Dive Brief:

The 50,000-home virtual power plant (VPP) Tesla is developing in South Australia helped maintain grid stability when a coal-fired unit in Queensland tripped offline and reduced system supply by 748 MW in October.

According to the Australian Energy Market Operator, the outage caused power system frequency to drop below normal levels but Tesla's VPP was able to inject power from hundreds of individual residential batteries to help return the system frequency back to stable levels.

This is not the first time a Tesla battery project has benefited the South Australian electric grid. Last year the Hornsdale Power Reserve project, which includes a 100 MW/129 MWh battery facility, twice stepped in when coal units went down.

Dive Insight:

The October incident, reported by the South Australian government last month, is an example of how battery storage can benefit the grid. And it is even more impressive given that the VPP project is still some ways from completion.

"Although the Virtual Power Plant is in its early days, it is already demonstrating how it can provide the network support traditionally performed by large conventional generators," South Australia Minister for Energy and Mining Dan van Holst Pellekaan said in a statement.

Once complete, the VPP will include 50,000 houses fitted with 5 kW rooftop solar systems and 13.5 kWh Tesla batteries. Together, they will be capable of delivering up to 250 MW of solar power and 650 MWh of energy storage.

So far, less than 1,000 homes have been completed. Still, the aggregated storage was able to make a difference.

According to the South Australian government, the VPP "detected the frequency drop and immediately injected power into the grid from hundreds of individual residential batteries installed on SA Housing Trust properties across the state."

The full program could be rolled out to 49,000 additional properties later this year.

Tesla has been moving quickly to add more energy storage in South Australia to help stabilize its grid. The ​Hornsdale Power Reserve project was completed in less than 100 days, following a pledge from Tesla CEO Elon Musk to install the battery quickly — or do it for free.