German energy storage firm Sonnen wants to sign up at least 2,000 Australian customers for SonnenFlat, a monthly ‘flat rate’, this year while their batteries are used to benefit the local grid.
With SonnenFlat, customers pay a monthly fee of between US$23 and US$42 which is worked out according to the size of the house and the generation capacity of its solar array.
Customers have access to as much electricity as they need which is also drawn from the grid. The company is currently selling around 200 units per month in Australia.
Sonnen uses the capacity of their system hosts’ batteries to respond to grid operator demands to balance power on the network, accumulating the revenues required to cover increases in customer electricity prices.
The service was launched in Germany last year September 2016 and according to Sonnen, the frequency regulation services to transmission network operators create the potential to generate approximately US$550 of economic value per customer each year.
The Australian energy storage market
Sonnen has partnered with Australian solar installer Natural Solar which has only been offering Tesla Powerwalls to its customers. Natural Solar CEO Chris Williams said in a statement that Sonnen’s systems will expand it offerings in a climate where demand for energy storage has grown by 1,000% in the past eighteen months in Australia.
Increasing energy prices have led to the need for solar arrays and energy storage systems, he explained.
According to Sonnen’s Global Head of Sales and Marketing Philipp Schröder, the Australian market is currently of great interest with its high penetration of rooftop PV, frequency electricity price ‘spikes’ and a liberalised market structure.
Sonnen claims that Australian householders can save US$2,277 on their electricity bills each year by joining SonnenFlat even though customers are expected to pay for the battery and other integrated hardware on top of the monthly fee.
Assuming an average electricity consumption of around 10,000kWh per year for a three-person household in Australia, currently paying around AUS$3,400 a year for utility power, the company claims SonnenFlat at a AUS$40 monthly rate could see a payback for the system of five to six years.
Flat rate a win-win
SonnenFlat aggregates and integrates thousands of Sonnen systems into a network to create a virtual power plant.
The main difference between launching the service in Germany and Australia is that electricity prices and feed-in tariffs (FiTs) vary across the different Australian states and territories.
Sonnen’s European virtual power plant, covering Germany, Italy, Austria and Switzerland is already serving 100,000 customers with electricity.
Schröder says that the technology behind SonnenFlat is based on the smart metering of each flow of electrons and consequently logging each transaction. It is centered around a lithium-iron-phosphate battery that comes with a 10-year warranty for over 10,000 charge and discharge cycles. In other words, it can be charged and discharged three times a day, more than many rival systems, according to Sonnen.
Systems are available from 2kWh up to 16kWh, sized in 2kWh increments.
In a press release, Schröder likens SonnenFlat to a mobile phone payment plan: “Households are struggling under ever changing and ever-rising power bills, and instead we are offering to pay those charges in exchange for a flat charge. It is like a mobile phone plan. Our SonnenFlat plan will allow households to plan their finances and save thousands of dollars a year in power charges.”
Sonnen’s offering follows AGL’s launch earlier this year of a virtual power plant in Adelaide that aims to connect 1,000 household batteries, which can be drawn from at times of heavy demand or short supply, but owners are still required to purchase power when their own storage or generation runs out.
In addition, although the Sunverge batteries used in this network are cheaper than the Sonnen batteries, thanks to a subsidy from the Australian Renewable Energy Agency, the cost would be recovered by the savings on electricity bills within four years, says Sonnen.