Energy bill after Powerwall installation

[T3SL4A]

I’ve just received my first quarterly bill after my Powerwall installation.
It says that I used 39% less power than the same time last year! Ok, that’s great. But my bill is $100 more!
Admittedly the rates have gone up slightly, not much. But the way I see it last year I had $240 credit for generated power. This year only $40 credit because the battery was using it to charge.
Am I to expect higher bills now I have a Powerwall? Should I be happy that I’m not using as much grid power and paying extra for it.
But I’ve heard that a Powerwall will pay for itself after around 8 or so years. That not happening for me.
How are other Powerwall owners handling their power?
Any help appreciated.
John

 

[mcktrnr]

$240 solar credit in a quarter, say 92 days @ 11c/kwh means you were sending approx average of 24 kwh /day unused power to the grid.
that's if your rate was 11c/kwh feed in ?
that's a lot, maybe your feed in rate downgraded

 

[mcktrnr]

from a higher rate

 

[T3SL4A]

$240 solar credit in a quarter, say 92 days @ 11c/kwh means you were sending approx average of 24 kwh /day unused power to the grid.
that's if your rate was 11c/kwh feed in ?
that's a lot, maybe your feed in rate downgraded

2019/84 days
Generated Peak Energy 8.2 kWh /day = 492 kWh @.29=$142
Generated Shoulder Energy 11.5 kWh/day = 966 kwh @ .10=$99

 

[jamesgo]

Which power retailer are you with that does time of use solar tariffs? But i'd say, look at your power plan and provider. With a powerwall, provided your not using much if any grid power, the highest cost component will be the daily supply charge. Find a plan that has a low supply charge with similar feed in tariff for the solar remembering that the Powerwall will be recharging during the morning/early afternoon and you won't be exporting until it's topped up. Some plans have BYO battery rebate as well which helps.

 

[JayTee]

But I’ve heard that a Powerwall will pay for itself after around 8 or so years. That not happening for me.
How are other Powerwall owners handling their power?
Any help appreciated.
John

8 year payback on a Powerwall? Best case might save $800 a year, 15 year payback would be more realistic.

 

[Vostok]

I’ve just received my first quarterly bill after my Powerwall installation. It says that I used 39% less power than the same time last year! Ok, that’s great. But my bill is $100 more!
Admittedly the rates have gone up slightly, not much. But the way I see it last year I had $240 credit for generated power. This year only $40 credit because the battery was using it to charge.
Am I to expect higher bills now I have a Powerwall? Should I be happy that I’m not using as much grid power and paying extra for it.
But I’ve heard that a Powerwall will pay for itself after around 8 or so years. That not happening for me.
How are other Powerwall owners handling their power?

First question - did you have solar before installing the PW2? In other words, are you comparing a quarterly power bill of house with solar compared to a later bill of house with solar + PW2? Or are you comparing house with no solar, to house with solar+PW2?

Second question - do you have your PW2 set to "Self Consumption" mode or "Time Based Control" mode?

Third question - what was your average daily grid consumption in kWh prior to solar+PW2, and after?

Fourth question - are you on a ToU grid tariff, and what is your FiT? In NSW, there are plans with FiT as high as 21c. ToU + high FiT makes a very big difference to your bill with PW2.

PW2 should definitely be lowering your bill. We went from no solar directly to solar+PW2. Our grid consumption has reduced by more than 80%, and our bill reduced by ~90% compared to what we had prior.

 

[T3SL4A]

First question - did you have solar before installing the PW2? In other words, are you comparing a quarterly power bill of house with solar compared to a later bill of house with solar + PW2? Or are you comparing house with no solar, to house with solar+PW2?

Second question - do you have your PW2 set to "Self Consumption" mode or "Time Based Control" mode?

Third question - what was your average daily grid consumption in kWh prior to solar+PW2, and after?

Fourth question - are you on a ToU grid tariff, and what is your FiT? In NSW, there are plans with FiT as high as 21c. ToU + high FiT makes a very big difference to your bill with PW2.

