The powerwall2 seems to be sold and installed as a ‘complete’ system. Not all battery installations are.
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I think I’ve mentioned it elsewhere, but worth mentioning again for the small number of people in the NT.
We have one provider - Jacana - the awkward product of the split of Power and Water Corporation into it’s logical parts - generation, transmission and billing.
Residential consumers here have two options - ‘Everyday Home’ and ‘Switch to Six’.
Buyback rate is 25.95 cents per kilowatt hour across both options.
‘Everyday Home’ is a flat rate of 25.95 cents per kilowatt hour.
‘Switch to Six’ is 30.61 cents per kilowatt hour M-F 0600-1800 and 23.34 cents per kilowatt hour M-F 1800-0600 and all weekend.
… so given my house is typically empty M-F daytime, I do all my heavy current use at night time 
It might be different if the house were occupied all day, especially during summer with A/C going flat out with mid-40’s temps …
It pays to investigate options. I know we are a special case here - in so many ways 
but for the other three people who live in the NT this might be worth noting …
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That’s about $2000 annualised.
It would be interesting to know your power bills prebattery/PV system as this seems a very high saving based on the average household power bills…or is it a business premise where the savings were generated as this would seem more realistic.
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Not sure what you think the numbers should be or where for but I have been focused on understanding our pay back time for our investment hence my tracking with a spreadsheet which I have kept since October 2014.
We have a normal domestic setup in Melbourne with what I think is a relatively low power usage. Pre panels and battery my spreadsheet shows that for the six months Oct 14 to Mar 15 power cost $870 (includes supply charge). At the time the cost per Kwh was around 23c (Powershop incorporates daily supply charge in their cost per Kwh). Today we pay 33c per Kwh. Now with 20 panels and a 13 Kwh Tesla powerwall from Feb this year to the end of Oct the cost for our power was $507 minus the $110 we have received from the feedin tariff cost to us therefore was $397.
Further, pre the battery for Jan and Feb this year with 20 panels our feedin was $84. I expect therefore that from now until Feb next year we will pay almost nothing for power and the feedin we receive will cover half the supply charge for the year .
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Julie, when you have a moment it might be helpful to all of us if based on how things are tracking now, you might share what you think your payback time might be?
Is it similar to what the sales staff from the installer suggested?
Every household is different. For any of us able to take up any government battery subsidy, the shorter the payback the more attractive the investment.
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The 2017 Electricity Price Trends Report (information Sheet) indicates that " The national weighted average consumption level is 4,596 KWh per year in 2016-17. At this consumption level, the national average total annual bill in 2016-17 is $1,294, exclusive of GST." The average power bill is based on $0.2816/kWh. Using $0.33/kWh, this would correspond to an annual bill of approximately $1516. It appears that in 2014/15 you annualised bill was in the order of $1740. In 2015/15, the average price was 28.47/kWh, or comparable to the 2016/17 prices.
Based on the above your consumption is above average and not low. It might be worth doing an electricity audit of your home which would include:
- what appliance/devices/lighting installed,
- what are on standby (not turned off at the power point),
- what are on but not used (for example lights at night in rooms not occupied, TVs left on with no-one actively watching, etc)
More information on how to do home energy audit can be found here:
OR
Once the audit is done, one can see where there is energy leakage from ones home (where {passive} energy is consumed by not actively used by residents). Turning off this usage can be a quick fix and can significantly lower power consumption. One can also look at changing say lighting or temperature of heating to further reduce energy costs.
These savings will improve the payback period for any batteries/PV system installed and also reduce the amount of electricity imported from the local distribution network.
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Our house is now very well insulated, we use low energy light bulbs, we have a few appliances on standby but the electrical engineer in the family says the leakage of power is tiny. I do turn lights off when we leave a room and do not run heaters in rooms we are not using ie no ducted heated and cooling. I suspect as I mention below, the difference is that our gas usage is small. We installed, prior to the panels, electric cooking appliances (just as well now we have panels) the only gas we use is hot water and one heater. our main room is heated by a reverse cycle AC.
My figures include the supply charge which the consumption figure quoted is unlikely to include. Supply charge is approximately $450 per year for our provider and includes GST. Add GST to the figure you quote and this would equate to approx $1900 per year. Of course usage will depend on where you live. You prompted me to look more closely at the average cost in Melbourne and it is approx $1600.
