Intermittent energy source: Difference between revisions

Revision as of 05:38, 23 April 2019

Revision as of 15:28, 11 May 2019

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* '''[[Capacity factor]]''', '''average capacity factor''', or '''load factor''' is the average expected output of a generator, usually over an annual period. Expressed as a percentage of the nameplate capacity or in decimal form (e.g. 30% or 0.30).

* '''[[Capacity credit]]''': generally the amount of output from a power source that may be statistically relied upon, practically the minimum power within a longer period, usually expressed as a percentage of the nominal power.<ref name='WindCC'>{{cite web |url=http://ejournal.windeng.net/3/01/GGiebel-CapCredLit_WindEngEJournal_2005_right_links.pdf |title=WIND POWER HAS A CAPACITY CREDIT |accessdate=2008-10-16 |last=Giebel |first=Gregor |work=Risø National Laboratory |archive-url=https://web.archive.org/web/20090318231423/http://ejournal.windeng.net/3/01/GGiebel-CapCredLit_WindEngEJournal_2005_right_links.pdf |archive-date=2009-03-18 |dead-url=yes |df= }}</ref>

* '''Firm capacity''' is the amount of power that can be guaranteed to be provided as [[base power]].

* '''Non-firm capacity''' is the amount of power above the firm capacity that is usually to be sold at higher price on the [[spot market]].

==Intermittency of various power sources==

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* [[Energy demand management]] refers to incentives to adjust use of electricity, such as higher rates during peak hours.

* Real-time variable electricity pricing can encourage users to adjust usage to take advantage of periods when power is cheaply available and avoid periods when it is more scarce and expensive.<ref name=CaliPolicy>{{cite web| url=http://www.energy.ca.gov/2005_energypolicy/index.html| title=2005 Integrated Energy Policy Report| date=November 21, 2005| publisher=California Energy Commission| accessdate=2006-04-21}}</ref>

* Instantaneous demand reduction. Most large systems also have a category of loads which instantly disconnect when there is a generation shortage, under some mutually beneficial contract. This can give instant load reductions (or increases). See [[National Grid Reserve Service]].

* Diesel generators, originally or primarily installed for emergency power supply are often also connected to the National Grid in the UK to help deal with short term demand supply mismatches.<ref>http://www.claverton-energy.com/commercial-opportunities-for-back-up-generation-and-load-reduction-via-national-grid-the-national-electricity-transmission-system-operator-netso-for-england-scotland-wales-and-offshore.html Commercial Opportunities for Back-Up Generation and Load Reduction via National Grid, the National Electricity Transmission System Operator (NETSO) for England, Scotland, Wales and Offshore.</ref>

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* Some energy is lost in transmission.

* The economic value of exporting variable power depends in part on the ability of the exporting grid to provide the importing grid with useful power at useful times for an attractive price.

{{See also|HVDC|Supersuper grid}}

==Penetration==