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[[File:Hypothetical dispatch curve, USA, Summer 2011.png|thumb|500px|Hypothetical dispatch curve (USA, summer 2011)<ref>{{cite web |title=Electric generator dispatch depends on system demand and the relative cost of operation |url=https://www.eia.gov/todayinenergy/detail.php?id=7590# |website=eia.gov |access-date=30 May 2022 |date=17 August 2012}}</ref>]]
If the minimum level of demand in the example will stay above 120 MW, the unit A will constantly run at full power, providing [[baseload power]], unit B will operate at variable power, and unit C will need to be turned on and off, providing the "intermediate" or "cycling" capacity. If the demand goes above 200 MW only occasionally, the unit C will be idle most of the time and will be considered a [[peaking power plant]] (a "peaker"). Since a peaker might run for just few tens of hours per year, the cost of peaker-produced electricity can be very high in order to recover the capital investment and fixed costs (see the right side of a hypothetical full-scale dispatch curve).
=== Redispatch ===
Sometimes the grid constraints change unpredictably and a need arises to change the previously set unit commitments. This '''system redispatch''' change is controlled in real-time by the central operator issuing directives to market participants that submit in advance bids for the increase/decrease in the power levels. Due to the4 centralized nature of redispatch, there is no delay to negotiate terms of contracts; the cost incurred are allocated either to participants responsible for the disruption based on preestablished tariffs or in equal shares.<ref name="SongWang2003">{{cite book | editor1 = Yong-Hua Song | editor2 = Xi-Fan Wang | author = Yong-Hua Song | date = 31 July 2003 | title = Operation of Market-oriented Power Systems | publisher = Springer Science & Business Media | pages = 150– | isbn = 978-1-85233-670-7 | oclc = 1112226019 | url = https://books.google.com/books?id=sS33yLR0U7EC&pg=PA150}}</ref>
== Minutes-ahead operation ==
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