(https://www.canstarblue.com.au/electricity/average-electricity-bills/) not sure if this includes GST and supply charge. I would expect it includes GST but not supply charge. It should also be noted that most Melbournians would use gas for heating in particular central heating which we do not so our gas bill is much lower. Same website says the average gas costs in Victoria is around $1200 per year. We would pay approx half of this.
I was also prompted to look at my figures again which come from the Powershop site. Dec 2014 (I only have figures post that date as that is when I switched provider) to May 2015 cost was $681. From May when the first 10 panels were installed to November cost of power was $649 (most of this cost was the heating over winter as we use electricity to heat our main room). Total cost for power was $1263 and we received $38 in feedin. I wish I had the figures pre panels for a whole year but I don’t because obviously for the months June to November we had the benefit of ‘free’ power from our 10 panels.
All this indicates to me how hard it is to get a real handle on savings and how to really compare apples with apples. Thank you for prompting me to look at this again in more detail. I really want to understand the savings of panels + battery
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Excellent suggestion but in my reply to phb I now understand just how hard it is to compare apples with apples so here goes.
Assumptions
- set up costs $18,000 - 20,000 (depends on quality of panels and if you use micro inverters). 20 panels (this is when a battery becomes worthwhile) installed with govt rebates, 13.5 kwh (Powerwal 2)
- limited gas appliances (one gas heater not ducted, hot water) gas spend approx $650 per year. Stove and cook top are electric
- location Melbourne
- lower cost power company (Powershop)
- does not include supply charge
- prior to the first panels installed and after installing electrical cooking appliances our electricity costs would have been around $1800 -$2000 per year. Power costs have gone up since then as well
Total cost of usage March 18 to Nov 18 (post battery) $508
Feedin $138 (March to Nov)
Total cost overall to date $371
Expect based on data from last summer our feedin (Dec -Mar) $80 (power usage from the grid has gone down of course)
Conservative likely savings per year $1500.
Pay off time would be 10-13 years assuming current power costs and no further rebates or higher feedin tariff
Notes:
Our first 10 panels I estimated would have been paid off in 3-4 years when I looked at the figures this was 2 years earlier than I expected.
As mentioned by others there are intangible savings such as when you use appliances, we cool our house when the battery is full and rising power costs. Of course we are using less green house gases.
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Agee, it is difficult to “Compare Apples”. Even when one is red and the other green? Appreciate your feedback.
The are marked differences in the electricity market between states and as @Fred123 has pointed out even within a state.
Comparing two similar houses may also be difficult. Our’s is ancient and wooden with small steep pitch roofs. Between late afternoon shading and roof orientations be have 5.5kW of panels to get the performance of 4kW of panels.
Your battery system appears to be doing what you expected? And the payback time may be shorter due solely to inflation or power pricing? All investments have some risk, but for a battery you also hold the asset which is reassuring for many. The environment benefits longer term and so does the grid at peak in the evening for every battery. The upfront commitment and investment as you have indicated has other benefits in your instance.
For households with quite low consumption like ours it takes much longer to get a payback on a standard hybrid system with battery. Our last quarterly bill is $301 for 735kWh including the daily connection charges. Small battery systems have a high fixed cost for the installation, inverter & charger, loss of supply changeover options etc.
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Hi Phil, I thought that for an average family home the bill was closer to $2,000pa, or from when I lived in NQ recently anything under $1,000 a quarter in summer! The fixed daily connection charge is also highly variable. Note some of us can pay up to $1.50 per day for not using any power at all.
There is much blending of data, between traditional family homes, modern compact houses, town houses and apartments. There is a more complex analysis of usage by zones in
However this also does not seperate out dwelling types. AGL for SEQ suggests for a 2 person dwelling 4,300 kWh pa or around $1,600 based on our billing. This excludes pools etc so the real household averages the retailers quote for houses are all up to 8,000kWh annually. From the 160 plus pages in the above report the range of data is very broad and often qualified.
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Here are some handy solar calculators provided by LG which I came across whilst looking at the data on the LG Chem RESU battery we are getting.
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Yes, the Allen report is well known for its sampling size and relative robusthess in data collection and analysis. If does look at zones/states as well as seasonal variations.
