Tesla Powerwall: Australian case study

Some interesting numbers coming in on the Tesla Powerwall, including one case study where a consumer saved nearly 90% off their power bill.

Read more:


A great result for that family and it really shows how the new technology is really starting to show increased benefits from being energy smart and generating at least some of your own power needs.

A big bit off topic but it is a result of that article as it shows how most renters miss out big time on any benefits, they are becoming the Electricity market poor.

What is partly needed is mandatory building codes that include the fitting of panels and solar hot water systems as part of any major renovations or new buildings. If an owner fits the panels and the house/unit is unoccupied then the generation of that power flows back to the grid and at least offsets some of the cost of the empty premises. There are other changes that could be implemented to ease this burden on renters including enforced Rent reductions for any premises not energy efficient, or that do not have solar/renewable energy supplies fitted.


As a renter I totally agree - would be great if more strata bodies started thinking down these lines.


Or maybe any landlords (for those who live in houses). Maybe the landlords could charge slightly more but less than the net savings in electricity so everyone is ahead (tenant has lower overall costs and the landlord can recoup some of the additional invested capital in the property.

One thing will be of interest is the likely savings will decrease over time as the batteries lose their storage capacity. This seems to be more of an issue with lithium ion batteries rather than alternatives such as zinc bromide flow batteries.

I also see that Telsa has removed the capacity guarantees from their current warranties…wonder if this is due to challenges of meeting the optimistic long term capacity targets.


Whilst I’d love to see this happen from an environmental perspective but also as someone who rented for many years it could never be implemented. The only way a scheme such as this would have any hope of getting up is by giving landlords real incentives to install solar. Government subsidies on FIT’s are out the window but there are other ways you could incentivize it, such as giving the owner credit for 100% of the install cost against land tax payments or council rates until the cost is covered.

Any attempt at mandatory codes for fitting solar would be fought tooth and nail by many groups left & right. It would open the door to all sorts of arguments, even red herrings such as “If you live in a hot area you need to install a pool on your property for renters”.

At the moment though I think there are more pressing things that need to be fixed for renters before we worry about whether they all have the opportunity to take advantage of solar. Making sure they have long term tenancy periods they can be confident in would be first on the list for many I think lol. Second would probably be regulating unfair rent rises when they happen for no reasons other than other properties in the area rise in value.

On topic love our Powerwall2. At this moment (10am) battery is up to 84% charge and we aren’t drawing anything from the grid whilst battery charges. From what we’ve seen at night via the app and logging directly into the Powerwall’s IP address it is covering all our power usage at night until bedtime. Don’t know about after that of course but whatever that is would be minimal in the scheme of things lol.


I certainly didn’t distinguish that in the changes to Building codes that it was just for renters, these changes are about every building that will be built or renovated. Sorry if my paragraph made it appear that way.

One of the fastest rising costs and major burdens for renters and households that do not have renewable energy sources is power. The number of people who have their power cut off due to bill stress is rising and this includes people who do not rent.

While I agree that long term leases and unfair rent rises are also important, the simple fact that a renter in the vast majority of cases is locked into power supply from corporations with no hope of altering that leaves them subsidising many landlords who choose to go Solar or other renewable energy ways in their own homes. Renters are also locked into rising energy costs as power bills go up as more people move to renewables and energy corporations seek their profits from those least capable of avoiding them (energy hostages if you like). Why shouldn’t they benefit from batteries, panels and other renewable energy technology benefits eg charging the batteries on off peak power when required.

Unfair rent rises for many are able to be contested in the various Administrative Tribunals and or bodies similar to the Qld Residential Tenancies Authority. But also consider that if leases become longer in this current “lock out from renewables” then renters will be placed in even greater bondage to both the whims of the owners and the power companies.

While Mandatory Building Codes might and likely will be fought against, there has to be change. Ignoring it/them only has bad outcomes both shorter and longer term for all of us and as a society avoiding changes because it will “never be implemented” is not in our best interests both civilly and environmentally. Yes, there can be ways to offset these costs to owners/renters/home buyers and as part of that process of mandating the changes these can be explored, valued, rated, and then implemented.


Yes I did misunderstand your post with regards who the mandatory requirements would be for. You make some great and valid points and in no way am I saying that things do not have to change regarding the shift to renewables for those that do not own their own homes. I wholeheartedly agree that every property should have solar or other alternative energy sources connected, especially in a country like Australia. I have a 6yo son and I’m already worried what type of world him and his mates will be inheriting - I spent some of my childhood growing up in Cannonvale in the Whitsundays and already he’ll never see what I saw every week. I’m just saying it will be a fight of epic proportions.

I can also say as a past renter that Residential Tenancies Tribunals aren’t everything they are cracked up to be when it comes to complaints from those renting. They operate well if a landlord is trying to evict you unfairly but any other complaint can often fall on deaf ears.

I can also say from past experience that if you asked me whether I’d like a guaranteed long term lease with fair rent or electricity savings via having solar and a battery installed for whatever time I lived there, my answer would without a doubt be the security of a roof over my head lol.


But it is a pity that it might become yes I have a roof over my head for the next ten years at fair rent but I won’t have enough money for power for 1 to 9 (varying by what power costs might become) of them. All those issues need to be addressed, they are integrated issues of affordability in the case of renters. How to resolve them all fairly to all involved I am not sure. What will be the answers will need great thought and planning.


On Topic - it seems that the former power reporting of our Tesla were inaccurate (or will prove to be). It was installed to only report on the power usage of the phase it was connected to, not across the three phases. Tesla are sending out the part for my installers to correct this promptly lol. Even though we are installing them one at a time across the phases, we still want to know what all phases are doing :stuck_out_tongue:.

