“90% off your bills” says Chris Bowen
With the solar and the right tariff, home batteries can really drop electricity bills. And the good news is that the government is pumping an extra $5bn into the Cheaper Home Batteries Program, due to its runaway success.
“According to energy department analyst, a households with existing rooftop solar could cut a further $1,100 from its annual power bill by adding a battery, while a home adding solar and a battery in one go could save as much as $2,300 a year – up to 90 per cent of a typical family electricity bill.”
Sophie Vorath, Renew Economy
Home Batteries at a glance – all that you need to know
New Battery Highlights Video
But how do you make sure a home battery is right for you? What size, features and tariff to maximise your savings? Check out our fast paced highlights video to learn more, or click through to chapter point links in bold below.
The Cheaper Home Batteries Program is a runaway success
The home battery rebate program has “really shaken up the whole battery world” says Trent Jones, with around 30% off – a 10kW battery can be purchased for “around $6,000”. The program has over performed expectations, 7,000 batteries are being installed per week prompting a $5bn funding extension.
Australian Government demonstration of how a home battery captures much more of household solar to use in the evening and overnight
Why buy a battery? What size?
The first question to ask is why do I want to buy a battery? What functions do I want? Blackout protection? More solar self consumption? Energy bill savings?
“Understanding the why, it’s like the basic life principles. why leads to what and how, but we’ve got to start with the why.”
Trent Jones, CEO All Electric Homes
What you want to do with your batteries matters in deciding the type of system, size of battery and battery features
Choosing system design and battery size depends on your energy profile, how much you use and when, whether you want to remove gas, add blackout protection or EV charging or be largely self sufficient.
“Do you plan on removing more gas from your property? Do you plan on going all electric?
Because if you are, we’re going to have a very different conversation around what size battery you need, because we’ve got to look at what you’re doing now, but what your load’s going to be like in the future.”
Trent Jones, CEO All Electric Homes
Designing a system to fit the household
Russell Williams explained that a battery has both size (kWh or capacity) and power (kW or speed) ratings
Matching size and usage. The battery rebate has allowed a lot more options, changing installers approach to system size and design.
- Light use – 5-8kWh, recommending GoodWe Sungrow for basic backup
- Average use – 10-15kWh recommending Tesla, Sigenergy, Sungrow with good features and manufacturing support.
- High electrification including EVs, air-conditioning and moving to fully electric –15-30kWh recommending Tesla, Sigenergy, Sungrow
Designing a system that matches your needs and maximises your savings depends on usage patterns, desired functionality and future plans
Rebates, affordability and getting out of gas
How could I afford the upfront cost of going electric? Victorian households have available $15-20,000 of State and Federal funding and rebates for solar, storage and electrification, depending on your situation, allowing you to cut up to 90% off your energy bills.
Electric appliances are three to four times more efficinct than gas appliances, plus you can power them yourself
Gas prices continue to rise – up 40% in last three years, so adding solar and a battery and going off freezes your energy costs as well as making a big contribution to a safer climate future.
Battery features and tariffs
Key battery features include:
- Static scheduling
- Ability to import and export to grid
- Blackout protection
- Load integration,
- Optimisation
A good installer will help you choose the right mix of functionality for your existing and future needs, depending on your needs and budget
The right kind of tariff is key to maximising your saving and your savings. The right kind of tariff will take advantage of lower off peak rates or even a free midday period.
- Flat rate is not advantageous
- Peak Off-peak (time of use) a minimum if you have a home battery
- Solar Saver with free period at lunch time better for good returns but requires scheduling
Tariff selection is fundamental to maximising savings – at least time of use, with solar soaker (saver) options a good option
Installation, switchboard and siting
From an installers perspective finding the right place for your battery is important – it can’t be in direct sun, say on a north facing wall, or on the opposite side of a habitable room like a bedroom, without fire protection. The garage is often used, but will usually need some kind of bollard protection.
A snapshot of the installation and approval process
Making sure the battery is right for you To summarise, considering battery objectives, your usage patterns, and desired features are important in matching a battery to your household to lower your energy usage from the grid, maximise your savings and protect the environment.
Watch our Home Battery Advantage highlights video here!
Home Batteries in more depth
Check out our recent home battery and solar webinar!
