Residential installers around Australia have been madly busy over the past nine years fitting solar PV systems to more than 2 million houses. Between 2010 and last year about 8.1GW of capacity was secured to household rooftops, and over that time the average system has more than tripled in size – from 1.97kW to 7.13kW.

Solar is popular, but it isn’t always easy to sell. Not every customer across the country has had a positive experience with solar, and many of them are disengaged. The steady rise in residential capacity is credit to the logic of converting to cheap, clean energy but also to the tenacity of installers.

Such is the struggle of fitting a new form of generation to houses that started life most likely wired up to coal-fired plant. But the built environment is always changing and solar PV systems, sometimes with storage, are slowly being included in new properties.

Housing developed by the South Australian government for participants of the National Disability Insurance Scheme includes 5.2kW of solar and a 10kWh storage unit.

Help where needed

Where solar saves money, it makes sense to include it in housing for occupants on slender budgets. In South Australia, the department of Families and Social Services is working with installer Natural Solar to incorporate solar-and-battery systems into speciality disability accommodation designed for participants of the National Disability Insurance Scheme. 

The program will start in a property development in Salisbury, South Australia, and – if all goes well – be rolled out to developments across the country.

In the initial development, each two-bedroom single-storey accessible home will be fitted with a 5.2kW solar system with Q-Cell panels a 10kWh Sonnen Battery Eco unit.

“The way these batteries will improve the quality of life for eligible participants of the NDIS is truly impressive,” says Natural Solar CEO and founder Chris Williams. “[The benefit] is twofold, for both the environment and the community.”

Each home will be eligible for sonnenFlat, a subscription-style service where consumers pay a flat fee for power and battery-maker Sonnen has liberty to on-sell excess energy from that customer’s solar-and-storage system. Under the plan residents will pay a monthly fee of $40, saving each household up to $1,520 a year (using the national annual average cost of power of $2,000 as a benchmark).

Subscribe and save

The sonnenFlat scheme is available to homes with Sonnen storage technology installed that are connected to eligible networks. It applies an annual kWh usage limit, beyond which subscribers pay an excess usage rate. In return, Sonnen buys excess electricity at an agreed feed-in tariff.

“Each household must produce the minimum annual generation quantity of energy over a 12-month period,” a sonnenFlat pricing guide says on the company’s website. “Where the annual energy production falls below the minimum annual generation, the annual usage allowance will be reduced proportionally…”

For the NDIS sites Natural Solar has developed a custom functionality where each battery retains a minimum of 20% charge at all times. In the event of a blackout or power outage, backup power will be activated, whereby the resident can prioritise household appliances to avoid disruption.

This is assisted housing developer inhousing’s first go at utilising renewable energy technology on its developments. “Solar and batteries open up huge potential for SDA tenants under the NDIS, and we can see the opportunity ahead,” says COO Geoff Barber.

The dynamic duo … LG Chem’s RESU10H battery is paired with a SolarEdge inverter in the clean energy option offered by Tangara.

Watts in the box

At the other end of the country, LG Chem is working with property developer Tangara Constructions and installer Solar Hybrids on solar-and-storage packages to buyers of new houses in Queensland, the state with by far the most residential capacity installed.

Buyers who take the clean energy option will move into a house with 6.5kW of LG panels and a 9.8kWh RESU10H battery connected to a SolarEdge hybrid inverter with backup functionality.

“It’s our most popular system,” says LG Chem general manager Jamie Allen of a set-up the company estimates can make 9.4MWh of electricity a year.

Depending on who you speak to, batteries are a tough sell or a booming business. State governments around the country are doing what they can to encourage Australians to invest in technology that allows them to store surplus solar energy, and Allen says LG Chem has “by far the largest market share” in the programs on offer.

“In Queensland we’re seeing a bigger uptake of smaller batteries whereas in South Australia people are trying to get the full subsidy, so they are aiming more for their 10-13kWh-sized batteries,” he says.

Subsidised nation

Allen provides a rundown: South Australia is offering up to $6,000 in subsidies for batteries for a total 40,000 systems; Queensland is offering $3,000 for 3,650 systems; the ACT government will pay a variable amount per kWh up to 36MW; Victoria is helping 10,000 homeowners with up to $4,838 on solar and storage retrofits; retailers AGL and Simply Energy are subsidising 1,000 systems for virtual power plant projects in South Australia, and Origin Energy is doing the same for 500 systems as part of a VPP trial in Victoria.

NSW is also working on distributed energy resources grants for a VPP scheme rollout, with up to $1,000 per system.

Owners of Tangara-built houses that include LG’s clean energy technology should feel no qualms about leaving the lights on.

Listen and learn

LG Chem is a dominant player in a growing market, but it can’t be complacent. Allen says education of consumers and installers is very important and the brand runs sales training sessions so prospective customers are pitched a “clear and honest expectation” of what a system can provide. “If that doesn’t happen, there is quite a bit of confusion out in the market,” he says.

It’s too early to really see evidence of storage’s full potential being exhibited, he says, at least until virtual power plant projects are finalised and set in motion. Until then feedback from customers is positive but he can’t provide aggregate data on how the installed fleet of LG Chem residential batteries performs. “In general the systems are using normal self-consumption; charged during the day and used during the evening and night.”

There are many battery brands and the technology is varying. Owners of some brands, he says, may not be able to charge their battery to full during daylight hours if it doesn’t have a high power charge rate, and likewise a discharge rate at night time.

Backup or blackness

One point the public needs help with is the fact that not every battery system or inverter it’s connected to will provide backup power. “That’s one piece of education consumers need to be aware of,” he says. “Some do, some don’t.” Some inverters have the capability to isolate from the grid and provide AC backup but others don’t. “If there’s a blackout, they can’t access the battery.”

It’s too early for anyone to claim expert predictive skills about how home storage systems will be incorporated into Australians’ energy regime once electric vehicles are part of our lives, but Allen suspects EVs may become useful assets for powering houses at night.

“A lot of this has got to do with the framework from the networks and retailers, who will have to get involved with different mechanisms of charging during off-peak periods, potentially from the battery or from generators.”

The Gillies Hall, running on 100% renewables, looks great from the street and feels great on the inside.

Student digs

Meanwhile, in Melbourne property developer Multiplex has delivered Gillies Hall, a student accommodation block 100% powered by renewable energy in line with owner Monash University’s net zero carbon emissions strategy.

The clean energy commitment was enabled with a combination of rooftop solar, an all-electric design and Monash’s power purchase agreement with Murra Warra Wind Farm.

As Australia’s property portfolio is renewed and replaced, expect to see solar and storage as mandatory requirements for a renewable energy future.