Solar and Powerwall/Powervault

Aruffell

Aruffell

Aruffell

Soldato
Joined
29 Dec 2004
Posts
5,653
Location
Chatham, Kent
Obviously with the whole government reducing rates of selling back to the grid and what not, there is a big thing about whether solar is still worth it, but I believe with the addition of a powerwall from Tesla or Powervault (UK company) then it makes more sense as you will be charging the battery up during the day and releasing it during the night opposed to still paying leccy prices during the night from the grid and it costing you.

I'm unsure if anyone has done the sums, but I currently pay £54 a month on electricity so over 10 years if I never paid it again, that would be £6480 based on those sums so in theory if the powerwall is £2000 as they expect and you can get solar panels for £4480 all in, then 10 years down the line it will all be paid off and anything above and beyond that is sold back to the grid is "gravy".

Anyone else been thinking about this? I ask as we are moving into a new home in June 2016 and solar panels were one of the first things that we were looking at getting but want to make sure that it's not going to be wasted money.

Thoughts and opinions are much appreciated :)

Thanks,

Andy
 
Hmm. This is something I am interested in and have been looking at but I think you would be looking to at least double that figure if you factor in installation and the fact that the prices for UK are usually just a matter of swapping the dollar sign for a pound sign. Also, not sure what size solar install you would be hoping for at that budget but think it would be too small to ensure you are charging the batteries fully every day, consider the house will still be running appliances at the same time!

Looking at the Powervault, it has much lower capacity/output compared to the Tesla, so you would need a lot more of them to sufficiently run the average household "off-grid". I have "reserved" a PowerWall online, although there is no contract or money paid to bind me to it, will be interesting to see if any viable alternatives come along by the time they are available next year.
 
Thanks for the reply. It's certainly an interesting time and another idea that I was thinking about is with the powerwall/powervault. If when you first get it installed, you could charge it from the grid and then just use the solar to kind of trickle charge it to maintain it to full. I'd have to do the sums but could possibly be the best way to go.

I honestly think that we are going to be surprised with the price of the powerwall and I think prices will come down as more gigafactories are opened.
 
Only ever looked at the powervault and iirc it uses lead sealed batteries which will, realistically, require replacing at least 3 times in the 10 year plan you have.
 
Li-Ion batteries then? You would still need to factor in cell degradation although it 'should' not be as bad as lead acid. Assuming a cycle a day you'd be looking at around 70% after 3 years but much depends on the cells in use by tesla. You would assume they'd be decent as tesla know their stuff.


Assuming your paying around 13p/kwh then your averaging 400ish units a month and assuming you've got a 'good' 4kw system you'd be looking at an average of 300 units generated a month so your never going to get a 'free' month out of this. You might over the peak months.

Also remember that tesla will bypass loads above 3.3kw so if you've a load bigger than that in total (electric shower, heck even a kettle is nigh on that plus anythign else thats runnign) you will still pay for it.

personally I dont think battery tech is far enough for this to be viable unless they came with a very long warranty which I doubt they will. Energy storage is still a very difficult thing, theres no wonder solution just yet.

Have you considered an EMMA type device to divert unused energy to a thermal store of some sort? Cost would depend what you start out with of course but its another option thats quite a bit cheaper with much less to go wrong
 
I've already got solar and had the 'we're in the area next week' door to door sales pop by. Had them round but they were very evasive over certain questions (can't remember what now though) which put me off that group.

After the 'meeting' I did some more research and came to the conclusion that with current solar tech and current battery tech it just isn't worth it in the UK, even in sunnier parts. The reason being is a really simple one, we wouldn't actually get to use the battery units very much.

I worked out that the only real time I'd end up using it would be winter when there's less sun to charge it. During the spring, summer and autumn most of the time I'd be up using electric would be covered by the solar panels already so I'd get no real use out of it.

In winter the usual solar gain is so low that it wouldn't be enough to charge the battery fully on most days. I do remember this was one of the questions the sales person was very evasive over because I realised this during his spiel.

So by the time you take into the cost of purchase, it was 4-8k iirc the cost of purchase far outweighed the supposed benefits. I'd get more savings by getting a more power friendly pc which would cost less lol.

Now if I was in a sunnier country then it would be something I'd consider but not in the UK.
 
:confused: most people are at work during the day and as such use next to no power. Hence batteries would be a good feature depending on cost pay backs.
 
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