More resources here:
- Download Russell Williams’ latest slideset
- Download Trent Jones’ latest slideset
- Download battery homeowner’s slides here and here
- David Coote – Analytical Engines slideset
For more perspective, check out our Home Batteries information page.
Lighter Footprints Convenor Jenny Smithers welcomes new faces to the Ashburton Community Centre
Trent Jones, All Electric Homes
Trent Jones is the Founder and Managing Director of All Electric Homes, a pioneering company dedicated to transforming residential and commercial energy use in Victoria.
Trent is a trained electrician and has been working in the field of electrification for the past 20 years. All Electric Homes provides an integrated trade service of electrical and plumbing services.
Trent Jones has built All Electric Homes as a multi trade business – very often the switchboard may have to be replaced if it is an old porcelain type
Trent introduced All Electric Homes and then explained the importance of a safe switchboard. Porcelain fuse boxes which in the past have had solar added are a fire risk, do not have safety switches and do not comply with current regulations. Upgraded safer fuse boxes have been mandated for rental properties.
Trent advised that the first question a householder should answer is why am I considering installing a battery?. Once the why has been answered you can be clear about your choice of battery size and how to obtain that objective.
Trent stated that there are three main motivating factors why people install batteries:
- environmental ( reducing emissions)
- outage protection
- reducing energy costs
Trent stated that if a householder has an old small solar system then that will not be compatible with adding a battery and the best option is to remove the old system and install a larger solar system with a battery.
Battery installers have to pay attention to siting considerations – south wall or garage preferably, room around it, fire proof barrier if a bedroom behind
Siting of batteries
There needs to be sufficient space for installation of batteries, if adjoining a habitable room there needs to be a fire proof barrier and if outside and on a north facing wall the battery needs sun protection. Garages are a common location for battery installation and they need to have sturdy bollards to ensure they cannot be knocked by a vehicle.
Warranty and backup are just as important as system size and battery features
Battery selection
Trent mentioned that the choice of battery should be determined by the functions the household is wanting and that the choice of brand of battery may now be influenced by the householders political opinions as well as size, price and features!
It is important to look at your existing electricity and gas usage. An installer should look at your current energy profile to be able to advise you as to the likely benefits from a battery and ensure you select the right sized battery. Trent thinks that the average size of installed batteries will increase as houses electrify and will likely be a 20kwh battery compared with current average of 10 kwh batteries.
Trent advised the audience to consider what other upgrades they may have planned for their property. Are they thinking of getting off gas heating which typically is 60 % of a household’s gas usage or hot water which is 40 % of a household’s average gas usage.
There are significant rebates available for electrifying gas hot water and gas heating systems.
If you have a small solar system say a 2kw system that is not going to meet your likely energy needs. Eg a 2 kw system cannot power a standard toaster.
An open system is preferable to avoid being left with a brick if the retailer goes broke, and it is important to look at VPP fine print
Virtual Power Plants and Vehicle to Home
Vehicle to home is coming but at present Australia has no standards and there is limited equipment available in Australia.
Trent’s advice was to read the fine print of the agreement with the provider and he suggested that VPP suits some people only.
If your car is V2H compatible and you have a bidirectional charger then it is worth at a system that is V2H ready, and also consider battery size related to future needs
David Coote, Analytical Engines
David Coote, a renewable energy and energy efficiency consultant, is the CEO of Analytical Engines, regularly advises households and businesses on how to reduce their energy bills and maximise their use of their solar energy.
David has worked with many clients to help them analyse the costs and benefits of a variety of energy solutions.
The Federal battery subsidy will be a shot in the arm for the installation of home batteries, running through an existing well accepted pathway the SRES scheme
David introduces home batteries, predicting that the Federal government home battery subsidy will result in there being several million home batteries installed in Australia over the next 10 years.
At present there are approximately 250,000 home batteries installed in Australia.
Why get a battery?
David Coote discusses the impact of solar and battery on generation and supply, and lists reasons to buy a battery – the solar system has to be big enough, but allows more self-consumption, lowering energy bills. Batteries also increase the benefits of solar saver tariffs, storing cheap power available in the middle of the day for later use. They also protect against outages if the inverter/battery system has islanding capacity.
The home battery subsidies are likely to represent approximately a $5000 saving for a 15 KWh battery and a 10KWh battery will cost approximately $6000 to $7000 to be installed.
