Tesla powerwall
Discussion
Also interested in this, but I can't make the sums add up in the slightest. We have a 4 kW array on the house that gets FITs etc and has been very successful in blunting the power bills with a DHW diverter and some basic power management (running machines during the day mainly). Anyone thinking of charging an electric car on top of this needs to be doing very low mileages in the summer only.....
Anyway, my new garage will have the capacity for a whopping array. In the winter that can drive the underfloor heating on sunny days .... but in the summer we will have excess. Unfortunately power walls seem to involve spending £6000 in order to save £200 a year. Without FITS, even the house panels would be economically unviable.
Anyway, my new garage will have the capacity for a whopping array. In the winter that can drive the underfloor heating on sunny days .... but in the summer we will have excess. Unfortunately power walls seem to involve spending £6000 in order to save £200 a year. Without FITS, even the house panels would be economically unviable.
rxe said:
Unfortunately power walls seem to involve spending £6000 in order to save £200 a year. Without FITS, even the house panels would be economically unviable.
This seems to be the problem with home solar installs in general. I had a quote last week of £11,500 for an install that would save me £650/year. Why would I even bother? Unless you have a driver other than cost savings, eg: you have an unreliable supply, or you want to go off grid to stick it to the man.Witchfinder said:
This seems to be the problem with home solar installs in general. I had a quote last week of £11,500 for an install that would save me £650/year. Why would I even bother? Unless you have a driver other than cost savings, eg: you have an unreliable supply, or you want to go off grid to stick it to the man.
I thought 4kw systems were the largest you could have on a domestic property and were around the £5-6k mark now. Was there something special about the system you were quoted on or are my assumptions about price just way out?I've been looking at battery and PV systems (we have a one third share of a wind turbine - about 8.5 year payback on that - we are 7.75 years since installation) and i don't think the maths is anywhere near stacking up for a Tesla Power Wall or anything similar. If the 13kWh (I think it's that) capacity Power Wall can only hold about £2 of electricity (we are at around £0.15/kWh at the moment), even if you manage to save buying its entire capacity every day (and I think that may well be too optimistic - but have never seen anyone publish any figures to show anything accurate) it's going to have about a 10-year payback, and I would worry it's a lot worse. I'd be less worried about PV having a 13 year payback as there's nothing much to go wrong with one. More to go wrong on a Power Wall - though that may be assumption more than knowledge...
I think their time will come, but mainly with selling back to the grid (which must surely come in the relatively near future) - so your batteries can buy cheap from the grid and sell back to the grid at higher demand times. This should also come in with EV's batteries I would expect
I think their time will come, but mainly with selling back to the grid (which must surely come in the relatively near future) - so your batteries can buy cheap from the grid and sell back to the grid at higher demand times. This should also come in with EV's batteries I would expect
Price very much depends on the site....
We were doing ours at the same time as extending and re-roofing the house, so zero extra costs for scaffolding and roof changes. Anyone scaffolding a house with a moderately complex roof could pay thousands before even buying the components. And the installation companies take the piss in exchange for the FIT certification.
When we do the garage, I'll buy a stack of panels and rails and do the whole thing myself. 13 kW array for about 10K panel cost + inverter.
We were doing ours at the same time as extending and re-roofing the house, so zero extra costs for scaffolding and roof changes. Anyone scaffolding a house with a moderately complex roof could pay thousands before even buying the components. And the installation companies take the piss in exchange for the FIT certification.
When we do the garage, I'll buy a stack of panels and rails and do the whole thing myself. 13 kW array for about 10K panel cost + inverter.
Garybee said:
I thought 4kw systems were the largest you could have on a domestic property and were around the £5-6k mark now. Was there something special about the system you were quoted on or are my assumptions about price just way out?
Here's the quote from E.On:YOUR RESULTS FOR SOLAR AND BATTERY STORAGE
£438 Annual savings - Your solar system could save you on average £438 per year.
Your solar system produces about 4,414 kWh per year.
£11,491 Cost
This is based on the biggest possible system for your home. E.ON Solar starts from £2,895 and with battery too from £5,995. We’ll give you all your options during your survey.
Witchfinder said:
Here's the quote from E.On:
YOUR RESULTS FOR SOLAR AND BATTERY STORAGE
£438 Annual savings - Your solar system could save you on average £438 per year.
Your solar system produces about 4,414 kWh per year.
£11,491 Cost
This is based on the biggest possible system for your home. E.ON Solar starts from £2,895 and with battery too from £5,995. We’ll give you all your options during your survey.
Sounds pricey to me, what batteries are they fitting? At the moment the best cost vs return for batteries is around the 6-8kWh mark and wouldn’t expect it to be more than £8-9k. Also they’re mis-quoting the generation if you’re in Manchester as the expected annual generation for 4kW system on a south facing roof at 38-40 dog pitch would be 4 x 937 = 3740kWh per annum. YOUR RESULTS FOR SOLAR AND BATTERY STORAGE
£438 Annual savings - Your solar system could save you on average £438 per year.
Your solar system produces about 4,414 kWh per year.
