Octopus Solar Panel quotes + a window on the roof

Jemma01

Hi

I was hoping to have two quotes by now, but Infinity Renewables didn't show up (dad used them).

I have several questions below, please:

1) I have a tiny window on the roof that lets in skylight onto an unused bathroom. I'm not bothered about it, and if it'll reduce the number of panels by 1 on the south-facing side, then I'd rather it be covered. Do I have that option? Or is it a legal requirement not to block it?

2) I have limited space as to where I can put the solar panel system. I don't have a garage/utility room, and under the stairs is already maxed out from the heatpump bits and bobs. From researching this forum, the roof is not an option. Can I put it outside and put a physical security system around it? Would this affect the longevity of the batteries?

3) My annual usage with a heatpump + underfloor heating is 4570kwh. The building next door blocks sunlight in winter, and then some trees block sunlight near the end of the day (say 7pm summer). The designer asked about a potential EV car, and I said a hybrid is a possibility.

Given my usage, I thought if I went for a Tesla Powerwall, I'd have fewer devices to worry about the location for. But then the quote from Octopus says otherwise

21 x JA Solar 450 Watt Panels (JAM54D41-450/LB) 1 x Tesla Powerwall 3.0 (11.04kW - 3 MPPTs) (Tesla) 1 x Tesla Powerwall 3 [Battery] (Tesla)
Total system price	£16,364.00

6,202 kWh ESTIMATED ANNUAL SOLAR GENERATION

So I asked for a second option with Microinvertors 

21 x JA Solar 450 Watt Panels (JAM54D41-450/LB) 21 x IQ8AC-72-M-INT [25 year warranty] (Enphase Energy Inc.) 2 x IQBATTERY-5P-1P-INT (Enphase Energy Inc.) 1 x BIRD-MESH-BLK
Total system price	£16,663.00

6,304 kWh ESTIMATED ANNUAL SOLAR GENERATION

To my surprise, they're suggesting that I'd be saving a bit more on the second option than on the Tesla option. They're my current supplier, and know my usage and address and how much electricity I use and what's possible in the area.

Potential savings and income

[Tesla] £37,119 (BILL SAVINGS) -  £16,364 (SYSTEM COST) = £20,755 OVERALL SAVINGS

[Enhpase] £39,187 (BILL SAVINGS) - £16,663 (SYSTEM COST) = £22,524 (OVERALL SAVINGS)

4) I would like a second and a third quote. Any recommendations? I would like to research the companies.

Much appreciated, thank you

matt_drummer

Don't buy a hybrid car!

Enphase are the best, I have this.

My Enphase microinverters were installed in 2014, nearly 12 years ago, no issues at all, will deal with shade issues and data is good. No inverter to worry about placing and if one micro inverter fails the rest still work.

Insist on bird mesh whatever you do!

The Enphase system will take up less space.

And lastly, do not buy a hybrid car!

QrizB

Jemma01 said:

4) I would like a second and a third quote. Any recommendations? I would like to research the companies.

I'm not particularly taken by either of the quotes you've had so far.

See for example this recent quote, 22 500-watt panels and a Powerwall 3 for £13.3k:

https://forums.moneysavingexpert.com/discussion/comment/81757544/#Comment_81757544

If you pop a PM to @Screwdriva he can put you in touch with a supplier that can supply and fit at that price.

Screwdriva

Jemma01 said:

Given my usage, I thought if I went for a Tesla Powerwall, I'd have fewer devices to worry about the location for. But then the quote from Octopus says otherwise

21 x JA Solar 450 Watt Panels (JAM54D41-450/LB) 1 x Tesla Powerwall 3.0 (11.04kW - 3 MPPTs) (Tesla) 1 x Tesla Powerwall 3 [Battery] (Tesla)
Total system price	£16,364.00

Just to share that I would go with the PW3 over Enphase (outdoor cold weather performance is second to none, 35% more capacity, better specs). That said, the price you've been quoted is exorbitantly high for very unethical panels. 

For perspective, installers I use to help others have shared that:

21 X Eurener 500W bifacial panels (10.5kWp)
1 Tesla PW3 w/ Gateway 2

..should cost ~£13K installed, inclusive of bird netting and a 10 year workmanship warranty. That's a £3.3K savings for a 1+ kWp larger PW3 based system, using a far more ethical & capable bifacial panel brand as a bonus. There's also a Direct to End User rebate for £375 from Tesla over this, bringing the final cost well below £13K.

The installer you contract should conduct an in person survey to determine the maximum # of panels that will fit on your roof - I'd push for the maximum number that will fit.  

Hope this helps!  

Jemma01

matt_drummer said:

Don't buy a hybrid car!

Enphase are the best, I have this.

