South Australia is in a "race against time" to get new generation in place for summer, as a report names SA and Victoria as the states most at risk of power supply shortfalls over the next two years.
The Australian Energy Market Operator says an average summer in 2017/18 would present a low risk of problems for Australia's power network.
But it says the network remains susceptible to extreme conditions, particularly if limitations on generation or transmission, or low solar and wind conditions, coincide with periods of peak demand.
In its Energy Supply Outlook, the operator says SA and Victoria are most at risk of shortfalls in such conditions, which could result in people losing power through load shedding.
The outlook says all regions will meet the power reliability standard over the next two years but SA, in particular, is "considered most at risk" of dropping below and must meet a range of conditions not to do so.
"Existing generation capacity must be available and operating, Pelican Point Power Station must return to full service," the report said.
"And the new battery storage and diesel generation contracted for by the government must be available as planned."
South Australian Premier Jay Weatherill said "it's a massive challenge" to get new generation running by summer but it was clear it was "absolutely necessary".
"It is a race against time," he told reporters in Adelaide on Thursday.
"We're working day and night on this."
AEMO chief executive Audrey Zibelman said the operator's latest analysis showed the power system was changing.
"There will be challenges that will need to be managed proactively on days of extreme conditions to maintain secure, reliable and affordable energy to Australian consumers," she said in a statement on Thursday.
Ms Zibelman said the operator was working closely with governments and market participants to improve capacity in the system, so it could better cope with extreme situations.
Initiatives already under way to boost capacity included ensuring there was enough generation fuel available, facilitating new generation and storage, and performing generation and transmission maintenance before the summer.
© AAP 2017