Capacity Factor

The capacity factor (facility utilization rate) is actual generation or traded volume divided by installed capacity. KPX's renewable generation forecasting scheme also calculates the hourly utilization rate as 'traded energy ÷ installed capacity'. The capacity factor strongly affects the levelized cost of electricity (LCOE).

Calculated from the capacity and traded energy in KPX's 2025 Electricity Market Statistics, 2025 capacity factors were nuclear about 77%, coal about 45%, LNG about 38% and solar about 13%. The numbers reflect the differences: nuclear is a baseload source run almost all the time because of its low variable cost, LNG runs more when demand is high, and solar generates only when the sun is up.

News-reading tip: a story about a surge in solar capacity and a story about solar generation are different stories. A low capacity factor for coal or LNG does not by itself mean the plants are useless; they may have run less because of dispatch order and grid conditions. The term is sometimes mixed up with availability, so check the definition.