What indicates a higher thermal efficiency in power generation?

A greater ratio of useful energy output to input indicates higher thermal efficiency in power generation because thermal efficiency is defined as the ratio of the useful work or energy output to the energy input. When this ratio is high, it means that a significant portion of the energy being consumed is converted into useful work or energy, minimizing losses.

For instance, if a power generation system produces a large amount of useful energy while consuming less energy, it is efficient. High thermal efficiency is desirable as it implies that the system is using fuel resources effectively, leading to lower fuel consumption and reduced greenhouse gas emissions per unit of energy produced.

In contrast, options such as more energy input than output would signify inefficiency, a balance between input and output may not optimize resource use, and increased waste heat production would typically indicate that a lot of the input energy is not being effectively converted into useful energy, which undermines efficiency.