Experts say two weeks of winter are holding Australia back from a 100 per cent renewably-powered electricity grid.

The Grattan Institute says a 100 per cent renewable electricity grid is an unviable target because of the “winter problem” – the period during which demand is high but renewable energy supplies are low.

It leaves a period of about two weeks when the gap in renewables cannot easily be filled.

Grattan experts say that policymakers should set their sights on 90 per cent renewables by 2040 instead, with the remaining 10 per cent coming from gas peaking plants. 

Detailed analysis is accessible here and here.