Home batteries hit 600,000 as households play big role in energy transition, but building transmission projects remains "critical", according to the latest AEMO energy plan.

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.

Soaring installations of batteries has helped halve the need for expensive new poles and wire projects out to 2050, according to the grid operator.

Home batteries hit 600,000 as households play big role in energy transition, but building transmission projects remains "critical", according to the latest AEMO energy plan.