£11,491 Cost
This is based on the biggest possible system for your home. E.ON Solar starts from £2,895 and with battery too from £5,995. We’ll give you all your options during your survey.
The results are based on a calculator rather than an actual survey. I'm also certain I could get a cheaper quote elsewhere. Even if it's significantly cheaper though, I'm not sure I could justify it. If it were likely to pay for itself in, say, 10 years, I'd be much more interested. I expect the are at least some maintenance costs to take into account.
Then the calculator is wrong. You can download data for how much energy you’ll generate per Kw per annum from the MCS website, however as I stated in my previous post, for Manchester it’s 937kWh per KW installed per annum. As you can’t fit more than 4kW (with a 3.68kW inverter) to a single phase domestic supply you aren’t going to get more than 3750kWh per year.
If you want to download a full spreadsheet of the kWh/kW installed (kk) you can get it from www.microgenerationcertification.org its called irradiance datasets.
Btw, I’ve been teaching new installers how to calculate annual performance today as part of an accredited course.
If you want to download a full spreadsheet of the kWh/kW installed (kk) you can get it from www.microgenerationcertification.org its called irradiance datasets.
Btw, I’ve been teaching new installers how to calculate annual performance today as part of an accredited course.
I had a Powerwall2 installed in Jun '17 along with a 3.7kWh inverter and 4.9kWh/p array.
Around the same time I moved to an PHEV (although do most journeys as pure EV).
From the end of March to pretty much the end of October, I'm generally self sufficient. Last years output was 4.7MW/h, and so far this year, Jan, Feb and March were all significantly higher.
As for running solely on the battery, judicious use of dishwasher and washing machine help here. Also when arriving home in the car in late afternoon or evening, I delay charging until mid morning the next day wherever possible.
I *think* over the year I'm about 80% self sufficient, on top of that FIT and Export payments come to a little over £300.
My Extra Energy monthly DD payments were £19 (dual fuel) before they rudely went bust. That's Gas (heating home only) and Elec (house and motoring).
Like the cars the Powerwall receives over the air updates, and after a shaky start (minor niggles with monitoring) it now appears to be rock solid.
Around the same time I moved to an PHEV (although do most journeys as pure EV).
From the end of March to pretty much the end of October, I'm generally self sufficient. Last years output was 4.7MW/h, and so far this year, Jan, Feb and March were all significantly higher.
As for running solely on the battery, judicious use of dishwasher and washing machine help here. Also when arriving home in the car in late afternoon or evening, I delay charging until mid morning the next day wherever possible.
I *think* over the year I'm about 80% self sufficient, on top of that FIT and Export payments come to a little over £300.
My Extra Energy monthly DD payments were £19 (dual fuel) before they rudely went bust. That's Gas (heating home only) and Elec (house and motoring).
Like the cars the Powerwall receives over the air updates, and after a shaky start (minor niggles with monitoring) it now appears to be rock solid.
This ^^^ kind of self management, with a little Ground/Air source heat pumping and alike really is where the innovation and direction to be eventually widespread and help with the likes of the UK's power generation and National Grid.
It would be great to start a rural newbuild integrating the likes of this.
It would be great to start a rural newbuild integrating the likes of this.
FeelingLucky said:
I had a Powerwall2 installed in Jun '17 along with a 3.7kWh inverter and 4.9kWh/p array.
Around the same time I moved to an PHEV (although do most journeys as pure EV).
From the end of March to pretty much the end of October, I'm generally self sufficient. Last years output was 4.7MW/h, and so far this year, Jan, Feb and March were all significantly higher.
As for running solely on the battery, judicious use of dishwasher and washing machine help here. Also when arriving home in the car in late afternoon or evening, I delay charging until mid morning the next day wherever possible.
I *think* over the year I'm about 80% self sufficient, on top of that FIT and Export payments come to a little over £300.
My Extra Energy monthly DD payments were £19 (dual fuel) before they rudely went bust. That's Gas (heating home only) and Elec (house and motoring).
Like the cars the Powerwall receives over the air updates, and after a shaky start (minor niggles with monitoring) it now appears to be rock solid.
Very interesting thanks.Around the same time I moved to an PHEV (although do most journeys as pure EV).
From the end of March to pretty much the end of October, I'm generally self sufficient. Last years output was 4.7MW/h, and so far this year, Jan, Feb and March were all significantly higher.
As for running solely on the battery, judicious use of dishwasher and washing machine help here. Also when arriving home in the car in late afternoon or evening, I delay charging until mid morning the next day wherever possible.
I *think* over the year I'm about 80% self sufficient, on top of that FIT and Export payments come to a little over £300.
My Extra Energy monthly DD payments were £19 (dual fuel) before they rudely went bust. That's Gas (heating home only) and Elec (house and motoring).
Like the cars the Powerwall receives over the air updates, and after a shaky start (minor niggles with monitoring) it now appears to be rock solid.
I can believe the 80% figure. We have solar hot water and with just two panels we get free hot water for 9-10 months of the year. I think adding a powerwall or similar would do wonders for our electricity, albeit at a price.
FeelingLucky said:
I had a Powerwall2 installed in Jun '17 along with a 3.7kWh inverter and 4.9kWh/p array.
