Tesla to unveil home storage batteries

Martyn1981

Brit by Brit: First UK home welcomes Tesla Powerwall + StorEdge storage solution

Mart.

Sterlingtimes

My annual export is 1400 kWh

Price of electricity saved by battery would be 1400 *£0.1104 = £154.56

Price of export of electricity lost through use of battery 1400 * £0.0485 = £67.9

Net annual saving = £86.66

Saving over 10 year guaranteed period = £866.60

This battery would need to price in at £866.60 to break even.

Martyn1981

Hiya Sterling. I suspect you're in a similar boat to me that the price needs to be a lot lower.

In reality, you wouldn't save 1,400kWh of import as there would be some losses in the battery system, also there will be days when you can't use all storage, so can't store as much the next day, or end up exporting. So total savings will be less again.

On the brighter side, you probably wouldn't want 6 or 7kWh of storage, so a smaller batt, as prices fall this decade, may help you hit an economic point. But still a long way off.

Mart.

gefnew

Hi All
Just had the monthly news letter fro cts about battery storage.
They quote the tesla powerwall onto existing solaredge system
would start from £4499 for 6.4Kwh capacity.
regards
gefnew

ASavvyBuyer

gefnew wrote: »

Hi All
Just had the monthly news letter fro cts about battery storage.
They quote the tesla powerwall onto existing solaredge system
would start from £4499 for 6.4Kwh capacity.
regards
gefnew

How many years will that take for most people to break even ? And will the batteries last that long !

pinnks

I import about 2,500 kWh per year. Ignoring the standing charge for now, that costs me about £275.

I generate about 4,500 kWh and use about 60% of that with my diverters, so, assuming I could bank all excess generation and use batteries for all of my non-generation needs - unlikely for a host of reasons - I could only save £275 per year.

Swap to a supplier with higher unit cost but no standing charge and that might rise by £60 or so making £335. Even then it would take 13 years to recoup the investment.

Put reality back into the equation and you're looking nearer to 20 years I would think, and one or two new batteries too.

Without subsidies of some sort, either for PV or cars, I can't see the industry reaching critical mass any time soon.

Martyn1981

Some news from the States, looks like Tesla stationary battery production is going to ramp up massively.

Let's hope we see some serious price drops in the domestic market this decade.

Tesla prepares major growth in U.S. behind-the-meter energy storage in 2016

GTM Research bases these figures on a 14A filing with the Securities and Exchange Commission, in which the company estimates that it will sell US$44 million in energy storage products, including its Powerwall residential battery system and PowerPack product, to SolarCity in 2016.

Tesla holds a multi-year contract to supply batteries to SolarCity, and this would be a 450% growth the $8 million in 2015 sales to SolarCity.

And remember, that's just the sales to SolarCity.

Mart.

macca9

Hi all, read through the thread and quite enjoyed the conversation, some of you clearly know and understand how this system works. I'm a terrible ignoramus however, and to put it all in perspective for myself, I have a question for you:

If a company were willing to install high spec PV panels alongside the Tesla powerwall for £10,000-£11,000 as option A, or option B less valued PV panels alongside tesla for £8,000-£9,000.

What would your thoughts be on this issue in the present climate obviously FIT is lower than previously. I spend on average £50 per month on electricity on my current tariff. I would expect this system to be able to absorb that cost, so saving £600 p/a plus giving me some back... again too dense to work that out at current FIT rate.

Thoughts please?

Martyn1981

macca9 wrote: »

Thoughts please?

Hiya macca, have a read of this thread for my thoughts:

Would you do it again?

At the moment the savings from batts, will almost certainly not be economic against cost, but more importantly, will definitely be less than the expected price reductions over the next few years.

Let's say things work really well and the batts (ignoring the direct PV savings) save you £200 a year, but the cost of the batt systems fall £300 a year, then ........ ?

So, work on the PV, try to get a good deal, there are adverts for £4k, but I've no idea if they are any good. Then make sure the system is batt friendly, with an inverter to which batts can be added easily in the future (so location may be important.)

Regarding savings, this is tricky to explain, but you'll understand much better once you have PV, so here goes:-

You can't prevent all import. In the summer it'll be quite easy, you use lots of PV, so import is low, then your batts are relatively full, because you have lots of spare generation (export) that goes into the batts. However, if the PV is running most of your leccy, then import savings from the batts will be quite low.

At the other end of the year, in the winter, you have higher consumption, less sun hours for PV to help directly, so 'great' lots of import that the batts can replace ...... but without lots of PV export to put into the batts, you won't have enough stored leccy.

The spring and autumn months could work very well, with more import to offset, and more export to redirect to batts.

Complete guess, but based on my personal ponderings for batts, I think 1,000kWh of additional savings may be possible, so perhaps as an initial guide you could add that figure to say £120 (£80 - £160) of 'normal' PV savings to give you an idea of annual leccy savings.


I must apologise for regularly being quite negative about domestic batts. In reality I think they will be game changers, it's just that it looks like a lot of things will be happening in the near future (next 5 years) and till then, they are simply too expensive for the UK.

Mart.

baldelectrician

What about the possibility of charging the batteries during the winter from off peak energy?


The basic arithmetic means you can buy power at 8p per Kwh and sue it to save you during the winter months when you don't make much...


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