What is the definition of combined cycle in power generation?

In power generation, combined cycle refers to a system that utilizes both gas and steam turbines to generate electricity, leveraging waste heat effectively. This approach means that one source of energy—typically natural gas—is utilized to produce electricity in a gas turbine. The waste heat from this process is then harnessed to generate steam, which drives a steam turbine to produce additional electricity. This sequential use of energy from a single fuel source illustrates the essence of the combined cycle process, as it allows for improved efficiency and maximized energy production from the same fuel inputs.

While the other options present various concepts relevant to power generation, they do not accurately capture the essential principle of combined cycle technology. For instance, using multiple generators of the same type does not address the concept of harnessing waste heat effectively, and relying solely on renewables does not align with the definition of combined cycle, which often includes fossil fuel sources in its operation to enhance efficiency.