Solar Suppliers Derby & A Few Questions

[spon88]

Like a number of us I guess recent energy prices increases have pushed us from being curious about solar to actively wanting to pursue it if possible. I've read a number of useful threads on here but before I start to get surveys and prices, I have a few questions I'd appreciate help with please:

• anyone here used a solar supplier in or around Derby/East Mids they would recommend please?
• I'm attracted to Powerwall because of the integration and what looks to be leading specs - is that really the case?
• can most fitters integrate Powerwall or are there specific suppliers?
• are we still at Powerwall 2 or is 3 on the horizon (real time, not Tesla time)
• my house has a pretty big roof but we are east/west facing - I see that a split array can still be useful if you understand a possible reduction in 20% in generation. Still worth it?

Any other tips appreciated before I dive in. I understand that payback can easilly be 10 years or more (maybe less now!) but that isn't my main concern. I like the idea of solar, self-sufficiency and doing our bit for the environment. I'm guessing it could be a £20k + investment but fair enough.

Thanks for any pointers/recommendations so I can push on with the project (or not!)

 

[phil4]

1. Sorry can't help.
2. Not got one yet, but a few things that you need to consider:

• Because it can send 5kW to your house, and this is above default DNO notification, you need DNO permission beforehand. Otherwise it's capped below 5kW.
• Because it's Tesla there's no direct controls for many things, and instead it tries to use Tesla's AI to charge/discharge at the right times.

3. I believe Tesla only sell via their approved resellers. I'm also not sure what commissioning is needed for it, that might make it hard for a normal sparky to do it. What I mean is hooking it up to the internet, and Tesla, so it appears on your app.
4. Still v2. No dates on a v3.
5. Should be fine. They might suggest you use optimisers (by default all panels on a "string" generate at the same rate, so if one is in shade, they all are. An optimiser removes this resriction, but costs extra and adds a failure point. And no, you can't have 12 strings) , or just use two strings and assume the losses as it goes over.

I've had quotes for 4.8KW Solar alone at around 11K, and PW adding another 10K to that, so depending on how many panels you have, 20K sounds about right.

 

[spon88]

1. Sorry can't help.
2. Not got one yet, but a few things that you need to consider:

• Because it can send 5kW to your house, and this is above default DNO notification, you need DNO permission beforehand. Otherwise it's capped below 5kW.
• Because it's Tesla there's no direct controls for many things, and instead it tries to use Tesla's AI to charge/discharge at the right times.

3. I believe Tesla only sell via their approved resellers. I'm also not sure what commissioning is needed for it, that might make it hard for a normal sparky to do it. What I mean is hooking it up to the internet, and Tesla, so it appears on your app.
4. Still v2. No dates on a v3.
5. Should be fine. They might suggest you use optimisers (by default all panels on a "string" generate at the same rate, so if one is in shade, they all are. An optimiser removes this resriction, but costs extra and adds a failure point. And no, you can't have 12 strings) , or just use two strings and assume the losses as it goes over.

I've had quotes for 4.8KW Solar alone at around 11K, and PW adding another 10K to that, so depending on how many panels you have, 20K sounds about right.

Very useful thanks, some key points I wasn't aware off. It looks like I'm in the right ball-park at £20k so I'll push on with getting some quotations. Presumably there is a list of approved solar suppliers somewhere - I'm really keen to only use someone based on recommendation if possible. Cheers

 

[scdoubleu]

I had my solar + PW2 installed by Carbon Legacy, based in the East Mids. Your £20k budget should be more than adequate.

 

[spon88]

I had my solar + PW2 installed by Carbon Legacy, based in the East Mids. You £20k budget should be more than adequate.

Excellent thanks. I'll start there. Presumably you were happy with their work?

 

[scdoubleu]

There were a few wrinkles with the install, some due to problems with their suppliers, others due to the nature of our installation. All fixed in the end, and can't fault their customer comms.

 

[spon88]

There were a few wrinkles with the install, some due to problems with their suppliers, others due to the nature of our installation. All fixed in the end, and can't fault their customer comms.

Thanks. Just called to get things moving. 2 week wait even for an an initial call-back but understandably they're ultra busy given recent events. Appreciated!

 

[phil4]

Another quick heads up. Not sure if this is true, but the supplier I got a quote from said the PW2 was on 12 months back order. You may find your supplier has a quicker way to get them, or has some already in stock, but thought it worth saying just in case.

