There are 'peaks and valleys' [=high and low periods] in electricity usage throughout the year.
He said I talk like a 'Valley girl'. And I said, “Like, whatever!”
the Shenandoah (River) 'Valley'
(..) (cables snapping) (metal groaning) No ! You'll swamp us ! (screaming) Though l walk through the valley of the shadow of death... You wanna walk a little faster through that valley ?! Row ! Pull together ! (screams) (..)1997 Titanic