Solar & Powerwall 2

Embattle

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In essence repeatedly high daily amounts and Powerwall was at around 60% capacity on the morning of the 23rd which was also a day when home consumption dropped to 13.3 kWh thus at noon it started sending it to the grid until about 19:00. I sort of fixed it the next day by turning the gas boiler off and immersion heater on, which chewed through the electricity rather well.

SunGift Energy was the company we used and the first they did was send around someone to do a survey before anything, they have software which takes into account any shading which in our case on the East side showed a small shading of 0.2% on one panel and 0.5% on another due to a forward roof and where the sun starts on the longer days. We've got no trees near the house to have any effect on the panels, so no shading from that which is good.

The dual sided panels are certainly interesting but they seem better suited to ground application, in essence the ones on a roof will have no gaps better them thus I would suspect little in terms of reflected sunlight reaching the underside.

Well we all would like some with that kind of efficiency but in reality the highest in a lab that has been achieved seems to be about 47% thus don't hold you breath for getting some for your roof anytime soon, maximum on the market seems to be just over 22% but the next step is probably going to be Perovskites which might eventually allow up to 30%.
 

Embattle

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So with April traditionally being the start of the 500+ kWh months it was nice to see a better figure this year than last, although I suspect looking at early weather forecasts May will be down on last years.

April 2020 - 578 kWh Gen - Self Powered 88% - Energy offset 100%
April 2021 - 639 kWh Gen - Self Powered 92% - Energy offset 106%
 

Embattle

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So as expected May 2021 was considerably worse than last years:

May 2020 - 773 kWh Gen - Self Powered 97% - Energy Offset 132%
May 2021 - 577 kWh Gen - Self Powered 79% - Energy Offset 92%

I suspect it'll be roughly the same overall come the end of the year, just got to wait and see.
 

Embattle

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6 Month Comparison:

Jan - Jun 2020 - 2509 kWh
Jan - Jun 2021 - 2409 kWh
 

Embattle

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Im always on the edge of buying. Just with a battery to really make use of it. It gets more expensive.
It is worth it without a battery as shown in my previous figures, at least it is if you intend to live there for a long while.
 

Moriath

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It is worth it without a battery as shown in my previous figures, at least it is if you intend to live there for a long while.
I guess the fact i work from home and am home most of the day would make that better As well.can retro fit a battery
 

Embattle

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If you work from home you can easily use the power you produce, for example if you are sitting there and it is a sunny day then you put the washing on etc.
 

Scouse

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Looking at getting my supply point changed (it's in a retarded place - the consumer unit is on the wall at head height as I come in through the door - people bang their heads on it). Want to move it to the back of the house, change the consumer unit (stick it in the utility room), and get the meter changed (from the fucking stick-a-key-in 22p/kWh kind!).

At the same time I figure I may as well ensure that the supply is good in the future for:

A) a solar and battery installation (that I fully expect the national park to tell me fuck off with, but then that might all change in a few years)
B) enough capacity for a few (3 maybe) rapid car chargers (not just fast, if I'm going to pay then I may as well get rapid)
C) enough capacity to run additional accomodation
D) more modern wiring so I can run a generator outside in the event of a power cut that would power the whole house

I've been on to the network operator to discuss moving the ingress point to the outside wall (and an electrician to do the consumer unit work up-front (I've still to contact the metering supplier - it takes all three to be onsite at the same time to ensure minimal energy disruption).

They've been really professional - submitting my initial request for formal quote got me a mail back. Then the next day a phone call to say they've got it and to expect a follow-up call. Then today a follow-up call to discuss my application on a preliminary level. A discussion of the above has led the lady to engage an engineer to give me a ring in a few days - and she's asked me to fill in a few forms regarding maximum demand, informed me that the transformer on my pole will have to be changed as it's not rated for anything other than running a toaster (and certainly nothing upstream).

Hell it's a complicated piece of form. She advised me to get in contact with my appliance supplier - and I said I've not got one - the move of the point, consumer unit and replacement of the meter is the important thing but if they're coming out I want to future-proof so I don't end up having to pay twice when I want to get solar, battery and/or electric vehicle charging points installed.

I guess I'll discuss with the engineer when he rings me in a few days. But it's a conversation I'm looking forward to.

Not paid a penny yet.


Contrast this to the council planning department at snowdonia national park. I filled out a large email detailing a pre-planning application. I burrowed through their website to find a stupid form to fill in and the email address that I needed to submit it to. It comes with a cost ladder, so I rang them up to ask for advice and the girl said "oh, you're not paying? I can't help - you'll need to ask a planner. No they're not in - leave them a message and they'll get back to you" - which I did, and they didn't.

I did some more digging, decided on "rung 2" - so rang 'em back and paid £250 or so. That was 8 days ago. Not even had email acknowledgement that the mail is in a queue to be looked at.

I also know that, because council, they're going to be utter shits about it. Despite me bending over backwards to make things completely obvious - including plans, profile, sitemap, photographs, numbered descriptions, bat survey results.