PW2 should definitely be lowering your bill. We went from no solar directly to solar+PW2. Our grid consumption has reduced by more than 80%, and our bill reduced by ~90% compared to what we had prior.

#1 I had solar a year ago. This is my first quarter with both.
#2 PW is set to “self powered” mode.
#3 average before: peak 5.13 off peak 5.2
Average after: peak 1.23 off peak 4.4
#4 FiT: peak .14 shoulder .11 off peak .09
2019 FiT Peak .29 shoulder .10
So my FiT is lower this year

 

[Vostok]

#1 I had solar a year ago. This is my first quarter with both.
#2 PW is set to “self powered” mode.
#3 average before: peak 5.13 off peak 5.2
Average after: peak 1.23 off peak 4.4
#4 FiT: peak .14 shoulder .11 off peak .09
2019 FiT Peak .29 shoulder .10
So my FiT is lower this year

Your FIT has come down a lot (from 29c to 14c) which, if you were exporting a lot of solar at peak times, would make a big difference. PW2 will result in less solar being exported as you note, so a double whammy.

The fact that your average daily grid consumption was so low pre-PW2 (5kWh per day peak and offpeak is pretty small) means that your scope to reduce grid costs was somewhat limited from the start.

PW2 will almost always save the owner money (everything else being equal) because it increases self-consumption of "free" solar power and correspondingly reduces grid consumption. But there are edge cases where it can do the opposite, depending on how much solar you export, your FIT, and how much grid you use (and when).

The payback time for PW2 does vary greatly. PW2 is unlikely to make financial sense for low users of electricity. Even for larger users the payback time is marginal (8+ years).

 

[paulp]

8 year payback on a Powerwall? Best case might save $800 a year, 15 year payback would be more realistic.

Not in SA, where we get a decent government rebate and pay a lot for power

 

[paulp]

I’ve just received my first quarterly bill after my Powerwall installation.
It says that I used 39% less power than the same time last year! Ok, that’s great. But my bill is $100 more!
Admittedly the rates have gone up slightly, not much. But the way I see it last year I had $240 credit for generated power. This year only $40 credit because the battery was using it to charge.
Am I to expect higher bills now I have a Powerwall? Should I be happy that I’m not using as much grid power and paying extra for it.
But I’ve heard that a Powerwall will pay for itself after around 8 or so years. That not happening for me.
How are other Powerwall owners handling their power?
Any help appreciated.
John

Powerwall gains are greatest where there is a big difference between your FIT and grid useage charges. A year ago I was 20c FIT and 31c grid usage(single flat rate 24/7). I export more than I import over a year (just), so the powerwall gain for me at that time was around 10c/kwh. Didnt stack up. Now that my FIT has been halved, and the government are doing a $6k purchase rebate the equation has made the purchase justifiable.

 

[miimura]

Is there any change in usage due to charging an electric car this year that wasn't present last year?

 

[T3SL4A]

Is there any change in usage due to charging an electric car this year that wasn't present last year?

Even though I was charging the car, I used 39% less energy! Thanks to the use of the battery. So I was able to use less energy but the battery was intercepting my export power, therefore my credits were less.

 

[JayTee]

Even though I was charging the car, I used 39% less energy! Thanks to the use of the battery. So I was able to use less energy but the battery was intercepting my export power, therefore my credits were less.

But did you have the EV last year? Without the EV all that power used charging wouldve been paid as FIT.

 

[pts260]

I have 9.5kW panel with a 8 kW inverter. PW2 installed.
With AGL rates per kWh.
Solar FIT $0.21
Peak rate $0.28
Controlled load $0.11

Daily Connection fee $0.88 (including controlled load)
NSW

Ago also have a virtual power plant (VPP) bonus. $100 sign up and $45 /qt.


Power Wall stats . Life time 95% self powered.
Example calendar year 2019
Solar production 11.3 MWh
Home usage 5.7 MWh
From PW 2.8 MWh
From grid 0.28 MWh
To grid 6.1 MWh

Calendar break down (rates pa)
Daily access $313
Grid supply $78
Solar Feed in -$1281

Net outcome (including VPP $180 pa) -$1070 pa

With Solar only $40 pa

No Solar $1909 pa.

