Which of the following is a disadvantage of gas turbines?

The choice of low thermal efficiency as a disadvantage of gas turbines reflects a common characteristic of this technology. Gas turbines typically operate at lower thermal efficiencies compared to other types of power generators, such as steam turbines, especially at lower loads. This is primarily due to the Brayton cycle used in gas turbines, which has inherent limitations in its thermal efficiency, particularly when compared to the Rankine cycle used in steam turbines that can achieve higher cycle efficiencies through condensation and the use of heat recovery.

In the context of power generation, lower thermal efficiency means that more fuel is required to produce a given amount of electricity compared to more efficient systems. This can lead to higher operational costs and increased fuel consumption over time, making gas turbines less favorable in applications where efficiency is a critical factor. While gas turbines have many advantages, such as rapid start-up times and the ability to operate on various fuels, their thermal efficiency limitations can be a significant concern for operators aiming to maximize energy output while minimizing fuel costs and emissions.