Off Topic - grahroll it has occurred to me that another potential problem you’d have to legislate for when mandating solar/renewable energy is twofold. Firstly making sure that landlords didn’t raise the rents to cover the costs, although to phbriggs2000’s point that could be an incentive for them to do it.
The major one in a changing energy market is to ensure landlords don’t become the tenant’s energy retailer! I can envision whole new worlds of pain for tenants if those that they pay their rent to also become those literally “In Power”! :open_mouth:


Legislation could also be enacted to force lower rents where no renewable energy was installed as opposed to allowing bigger rents where renewables are installed, just as legislation could be enacted to require new house planning laws that require renewable energy source be installed. Some of this requires a change in what we perceive as the normal state of affairs. If it was normal to have renewables installed then the abnormal would be if it wasn’t not the current if it is installed it is abnormal. The other thing not all markets should be laissez-faire, some definitely need controlling/regulation.

I stated that it will need to be well thought out what answers are to be put in place, but taking no action is not the answer. Currently a property owner can certainly use the solar power fitted as an incentive for someone to rent (even at increased rents) but do they become the retailer? I think the risks in most cities is unlikely but certainly if they became off grid then the renter would be reliant on what the owner had installed and would have to weigh up what power was available to them and the lifestyle they might want.

While trying to think of norms I remember Tennant Creek’s usage of Solar Hot water. It was normal, even expected, that a house or building would have Solar Hot water fitted and if it didn’t it was an oddity. The same about the houses structures themselves with the vast majority being steel framed to reduce the risk of termite damage and the power poles being made of steel rather than wood for the same reasons. Elsewhere this might not be what is expected but there it was.


My concern regarding landlords becoming the retailer was not limited to off grid situations. The changing of the energy market operating rules are opening the door to anyone with solar being able to sell their production on the market - my name is already down on the list of interested parties. In my case it was to be able to sell our exported energy at a price above the FIT but at much below the current retail rates to a family who is struggling day to day. I will be able to do this as the current talking points on it is that being energy that I produced I can set my own price point on it. The energy from producers like me would be tracked and sold via a third party organisation but of course the nuts and bolts are still being worked out.

Yes I totally agree that the energy situation as it stands in unsustainable (no pun intended). I’m more centrist in my beliefs than left leaning, however I’m a firm believer that essential services such as electricity, water & gas should never have been given over to the private sector. They are things that should not be run for profit, but supplied at whatever the cost is to supply and run it. The short sighted mantra of our political parties has led to everything being sold off to make the books look good for the next election. Don’t get me started on the idiocy of selling off NSW Lotteries for a song, not that I count that as an essential service of course lol.


I still say our Building Codes should be amended to enforce Panels or similar renewables being fitted to new housing or as part of major renovations.

California has now gone down part of that path:

In June 2018 the Qld Govt is providing a limited release of interest free loans for some homeowners to go solar and install batteries. Their site advises the numbers available “Funding for the program is capped and places will be limited. It will help 5,000 customers, with around 3,500 solar assistance packages and 1,500 battery assistance packages being made available”. To read more about the scheme visit their site at:



Two good articles there, and must admit surprise at how far California have gone in their renewable energy target - good job to them. I must admit I’m warming (no pun intended) to your idea of Australia heading down the California path regarding this issue. It would have to be a well researched, well though out and implemented piece of legislation though, so not sure our current political manure crop are capable of getting it right lol.


We’ve updated our case study on the Tesla Powerwall:


Just a couple of comments about the article:

Not all, as some people get zero FiT for their PV power exports.

Make that SOME battery prices dropped, the cost of my latest (LiFePO4) battery was higher in 2016 (and remains so now) than when I installed it in 2012.

Personally, I’m not too keen on calling grid connected batteries “solar batteries”, they are just batteries, and how they are charged varies.


That would make it a coal battery in NSW :wink:

I suspect the 25% bill reduction Nick estimates for the small 7kWh battery may be on the optimistic side, I think his PV array is doing most of the 75% bill reduction not due to reduced usage.


Do these savings include the energy reduction from 22 to 17kW per day due to been more conscious in what electricity used (inc. improved energy efficiency)?

Using these figures in savings from battery installation will bias the results and make payback periods shorter. Any household savings through changes in behaviour of use or through improved energy efficiency should be externalised from the results as they can occur whether or not the battery is installed. These figures alone result in a saving of about $500 per year…or about 23%. Any battery savings should be adjusted acoredingly.


… almost sounds to me like a good FiT will beat a battery … if I look at my situation, I could spend a lot of money going battery or even off grid, or stay connected and make a profit from FiT and not pay a power bill. Maybe it won’t be like that forever, but it’s working for me now :wink:


Indeed, conflating a number of factors and guessing at their individual contributions does not give a meaningful idea of the value of all of them. As Peter points out, the reduction in energy usage is quantifiable, so that proportion of savings is believable. It is very unlikely that the “savings” from the battery approach that proportion. The PV system will be the main factor in the bill reduction by far.

Also, just going on the bill doesn’t really help with a detailed analysis, actual kWh usage on each bill (and previous years data as well) and daily charges etc need to be factored in as well.


Tesla Powerwall 2 home storage batteries have increased in price again, the second increase in 6 months…Powerwall 2 battery is now $A13,300, including goods and services tax, but not including the cost of installation.

In the last six months, the retail price has increased from $A11,700 to $13,300, and increase of $1600 or about 14%.


Now that Elon Musk is the richest person on the planet, he probably intends to keep it that way.