Batteries are not easy to sell to homeowners but the various incentives offered around Australia are easing the deal and sales are riding upwards – although suppliers seldom share data.

The logic of saving surplus solar energy is impossible to miss. If you’re smart and you own solar, you install a battery. But what do you do if you already have solar and a battery, and the battery-maker then offers to sell you power for less than you already pay each month?

The sonnenFlat deal, offered to owners of sonnen batteries, is a unique offer in a market where hardware and services are often separated, but sonnen Australia-Pacific CEO Nathan Dunn expects the energy option to take hold among clients now that Victoria has come on board.

The offer is currently available throughout NSW, South Australia, the ACT, Tasmania and south-east Queensland.

Sonnen Australia-Pacific CEO Nathan Dunn is looking forward to seeing the potential in distributed energy resources.

Beyond hardware

Germany-headquartered Sonnen is a hardware company, no doubt, but Dunn also describes it as offering “energy services”, notably with its sonnenFlat retail offering. Its “energy bundle” starts from a $42 monthly subscription that offers the customer all the electricity they can use up to an annual cap (7,500kWh for $42 a month, 10,000kWh for $52 a month and 12,500kWh for $62 a month).

In return, sonnen gets access to what’s stored in the householder’s sonnen battery.

“It gives us more ability to understand more around how to connect to prospective virtual power plants around Australia and helps us with the development of the sonnen proposition,” Dunn says.

The offer was launched around the middle of 2017 and Dunn can’t provide details about the number of sonnen-owners who have signed up to sonnenFlat.

“We’re undertaking a refresh of the model to make it more visible to some of those customers [who have installed a sonnen battery],” he says. “We had a focus in the past on hardware and not the combined entity.”

Virtual retailer

The announcement that the service is now offered in Victoria means the eastern seaboard is covered.

“Victoria was the final market we needed to close,” he says. “That gives us the ability to say we are most probably the only energy retailer that can serve customers across the majority of states on the eastern seaboard.”

Dunne’s reference to sonnen as a “retailer” shouldn’t be read literally. He is describing the battery-maker’s professional partnership with Energy Locals, which issues the bills.

The benefit for sonnen, he says, is it will be able to take a deep read of its customers’ energy habits and understand how batteries are used. It can also “ask the owners to share some of the energy they store in that battery”, which will enable it to provide services – voltage fluctuations, frequency control, etc – to generators and networks.

“The benefits will come as we get to a point of critical mass,” he says. “We’re not there at this point but we will be very quickly, based on us closing the Victorian gap.

“It was only in Victoria that we came across a number of challenges from a certification perspective. I can’t speak about the specifics of those challenges.”

Data in the making

The company is currently running trials around aggregation of customer data. Once the software is running with rigour, sonnen will be ready to share its findings, he says.

It’s “highly unlikely” that Energy Locals will on-sell surplus solar from sonnenFlat customers, he says. “Any other customer of Energy Locals is dealt with individually by Energy Locals.”

The technology can interact with the grid to address voltage wobbles on feeders where solar penetration is high, he says, but it’s too early to report on newly calmed signals in suburbs rich with sonnen battery-owners.

“We have the ability to help smooth and manage some of those frequency fluctuations,” he says. “If there was an area where there was a significant spike or problem from the voltage fluctuation perspective and there was a healthy enough installation rate of sonnen batteries we definitely would be able to help.”

For the month of June 2019, sonnen will offer a sonnenFlat Energy Bundle where customers signing up for sonnenFlat can claim $1,000 off their new sonnenBatterie purchase.