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Tesla Powerwall 2 economics- any real data?
- Thread starter mikemillar
- Start date
The Powervault 3 looks to me that it is Renault Nissan batteries sounds amazing chemistry time will tell how good they are recycled poor quality batteries degradation of Nissan and Renault batteries in their cars are well documented hope you are not disappointed
If I had 8kw of solar then I would have went for the tesla battery.
But my 4kw system would struggle to fully charge the tesla battery except on the best summer days.
Hopefully I will be ok with the 10 year warranty.
Getting mine installed in early March.cant wait.
But my 4kw system would struggle to fully charge the tesla battery except on the best summer days.
Hopefully I will be ok with the 10 year warranty.
Getting mine installed in early March.cant wait.
Hi subevo done some digging on these cells for you
Lithium iron phosphate battery
The lithium iron phosphate battery, also called LFP battery, is a type of rechargeable battery, specifically a lithium-ion battery, which uses lithium iron phosphate as a cathode material, and a graphitic carbon electrode with a metallic current collector grid as the anode. The specific capacity of is higher than that of the related lithium cobalt oxide chemistry, but its energy density is slightly lower due to its low operating voltage. The main problem of is its low electrical conductivity. Therefore, all the cathodes under consideration are actually/C. Because of low-cost, low-toxicity, well-defined performance, long-term stability, etc. is finding a number of roles in vehicle use and backup power
Specific energy:90–110 Wh/kg (320–400 J/g or kJ/kg)
Energy density:220 Wh/L (790 kJ/L)
Specific power:around 200 W/kg
Energy/consumer-price:3.0–24 Wh/US$
Time durability:> 10 years
Cycle durability:2,000 cycles
Nominal cell voltage:3.2 V
Lithium iron phosphate battery
The lithium iron phosphate battery, also called LFP battery, is a type of rechargeable battery, specifically a lithium-ion battery, which uses lithium iron phosphate as a cathode material, and a graphitic carbon electrode with a metallic current collector grid as the anode. The specific capacity of is higher than that of the related lithium cobalt oxide chemistry, but its energy density is slightly lower due to its low operating voltage. The main problem of is its low electrical conductivity. Therefore, all the cathodes under consideration are actually/C. Because of low-cost, low-toxicity, well-defined performance, long-term stability, etc. is finding a number of roles in vehicle use and backup power
Specific energy:90–110 Wh/kg (320–400 J/g or kJ/kg)
Energy density:220 Wh/L (790 kJ/L)
Specific power:around 200 W/kg
Energy/consumer-price:3.0–24 Wh/US$
Time durability:> 10 years
Cycle durability:2,000 cycles
Nominal cell voltage:3.2 V
I just spoke to the Tesla Powerwall people and asked a lot of questions. However, the current price, which is on the Tesla website, but you have to dig a bit and find the Powerwall page, it's £6200 for the battery plus £650 for 'supporting hardware' plus installation, all including VAT. The 'supporting hardware' is a separate box called the gateway which does the communicating -you have to have it so quite why they price it separately I've no idea.
The 'installation costs, however, are out of date on the web page -stated as £950 to £2800. The sales guy said installation prices had gone up, don't they always! and my straightforward installation would be about £1400. That pushes it from not quite breaking even to definitely not breaking even for me.
The PW2 seems to be normally configured on the basis that you charge with solar during the day, keeping gris usage to a minimum, and use up the battery in the evening and night. If you've got the Tesla App, swipe right for a demo.
In UK you need a big solar installation, like Stag has, to make this viable. I was working on the basis of using the battery during the day to completely supply my peak rate demand, which it easily could, and charging on the night rate, supplemented by solar when available. The maths doesn't quite work out yet for me. Give it a another couple of years or so when hopefully the cost should come down and it might be.
One potentially big negative at the moment is that I don't think you can use it as a backup if there's a power failure. I might be wrong on this, Tesla may have implemented it recently, but it's to do with the regulations. The power wall has two connections to your consumer unit - unless there's a positive disconnect from the grid if there's a power outage your solar or powerwall could electrocute the poor little man who comes to fix the supply problem down the line.
If you haven't seen the recent Fully Charged video it's well worth viewing.
The 'installation costs, however, are out of date on the web page -stated as £950 to £2800. The sales guy said installation prices had gone up, don't they always! and my straightforward installation would be about £1400. That pushes it from not quite breaking even to definitely not breaking even for me.
The PW2 seems to be normally configured on the basis that you charge with solar during the day, keeping gris usage to a minimum, and use up the battery in the evening and night. If you've got the Tesla App, swipe right for a demo.
