Base load vs peaker plants: Which statement correctly describes their operation and examples?

• A. Base load plants run continuously to meet minimum demand; examples include coal, nuclear, and hydro. Peaker plants run only during peak demand; examples include natural gas turbines and diesel generators.
• B. Base load plants are only used for emergency cases; Peaker plants run continuously.
• C. Base load plants refer to renewable energy sources only; Peaker plants refer to fossil fuels.
• D. Base load plants are cheaper to build but more polluting; Peaker are clean and expensive.

Answer: (A)

At the heart of the idea is how power plants are scheduled to meet demand. Base load plants are kept running continuously to cover the minimum level of electrical demand that exists most of the time. They’re chosen for their ability to produce a steady, fairly low-cost output over long periods, which gives them high capacity factors. Coal-fired and nuclear plants are classic baseload examples because they can run reliably for long durations and don’t need to be turned on and off with every fluctuation in demand. Hydro can also serve as base load when water supply is steady, providing steady output rather than frequent ramping.

Peaker plants, on the other hand, are designed to respond quickly to spikes in demand. They sit largely idle or run at low output until demand or prices surge, then they’re brought online to meet the short-term need. They emphasize fast startup and flexible operation, even though their short-run costs per megawatt-hour are higher. Natural gas turbines and diesel generators fit this role well because they can reach full power within minutes.

So the statement that base load plants run continuously to meet minimum demand with coal, nuclear, and hydro as examples, and peaker plants run only during peak demand with natural gas turbines and diesel generators as examples, correctly captures how these two types of plants operate and what kinds of plants typically fit each role.