AEMO says the outlook for Western Australia's main electricity grid has improved since last year, thanks in part to the impact home batteries are having on peak and minimum demand.

South Australia's SA1 trading region reached the NEM AU$20,300/MWh price cap twice during the evening of 21 June.

Australia's main grid chalked up its worst one-day wind drought in more than two years over the weekend, catching batteries short in one state in particular.

AEMO says the outlook for Western Australia's main electricity grid has improved since last year, thanks in part to the impact home batteries are having on peak and minimum demand.