和经济性研究

Research on positioning and economy of emergency standby power supply based on dual carbon background

应急备用电源是贯彻和落实碳达峰和碳中和工作方案的必要措施,是促进煤电行业优化升级的重要举措,其运行状态可分为长期停运、热备用和运行3种状态。2019年以来,夏季全社会用电负荷屡创新高,电力系统也历经迎峰度夏、能耗双控政策和新能源大规模波动的极端考验,全社会电高峰期均可由在运电源提供充足电力,火电机组承担了大量调峰和调频服务。挂网煤电机组负荷率相对较低,2021年煤电机组利用小时数为4448 h,顶峰能力由挂网机组承担。这种局面导致应急备用电源长期处于停运状态,不能很好解决电力系统出现的临时性电源短缺问题。在新能源发电突降,正常备用煤电机组不能按时启动时,长期停运的应急备用电源应急启动时间更长,不能起到顶峰和短时间快速带负荷的作用。在经济层面,应急备用电源的长期停运也会导致冷却水系统、轴承、烟道、受热面、换热器、疏水管等部位加速腐蚀,维护检修工作量一般不会少于机组正常运行,运行维护工作量的大幅增加,导致运维成本高。对某服役到期的300 MW机组进行应急备用期间的运维费用测算,需运维费用约7063万元/a,随着备用时间的延长,费用将升高。在不计算设备折旧,假设运行期间成本和收益相抵的前提下,该300 MW应急备用电源按年运行168 h,负荷率按80%,应急备用成本约1.75元/kW时,与其他调节方式相比较,没有优势。煤电应急备用电源备用费用高,应急启动时间长,严重影响其发挥其应有的应急备用功能。

Emergency standby power supply is a necessary measure to implement the carbon peak and carbon neutralization work plan,and an important measure to promote the optimization and upgrading of the coal power industry.Its operation status can be divided into longterm shutdown,hot standby and operation.Since 2019,the power load of the whole society has repeatedly reached new highs in summer,and the power system has also experienced extreme tests of peak summer,energy consumption dual control policy and large-scale fluctuations in new energy.During the peak period of electricity in the whole society,sufficient power can be provided by the operating power supply,and thermal power units undertake a large number of peak shaving and frequency modulation services.The load rate of grid connected coal-fired power units is relatively low.In 2021,the utilization hours of coal-fired power units will be 4448 h,and the peak capacity will be borne by the grid connected units.This situation leads to the long-term shutdown of the emergency standby power supply,which can not solve the problem of temporary power shortage in the power system.When the new energy power generation plummeted and the normal standby coal-fired power unit could not be started on time,the emergency start-up time of the long-term shutdown emergency standby power supply was longer,which could not reach the peak and the pain of rapid load in a short time.At the economic level,the long-term shutdown of the emergency standby power supply will also lead to accelerated corrosion of the cooling water system,bearings,flue,heating surface,heat exchanger,drain pipe and other parts.The maintenance and overhaul workload is generally no less than the normal operation of the unit.The substantial increase in the operation and maintenance workload will lead to high operation and maintenance costs.The operation and maintenance cost of a 300 MW unit due for service during the emergency standby period is estimated to be about 70 million 630 thousand yuan/a.With the extension of the standby time,the cost will increase.Without calculating the depreciation of equipment,assuming that the costs and benefits during the operation period are offset,the 300 MW emergency standby power supply operates 168 h a year,the load rate is 80%,and the emergency standby cost is about 1.75 yuan/kWh.Compared with other regulation methods,it has no advantage.The high standby cost and long emergency start-up time of coal power emergency standby power supply seriously affect its due emergency standby function.