 

[spon88]

Cheers for that. I'm already finding that certain gear is quite scarce. Looking at our energy usage profile, I'm guessing that a decent chunk of our generation would be used during the day using an east/west split array. We run a biggish home office with servers, ups etc. I need to have it properly assessed but it may be that the solar goes in first and then the battery (if viable) follows up as soon as it's available. I may need to start doing some sums! The potential to top the battery on cheap(er) overnight rate is also handy. All that said, I won't be doing this based purely on financial reasons as it doesn't really stack up on that alone.

 

[WannabeOwner]

I'm attracted to Powerwall because of the integration and what looks to be leading specs - is that really the case?

Might be worth a look at EVM YouTubes (link below). He a self proclaimed Yorkshireman (i.e. short arms, deep pockets applies) and has done some useful analysis of Costs / payback etc. He's owned Tesla cars but his battery is GivEnergy, so that would give you one contrast at least.

FWIW my battery is PowerWall and I'm happy with it.

my house has a pretty big roof but we are east/west facing - I see that a split array can still be useful if you understand a possible reduction in 20% in generation. Still worth it?

I think that is a benefit, but perhaps not if you also have battery. South facing will give you max generation - optimal of course.

However, East / West will give you a spike in the morning, and another in the evening (when you come home), which makes it more likely that you will use what you are generating (than a single, bigger, spike mid-day for South facing).

With battery any excess can go into that of course, so point is moot.

You could also consider e.g. Zappi car charger - when that detects export to grid it start charging the car (once sufficient AMPs export detected). You can also have e.g. an Immersion heater come on so as to avoid exporting anything.

if you have PV, Car Charger (not sure if it is a requirement that that is a Tesla brand) and PowerWall then Tesla offer 24/7 price of (I think) 12p per unit. That's on the basis that they will export your battery at peak (when presumably they can make money as a "Peaker Plant"). You get 12p for export, and import, so anything that is exported you can "buy back" at the same price (you'll lose out on some small losses)

Because it's Tesla there's no direct controls for many things, and instead it tries to use Tesla's AI

Eh? No AI if you using "time based" surely?. That works just fine for me.

 

[phil4]

I'm in a very similar boat... currently waiting for DNO approval (or not) before I press on.

I think we use a good 20-30kWh per day when ignoring car charging, with both of us working from home and the like. So as you say, it wouldn't surprise me if a big chunk of the solar is used during the day. So like you I'd be quite happy getting the solar part in first, and deal with the battery later. It'd be beneficial, but no reason to wait.

 

[phil4]

Eh? No AI if you using "time based" surely?. That works just fine for me.

I might have been wrong, what I mean by that is the ability to do fine grained, but sensible stuff, like charge up from the 5p in the middle of the night because the forecast is for a cloudy day tomorrow, or the opposite, only charge a little bit because it's set to be sunny.

I'm not saying it has no control at all, just that I'm pretty sure some of the finer controller stuff is out of reach. A bit like in the car you can set the start time for charging, or the end time... but can't set both.

 

[WannabeOwner]

We run a biggish home office with servers, ups etc

me too. I have background power consumption of 1.5kw and that's despite having a very Eco house in all other respects. Physical On/Off switches on TVs rather than leaving them on Standby, that sort of thing on top of all whitegoods when replaced we choose the best energy rating. Same with servers, we pay more for efficient power supplies - TCO works out cheaper.

I need to have it properly assessed

You could read your meter regularly to get some figures (or grab some data from SmartMeter if you have one to get an idea of "at peak" and so on)

A plug in Watt Meter is a good way of finding out what a specific device uses. Perhaps an Owl meter (Clamps the LIVE feed to the house) for "instant" readings of house usage. To get useful data from that you might choose to throw all your breakers off, and then ON selectively to see what each circuit is drawing - Fridge / Freezer, servers, etc. Can also turn on Oven / Hob with everything else off as an experiment.

You may have something running that you didn't know about or have forgotten. I had a transformer for my front door bell which had probably been there since the house was built in 1960 - I probably could have relied on it to heat the whole house! and a couple of American style fridge-freezers that the previous owner left behind were running at £250 p.a. electricity each until I cleaned out their filters. I should have noticed that it was constantly noisy in the kitchen ...

