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Solar Panels UK - is it worth it?

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Thanks for those.. it wasn't so much that I wanted to avoid giving them my details as I'm already in the process of getting a quote and install from them, and don't want to go confusing things :)

The rule of thumb page isn't one I'd seen before. Based on that, I should have a 5.3kw array + 8.2kwh battery for approx 70% solar use (and rest from off peak)

That roughly tallies with my back of a napkin spreadsheet - when I added the 5kwh N array it gives a total with the 2.6 south of around 5300Kwh per year which is around my estimated usage. And the 8.2kwh battery looked to roughly match with that
 
Interestingly I'm limited on how much solar I can put up, roof just isn't that big... but also use quite a lot during the day (both of us work in IT, and I'm home 2 days per week, my other half full time working from home). So our usual daily usage seems to be around 26kWh before factoring in any car charging.

Solar so far seems to be max of about 5kWp.

Thus my game plan is battery (2 Powerwalls) to cover as much as that as possible, and charge them as much as possible from Solar, then top up with 5p during Go's cheap period... and then try and use that for the rest of the day.

It's the large daily usage that's the killer for me.
 
It's the large daily usage that's the killer for me.

me too. Some servers here ...

Can you cut your usage - Laptop instead of PC perhaps? We now specify best quality (i.e. lowest power draw) post supply for all our PCs/Server. Our work servers run about £750 p.a. for Electricity, and then they need some aircon cooling cost too.

You've probably already done it, but worth using a plug in meter to see what each device is drawing. Maybe you will find something parasitic. Once we had eliminated everything else we threw all the breakers and enabled one by one to find the culprit. Stone-age 1960's transformer running 24/7 to generate a few volts for the front door bell
 
I've got brain ache from all the quotes, and variations, some selling what I didn't ask for, some not really knowing what they are talking about, especially when you've done some research.
It looks like I've settled on 7.2kW solar array, two hybrid inverters and two 8.2kW batteries. This with powered micro inverters for each panel for improved efficiency, other things like an updated heavy duty cable run to the garage and new consumer unit etc. - all in about 16.5k 😮
 
me too. Some servers here ...

Can you cut your usage - Laptop instead of PC perhaps? We now specify best quality (i.e. lowest power draw) post supply for all our PCs/Server. Our work servers run about £750 p.a. for Electricity, and then they need some aircon cooling cost too.

You've probably already done it, but worth using a plug in meter to see what each device is drawing. Maybe you will find something parasitic. Once we had eliminated everything else we threw all the breakers and enabled one by one to find the culprit. Stone-age 1960's transformer running 24/7 to generate a few volts for the front door bell

Yeah, I've got a plug meter thing, and do try and make choices where I can to limit use, we've LEDs everywhere, hallways are on PIR to turn them off. But the flip side gas is only used for heating/hot water, the rest of the kitchen (ovens, hob etc) are electric... then there's the computers etc. etc.

But equally I'm not into replacing kit for the sake of reducing the wattage a little... we'll get there :)
 
I'm not into replacing kit for the sake of reducing the wattage a little

Me too (just to clarify :) ), but on new kit we are happy to spend-some to save-some. e.g. very low energy central heating circulation pump. Trouble is, those sorts of things the installer will just put in "bog standard" unless the home owner knows to ask the question.

Modern computers are power hogs ... and I've a number of WiFi nested widgets to achieve coverage throughout the house, far too many separate devices to get COMMs (Fibre, ISDN backup, and then the switches they connect to for onward travel). Most of them have external bricks for power supplies, which I suspect are cheapest-parts, rather than planet-first. And, sadly, on 24/7.

We have isolator switches on anything that we used to use standby for - TVs and so on. Home office has dado rail of 13AMP sockets on two circuits, and switch-by-door to turn off the one that has everything that doesn't need to be left on - I use that if I'm leaving office for more than a few minutes, it leaves the PC on)

But my background power consumption is still embarrassing ...
 
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Me too (just to clarify :) ), but on new kit we are happy to spend-some to save-some. e.g. very low energy central heating circulation pump. Trouble is, those sorts of things the installer will just put in "bog standard" unless the home owner knows to ask the question.

Modern computers are power hogs ... and I've a number of WiFi nested widgets to achieve coverage throughout the house, far too many separate devices to get COMMs (Fibre, ISDN backup, and then the switches they connect to for onward travel). Most of them have external bricks for power supplies, which I suspect are cheapest-parts, rather than planet-first. And, sadly, on 24/7.

