# Dynamic Modeling and Validation of Peak Ability of Biomass Units
## 1 Introduction  
The dual-peak characteristics of China's power load during both winter and summer are becoming increasingly pronounced. The proportion of cooling load in summer and heating load in winter is increasing. In some provinces, the proportion of cooling load in summer to the maximum power load reaches 40-50%, or even more than 50%, and the power supply and demand are in tight balance [1]. Taking Henan Province as an example, the power security situation in Henan Province during peak summer is severe and complex. It is estimated that the maximum load of the Henan power grid this year is 83.5 million KW, an increase of 5.58 million KW year-on-year, an increase of 7.2%. This year, the peak gap is 7.5 million KW, and the power supply situation is grim. Due to the randomness, uncertainty, transients and other weather-dependent characteristics of renewable energy such as wind power and photovoltaics, the severe situation regarding the power supply is further increased. Due to their advantages of providing environmental protection and short-term peak ability (maximum power output), biomass generating units gradually play a certain role in summer and winter [2, 3, 4]. In recent years, the biomass industry at home and abroad has shown a sustained growth trend, and countries are competing to promote the introduction and innovation of biomass power generation technologies, such as biomass mixed combustion powergeneration and biomass gasification power generation. Among them, the Battelle Biomass Gasification Power Generation Demonstration Project in the United States represents the world's most advanced level of biomass energy utilization. However, the high difficulty of using tar treatment technology and gas turbine transformation has limited the promotion process of commercial projects. In order to analyze the peak ability of biomass units, it is necessary to establish a dynamic model from biomass fuel to unit load, to provide theoretical support for analyzing the peak ability of biomass units. At present, the research mainly focuses on the dynamic modeling of coal-fired units. Reference [5] established a model of 300 MW subcritical circulating fluidized bed units, which was verified by field data. Reference [6] established a dynamic model of \"two-input and two-output\" suitable for the direct energy balance control structure for a 300 MW subcritical pulverized coal boiler. Reference [7] considers the feed water heater system, bypass system and feed water pump, studies the dynamic mathematical model of coal-fired units suitable for fast cut-off technology, and verifies it at a 50% and 100% load. Reference [8] established the dynamic model of the steam turbine with condensing extraction back pressure and a combined cycle gas turbine, and studied the suppression mechanism of water level fluctuation and the design of a water level controller under transient switching mode. In Reference [9], a multi-input and multi-output dynamic model of the incinerator was established through image feature recognition and the transfer entropy algorithm. At present, there is little research on biomass combustion boilers. Because the biomass combustion mechanism is different from the coal combustion mechanism, the unit load and fuel composition have a great impact on the power generation efficiency of the whole power plant, and the dynamic model research needs to consider the different combustion characteristics. For biomass units, Reference [10] conducted a physical analysis of the combustion process in the furnace of a vibrating biomass grate furnace unit based on the combustion characteristics of biomass combustion, but is limited to the study of the combustion characteristics in the furnace. Reference [11] established the mathematical model and simulation model of biomass power plant combustion systems based on virtual data processing technology.