Capacity factor
[1] The theoretical maximum energy output of a given installation is defined as that due to its continuous operation at full nameplate capacity over the relevant period.
The average capacity factor can also be defined for any class of such installations, and can be used to compare different types of electricity production.
Other factors include the design of the installation, its location, the type of electricity production and with it either the fuel being used or, for renewable energy, the local weather conditions.
Additionally, the capacity factor can be subject to regulatory constraints and market forces, potentially affecting both its fuel purchase and its electricity sale.
For example in Finland, capacity factor during the cold winter months is more than double compared to July.
[6] While the annual average in Finland is 29.5%,[6] the high demand for heating energy correlates with the higher capacity factor during the winter.
Taking the average figure for annual generation gives a capacity factor of: At the low range of capacity factors is the photovoltaic power station, which supplies power to the electricity grid from a large-scale photovoltaic system (PV system).
An inherent limit to its capacity factor comes from its requirement of daylight, preferably with a sun unobstructed by clouds, smoke or smog, shade from trees and building structures.
Since the amount of sunlight varies both with the time of the day and the seasons of the year, the capacity factor is typically computed on an annual basis.
For example, Agua Caliente Solar Project, located in Arizona near the 33rd parallel and awarded for its excellence in renewable energy has a nameplate capacity of 290 MW and an actual average annual production of 740 GWh/year.
A plant can be out of service or operating at reduced output for part of the time due to equipment failures or routine maintenance.
Base load plants usually have low costs per unit of electricity because they are designed for maximum efficiency and are operated continuously at high output.
Governments differ in their wiliness to accept risks of power outages and lack of resilience against natural disasters and military attack on electricity grids.
[17] However, according to the SolarPACES programme of the International Energy Agency (IEA), solar power plants designed for solar-only generation are well matched to summer noon peak loads in areas with significant cooling demands, such as Spain or the south-western United States,[18] although in some locations solar PV does not reduce the need for generation of network upgrades given that air conditioner peak demand often occurs in the late afternoon or early evening when solar output is reduced.
According to the US Energy Information Administration (EIA), from 2013 to 2017 the capacity factors of utility-scale generators were as follows:[30] However, these values often vary significantly by month.
The following figures were collected by the Department of Energy and Climate Change on the capacity factors for various types of plants in UK grid:[31][13][32][14][33][15][34][16][35][36]