Around the same time I moved to an PHEV (although do most journeys as pure EV).
From the end of March to pretty much the end of October, I'm generally self sufficient. Last years output was 4.7MW/h, and so far this year, Jan, Feb and March were all significantly higher.
As for running solely on the battery, judicious use of dishwasher and washing machine help here. Also when arriving home in the car in late afternoon or evening, I delay charging until mid morning the next day wherever possible.
I *think* over the year I'm about 80% self sufficient, on top of that FIT and Export payments come to a little over £300.
My Extra Energy monthly DD payments were £19 (dual fuel) before they rudely went bust. That's Gas (heating home only) and Elec (house and motoring).
Like the cars the Powerwall receives over the air updates, and after a shaky start (minor niggles with monitoring) it now appears to be rock solid.
Similar tale here. Installed end of June '17, 5.95kWrP system with a 5kW inverter. Also have a PHEV for it to feed. First year saved a total of just over £900 in reduced bills and FIT payments received. Self powered ratio came out to 65% Production that period was 5.15MWh A different power usage pattern could have made use of the pretty significant amount of power that got fed back to the grid during the brighter parts of the year and made the self powered figure better.Around the same time I moved to an PHEV (although do most journeys as pure EV).
From the end of March to pretty much the end of October, I'm generally self sufficient. Last years output was 4.7MW/h, and so far this year, Jan, Feb and March were all significantly higher.
As for running solely on the battery, judicious use of dishwasher and washing machine help here. Also when arriving home in the car in late afternoon or evening, I delay charging until mid morning the next day wherever possible.
I *think* over the year I'm about 80% self sufficient, on top of that FIT and Export payments come to a little over £300.
My Extra Energy monthly DD payments were £19 (dual fuel) before they rudely went bust. That's Gas (heating home only) and Elec (house and motoring).
Like the cars the Powerwall receives over the air updates, and after a shaky start (minor niggles with monitoring) it now appears to be rock solid.
I too had some niggles to start with, some firmware ones that have been fixed/worked round plus one hardware failure - the pump for the thermal management system failed about 6 months after installation, which meant it refused to charge a lot of the time as it was too cold. Took some persistence to get past 1st line support, but once I reached second line they quickly got it diagnosed and had a new PW installed (eventually). Having just checked my e-mail record, it actually took about 3 months of service calls, the reply invariably being 'there's an update coming, see if that fixes it' and it wasn't until I sent a pretty strong Mr Grumpy letter did it get passed upwards.
Just checked the Solar Edge site, for the calendar year 2018, the system produced 5.66MWh, exported 1.09MWh of that. I imported 2.33MWh, 66% self powered.
4Q said:
Then the calculator is wrong. You can download data for how much energy you’ll generate per Kw per annum from the MCS website, however as I stated in my previous post, for Manchester it’s 937kWh per KW installed per annum. As you can’t fit more than 4kW (with a 3.68kW inverter) to a single phase domestic supply you aren’t going to get more than 3750kWh per year.
If you want to download a full spreadsheet of the kWh/kW installed (kk) you can get it from www.microgenerationcertification.org its called irradiance datasets.
Btw, I’ve been teaching new installers how to calculate annual performance today as part of an accredited course.
You can have more than 3.68kW of renewable energy on a single phase supply, the only issue is that should the local network require any upgrade in order to allow this the cost comes to the user. This doesn’t mean that there will be a cost though so best to speak to your friendly local distributor. Anyone interested in this needs to be away that as of this month the notification process changed slightly and it is g98 or g99 you need to be looking at. Other options you have would be a constraints panel so that you can have whatever value of renewable you wish but the local network will only ever see the set amount agreed with you and the network operator. If you want to download a full spreadsheet of the kWh/kW installed (kk) you can get it from www.microgenerationcertification.org its called irradiance datasets.
Btw, I’ve been teaching new installers how to calculate annual performance today as part of an accredited course.
All opinions are my own.
Needless to say, the break even on ROI has come forward, and the amount saved on domestic energy has increased.
Unfortunately, the price of battery storage has also gone up, I seen to remember my package (4.95Kw/p 3.7Kw inverter and Powerwall 2) came in at just under £10k fitted. And I got in before the FIT was dropped.
My annual FIT payments are a little over half my annual DD for Gas and Electric resulting my annual cost for energy around £272 (including charging a M3P)
Unfortunately, the price of battery storage has also gone up, I seen to remember my package (4.95Kw/p 3.7Kw inverter and Powerwall 2) came in at just under £10k fitted. And I got in before the FIT was dropped.
My annual FIT payments are a little over half my annual DD for Gas and Electric resulting my annual cost for energy around £272 (including charging a M3P)
andyb28 said:
Sorry for dragging up an old thread. I looked for a more recent one but couldnt find any.
For the people that went down the Powerwall 2 / Solar route for EV charging. How is this now looking in 2022 and the new Electricity costs?
There's a few threads on the subject in the DIY forum.For the people that went down the Powerwall 2 / Solar route for EV charging. How is this now looking in 2022 and the new Electricity costs?
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