Tesla to unveil home storage batteries

oldskoo1

I saw the release video the other day and initial impression is this is another game changing product from tesla. Nothing new but a better packaged solution I suppose like what apple do.

However I think this will do very well for business and it might be a bit slow for residential.

I've written down some basic numbers and it doesn't seem like a money saver for me. So many different ways to dice the pie but when you have solar pv, iBoost and a 10a/2kW electric car charge you have very little if nothing at all to divert to a battery on a typical 4kW install here in the UK.

I reckon it would take 10-12 years to payback. It is however useful, in the sense it makes you feel accomplished for getting your electrical energy almost entirely from renwable sources.

I will consider one but I would be more interested when the price drops a little I may consider one more.

I have yet to calculate what charging it up at e7 and using it in the day would cost. I reckon a similar payback time especially as the only people to consider this probably won't have solar. They will need an inverter, in fact I'm not even sure if this is compatible with my solar inverter.

zeupater

Hengus wrote: »

Think laterally. I looked carefully at my pattern of car usage and I concluded that the purchase of an EV made complete sense. Putting PV solar to one side for the moment, my annual savings on road tax, fuel and insurance will amount to about £850 per year. The car is only serviced once every 2 years. What I failed to factor in was the ability to charge the car from my PV Solar when the sun is out. Last month, I drove nearly 360 miles and my total electricity cost was about £1.23 for the month. This works for us as I am retired, and the cost of the battery is paid for as part of the cost of the car. 360 miles range equates to about 85kWhs of electricity or a further saving of about £9 on my 'fuel' bill compared to having to charge at the standard kWh unit price.

..... :rotfl:... :rotfl:... :rotfl:... :rotfl:

... Thanks, really made me laugh .... MrsZ's will cost more over the life of the vehicle than any comparable sized non-premium brand standard engine vehicle and this would almost certainly be the case for almost everyone else .... the only monetary 'saving' in her case is in moving from an almost 3 tonne 'premium brand' SUV with high insurance, high tax, high servicing & low MPG ....

EVs at the moment are simply a lifestyle choice for those of us who are fortunate enough to afford to make it, however we attempt to justify it, and that will be the case until the 'whole life' cost comes into line with standard mass-production equivalent offerings ... The point being missed with the Tesla battery offering is that they have invested in the first really high capacity manufacturing facility for this product in order to use economies of scale to produce a commercially affordable battery pack solution which can be used in automotive, commercial or domestic products, which in turn benefits the viability of their own primary product line ... EVs ...

HTH
Z

Minrich

Batteries seem to be a good way to store solar energy created during a sunny day and run the house , but what about the winter months ? A few years ago our house roof was covered in snow for 2 months ish . Topping them up with Economy7 electric will be ok initially but won't the extra use at night be noticed by the energy companies and they will hike the price of the units . Also won't the alteration of your system invalidate your FIT ? Surely the Government cannot pay you for it if you no longer export any electric ?

Ectophile

There's no connection between the FIT and how much electricity you export. You can even claim FIT payments for a completely off-grid system.

Minrich

Ectophile wrote: »

There's no connection between the FIT and how much electricity you export. You can even claim FIT payments for a completely off-grid system.

So why call it a FIT then , if you don't have to feed in? Why don't they just give you £x a month for your xkw install? Seems odd to me ?

zeupater

lordgarner wrote: »

Could MSE create a calculator that enables people to determine if it would be economic to install home batteries enough to store a complete days electricity, charged by Economy 7 or better, than to use normal tariff electricity. Obviously all costs need to be included, capital costs, installation etc.

Not having solar panels nor the ability to install them as I live in a flat, i would like to determine if the Economy 7/Tesla battery combination has a pay back period that I would consider.

Also would it be practical to take my system to a new home?

Hi

Realistically, without some form of installation subsidy, savings from these battery packs isn't really viable at the moment ...

Considering that the Government are providing vast subsidies to generating plant operators to build/maintain generating capacity to cope with peak demand, I would expect that a scheme (similar to FiT/RHI) will be launched to aid the take-up of these systems. It simply makes sense to address demand-side energy as opposed to supply-side as it also improves consumer energy usage awareness as well as smoothing the generation/demand curve. On a pound spent for pound effect basis, fully subsidising domestic energy storage would probably have a better overall return than subsidising new generating capacity ...