In UK you need a big solar installation, like Stag has, to make this viable. I was working on the basis of using the battery during the day to completely supply my peak rate demand, which it easily could, and charging on the night rate, supplemented by solar when available. The maths doesn't quite work out yet for me. Give it a another couple of years or so when hopefully the cost should come down and it might be.
One potentially big negative at the moment is that I don't think you can use it as a backup if there's a power failure. I might be wrong on this, Tesla may have implemented it recently, but it's to do with the regulations. The power wall has two connections to your consumer unit - unless there's a positive disconnect from the grid if there's a power outage your solar or powerwall could electrocute the poor little man who comes to fix the supply problem down the line.
If you haven't seen the recent Fully Charged video it's well worth viewing.
The "supporting hardware" is primarily the Energy Gateway. You only need one of those per installation, so it is more accurate to give a price per Powerwall, plus the Gateway separately.
In the USA and Australia Tesla offers a different box called the Backup Gateway. It includes an automatic transfer switch to isolate your home from the grid during a power cut. With the Backup Gateway, the Powerwall and solar remain online to power your house. When the grid power returns, the Powerwall re-synchronizes itself to the grid and closes the switch without any power interruption. My understanding is that there are regulatory reasons that the Backup Gateway is not used in Europe. That's a shame really. It works quite well and if you cut back your usage appropriately you can run your house indefinitely on solar and battery. It's quite appealing for disaster preparedness.
In the USA and Australia Tesla offers a different box called the Backup Gateway. It includes an automatic transfer switch to isolate your home from the grid during a power cut. With the Backup Gateway, the Powerwall and solar remain online to power your house. When the grid power returns, the Powerwall re-synchronizes itself to the grid and closes the switch without any power interruption. My understanding is that there are regulatory reasons that the Backup Gateway is not used in Europe. That's a shame really. It works quite well and if you cut back your usage appropriately you can run your house indefinitely on solar and battery. It's quite appealing for disaster preparedness.
Big fan of my Tesla Powerwall 2. I do monthly updates on my YouTube channel of my Solar setup and battery performance.
Going to be interesting now I am adding the Model S to the mix.
Spectrum Geeks
Going to be interesting now I am adding the Model S to the mix.
Spectrum Geeks
Thanks Dale, that's a very useful link for explaining the practicalities of what you can do with Powerwall 2.
Regarding energy prices, I've been with Affect Energy since 2016 because they had a really good off-peak rate, 5.8p/kWh on my current deal. I just discovered that they have been taken over by Octopus and the new rate has jumped up to nearly 10p/kWh!! (Similar to Octopus rates, surprise surprise). I'll be switching soon! USwitch brings out EDF Easy Online March 20 as about the best deal - only 4.3p/kWh for Low. Peak rate is a high 22.9kWh but as I use only a quarter of peak compared to Low rate it's still a much better deal. If I do decide to install a Powerwall 2 and can configure it to supply nearly all my peak. it becomes even more economic. Just shows he you've got to watch what your energy supplier is up to!
I also see that PW2 now has 4 configuration modes - the most sophisticated of which is Advanced Time Based Control (cost saving). Apparently this analysis your usage and automatically adjusts input and output to get the most cost effective solution. The Tesla sales guy said that in future it will also analyse forecast weather!! How cool is that! I now understand what he was telling me about options, but wait to be convinced. on the weather thing However, I can manually assess likely cloud cover hour by hour, partly from the Met Office website and partly on the paid Topmeteo site ( very useful for pilots - tells me if there's fog in the channel!). I use could cover data to decide whether to put the washing machine on during the day or by timer on night rate. great if it could be automated!
About use of Powerwall 2 as a backup in the event of grid power failure, I have found information which says that PW2 installations now include a mains isolator that enables this, preventing PW2 from pushing amps up a dead grid connection. Does anyone know if this is legal in the UK - i.e. can you do it?
Regarding energy prices, I've been with Affect Energy since 2016 because they had a really good off-peak rate, 5.8p/kWh on my current deal. I just discovered that they have been taken over by Octopus and the new rate has jumped up to nearly 10p/kWh!! (Similar to Octopus rates, surprise surprise). I'll be switching soon! USwitch brings out EDF Easy Online March 20 as about the best deal - only 4.3p/kWh for Low. Peak rate is a high 22.9kWh but as I use only a quarter of peak compared to Low rate it's still a much better deal. If I do decide to install a Powerwall 2 and can configure it to supply nearly all my peak. it becomes even more economic. Just shows he you've got to watch what your energy supplier is up to!
