Reasons For Reduced Capacity Factor
There are several reasons why a plant would have a capacity factor lower than 100%. The first reason is that it was out of service or operating at reduced output for part of the time due to equipment failures or routine maintenance. This accounts for most of the unused capacity of base load power plants. Base load plants have the lowest costs per unit of electricity because they are designed for maximum efficiency and are operated continuously at high output. Geothermal plants, nuclear plants, coal plants and bioenergy plants that burn solid material are almost always operated as base load plants.
The second reason that a plant would have a capacity factor lower than 100% is that output is curtailed because the electricity is not needed or because the price of electricity is too low to make production economical. This accounts for most of the unused capacity of peaking power plants. Peaking plants may operate for only a few hours per year or up to several hours per day. Their electricity is relatively expensive. It is uneconomical, even wasteful, to make a peaking power plant as efficient as a base load plant because they do not operate enough to pay for the extra equipment cost, and perhaps not enough to offset the embodied energy of the additional components.
A third reason is a variation on the second: the operators of a hydroelectric dam may uprate its nameplate capacity by adding more generator units. Since the supply of fuel (i.e. water) remains unchanged, the uprated dam obtains a higher peak output in exchange for a lower capacity factor. Because hydro plants are highly dispatchable, they are able to act as load following power plants. Having a higher peak capacity allows a dam's operators to sell more of the annual output of electricity during the hours of highest electricity demand (and thus the highest spot price). In practical terms, uprating a dam allows it to balance a larger amount of intermittent energy sources on the grid such as wind farms and solar power plants, and to compensate for unscheduled shutdowns of baseload power plants, or brief surges in demand for electricity.
Read more about this topic: Capacity Factor
Famous quotes containing the words reasons for, reasons, reduced, capacity and/or factor:
“I should like to know what is the proper function of women, if it is not to make reasons for husbands to stay at home, and still stronger reasons for bachelors to go out.”
—George Eliot [Mary Ann (or Marian)
“One of the reasons for the failure of feminism to dislodge deeply held perceptions of male and female behaviour was its insistence that women were victims, and men powerful patriarchs, which made a travesty of ordinary people’s experience of the mutual interdependence of men and women.”
—Rosalind Coward (b. 1953)
“Realism, whether it be socialist or not, falls short of reality. It shrinks it, attenuates it, falsifies it; it does not take into account our basic truths and our fundamental obsessions: love, death, astonishment. It presents man in a reduced and estranged perspective. Truth is in our dreams, in the imagination.”
—Eugène Ionesco (b. 1912)
“The capacity to give one’s attention to a sufferer is a very rare and difficult thing; it is almost a miracle; it is a miracle. Nearly all those who think they have this capacity do not possess it. Warmth of heart, impulsiveness, pity are not enough.”
—Simone Weil (1909–1943)
“Weapons are an important factor in war, but not the decisive factor; it is people, not things, that are decisive. The contest of strength is not only a contest of military and economic power, but also a contest of human power and morale. Military and economic power is necessarily wielded by people.”
—Mao Zedong (1893–1976)