So for 2019 had benefit of ~$1000 pa for the PW 2 or about a 12 year pay back
for solar payback period of only 5 years.

Having Said that, not having experienced 4 blackouts of > 1 hour (one was 8 hrs), and numerous shorter ones had its own value.

 

[pts260]

BTW I did this for as much my own interest as to share. My feeling was that the PW2 would barely prove cost effective over the warranty period. And yes I haven't included opportunity cost.
So summary, PW2 not the most economic decision based on a reliable electricity supply.
Also I tend to do most charging at supermarkets

 

[jaykaye]

I have 9.5kW panel with a 8 kW inverter. PW2 installed.
With AGL rates per kWh.
Solar FIT $0.21
Peak rate $0.28
Controlled load $0.11

Daily Connection fee $0.88 (including controlled load)
NSW

Ago also have a virtual power plant (VPP) bonus. $100 sign up and $45 /qt.


Power Wall stats . Life time 95% self powered.
Example calendar year 2019
Solar production 11.3 MWh
Home usage 5.7 MWh
From PW 2.8 MWh
From grid 0.28 MWh
To grid 6.1 MWh

Calendar break down (rates pa)
Daily access $313
Grid supply $78
Solar Feed in -$1281

Net outcome (including VPP $180 pa) -$1070 pa

With Solar only $40 pa

No Solar $1909 pa.

So for 2019 had benefit of ~$1000 pa for the PW 2 or about a 12 year pay back
for solar payback period of only 5 years.

Having Said that, not having experienced 4 blackouts of > 1 hour (one was 8 hrs), and numerous shorter ones had its own value.

I have a 9.5kW solar system too but with Energy Australia who recently reduced our Feed-In Tariff from 12.5c to 10.5c so now i'm looking around to swap providers to someone who gives me the benefit of having a decent solar set up. I am thinking AGL, but haven't decided yet. Need to run the numbers.
A PW2 install was not good for us. I have 3-phase and will wait until they support it properly. I am guessing you have 3-phase too (otherwise you feed-in will be limited to 5kwh on a single phase), how did you set up the PW2 across the phases?

 

[pts260]

I am guessing you have 3-phase too (otherwise you feed-in will be limited to 5kwh on a single phase), how did you set up the PW2 across the phases?

No, I have Single phase. Power wall provides backup to entire house, but not controlled load hot water. 5 kW is max inverter size without permission. I applied for 8kW inverter and was granted. I understand that it depends on the house demand eg. Pool pump, PW, aircon etc. and local community demand / utility line capacity etc. Most domestic electricity plans allow a limit of 10 kW maximum solar installation. Electricity plans seem more like mobile phone plans these days, you can pick and choose several different plans / rates within same provider.

 

[paulp]

BTW I did this for as much my own interest as to share. My feeling was that the PW2 would barely prove cost effective over the warranty period. And yes I haven't included opportunity cost.
So summary, PW2 not the most economic decision based on a reliable electricity supply.
Also I tend to do most charging at supermarkets

We get a significant government grant for a powerwall in SA, as well as higher power rates and lower FIT. Its important that people consider their situation correctly, as you have done, before making a decision. The payback in SA, for my circumstance, is much quicker for solar and powerwall.

 

[paulp]

I have a 9.5kW solar system too but with Energy Australia who recently reduced our Feed-In Tariff from 12.5c to 10.5c so now i'm looking around to swap providers to someone who gives me the benefit of having a decent solar set up. I am thinking AGL, but haven't decided yet. Need to run the numbers.
A PW2 install was not good for us. I have 3-phase and will wait until they support it properly. I am guessing you have 3-phase too (otherwise you feed-in will be limited to 5kwh on a single phase), how did you set up the PW2 across the phases?

A single PW2 works across 3 phases with the new controller. It just wont provide power to 3 phase equipment in a blackout.