I also see that PW2 now has 4 configuration modes - the most sophisticated of which is Advanced Time Based Control (cost saving). Apparently this analysis your usage and automatically adjusts input and output to get the most cost effective solution. The Tesla sales guy said that in future it will also analyse forecast weather!! How cool is that! I now understand what he was telling me about options, but wait to be convinced. on the weather thing However, I can manually assess likely cloud cover hour by hour, partly from the Met Office website and partly on the paid Topmeteo site ( very useful for pilots - tells me if there's fog in the channel!). I use could cover data to decide whether to put the washing machine on during the day or by timer on night rate. great if it could be automated!
About use of Powerwall 2 as a backup in the event of grid power failure, I have found information which says that PW2 installations now include a mains isolator that enables this, preventing PW2 from pushing amps up a dead grid connection. Does anyone know if this is legal in the UK - i.e. can you do it?
This is not currently available with the Powerwall 2 in the UK, we need the updated gateway which will enable the islanding of the house so it can be used during a power outage. This is supposed to be out this year, but the price seems to be going up, last I read was its about £800 plus fitting. I don't get many power cuts so I will probably give it a miss.
Thanks Dale, the gateway is currently £650. Powercuts - likewise, now. Used to get quite a lot we're on overhead lines - Off for 2 weeks in 1987. We did have a big one last year and they put in a big generator down the road for a couple of weeks - during which time the pikeys stole the copper connector cables! - second power cut.... For us it's just a nice thing to have for future proofing.
I've just visited a local Model S and Powerwall 2 owner who I've known for 4 years. He is a retired nuclear physicist, but still with a high level finger in several relevant pies and knows a lot about Powerwalls and energy supply - see my post on the 'best energy tariffs' thread.
He tells me that Powerwall certainly does use different technology to Model S and other electric car batteries. The reason is that Tesla car battery chemistry is optimised for producing short bursts of very high power. Powerwall battery chemistry is optimised for price and life. It gives a much larger number of discharge/recharge cycles and it only has to supply relatively constant much lower output. DON'T even THINK about the possibility of your Model S battery to power your house (unless you're going to sell it soon maybe) - you'll seriously shorten it's life. Makes you wonder how Nissan and Octopus are going to deal with their battery warranty.
Having done a lot of difficult spreadsheet calculations, my conclusion agrees with my friend's statement that the economics is a gamble. It's so heavily influenced by long term future electricity prices (see energy tariffs thread again). However, it does start to look as though it's going to work best with a much larger solar array than 4kWh and probably 3-4 PW2 batteries. He has a 14kW solar array and a 4 PW2 installation. His was installed a year ago and he anticipates being self sufficient for 6-8 months of the year (Southern England). He also has a 2kW baseline home consumption and 2 Tesla's! I thought mine was high at 400-500 watts! Actually, the economics of extending my solar array look quite good, even though you don't get the FIT on it and it has to be separate from the existing 4kW system.The 5% VAT if you fit more solar and the PW2 batteries at the same time also helps.
Other points are PW2 appears to forecast the power requirements for the next day and adjust the charging accordingly. The Tesla salesman I spoke to mentioned that Tesla was trying to integrate cloud cover forecasting, looks like they may have succededed.
Although technically easy, a grid connected PW2 cannot yet be used to supply the house during a power cut, for legal reasons - you'll electrocute the line repair man. I guess this will come.
WannabeOwner
Well-Known Member
I sincerely hope that isn't just "normal domestic use" ...
I have a manual switch to isolate house from grid (to us a generator in a power cut). I'm not a Sparky, but I haven't understood why some sort of relay can't be used to achieve that as part of the PowerWall install.
Heads up to anybody about to order - just placed my order directly with Tesla - was told by their representative that the quote (about £8600 inc VAT) is only valid today before an approx £1K increase tomorrow.
The price from tomorrow apparently includes the Backup Gateway or whatever it’s called.
Could have been a sales trick but don’t see why - other quotes I had said Backup Gateway was coming Q2 or Q3.
FWIW, quote directly from Tesla was about £1200 cheaper than from other (who mostly pushed PylonTech or Sonnen).
Mike
The price from tomorrow apparently includes the Backup Gateway or whatever it’s called.
Could have been a sales trick but don’t see why - other quotes I had said Backup Gateway was coming Q2 or Q3.
FWIW, quote directly from Tesla was about £1200 cheaper than from other (who mostly pushed PylonTech or Sonnen).
Mike
I have an PW2 on order for my house in sw Ireland for more than a year. Still waiting for Tesla to get things organise in IE. Thinking of ordering another PW2. Total installed 18 panels. A gateway is usefull as I am in a rural place where power cuts happen a couple of times a year.
The supporting hardware (gateway) is currently quote as £650 on the Tesla website, so wouldn't that be an increase of £150?
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