Duck curve
[3][4] In some energy markets, daily peak demand occurs after sunset, when solar power is no longer available.
In locations where a substantial amount of solar electric capacity has been installed, the amount of power that must be generated from sources other than solar or wind displays a rapid increase around sunset and peaks in the mid-evening hours, producing a graph that resembles the silhouette of a duck.
[10] Short term use batteries, at a large enough scale of use, can help to flatten the duck curve and prevent generator use fluctuation and can help to maintain voltage profile.
[15] The California Independent System Operator (CAISO) has been monitoring and analyzing the Duck Curve and its future expectations for about a half a century now and their biggest finding is the growing gap between morning and evening hours prices relative to midday hours prices.
[18] During the midday, large amounts of solar energy are created, which partially contributes to lower demand for additional electricity.
Orange curve: (the duck curve) supply of electrical power from dispatchable sources,
Gray curve: supply of solar electrical power
Data is for the State of California on October 22, 2016 (a Saturday), [ 1 ] a day when the wind power output was low and steady throughout the day.
The orange curve rises steeply from 17:00 to 18:00 as the sun sets, requiring about 5 gigawatt of generating capacity from dispatchable sources to come on line within one hour.
