New residential energy storage pilot projects to showcase promise of energy independence

In a sign of the times and an indication of things to come, a total of 22 homes are to be fitted out with emergency backup energy storage systems in a pilot project overseen by Australian energy storage solution wholesaler, 360Storage. The company’s energy storage solutions have already been installed in nearly 1,000 grid-connected homes across the country, but these are the first that will enable households to keep the lights on even when the grid goes down.

Over the past 18 months, accredited dealers for 360Storage have installed hundreds of 360Storage’s City Solution units in households across the country. The City Solution is currently the most successful energy storage solution released in Australia but up until now had the limitation of not having grid failure protection built in. Two systems using 360′s new City Solution EPS (Emergency Power Supply) unit have been up and running in Melbourne for about two months, with another 20 slated to be installed at locations across South Australia, Victoria, NSW and Queensland in the near future.

The purpose of the project is to gain an understanding of how the latest upgrade to the company’s premier energy storage solution will operate in practice, but the experience will also undoubtedly be a useful education for the industry at large.

The roll-out is significant because it represents one of the first big pushes for the commercialisation of residential energy storage with emergency backup functionality in Australia. Although home battery storage (almost always mentioned in the same breath as solar PV) has been a hot topic as Australia’s state-based feed-in tariffs have been cut and electricity rates have skyrocketed, prohibitively high energy storage technology prices have kept battery systems from gaining the same degree of popularity that rooftop solar energy systems have. Could this launch be the harbinger of the shift towards energy independence that Australian homeowners have been waiting for?

To get a better picture of what these projects are all about, we reached out to 360Storage to learn more. Some of the key points of the pilot project and features of the systems are highlighted below.

Australia sees ample demand for energy storage, with a focus on saving money

360Storage Business Development Manager Tom Kuiper said that there was no shortage of candidates for the pilot projects. “Over the past few months we have seen significant interest in these systems from both our Dealer Network and the end-consumer directly,” he says. “Because of this we found it relatively easy to find suitable test sites.” Each system is fully paid for and owned by the homeowners. “We found consumer demand strong enough for people to take the plunge, knowing the first few installations may not be perfect.”

“Because the City Solution allows consumers to use their solar energy at night,” Mr Kuiper says, “the additional savings compared to a standard solar systems are equal to their evening/night time consumption.” He takes the example of a household that uses a total of 20kWh per day, with about 8kWh being consumed during daylight hours and 12kWh at night.

“If we assume this consumer pays $0.30/kWh, with a solar-only solution they would save about [$0.30 x 8kWh x 91 days =] $218.40 per quarter. With the City Solution, on the other hand, they could save up to [($0.30 x 8 x 91) + ($0.30 x 12 x 91) =] $546 per quarter. If we then take into consideration likely electricity price increases it is easy to see the financial benefits of a system like this,” he says.

What’s in a 360Storage City Solution?

Each City Solution EPS consists of a hybrid inverter with a built-in 50-amp charger. A transfer switch is used to switch over in case of a grid failure. Pylontech lithium ion batteries have been selected for their reliability, limited physical space requirements, minimal maintenance requirements and long lifespan. Each battery supplies 2kWh of usable energy and can be linked together to build a battery bank of 12kWh in total. Systems come with a 5-year warranty but batteries have an expected lifespan of 10-11 years; the rest of the system is expected to last 15-25 years

City Solution

Photo of one of the City Solution installations in Melbourne: The system consists of a 5kW rooftop solar array, with 6kWh of battery storage and Emergency Power Supply functionality.

How were the energy storage systems sized?

Mr Kuiper says that the systems have been sized to meet the individual electricity needs of the pilot participants using sales and sizing software available to 360Storage partners. The software takes into account a number of variables which help to determine what size system would best suit a customer’s electricity usage patterns. The solar PV array capacity for projects in the pilot is around 5-6kW, while storage capacity ranging as much as 2-12 kilowatt-hours. Once equipped, homes will be able to rely on the City Solution units for 80-100% of their electricity supply.

Sizing an energy storage system whose purpose is to supply almost all of a home’s electricity is a much trickier endeavour than sizing a simple solar PV array whose main purpose is to offset daytime electricity use. Depending on the electricity usage patterns and retail electricity tariff of the home in question, the flow of electricity to and from solar panels, battery bank and electricity grid will need to be managed differently.

As a matter of best practice, systems in the pilot were designed so that the electricity produced by the solar array will be enough to meet daytime electricity demand for the home. Evening electricity needs (4-11pm) are then met by the battery bank, and anything after that (11pm-6am) will be purchased from the grid and low off-peak rates (where available). In cases where off-peak are unaffordable or unavailable, the size of the storage component of the system has been be increased to compensate.

Grid-friendly, but with a battery backup for blackouts

One of the key features of the City Solution that helps it stand apart from ‘previous generation’ energy storage devices is its ability to understand how to prioritise the available sources in order to optimise economic outcomes. This means that it can strategically use the grid to draw in energy or charge batteries when grid electricity is cheapest. While 360Storage is not promising total grid independence for the project participants, it’s clear that participants will come pretty close.

Homes participating in the pilot project will not only have lower power bills – they will also have power when the grid goes down. The City Solution’s emergency power supply (EPS) functionality is another feature that puts it squarely in the category of ‘next generation’ energy storage solution. Unlike conventional systems which – due to anti-islanding standards – are required to switch off in the event of a blackout, pilot participants will literally be able to turn the power back on with the flick of a switch should the grid go down.

The relatively new nature of this type of technology is the main reason that 360Storage opted to launch the suite of projects as a pilot, with the aim of learning and improving their technology in mind. “Tests in the factory and labs have been completed and turned out well, but nothing beats simple practical testing to ensure that when we roll this out to the mass market in the middle of this year installers, retailers and consumers can be certain the whole installation process has been ironed out and the consumer experiences is flawless,” Mr Kuiper said.

© 2015 Solar Choice Pty Ltd

James Martin II