What does dispatchable power mean in electricity systems?

• A. Power that can be readily called on demand and adjusted to meet demand
• B. Power produced at a fixed rate regardless of demand
• C. Power that is always from renewable sources
• D. Power that is only used during disasters

Answer: (A)

Dispatchable power means generation that grid operators can call on quickly and adjust up or down to match real-time electricity demand. The essential idea is controllability and reliability: you can ramp output when demand rises and scale back when it falls, ensuring the system stays balanced.

This is different from sources that are not easily controlled or guaranteed to produce a given amount, such as wind or solar, whose output depends on weather. It also includes a range of technologies typically used to meet demand on short notice, like natural gas or hydro plants, and even energy storage that can discharge when needed. Nuclear plants and some coal plants are less flexible, so they don’t respond as readily to rapid changes in demand.

So the best description is power that can be readily called on demand and adjusted to meet demand.