Sizing and features
Sizing the battery depends on the size and timing of the load, size of the solar system, whether you will add more load by getting rid of gas and the type of tariff
Since part of the cost is a fixed installation cost it is worth considering installing a higher capacity battery. A battery between 8 to 15 kwh is a reasonable size for the average household.
8KW of solar saves the most, adding a battery add a bit less than half again but a bigger battery adds little more
David outlined the issues a householder planning to install a home battery needs to consider and know :
- how to select a quality battery
- what functions the battery needs including outage protection requires that the battery and inverter must have “ islanding capability”, not all batteries and inverters provide outage protection.
- static scheduling is very important – being able to set times to upload and block upload as well as discharge times
- how to select the correct capacity battery so that the householders can maximise their energy bill savings and optimise use of their rooftop solar energy. – consider adding more solar
- make sure that there is easy access for the householder to be able to view the battery data
- make sure that you can set when the battery can and cannot charge or discharge and also that the battery can be charged from the grid
- select a battery that has open standards
Tariffs
David discussed the different electricity tariffs that are available. Choosing the right tariff is critical to getting the best return from your battery. At the very least you should be on a time of use tariff (TOU) or consider a solar saver tariff, especially with an EV.
The key points were:
- Solar feed in tariffs are now very low often around 3c /kwh ( this makes getting a battery more attractive financially)
- If you have a battery you should make sure you have a time of use tariff not a single rate tariff
- At present an average time of use tariff would be 15c/kwh off peak and 25 c/kwh peak
- Solar saver tariffs offer cheap power across the middle of the day, some offer free power from, say, 11 am to 2 pm
- If you are still getting a high solar feed in tariff say 10c/kwh it is likely you are paying a high fee for power used at other times of the day perhaps up to 40 c/kwh
Home energy management systems
David spoke about the benefits of power use optimisation. He thinks that home energy management systems will be increasingly adopted. Home energy management systems will be able to integrate the optimum use of the solar and battery system, heat pumps, ev charging and other household energy use. He reminded the audience of the importance of selecting a home battery that can be integrated with a home energy management system.
A home energy management systems (HEMS) will give you finer control in integrating self generation, storage and optimising loads for maximising savings
Battery life
David stated that being gentle with your battery charging and discharging is likely to result in a longer battery life.
Financial benefits
David estimated that the average household with solar and a 10kw/hr battery is likely to achieve savings of between $700 and $800 a year. Visit the calculations below, visit the slideset, or listen on the recording here.
You can see some of the workings in estimating the savings from an average household on a 10KWh battery – this has to be adjusted for each household’s circumstances
Community Benefits
David lists community benefits including increased household resilience, self consumption and lowered bills, improved grid stability and the potential to help renters. He explains that increased household battery uptake will reduce the need for transmission of electricity. Building electricity transmission lines is expensive and socially divisive.
Household batteries will reduce pressure on the grid, easing the ramping before the evening peak, stabilising voltage, increasing household resilience and lowering and delaying transmission rollout
In conjunction with the household battery scheme, the Australian government is also installing much larger community batteries to provide resilience across the grid. These have similar benefits.
Virtual Power Plants and renters
David has little enthusiasm for VPP’S: “you are handing over control of your energy system to someone else to make money out of your system”
For renters and apartments owners, portable battery systems are available and he thinks they may be adopted more commonly in the future.
Owners Experiences
Carolyn Ingvarson – early adopter
Carolyn Ingvarson – early adopter with solar hot water in 2008 and 16 panels in 2012, and in 2021 added second solar system a 13.5 KWh Powerwall I battery “sitting on slate” with a fire wall and EVs
Carolyn added a second lot of panels, heat pumps, a battery and now they drive two EVs
“This is the driver for us, to say, what can we actually do for our footprint. And this is why fundamentally we’re doing it.”
Carolyn Ingvarson
After adding more solar and a battery, and nearly removing gas, Carolyn is saving over 10 tonnes of CO2 each year
Within $5000 of annual savings Carolyn estimated that the battery saved over $1000 per year, and once the remaining small gas bill goes the savings will improve as there will be no connection costs.
As well as savings of over $5000 per year from energy bills savings and EV savings the system has protected against 44 outages
Russell Williams – Sig Energy and Solar Saver Tariff
Russell Williams, after a lot of research, went with 8 kW/16 kWh Sig Energy battery which is bidirectional and stackable, and 12 kW solar in heritage area, which meant a planning permit. He has an EV and is on a solar saver tariff.