We have isolator switches on anything that we used to use standby for - TVs and so on. Home office has dado rail of 13AMP sockets on two circuits, and switch-by-door to turn off the one that has everything that doesn't need to be left on - I use that if I'm leaving office for more than a few minutes, it leaves the PC on)

But my background power consumption is still embarrassing ...
hmmm, my comms cabinet with ADSL modem, Router, switches which supply PoE for all the hotspots around the house, a smart things hub and our always on server uses about 100w continuous drain. Because its 24/7 its actually our biggest drain. Server is getting replaced shortly and will hopefully shave a few W's, but I don't know the balance of sub parts in there as powering any of it down to instrument is a total pain.

Work screen + laptop combo sits around 60w, but only for the hours i'm in front of it. And my main PC is a beast, but also only on when actively in use.

100w continuous is ~£2-£2.50/day.
 
I did try using a Raspberry Pi as my main computer to remote onto work, but found RDP almost unworkable with multiscreens both end. Whereas doing it via my windows machine it's like sitting on the same computer, entirely flawless.

So as I say, it's not that I'm not trying.
 
100w continuous is

I have 1.5kW 24/7 that I can't do anything about :(

Getting 13AMP sockets with integral USBs there were NOT always-on was challenge enough ...

Although, typing this I wonder if I could put in a [high quality, low power consumption] low voltage supply, and replace the various bricks with feeds off that. I have 3 separate COMMS cabinets in the house though ... so a single location transformer wouldn't do all of them :(

Small cabinet where the GPO (if you remember them ...) stuff comes in. Two or three bricks there, That just has a single CAT 5 to main COMMs cabinet.

Main COMMs cabinet has majority of bricks. That houses servers, CCTV, all the main HA, InfoTainment boxes.

Then there is a COMMs cabinet down the far end of the house. Thinking about it there is a switch in there, and some HA stuff, but perhaps no bricks as the WiFi thingies dotted about the house are all PoE

I need to count the bricks and plug them into my logging meter to see how much background they account for.

I would put up a wind turbine (for Winter power when PV is negligible) but everything I have read about "domestic sized" seems to be boy's-own rather than plug-and-forget. I have a tower and logging anemometer (intent was to log 12 months wind to see if it is any good), but I haven't even felt it was worth doing that experiment ... I have clear farmland toward prevailing wind though.
 
had a crack at my own spreadsheet looking at cost and savings based on different battery sizes (my current pain point trying to 'right size' the storage)
8.2kwh should be fine, with some additinoal savings moving to 10.5kwh and very little if any saving beyond that (for my current use).

View attachment 781559
good work!
did you take in consideration the speed of charge and discharge of the powerwall :
as per the specs for the powerwall 2 the maximum continuous charge is 3.68kWh and for discharge 5kWh
1647453344064.png
 
Spirit disagree:
Interesting. That's prompted me to look back through all the correspondence when I was having solar/PW installed. I do have a G100 export limitation of 6 kVA applied, which matches the combined output of my solar inverters. The same correspondence says "1 x Tesla Powerwall (Restricted to 3.68kVA)". No mention of PW export restrictions though, one would assume, such a restriction will apply.

I feel another email to Western Power coming on...
 
good work!
did you take in consideration the speed of charge and discharge of the powerwall :
as per the specs for the powerwall 2 the maximum continuous charge is 3.68kWh and for discharge 5kWh
View attachment 781680

kinda - no complex formula but I’m on intelligent octopus so a 6 hour window which would charge any of the options I looked at to full in off peak, and my peak solar is 2.5kw so no problem for topping up. There will inevitably be demand spikes from our house which will trip over into grid usage but thats difficult to calculate and I’d be happy with those being approx figures.
 
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Its worth pointing out that GivEnergy are refreshing their product line. They've launched a new 9.5kWh battery and a new hybrid inverter with a higher 3.6kW output.
No idea on prices, but if they are priced somewhere near the current prices then 2 x 2nd generation inverters and 2 x 9.5kWh batteries would cheaper than a Powerwall and offer 7.2kW of battery output and 19kWh of storage.
 
Its worth pointing out that GivEnergy are refreshing their product line. They've launched a new 9.5kWh battery and a new hybrid inverter with a higher 3.6kW output.
No idea on prices, but if they are priced somewhere near the current prices then 2 x 2nd generation inverters and 2 x 9.5kWh batteries would cheaper than a Powerwall and offer 7.2kW of battery output and 19kWh of storage.

if similarly priced, 9.5 would be good - I was thinking two of the 5.2 but 9.5 is close enough if cheaper. I need an AC inverter though so the new hybrid woudln't help I don't think - unless I can use it as an AC one alongside an existing PV inverter? I'd appreciate the higher output possibility