The data for Queensland in the report is not dissimiliar to that you have indicated for AGL. Using the Qld government energy made easy comparison site, the bill for 4600kWh in Brisbane would range from $1320 to $1880 ($0.287/kWh to $0.409/kWh inc. retail, network and metering charges)
Seasonal variations in different zones, use profile and also whether on a regulated or contestable market supply will also affect the final bill, but a figure around $1500 national average sounds about right.
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For a typical house separate to the average of all retail customers I noted Choice’s guide to solar energy suggests 20kWh per day. This is equivalent to 7,300kWh pa!
Our past winter norm for Townsville with a family of 5 including 3 teenagers was 28kWh per day including off peak HW and cooking. Pre LED lighting days of course!
Not so average, but factual.
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Still waiting for the state (Qld in my case) to offer incentive to add battery in exchange for giving up the high feed-in tariff contract we signed back in 2009.
It would be a win-win situation.
Back in those days you could sign contract with government (and retailer) to get ‘good’ feed-in rate for twenty years. But there were strict limits on the maximum size of the system.
Our solar and battery system had its first real test last week when the Ergon supply went down at 7:40 PM, where upon it automatically switched to the backup mode so that all lights, fans and one power circuit were still available.
When we awoke in the morning. the power was back on and I called Ergon when I could not find anything on their website so as to try to find out what had caused the outage and when the power was restored.
I was finally told it was restored at 3:30 AM but I could not get a straight answer as to what had happened, only that it was an “unexpected outage” and their had been “some damage” of unknown causes.
There was a massive 3 axle trailer-mounted diesel powered generator on the edge of our street a few houses away feeding the sub-station in the easment.
I heard my wife talking with someone outside and I saw an Ergon truck parked across our driveway so I went out to enquire and was told that the employee had isolated our solar system at the meter box and it would not affect our power.
When I returned inside, all the lights, fans and the one backup power circuit were off so I drove around the other side of the circuit and caught up with the employee at the other trailer mounted generator which was feeding into another sub-station.
He returned to our place and he could not understand what had occured and he ended leaving our solar system connected but with the battery isolator switch turned off.
When the generators were shut down mid-afteroon, I turned the battery isolator switch back on but the battery would not reconnect until I shut the inverter down and rebooted it.
I then went to our nextdoor neighbours’ house, who have an identical system, where Ergon had turned their system back on at the switchboard but it was not working until I shut the inverter down and rebooted it.
Apparently an underground cable which feeds our area had failed, a regular occurence in the Cairns CBD and other areas.
Ergon. the electricity provider with a tin-plated network at solid gold prices.
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It seems consumers are being misinformed about the savings, facts and payback time in installing batteries.
See Solar Quotes article
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Welcome @cliveed_15 and thanks for the post.
Many Choice members are familiar with the Solar Quotes web site. There is some great and useful content about solar systems.
It’s a great question being asked as to whether the advertising has been misleading. Solar Quotes have a free battery system calculator tool if anyone is interested.
Previous discussions in the Choice Community have suggested for many consumers, batteries added to a solar PV system do not pay for themselves in electricity bill savings. Solar Quotes online calculators confirmed that for our home.
There may be other reasons to invest including off grid, backup to power the fridge in areas prone to long power disruption, feeling green, zero or very low feedin tariffs, to suggest a few.
An objective assessment for most consumers suggests that investing in a PV system alone can deliver similar savings to an expensive Battery + PV system.
Edit
Added link
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We have a LGchem 6.5 battery fitted to our 4kw PV system, the sales rep. inferred we would have savings of $300 per quarter where-as real life came out at about $100.Our power line is SWER line and used to be unreliable with any storms around. I have 2 UPS to protect the computer and other Electronic devices, it was common to hear them beep from I assume low voltage, with the battery fitted hearing the UPS beep became a rareity so I wonder if in our case the Battery acts as a UPS for whole house. ps I live in central Queensland outside of Yeppoon.
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If your system is configured to operate independently when the grid goes down, then yes, the LG Chem battery is a sort of UPS for your house- just so long as you don’t exceed the maximum allowable load- either for the battery, or the inverter, which ever is lowest.
Your actual savings will depend a lot on your power usage patterns, but I’m sure a lot of installers are rather optimistic in the claimed savings you will see.
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