Tesla Powerwall 2 - drops DC, adds inbuilt inverter and monitoring system

[readiescards]

Just been called by Tesla confirming:

• https://electrek.co/2017/03/02/tesla-powerwall-2-dc-version-ac/
• But also saying the AC version will now have its own Tesla built invertor and monitoring system
• Price increased to £6400 
• Starting initial visits in a couple of weeks
• Still supporting full off-grid

Edited March 6, 2017 by readiescards
add off-grid bit

[ProDave]

So £6400 for a 14KWh storage system.

 

Lets be generous and say I can use all 14KWh of stored energy from it every day, saving about 15p per KWh compared to the grid, so saving £2.10 every day. That's a maximum saving of £766 every year, so will take 9.66 years to pay for itself.  How far will the batteries then be from end of life and needing replacement?

 

Numbers still not stacking up for me I am afraid.

[Barney12]

1 hour ago, ProDave said:

So £6400 for a 14KWh storage system.

 

Lets be generous and say I can use all 14KWh of stored energy from it every day, saving about 15p per KWh compared to the grid, so saving £2.10 every day. That's a maximum saving of £766 every year, so will take 9.66 years to pay for itself.  How far will the batteries then be from end of life and needing replacement?

 

Numbers still not stacking up for me I am afraid.

 

The warranty is 10 years so it seems that all you do is pay for your electric up front.

Plus I guess there are install costs on top of the unit cost?

[lovo]

Yup, they don't make economic sense yet, perhaps another generation will make the difference though.

[lovo]

Some prices here - http://www.solarfixni.co.uk/solarpanelsystems/tesla/

 

L.

[MikeSharp01]

If it never pays back the market must be very limited probably to users like:

1. People who have to be off grid.

2. Die hard eco warriors who want to max out their PV system and can afford the cost.

3. People who don't get the 'economics'. 

4. Early adopters who want the latest widget and where they get 'value' out of the plaudits of others for owning such widgets.

5. Any others? 

 

The quicker they get the glass / sodium battery out of the lab and into production the better because only when battery technology and associated parafinallĺilia can match grid prices will they get real traction. 

[jack]

I had a similar conversation with our solar installer the other day (I'd called them with an enquiry about something else and talk eventually turned to the new Powerwall).

 

The problem is that I think we used something like £650 in electricity last year, excluding FITs.  That's with zero optimisation, not using the cheapest electricity provider, and only one person in the house (me!!!) making any effort at all to reduce energy consumption.

 

Given that showering is the biggest consumer of energy in our house, and that we already get "free" hot water via an immersion diverter for at least 6 months of the year, I can't see how we could save more than £100-200 per year with a system like this.  

 

The solar installer had to admit that it's hard to make the numbers stack up once you get into low energy houses.  I think he was genuinely surprised at how little energy we use, even though he knew about our house's construction.  

[Jeremy Harris]

Same here, the economics just don't add up.  One issue worth looking very, very carefully at is the battery warranty.  I haven't read the small print for the Tesla system, but the 8 year warranty on the lithium ion battery in my car doesn't cover "normal range reduction as a result of battery ageing".  I believe that the Nissan Leaf battery warranty has a similar limitation.

 

This means that your battery capacity will start to reduce gradually from the day it's installed, but the reduction in capacity may not be covered by the warranty.  In the case of my car I've been told that a 20% capacity reduction would not be considered grounds for a warranty claim, but I've no idea what the policy is for other suppliers.

 

I may well fit a semi-off-grid system in the future, as much for the fun of designing and building it as anything else, and as a way of providing a bit of a buffer for power cuts.  I'm not kidding myself that it will make economic sense, even though a DIY system would cost a fair bit less than a ready built one.  My inclination is to fit some big NiFe cells, as they have a life of at least 30 to 40 years, probably more, so at least the battery would probably recover its capital cost, perhaps even in my remaining lifetime..............