Solar and Tesla powerwall vs regular battery

lukepugh

Hello, I am after a bit of advice from people who have solar and battery set up or a tesla powerwall and the pros and cons of both.

I recently ordered 2 EVs which are due to arrive later this year and this got me looking into the most efficient way of charging by taking advantage of cheaper night rates.
When researching tarrifs I discovered the Tesla Energy Plan and looking at some figures, for my situation, it seems almost too good to be true.

My average usage without EV charging is around 550kwh per month ( based on an average since moving into a new property in July)
I expect my usage to almost double when I start charging at home (this from a rough estimate for driving 25k+ miles per year and only charging at home)

This would mean an approx annual consumption of around 13000 kwh

If prices rise as expected later this year to say 30p per kwh that would equate to £3900 a year (£325 a month)

If I were to install solar and a Tesla Powerwall this would allow me to switch to the Octopus Tesla Energy Plan and only pay 12p per kwh.
This would reduce my annual bill to £1560 (£130 a month) 
There would also be additional savings as if I use any power I generate this would cost 0.
But just based on the savings on unit cost I would be saving almost £200 per month!

I know there would be the initial outlay to have equipment installed but I could take out a 5 year loan to cover the cost with repayments roughly similar to what I would be saving which would mean it would pay for itself in 5 years... Less if you factor in any free energy that I take advantage of.

This got me looking at some forums and there are suggestions that the powerwall isn't worth it and cheaper upfront cost for a regular solar/ battery/ inverter with a different tarrif (Octopus go or Agile) may be better but a little more complicated as you need to manage your usage to off peak hours where possible. 

The Tesla plan for me seems more straightforward.

I have emailex a few local companies requesting quotes and advice and am waiting their replies but just wanted to hear from anyone who has solar and Powerwall or a regular battery set up and what their experience has been.

And also to point out if I may be missing something in my calculations or if it really is a good a deal as it looks?

arty688

Might be worth taking a look at intelligent octopus as well its better than GO if you have a compatible car.

The problem is working out payback is you have based it on worst case.
A better payback calculation should use best available tariff vs TEP.

eg Intelligent vs TEP

so 6 hours of 7.5p and 18h 30p vs 12p 24hrs

lukepugh

arty688 said:

Might be worth taking a look at intelligent octopus as well its better than GO if you have a compatible car.

The problem is working out payback is you have based it on worst case.
A better payback calculation should use best available tariff vs TEP.

eg Intelligent vs TEP

so 6 hours of 7.5p and 18h 30p vs 12p 24hrs

If I were getting a Tesla than 100% the TEP would be the way to go as its 8p for 24hrs.

Even at 10-12p I think it's a great deal and would be happy with break even after 5 years.

But if another system and tarrif could offer similar savings and payback for less up front cost then I would obviously opt for that ... especially with reduced up front outlay.

I will take a look at the intelligent plan.
Thanks

NigeWick

I'm with the Tesla tariff from Octopus as I own a Tesla M3LR and Powerwall 2. It's now 11.76p per kWh in and out with standing charge is 20.95 p per day. Our 4.6kW solar system heating water as well as powering the house means we don't use any gas from about mid April to mid October. Latest month's bill shows cost of electricity £53.80 and total electricity credits £51.11. 

arty688

When getting solar I did look at the PW2 and TEP but it was already more than I wanted to spend and with my useage I would have needed 2 x PW2 to qualify .

lukepugh

NigeWick said:

I'm with the Tesla tariff from Octopus as I own a Tesla M3LR and Powerwall 2. It's now 11.76p per kWh in and out with standing charge is 20.95 p per day. Our 4.6kW solar system heating water as well as powering the house means we don't use any gas from about mid April to mid October. Latest month's bill shows cost of electricity £53.80 and total electricity credits £51.11. 

So am I reading correctly that your electricity bill was net £2.69 for the month?

Aceshigh84

I've got solar PV and PowerWalls but am staying on the Octopus Go tariff as this is more cost effective for me based on my family's usage profile.

Yes, the cheap rate window is lower at only 4 hours but the rate is also less (7.5p /kWh). The PowerWalls can charge at 5kW each and so I can easily fill them in less than 4 hours in addition to charging EVs and running dishwasher, etc. so I don't actually require the larger cheap rate window.

I am not able to easily extend the system though as I'm up against the ENA limit of 17kW export capability.

If you don't need the high discharge rates (up to 5kW per PowerWall installed) but you are after large capacity, then it may be more economical to go with a Pylontech based system and just add more batteries.

noitsnotme

We currently use around 6700kWh a year which will cost around £2100 on the current BGas tariff.  Hopefully getting an EV shortly and expect to do around 10000 miles a year (Kia e-Niro if that makes any difference).

If I was to install a Powerwall 2, could that charge fully during the Octopus Go 4 hour window and also top up charge the car?  I’m assuming that could potentially then provide all the power to the household for the following day?  If so, I’d not pay more than currently 7.5p per unit and then further savings from solar.  Ignoring the cost of charging the car, that would save around £1400 a year over my current BG tariff.

Are my assumptions correct?

EcoScruples

I have a Huawei Lunar 2000 10kw battery and it seems very good.
My plan is to get onto Octopus Go in a few weeks so I can take advantage of the off peak rate to charge my battery overnight.
What was it you wanted to know about other batteries as the title suggests you are in 2 minds to go Tesla because of cost? 

arty688

noitsnotme said:

We currently use around 6700kWh a year which will cost around £2100 on the current BGas tariff.  Hopefully getting an EV shortly and expect to do around 10000 miles a year (Kia e-Niro if that makes any difference).

If I was to install a Powerwall 2, could that charge fully during the Octopus Go 4 hour window and also top up charge the car?  I’m assuming that could potentially then provide all the power to the household for the following day?  If so, I’d not pay more than currently 7.5p per unit and then further savings from solar.  Ignoring the cost of charging the car, that would save around £1400 a year over my current BG tariff.

Are my assumptions correct?

The problem with your assumptions are you seem to be comparing now and 3 changes. It might be worth looking at
now vs GO
now vs GO and solar
now vs GO,solar and PW2

and estimating how much each will save if you are after an ROI.

Also if you are getting solar and PW2 you might want to consider the TEP from Octopus.
Also there is Intelligent Octopus if your EV is compatible.

Mikeyboy01443

I've just finished my first month with battery and solar and its made a huge difference to my consumption, both gas and electric.
Do you specifically want the tesla or just any battery?
I have read anecdotally about the tesla plan that as they control the charge / discharge that they could discharge your battery when you want to keep that energy for your own use?
Originally i changed to Octopus to go on to the Go tariff but I'm now going to stick to the standard until winter and then change to go...
My thinking being i barely use any grid electric now, and if i do i will be using the cheaper rate than GOs 35p rate, as i may not be able to always control when i import electric. 
Plus i can go on outgoing agile which will pay me much better rates for export than if i was on go and on the SEG tariff... 
So that is one other approach you may want to consider