Electric generator capacity factors vary widely across the world

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Electric generator capacity factors vary widely across the world

September 8, 2015

The technologies used to generate electricity are similar across regions of the world, but the pattern of use for those generating technologies can be significantly different. Analysis of electric generating plant utilization (measured by annual capacity factors, or the ratio of generation to capacity) over a five-year period shows a wide range of variability among fuel types and across world regions.

These differences in annual capacity factors can be attributed to a wide range of factors:

  • Differences in daily load patterns, which reflect the mix of demand from buildings and industry, among other factors
  • Differences in operating costs, mainly driven by fuel costs
  • Planned and unplanned outages of units to meet regulatory and maintenance requirements
  • Variation in the efficiency of electric generating technologies using the same fuel type
  • Constraints due to resource availability commonly associated with generators relying on renewable resources.

Capacity factors can also be affected by partial-year generation effects, especially for technologies with recently installed capacity. By convention, the numerator of the capacity factor is based on actual generation, while the denominator is based on what that generator could have provided, assuming continuous operation for a full year. Projects built in the second half of the year will only have a few months of generation to report, resulting in capacity factors lower than expected for a full year of operation. The data presented here reflect the five-year average ending in 2012, the most recent year with both generation and capacity data for all geographic areas discussed.


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