The Australian Energy Council has warned South Australia about the risks of solar power.

A quarter of South Australian homes have rooftop solar panels, and the numbers are growing.

The company that owns the state's power transmission network, ElectraNet, says the massive popularity so far and predicted uptake of solar and batteries could actually make it more vulnerable.

Australian Energy Council chief executive Matthew Warren said the state could fall into blackout on days of “minimum demand” — when people use the least amount of power, and all of it can be drawn from solar.

“It could be as early as 2023 when the energy coming from rooftop systems in South Australia is all the electricity that state needs to run the grid,” Mr Warren said.

“While that's interesting, that poses technical challenges in how we keep the grid stable.”

The companies Mr Warren represents are trying to work out how to pay for a grid that is now becoming just a backup.

“We know we have to decarbonise our energy systems, we know we have to use more renewables — but no-one really planned to get to the levels of renewables that we have in South Australia right now,” he said.

Trials are underway across the country, seeking ways to include battery storage into our future energy mix.

Most firms want to spend less on infrastructure while increasing energy security, but that would not reduce the risk of those days of minimum demand.

Mr Warren says SA needs a secure power source.

“You can’t simply rely on an interconnector for all the system security,” he said.

“If the interconnector drops out, or there's a fault, or whatever happens to it, there is no system security — there is nothing regulating frequency and voltage in the grid.”

The State Government's solution — more gas-fired generation, or a second interconnector — is likely to push up prices, which Mr Warren says will lead to more people moving to solar and batteries.

“Most solutions, by definition, tend to push up prices, because if they were cheaper we would do them anyway,” he said.

South Australian Energy Minister Tom Koutsonis wants Federal Government help.

“Without that national framework, you are going to get these perverse outcomes,” he said.

The minister will soon make a call for reform at a meeting of the Council of Australian Governments (COAG).

“Talk is cheap — it is now time for national leadership,” he said.

“It is now time for the Prime Minister to get serious about bringing climate policy and energy policy together.”

The Federal Government has commissioned a preliminary report on the state of energy security, to be delivered by the end of the year.