Effect of Mean Ambient Temperature Rise on the De-Rating of Conventional Power Plants in Iran

The electric power generation capacity of almost all types of power plants is reduced by increase of the mean ambient temperature. This is more serious for the conventional power plants, i.e., thermal steam, gas turbine, and combined cycle power plants. This is obviously occurring phenomena because of decreasing of heat transfer rate, which is in compliance with the first and second laws of thermodynamics. Usually, the constructor of the power plant defines guaranty figures, including the net electric power output of the power plant based on the ISO ambient conditions, i.e. an ambient temperature of ۱۵ºC, ۶۰% relative humidity, and sea level pressure (i.e. ۱۰۱.۳۲۵ kPa absolute pressure). The constructor also provides a series of correction corves for some agreed selected ambient conditions, according the customer’s need, which enables the power plant utilization & management team to estimate the net electric output power of the power plant at his interested ambient conditions. The de-rating of conventional power plants of Iran is usually occurred within mid of April to end of September time window. This review result indicates at the present time, the net ambient temperature rise-based electric power de-rating of conventional power plants of Iran is expected to be about ۲۵۸۴ MW (i.e., ۳.۴%). Although this may seem a reasonable value, it causes a significant power shortage for Iran’s electric power generation grid which already suffers from power shortage. In this paper, the temperature-based power de-rating of Iran’s conventional power plants and its approximate value is discussed briefly.

کلیدواژه ها:

Conventional power plants ، Cycle efficiency ، De-rating ، Mean ambient temperature ، Electric power demand