Intermittent energy source: Difference between revisions

Revision as of 18:08, 27 March 2007

Revision as of 18:29, 27 March 2007

Line 1:

'''Intermittent power sources''' are sources of [[power generation]], primarily [[electricity]], whose power output is normally either [[variable]] or [[Intermittency|intermittent]]. All power sources are intermittent in the sense that they can fail or be taken off line for maintenance, so back-up generation has to be available for all generation types.

If the [[power plant operator|operator ]] has a high degree of confidence of being able to increase or reduce power output whenever required by a central dispatcher, then the power is said to be [[dispatchable generation|dispatchable]], as with many conventional sources, particularly fossil and hydro. The method of managing this will depend on the structure of the system and whether or not the system uses [[electricity market]]s.

Many sources of [[renewable energy]] are not dispatchable in this sense and are considered intermittent or variable, such as [[Wind power|wind]] and [[Solar power|solar energy]]. Since demand and supply of electricity must be balanced at all times to maintain grid stability, the variable output of large proportions of intermittent/ variable power sources may require technical, pricing, and/or other solutions. The cost of these solutions will influence the mix of power sources in a given grid. Proponents of the large scale use of intermittent and variable sources claim that these challenges can be dealt with at reasonable cost by application of a range of techniques, including the use of dispatchable plantpower.

Solutions for managing mismatches between demand and supply exist in all managed grids, and include supply management (increasing or decreasing energy output from grid-connected plants) and, demand management (increasing or decreasing demand, which may include [[load shedding]], [[demand management]] or [[energy storage]] for later use).

Intermittency is most properly used to refer to power output that may go off-line entirely at various times: that is, the power output states have a [[binary]] or ''on-off'' nature. [[Variable]] power sources may show substantial differences in output, but generally would not "trip" on or off in extremely short periods of time (particularly with greater geographical spread or distribution); in this sense, intermittent power sources may be reliable but highly variable. Throughout this article, the two terms intermittency and variability are generally used interchangeably, as intermittency has become the most commonly used term to describe this issue.