Why can a gas-turbine power plant start faster than a steam power plant?

A gas-turbine power plant can be placed on-line within minutes, whereas a steam power plant requires many hours for start-up.1

The primary reason for this difference is the operational complexity of the systems. A steam power plant relies on a steam generator that must be brought up to temperature and pressure, a process that is inherently time-consuming. In contrast, a gas-turbine engine is a more compact system that does not require the extensive thermal preparation needed to generate steam.1

For start-up, a gas turbine simply requires an external motor—such as an electric motor or a small diesel engine—to reach the necessary operating speed. Because of this rapid start-up capability, gas-turbine engines are frequently utilized as "peak load" plants to provide electricity during short periods of high demand.21