Getting off-grid

A residential energy system at an off-grid property in South Australia is the first completed customer deployment of Australian battery company Redflow Limited’s ZCell batteries.

Previously, mains power was available in only one corner of the hilly 100 ha Willunga property owned by the family of Alan Noble, engineering director for Google Australia and New Zealand.

Noble said extending mains power further across the hilly terrain would be substantially more expensive and less flexible than the off-grid solution with two ZCell batteries, which can store 20 kilowatt hours (kWh) of energy, powered by solar panels on the roof of a large implement shed.

The batteries, which were integrated with 12 Australian-made Tindo Solar panels and two Victron battery inverters by ZCell installer Off-Grid Energy Australia, continued working uninterrupted during the recent storm-caused power failure that blacked out the rest of South Australia.

Noble said he had installed the ZCells to provide him with flexibility, safety and affordability.

“We wanted the flexibility to build anywhere on the site without having overhead powerlines,” he said.

“Secondly, we have power when we need it. If there is a bushfire here, we can power our pumps properly, whereas electricity distributor SA Power Networks has a policy of actually shedding power during high bushfire-risk days, so precisely when you need the power, they shut it down. Without the ZCells, we’d be running around trying to fire up generators during hot days, which is not practical.

“Also, we want to make this property as automated as possible. I want it so we can move water automatically, based on the power to turn on pumps, to turn on sprinklers and turn on any fire defences. We can only do that if we have our own on-site power.

“Last, but not least, I really like the idea of being self-sufficient. The way I see it, grid power is getting more and more expensive, so this is an investment that in the long term is going to be worth it,” he said.

Noble said he had chosen Redflow’s ZCell zinc-bromine flow batteries, rather than lithium-based alternatives, for two reasons. “Firstly, they can cope with a high-heat environment, which is not true of a lot of batteries.

“It does get hot here in the summer, as the shed is not air-conditioned. Also, getting back to the earlier point about having power when you need it most, on really hot, high-risk bushfire days, I want to make sure my batteries are working on those extreme-heat days.

“The other benefit is that you can have them just sitting there. Conventional batteries don’t like being fully discharged. Longer term, that’s less of an issue, but over the next couple of years while we’re not living here full-time, it’s nice to know that I’m not going to destroy the batteries if they’re fully discharged. They’re also relatively compact batteries too, so they don’t take a lot of space.

“Also, ease of use is a nice factor with ZCell. It’s all very easily managed through the BMS (Battery Management System), both on-site and through the internet. I’m looking forward to setting up my rules and have everything automated so it’s just working quite happily.

“Finally, I kind of like the idea of doing my part to support Redflow as an Australian company, which was also the reason I chose photovoltaics from Tindo Solar, which is based in Adelaide,” Noble said.