Explain the concept of capacity factor for solar and wind.

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Capacity factor tells you how much energy a solar or wind installation actually delivers over a period compared with how much it would deliver if it ran at its nameplate (maximum) capacity the whole time. It’s calculated by taking the energy produced during the period and dividing it by the plant’s nameplate capacity times the number of hours in that period. This captures real-world variability: sun isn’t always available, wind isn’t constantly blowing, and maintenance or curtailment can reduce output. For example, a 100 MW plant that produces 876,000 MWh in a year has a capacity factor of 876,000 ÷ (100 × 8,760) ≈ 10%, reflecting limited running time. In practice, solar tends to yield lower annual capacity factors (often in the teens to mid-20s) and wind higher, depending on location. Capacity factor is different from efficiency, which is about how effectively energy is converted to electricity, not how much time energy is produced. This metric helps compare projects and estimate annual energy yield and cost-effectiveness.