 

[WannabeOwner]

charge up from the 5p in the middle of the night because the forecast is for a cloudy day tomorrow,

You'd have to fiddle with how long you want it to charge "tonight" based on your assessment of what the weather will be tomorrow. That can be done manually, bit tedious though ... Might be better to work on never exporting anything and not worry too much about what you (then) have to buy.

It won't do the sort of ToU tariff which changes every half hour ... I suspect that is because Tesla would prefer you give them that role, and just buy your juice from them. In that situation a different brand battery (which does keep back reserve for the ToU peak periods) would be worth considering

P.S. A possible benefit of PowerWall is what they might choose to add OTA in the future ...

 

[spon88]

Really useful guidance, thanks all. I certainly need to do some further calcs if only to convince myself that it won't be a complete waste. I'm pushing out for a few quotations now and looks like the lead-time might be considerable. It's also renewed my focus on other things like wall insulation - we put really deep stuff in the loft a couple of years back which made a noticeable difference but the cavity walls also need revisiting. There's a lot to evaluate and I appreciate your help. Cheers.

 

[WannabeOwner]

further calcs if only to convince myself that it won't be a complete waste

EVM YouTube has a video on "Solar Panels - Do They Make Financial Sense in 2022?" using his Whiteboard of Truth

 

[WannabeOwner]

It's also renewed my focus on other things like wall insulation

Don't know what sort of house you have, but might be worth considering what would be needed to improve the house to Passive House or EnerPHit standard.

I would expect that a retrofit is unaffordable ... but the benefits are significant in terms of comfort and health (especially for anything respiratory)

Moving to a Passive House (if you can find one and aren't wedded to your current home) would be an option if retro fit unaffordable.

Even allowing for all that, having PHPP calculations done on your house would tell you what was possible. Old thatched cottage would get a 90% saving on heating ... even a brand new Barrett Taylor Wimpey would save 75% - shocking that we keep chucking up such non-Eco housing

 

[spon88]

Don't know what sort of house you have, but might be worth considering what would be needed to improve the house to Passive House or EnerPHit standard.

I would expect that a retrofit is unaffordable ... but the benefits are significant in terms of comfort and health (especially for anything respiratory)

Moving to a Passive House (if you can find one and aren't wedded to your current home) would be an option if retro fit unaffordable.

Even allowing for all that, having PHPP calculations done on your house would tell you what was possible. Old thatched cottage would get a 90% saving on heating ... even a brand new Barrett Taylor Wimpey would save 75% - shocking that we keep chucking up such non-Eco housing

We had considered moving but with the kids (almost) having left, we've decided to refurb and stay put. Lots of friends around here too. Our place is a typical, fairly large 1995 modern construction and I've been progressively upgrading the average cr@p it was built with back then. Still plenty to do and hopefully some solar in the mix too. It will aslo be a nice new piece of tech to play with as I approach retirement

Totally agree about the dismal UK construction standards, some of the worst in Europe when it comes to energy conservation I believe.

 

[Fred2]

Depending on your usage profile, you may find the tesla energy plan (available via octopus) interesting. You give up control of your powerwall, but in exchange you pay the same amount for imports as for exports. The exact price varies per region, but it's 10-12p/kWh at the moment. As far as imports go, that's a bloody steal at the moment and it's better than anything other than agile outgoing octopus for exports.

If you'll have enough solar/battery that you barely need to touch the grid then it probably doesn't make sense, but if you do need to draw a lot a certain times of the year (eg winter) then it can be a good deal.

 

[spon88]

Depending on your usage profile, you may find the tesla energy plan (available via octopus) interesting. You give up control of your powerwall, but in exchange you pay the same amount for imports as for exports. The exact price varies per region, but it's 10-12p/kWh at the moment. As far as imports go, that's a bloody steal at the moment and it's better than anything other than agile outgoing octopus for exports.

If you'll have enough solar/battery that you barely need to touch the grid then it probably doesn't make sense, but if you do need to draw a lot a certain times of the year (eg winter) then it can be a good deal.

Excellent, another one on my list to check, thanks. I think that working from home and with the power-hungry office, solar could be advantageous in that we can likely use a good proportion of what we generate. Then stick the rest in the battery for back-up. With energy prices rocketing and little sign that it will come back down in the near future, solar is certainly more attractive than it was. That video posted above was also very handy.