Power system operations and control: Difference between revisions

Revision as of 20:56, 2 June 2022

Revision as of 20:01, 24 July 2022

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In real systems the cost per MWh usually is not constant, and the lines of the dispatch curve are therefore not horizontal (typically the marginal cost of power increases with the dispatch level, although for the [[combined cycle power plant]]s there are multiple cost curves depending on the mode of operation.<ref name="BayónGarcía NietoGrau2013">{{cite journal | last1 = Bayón | first1 = L. | last2 = García Nieto | first2 = P. J. | last3 = Grau | first3 = J. M. | last4 = Ruiz | first4 = M. M. | last5 = Suárez | first5 = P. M. | title = An economic dispatch algorithm of combined cycle units | journal = International Journal of Computer Mathematics | date = 19 March 2013 | volume = 91 | issue = 2 | pages = 269–277 | issn = 0020-7160 | eissn = 1029-0265 | doi = 10.1080/00207160.2013.770482 | pmid = | url = https://www.unioviedo.es/bayon/osh/41.pdf}}</ref>

[[File:Hypothetical dispatch curve, USA, Summer 2011.png|thumb|left|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 on the left).