Understanding Auxiliary Consumption in Thermal Power Stations: Importance and Impact

Auxiliary consumption in a thermal power station refers to the portion of the generated electrical power that is used to operate the station's own equipment and systems. This includes energy consumed by various components such as pumps, fans, boilers, lighting, control systems, and other auxiliary equipment. Understanding this concept is crucial for assessing the overall efficiency and performance of the power station.

The Components of Auxiliary Consumption

A thermal power station is a complex system that requires a significant amount of power to operate its own machinery and systems. This auxiliary consumption can be divided into several key components:

Pumps: Including water supply cooling systems and fuel handling. Fans: Responsible for air supply and flue gas handling. Boiler: For combustion air supply and feedwater systems. Lighting: Illumination of various areas within the plant. Control Systems: Monitoring and controlling operations. Other Auxiliary Equipment: Such as transformers, switchgear, and maintenance systems.

These components are essential for the smooth operation of the power station. Each consumes a portion of the generated power, which is often expressed as a percentage of the total power generated by the station.

Importance of Auxiliary Consumption in Power Efficiency

Auxiliary consumption is an important factor in assessing the overall efficiency of the plant. Higher auxiliary consumption reduces the net power output available for sale or distribution. Typically, auxiliary consumption in thermal power plants ranges from 5% to 15% of the total generation capacity. The efficiency of the plant can be significantly affected by the design and operational efficiency of these auxiliary components.

Take, for example, a 200 MW thermal power station, where auxiliary consumption is roughly 10% of the power at the generator end. This mainly comprises high inductive loads of motors for the Boiler Feed Pump (BFP) and the Boiler Fans (FD and ID PA).

Auxiliary Power Consumption in Thermal Power Stations

Apart from generation, various pieces of equipment within the power plant require certain voltages to operate. This internal power consumption is referred to as auxiliary power consumption (APC). APC typically accounts for 12% to 15% of the total generation. For a 10 MW thermal power plant, auxiliary consumption is around 850 to 1000 kW. The main consumers of this power are the Boiler Feed Pump (BFP) and the ID and FD fans.

The Bottom Line

Understanding and managing auxiliary consumption is crucial for optimizing the performance and efficiency of thermal power stations. By minimizing unnecessary energy usage and improving the design and maintenance of auxiliary equipment, power stations can maximize their net power output and contribute to a more sustainable energy supply.