South Australia's energy network has been struggling of late — there were forced blackouts for tens of thousands of homes during a heatwave last month because there wasn't enough power to meet demand.

But Tesla thinks it has a solution.

The company's billionaire boss Elon Musk says he could install a battery farm capable of fixing the system within 100 days of signing a contract.

It's a suggestion that the Grattan Institute's energy expert Tony Wood says should be taken seriously, but it's not the only electricity storage option that's available.

What's the advantage of electricity storage?

The idea is that energy storage technologies can take power during off-peak hours and put it back into the grid when it's needed.

As well, wind and solar are intermittent sources of electricity generation, so this power needs to be stored if the grid is to rely entirely on renewables. (Keep in mind that South Australia already gets about 50 per cent of its energy from renewables, mostly wind and solar.)

One storage technology that's getting a lot of press is Tesla's Powerpack.

Tesla says this battery is "infinitely scalable" — that means a business could buy a single Powerpack so that it still has power during a blackout, while a city, state or country could install hundreds, thousands or even millions of them in order to support an entire grid.

In 2015, Musk said you'd be able to transition the United States to renewable energy with 160 million of them, and the entire world with 900 million.

Don't presume he was just speaking theoretically, either; this is the same man who last month was spruiking his plan to send tourists around the Moon in 2018.

Where has battery storage already been done?

Tesla has already built what it describes as "the largest lithium ion battery storage project in the world" in Southern California.

It says the battery farm consisting of 396 Powerpack 2s can power more than 2,500 households for a day.

Why haven't we done this in Australia already?

It's always been too expensive to be practical.

For it to make sense as an investment, the savings would have to be greater than the costs of installing and running the batteries in the first place.

The reason interest in these batteries is growing is because they're getting cheaper every year.

But whether or not they make economic sense yet is still up for debate. Roger Dargaville, from the Melbourne Energy Institute, suggested in The Conversation that they don't.

Currently, large-scale batteries are much more expensive than "off-river pumped hydro energy storage".

Wait, what is "off-river pumped hydro energy storage"?

PHES as it's known simply involves pushing water uphill.

"When there is excess electricity, water is pumped through a pipe or tunnel, to the upper reservoir," ANU sustainable energy expert Andrew Blakers wrote in The Conversation.

"The energy is later recovered by letting the water flow back down again, through a turbine that converts it back into electricity. Efficiencies of 90 per cent in each direction are possible."

So when you've got power to spare, send water uphill; when you need power, send it back down. Quite ingenious, really.

Currently, this technology represents 97 per cent of electricity storage around the world. Professor Blakers says used in combination with wind and solar, PHES is cost-competitive with fossil fuel power stations.

Last month, EnergyAustralia chief executive Catherine Tanna said a desert site in South Australia would be perfect for a proposed pumped hydro venture.

The company is backed by federal funding and if its project goes ahead, the target date for operations is 2020.

"If a pumped hydro project of this scale had been available recently in South Australia, there wouldn't have needed to be the load shedding that occurred there," Prime Minister Malcolm Turnbull said.