The Sydney network has committed to a trial to test whether community storage can settle voltage levels as demand for rooftop solar continues.

The battery storage required to police rising levels of solar exports into the grid is slowly arriving in cities around Australia. The latest edition is a 150kW/267kWh unit in northwest Sydney, owned and operated by local network Ausgrid.

The MTU EnergyPack QS battery in Beacon Hill is the first of three planned by the network in a trial that will harness and store solar power from local homes, allowing more renewable energy into the grid while minimising the net effects of rising voltage levels around midday.

“This is an exciting milestone for Ausgrid and the first step in our community solar battery project which we know can benefit customers by keeping downward pressure on energy prices by reducing peak demand, and supporting the use of renewable energy,” said Ausgrid CEO Richard Gross at the unveiling.

A community battery allows multiple households within a certain radius to “share” a storage system, Gross said. “This can save households thousands of dollars on the upfront cost of an individual battery, and allow them to effectively use more of the solar energy their home systems generate – bringing down their electricity costs.”

The Northern Beaches installation is the first of three community batteries planned for the Ausgrid network in 2021, with units planned for the City of Canterbury Bankstown and Lake Macquarie City Council.

Flexibility is key

Ausgrid chief customer officer Rob Amphlett Lewis explained the strategy to EcoGeneration in an interview that will be published in coming weeks, but some of the highlights from the discussion are included here:

You haven’t partnered with a retailer yet but can you explain how customers with solar will interact with the battery?

“We are not charging the customer anything; we are effectively running this as a net benefit to the [solar-owning] customer. If the customer was going to rent this from us for, say, $500 a year, and he saves $800 a year, he’s $300 a year better off. We won’t have a situation where we are charging the customer for the service, and that’s a way we can get around the [Australian Energy Regulator’s] ring-fencing process.

“If this trial was never going to use a retailer, we would need a market participant to access FCAS and wholesale markets. But we don’t need a retailer to provide the service to the end customer.

“That’s the benefit of networks providing this service; you can have a rental space within a community battery and you can switch your retailer without having to have a new contract with a different retailer.”

What are your thoughts on residential storage?

“For us, we think sharing is always so much better. Residential storage is fairly high-cost. You don’t have the scale benefits or the diversity benefits that come from sharing. We feel shared community batteries offer a much better economic outcome and can really support decarbonisation in a much broader sense than just an individual home battery.”

What happens in the middle of a hot day if it’s more profitable to discharge than charge with solar exports?

“The battery will operate to make sure the network is stable; that’s our primary concern. The beautiful thing about the virtual battery is that if that solar energy gets used to prevent a problem occurring for the community, when an individual draws down from the battery – and the battery hasn’t got spare capacity – they’ll be charged as if they had drawn their own power from the battery.

“Where there is surplus, and the battery is discharged, the individual will draw down from the grid and be charged as if they were drawing from the battery. It’s that characteristic that makes it cheaper than owning your own battery. The customer will have the financial experience of owning her own battery, but the battery she is contributing to will perform the best outcome for the local community.

“Flexibility in the network is the most important characteristic that will help us decarbonise. We think this has a huge role in providing flexibility of demand supply into the grid at a low cost.”

If the trial goes well, how many community batteries would you expect to deploy around Sydney?

“The NSW Electricity Infrastructure Roadmap calls for 2GW of storage by 2030, and we could provide 400MW of batteries through this model – effectively 20% of the batteries required by the state. That would mean 2,000 or 3,000 [of Ausgrid or similar-sized community batteries] across the state.”