magutosh Posted June 10, 2021 Share Posted June 10, 2021 I struggled to find much info previously before our build, now it's completed, I'd like to share our experiences for those who are in a similar dilemma as myself. Our build has a south east facing pitch at 40 degree, designed to be optimised for solar pv, with 16 in roof panels installed, total of 5.3kwh output, in Stockport, Northwest, by no means the sunniest part of the country. We wanted a storage battery from the start, which plays a catalyst in energy dependency since we only have electricity, which also powers air source heat pump, in the end we decided on Tesla Powerwall, more capacity, better warranty, cheaper tariff (Tesla Power Plant or Tesla Energy Plan if you also drive a Tesla), better app control and more advanced battery tech etc. Some, including ourselves were skeptical about how well our theory would work, whether there would be enough sunshine to even fully charge the battery, never mind export back to the grid to offset cloudy days. The results are staggering. We have 82% energy offset since the system was commissioned (two months approx) including charging EV, and recently we are running 98% self sufficiency, with battery getting full charge by 10am! Selling the rest back to the grid for the same cost as we draw from it, thanks to Tesla's tariff. Of course, on rainy days we draw from the grid, but it's definitely looking like a worthy investment, especially when we experienced our first power cut, battery took over seamlessly, and the only house on the street with lights on! We now only wish to installed more solar pv on the rest of the roof! So far, solar pv + storage battery is working very well, far exceeded our expectations, and it's worth bearing in mind, it is not about the absolute saving on your electricity bills, but more self sufficiency and energy independence. Of course, the longer you have the system running, the more you will save, it is only a matter of time to recoup initial investment. 5 Link to comment Share on other sites More sharing options...
jack Posted June 10, 2021 Share Posted June 10, 2021 7 minutes ago, magutosh said: So far, solar pv + storage battery is working very well, far exceeded our expectations, and it's worth bearing in mind, it is not about the absolute saving on your electricity bills, but more self sufficiency and energy independence. Of course, the longer you have the system running, the more you will save, it is only a matter of time to recoup initial investment. Very interesting, thanks. It'll also be good to see how you go across the whole of the year, including the colder months when insolation is so much lower. Do report back! Link to comment Share on other sites More sharing options...
Happy Valley Posted June 10, 2021 Share Posted June 10, 2021 Can I be so bold to ask how much the Tesla powerwall cost to supply and install? Do they need a specific design or make of solar panels to connect? I like the idea of self sufficiency especially in 5 or 10 years time but not yet convinced whether it will ever pay for itself before the batteries require replacing. We are not far away from you between outside Macclesfield so your experience with it will be extremely helpful. Link to comment Share on other sites More sharing options...
Bramco Posted June 10, 2021 Share Posted June 10, 2021 Take a look at the naked solar site -> https://nakedsolar.co.uk/storage/ There's a table lower down the page with installed costs as well as cost per kWh - Tesla come out surprisingly competitively priced as well as having better specs. They have a similar pricing table for PV as well. Simon 1 Link to comment Share on other sites More sharing options...
Dave Jones Posted June 11, 2021 Share Posted June 11, 2021 had a Powerwall installed a few years ago. Have 3.85kw of solar on the off on the original FIT so it has already paid for itself many times over. For the winter I am on a time of day tariff so the Powerwall charges itself up when its very cheap and provides power when rates are expensive. Very pleased with it but if it wasnt for the solar FIT it would take many many years to pay for itself. Link to comment Share on other sites More sharing options...
magutosh Posted June 21, 2021 Author Share Posted June 21, 2021 On 10/06/2021 at 11:38, jack said: Very interesting, thanks. It'll also be good to see how you go across the whole of the year, including the colder months when insolation is so much lower. Do report back! Will do in due course! On 10/06/2021 at 14:20, Happy Valley said: Can I be so bold to ask how much the Tesla powerwall cost to supply and install? Do they need a specific design or make of solar panels to connect? I like the idea of self sufficiency especially in 5 or 10 years time but not yet convinced whether it will ever pay for itself before the batteries require replacing. We are not far away from you between outside Macclesfield so your experience with it will be extremely helpful. Powerwall costs £8400 I think, which is fixed by Tesla, doesn't matter which installer you use. The connection is through Tesla Gateway, which diverts the electricity to the house, battery or back to the grid, very cleverly done. At the point of our build, tesla is the only battery comes with 10 year unlimited warranty. On 11/06/2021 at 07:40, Dave Jones said: had a Powerwall installed a few years ago. Have 3.85kw of solar on the off on the original FIT so it has already paid for itself many times over. For the winter I am on a time of day tariff so the Powerwall charges itself up when its very cheap and provides power when rates are expensive. Very pleased with it but if it wasnt for the solar FIT it would take many many years to pay for itself. With powerwall and solar pv, you can join tesla's tariff, which you pay and get paid the same (11p per kwh, no standing charge), when you draw power from the grid and export it back. I think that might be the next best thing after FIT. Slim chance of paying it itself but hopefully summer exports can offset the winter demand. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted June 21, 2021 Share Posted June 21, 2021 5 minutes ago, magutosh said: Slim chance of paying it itself but hopefully summer exports can offset the winter demand. At 11p/kWh, that is about the same as my E7 night rate and about 11p saving over my day rate. Trouble is I only use between 1 and 2 kWh during the day. So £9000 / £0.11 = 81,818 kWh 81,818 kWh / 2 = 40,909 days 40,909 days / 365 days = 112 years The price needs to come down tenfold. Link to comment Share on other sites More sharing options...
Fly100 Posted June 22, 2021 Share Posted June 22, 2021 I actually worked this out last night based on year so far. I had to have Solar as part of my New Build so I went Medium size due to DNO restriction of 5kw Max export. ^.2KW system. Using Tesla Tarriff I would be currently £80 better off YTD. That said I dont export much as we divert spare to the immersion heater and doing heavy use items ( washing / dishwasher) due the day around the Solar Production.No dounbt a Power wall would remove the peaks and troughs. Buying the Powerwall would not be a good use of £8k, that said as Energy prices riase and Technology improves there will be a time in the future where its worth reconsidering. Link to comment Share on other sites More sharing options...
joth Posted June 22, 2021 Share Posted June 22, 2021 On 21/06/2021 at 08:32, magutosh said: Powerwall costs £8400 I think, which is fixed by Tesla, doesn't matter which installer you use How is that not illegal? https://www.howatavraamsolicitors.co.uk/know-illegal-supplier-set-price-products-sold/ Link to comment Share on other sites More sharing options...
Bramco Posted June 22, 2021 Share Posted June 22, 2021 15 minutes ago, joth said: How is that not illegal? https://www.howatavraamsolicitors.co.uk/know-illegal-supplier-set-price-products-sold/ Tell that to Apple and many other electronics suppliers that manipulate prices and always have done... Simon Link to comment Share on other sites More sharing options...
Pocster Posted June 22, 2021 Share Posted June 22, 2021 On 21/06/2021 at 08:32, magutosh said: 11p per kwh, no standing charge), This tariff is set to change new year . There will be a standing charge and the cost per unit ( I.e the 11p you state ) will vary by region …. Link to comment Share on other sites More sharing options...
Fly100 Posted June 23, 2021 Share Posted June 23, 2021 You still get paid your Generation Tarrif from what I read. 1 Link to comment Share on other sites More sharing options...
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