In what unit are steam generators typically rated for turbo-alternators?

Steam generators for turbo-alternators are typically rated in megawatts. This is because megawatts represent a significant power output that is suitable for measuring the electrical generation capability of large steam generators used in power plants. The megawatt rating reflects the total electrical power that can be generated and is particularly useful in assessing a generator's efficiency and output in relation to the demands of the power grid.

Kilowatts, while also a measure of power, are more commonly used for smaller scale applications or equipment. Horsepower is an older unit of measurement for power that is less applicable to the context of steam generation for electricity, as it relates more to mechanical horsepower for engines. Lastly, kilograms per hour are a measure of mass flow rate and are typically used to specify the amount of steam produced by a generator, rather than its power output. Thus, the most appropriate and relevant unit for rating the output of steam generators in relation to turbo-alternators is indeed megawatts.