They'll make basic mistakes left, right and centre that could end up either denying me the ability to do basic stuff (like power or insulate my house in a modern fashion with minimal visual impact - instead forcing me to stick a whacking great gas canister outside that everyone can see, just in time for them to be made obsolete).

:eek:


Anyway. I've asked the authority whether I can stick a 10kw array in one of my fields. Roof isn't suitable. I've no idea if 10kw is even remotely sensible for a house our size if we run fully off 'leccy. I guess heating in the winter months would be hellishly expensive if it was all electric under floor - especially as we'd not be producing when we needed it - so would probably be drawing from the grid.

Whaddya reckon @Embattle? If they miraculously give the go-ahead, is it even worth pursuing?
 

Embattle

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@Scouse

So firstly let me say I'm in no way an expert ;)

A) As you say you never know what will be the policy now and I certainly expect the legislation to change more to support such technologies even in the most protected areas, if not then the technologies will improve such as solar roof tiles etc. so the visual impact would be reduced. As for the battery this really won't be affected by planning since it is largely out of sight or inside a building etc.
B) I wonder what you mean by rapid, on a single phase which is the standard for a house you'll only be able to charge a car at a rate of 7kW with 11kW being available on 3 phase but that also requires the car to have the 11kW capability. Remember our homes run on AC and those rapid chargers in public places are DC thus have very high rates of charge not available in homes. In the end a 7kW charge point will fill a battery from near 0% 10-12 hours.
C) I suspect that won't be a big issue if they do some upgrades.
D) Well if you are doing the house wiring it shouldn't be an issue, but a battery will add cover as well if you go that route.

So here are a few graphs from our system as examples of 2020 solar production:

Screenshot_20210915-193553.jpg

And the two months below showing the best month (July) and the worst month (Dec):

Screenshot_20210915-194243.jpgScreenshot_20210915-194200.jpg

So lets say you get a 10kWh system that'll produce somewhere in the region of 2.5-2.7 times as much energy as mine but you would still need grid electricity a lot in the colder months, we use gas for heating and water and in December the house used an average 21.5kWh (Low 15.1kWh - High 28.2kWh). All forms of heating benefit from good insulation which is now possible on more houses including older houses than in the past, even more so when using electricity to heat via devices such as air sourced heat pumps. However the biggest issue will be the additional required paperwork when you exceed a 4kWp solar system and this may involve considerable additional costs considering the current stand of you power supply, again it is something to check out at the time and see what the options and costs are for all possibilities.
 

Scouse

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Ta. I'm going to get a local solar pv company to come out so I can talk to 'em. Even if it means dick.
 

Moriath

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@Scouse

So firstly let me say I'm in no way an expert ;)

A) As you say you never know what will be the policy now and I certainly expect the legislation to change more to support such technologies even in the most protected areas, if not then the technologies will improve such as solar roof tiles etc. so the visual impact would be reduced. As for the battery this really won't be affected by planning since it is largely out of sight or inside a building etc.
B) I wonder what you mean by rapid, on a single phase which is the standard for a house you'll only be able to charge a car at a rate of 7kW with 11kW being available on 3 phase but that also requires the car to have the 11kW capability. Remember our homes run on AC and those rapid chargers in public places are DC thus have very high rates of charge not available in homes. In the end a 7kW charge point will fill a battery from near 0% 10-12 hours.
C) I suspect that won't be a big issue if they do some upgrades.
D) Well if you are doing the house wiring it shouldn't be an issue, but a battery will add cover as well if you go that route.

So here are a few graphs from our system as examples of 2020 solar production:

View attachment 44907

And the two months below showing the best month (July) and the worst month (Dec):

View attachment 44909View attachment 44910

So lets say you get a 10kWh system that'll produce somewhere in the region of 2.5-2.7 times as much energy as mine but you would still need grid electricity a lot in the colder months, we use gas for heating and water and in December the house used an average 21.5kWh (Low 15.1kWh - High 28.2kWh). All forms of heating benefit from good insulation which is now possible on more houses including older houses than in the past, even more so when using electricity to heat via devices such as air sourced heat pumps. However the biggest issue will be the additional required paperwork when you exceed a 4kWp solar system and this may involve considerable additional costs considering the current stand of you power supply, again it is something to check out at the time and see what the options and costs are for all possibilities.
Why do they require more paper work over 4kWp ? Cause they think you sre a generator rather than public user?
 

Embattle

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Why do they require more paper work over 4kWp ? Cause they think you sre a generator rather than public user?
Well technically you are a provider at any level but under 4kW it is a lot simpler as I believe in general most a DNOs network can handle a sub 4kW return so you just have to inform the DNO but above this level it gets more complicated, it is worth always remembering the hardware in the grid when it comes to homes was really only designed to deliver power not receive it.

Finally yesterday we got a smart meter installed so I might change to a tariff with a cheaper night rate and load the powerwall with energy over night, also get the dishwasher to do its thing in the time slot as well.
 

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