As for portability, the units we're talking about aren't exactly small, or light .... you're talking about modules ~4'x3'x7" (1300x860x180) weighing 100kg each (http://www.teslamotors.com/powerwall), so we're really talking solid walls as opposed to partioned ... there's also the efficiency of the units - at 92% we're looking at the difference being either noise or heat .... wherever the system is placed/moved to, a suitable location needs to exist ...

HTH
Z

Martyn1981

Minrich wrote: »

So why call it a FIT then , if you don't have to feed in? Why don't they just give you £x a month for your xkw install? Seems odd to me ?

The idea of the subsidy is that it pays on generation. That way there will always be a need to bring costs down, whereas with upfront subsidies you rarely see much long term benefit. I don't think it should be paid on capacity, as generation will vary by location, and those with poorer generation (like myself) should receive proportionately less.

Yes, the name feed in is a bit confusing, but remember that a house is part of the grid too, so panels supplying the house are feeding the grid if you look at it as one big monster. Next is the realisation that export and offset are the same thing. Both have the same effect on the grid - give it an extra kWh to play with (export) or don't take a kWh from it by using own generation (off-set) leaving it one more kWh to play with.

Batteries simply mean that the amount of export would reduce, but the amount of offset would increase. So no net change (apart from battery losses), but the time of day would change, for example instead of giving the grid more mid day, you'd take less from it in the evening.

FiT for off-grid may seem odd, but imagine a house that was placing demand on the 'grid' going off-grid via own generation. It's generation still acts as off-set since the properties demand is no longer felt by the grid.

At some point the government will need to re-assess the export part, but even with water heating diversion, I suspect the 50% deemed export will work against the average PV'er for a decade or more at least.

Mart.

System

Sterlingtimes wrote: »

Interesting. What was the difference between the price of your car and the nearest petrol equivalent? It could suit me since I live 6 miles from work but use company funded transport for business purposes.

This is typical of what is around at the moment:

'we are now offering the Zoe Dynamique Intens on a 2yr PCP @ 5k miles per annum for £69 a month with no deposit - obviously the battery rental is on top of that, worth noting that Renault UK have increased this since 1st May so now starts from £45 a month.'

So if we assume that the average car will do 50mpg at £1.20 per litre then the saving in petrol is 100*4.54*1.20 or £545 per year. You would also save the road fund tax; get lower servicing costs and lower insurance. Putting the additional savings to one side, then even with PCP fees and battery hire totalling £114 per month, the cost to you per month is £114 -£45 or £69 per month for a new car.

PV Solar charging for my car (my car is on charge at the moment), is giving me pretty well free motoring. My town also has free 7kW chargers in a public car park and Ecotricity offer free rapid charging on motorways. I own my car and it has an 8 year/100000 mile battery warranty (not less than 70% charge at 8 years). Currently, new EVs attract a £5000 grant. My guess is that this will disappear very soon - a bit like reducing FITs.

The above will not work for everybody but looking at the SpeakEV.com website there are many business car users that are switching to EVs to reduce costs and BiK.

Andy_WSM

Hengus wrote: »

This is typical of what is around at the moment:

'we are now offering the Zoe Dynamique Intens on a 2yr PCP @ 5k miles per annum for £69 a month with no deposit - obviously the battery rental is on top of that, worth noting that Renault UK have increased this since 1st May so now starts from £45 a month.'

That's a great price. I'd be tempted myself to move to a Zoe at that! I've looked before, but it was just a tad expensive for what it is.

So where's the offer? I can't find it on the Renault site!

I'd only be looking for around a 5,000 mile a year deal, so the cheaper battery rental package which covers 7.5k a year I think.

Am I right in saying that the Zoe has the variable rate charge system, so if I wanted to use excess PV I can set it to charge at say 1.5kWh / 2kWh instead of the full 7kWh that the charger would provide if required to?

Martyn1981

Hengus wrote: »

Currently, new EVs attract a £5000 grant. My guess is that this will disappear very soon - a bit like reducing FITs.

Hiya. I think I heard recently that this years subsidy allocation is getting used up fast. Apparently the Mitsubishi model(s?) have proven very popular.

Mart.