After a lot of thorough research David settled on a 8kW 16kWh Sig Energy battery along with solar aiming to maximise self sufficiency
“I went through it and decided on this new Chinese brand called Sig Energy. It’s very new, but it’s got a lot of good capability. It’s got bi directional vehicle to grid capability. And it’s stackable.”
Russell Williams, Electrify Boroondara
Russell charges both the battery and EV during the free midday period (11-2pm) which is when he charges the battery and the car and runs the dishwasher, and then he can discharge to collect a high feed in tariff (15c) during the evening peak.
Russell’s battery, coupled with a bigger solar system and a solar saver tariff, maximises value and self sufficiency, even in the winter
Despite the big solar system, it doesn’t keep up with demand during the winter, which is where the battery and the solar saver tariff come in. Russell is scheduling to get rid of the gas very soon.
David Strang – starting again
David Strang had originally purchased solar then an Alpha Ess battery which worked well in summer, but was not enough for winter. The Alpha Ess did not allow controls for grid export, which mean he couldn’t take advantage of the evening peak on the Solar Saver tariff, plus the battery did not work well with Amber.
David’s 2018 solar system paid for itself very quickly but the Alpha Ess battery did not go so well with Ember
Now after shifting recently David is replacing the old solar PV system and adding a large battery having already replaced gas ducted heating with heat pump air conditioners, and installed heat pump hot water and induction cooking and replaced the fuse box.
Due to limited roof space David Strang has opted to install a larger battery helped along by the generous rebate. This will contribute to grid stability feeding into the peak with a solar saver tariff.
Audience questions
Question One – community benefits from subsidies and electrification support
The community benefits through more efficient appliances leading to reduced or delayed network infrastructure build out, especially if subsidies and be given to Australian companies. Also the gas is running out in Victoria so supporting electrification is doubly beneficial.
As well as questions on price and appartments, quite a few audience members were interested in vehicle to home technology as well as the upcoming electrification Expo on October 12th
Question Two – vehicle to home (V2H) charging timing
Trent suggested looking at home energy bills first to see if there is capacity and demand to make waiting for V2H or another form of storage worth it. He believes V2H is soon given the number of trials. However, there has to be enough solar surplus. Given that the rebates fall over just five years it may be worth considering a battery sooner than later.
“Do you have a big enough solar system to run the home and charge a battery”?
Trent Jones, All Electric Homes
Question Three – given the subsidies are battery prices going to go up or down?
Trent talked about upcoming supply chain issues at a projected 7000 battery installs a week, but also a shortage of inspectors to sign off – the wait is at least two weeks at present. However at the end of five years a battery for six grand, “you might be paying two grand for”. Your 40 kWh car battery is likely to disrupt that further at that point.
Thanks so much for David Strang and the Energy Transition Group for organising this event, Trent Jones, Russell Williams and David Coote for answering questions and Sarah Hegarty for her close
Questions Four to Six – V2H with Sig Energy and older vehicles, Tesla and Leaf/Mitsubishi
V2H capacity partly depends on DC vs AC and also bidirectional vs one directional charging.
There have been 30 different vehicles approved to work with Sig Energy, but only the F-150 has been approved in Australia so far. Tesla already has DC charging so “is already there” for V2H. Nissan and Mitsubishi use a bidirectional AC Japanese standard, and so far the V2H trials have been with Nissan and Mitsubishi.
“So if anyone is on an embedded and actually you’re not required by any means to actually go with that network, you’ve got the ability to to choose whoever you want. But generally they set it up so you benefit from it. You get a group discount and whatnot.”
Trent Jones, All Electric Homes
Question Seven – adding solar to an apartment block
The question is about an embedded electrical network and embedded hot water.
Trent mentioned a case study with18 appartments with old gas hot water where they were spending $19,000 on gas. Solar share is only set up for 15 appartments, so All Electric Homes put in hot water heat pumps and 11KW of PV on the roof modelled at $16,000- $16,500 savings a year. They will look at the hot water load at night and balance that with a battery.
“This project’s been running ten months and we’re on track to actually make $17,000 savings in the first year.
The return on investment is 1.9 years”
Trent Jones, All Electric Homes