My Enphase microinverters were installed in 2014, nearly 12 years ago, no issues at all, will deal with shade issues and data is good. No inverter to worry about placing and if one micro inverter fails the rest still work.

Insist on bird mesh whatever you do!

The Enphase system will take up less space.

And lastly, do not buy a hybrid car!

Thanks so much, I'm really keen on that option.

What's your beef with the hybrid car 😆

QrizB said:

Jemma01 said:

4) I would like a second and a third quote. Any recommendations? I would like to research the companies.

I'm not particularly taken by either of the quotes you've had so far.

See for example this recent quote, 22 500-watt panels and a Powerwall 3 for £13.3k:

https://forums.moneysavingexpert.com/discussion/comment/81757544/#Comment_81757544

If you pop a PM to @Screwdriva he can put you in touch with a supplier that can supply and fit at that price.

Thank you, I'm keen on a 500w panels, but not feeling the Tesla 3 with microinverters. Seems to have mixed reviews.

Screwdriva said:

Jemma01 said:

Given my usage, I thought if I went for a Tesla Powerwall, I'd have fewer devices to worry about the location for. But then the quote from Octopus says otherwise

21 x JA Solar 450 Watt Panels (JAM54D41-450/LB) 1 x Tesla Powerwall 3.0 (11.04kW - 3 MPPTs) (Tesla) 1 x Tesla Powerwall 3 [Battery] (Tesla)
Total system price	£16,364.00

Just to share that I would go with the PW3 over Enphase (outdoor cold weather performance is second to none, 35% more capacity, better specs). That said, the price you've been quoted is exorbitantly high for very unethical panels. 

For perspective, installers I use to help others have shared that:

21 X Eurener 500W bifacial panels (10.5kWp)
1 Tesla PW3 w/ Gateway 2

..should cost ~£13K installed, inclusive of bird netting and a 10 year workmanship warranty. That's a £3.3K savings for a 1+ kWp larger PW3 based system, using a far more ethical & capable bifacial panel brand as a bonus. There's also a Direct to End User rebate for £375 from Tesla over this, bringing the final cost well below £13K.

The installer you contract should conduct an in person survey to determine the maximum # of panels that will fit on your roof - I'd push for the maximum number that will fit.  

Hope this helps!  

Thanks for your help. I appreciate the information. I'm very keen on the microinverters to address shading in winter time and the modular fault system, and I really don't have a lot of space, even outside it'll have to go next to the heat pump and I'm unsure how that's serviced and whether the space is sufficient for both to be serviced without restricted access.

Do they do anything other than a Tesla 3? I'd be keen to speak to them and research their reviews.

Screwdriva

Jemma01 said:

Thanks for your help. I appreciate the information. I'm very keen on the microinverters to address shading in winter time and the modular fault system, and I really don't have a lot of space, even outside it'll have to go next to the heat pump and I'm unsure how that's serviced and whether the space is sufficient for both to be serviced without restricted access.

Do they do anything other than a Tesla 3? I'd be keen to speak to them and research their reviews.

I may be reading this incorrectly, but it does appear that there is some previous advice shared that may be slightly inaccurate.

1) Enphase Microinverters or SolarEdge Optimizers are two types of devices to help reduce generation losses from substantial shading, achieved by isolating heavily shaded panels. They are not capable of generating additional power and can be overkill for minor shading. BTW, I have optimizers on my roof as I have heavy shading from a chimney and 3 roof aspects spread across SSE/ ENE/ WSW. 

2) The Powerwall 3 is not compatible with Enphase Microinverters or SolarEdge optimizers. It can be used as a AC coupled battery but this less efficient from a power and cost standpoint. 

3) Did Octopus Energy visit your property for a survey? I suspect not. The reason I ask is, very often shading is minor enough for the panel's own bypass diodes to mitigate. The PW3 has three built in strings, which means that the panels exposed to winter shade can be isolated from the rest of the system using clever system design, effectively achieving a similar result at a substantial savings.

4) Counterintuitively, it may benefit your heat pump to have the PW3 installed alongside it, as the PW3's heat exhaust may be captured by the heat pump to heat your home. This will make a negligible difference, but I know several homeowners who have installed both side by side.

I always recommend keeping an open mind, letting a quality installer visit your property to design a correct system and then deciding on the best option, once presented to you. Hope this helps! 

debitcardmayhem

Sound advice from @Screwdriva especially 

I always recommend keeping an open mind, letting a quality installer visit your property to design a correct system and then deciding on the best option, once presented to you. Hope this helps! 

Jemma01

Screwdriva said:

Jemma01 said:

Thanks for your help. I appreciate the information. I'm very keen on the microinverters to address shading in winter time and the modular fault system, and I really don't have a lot of space, even outside it'll have to go next to the heat pump and I'm unsure how that's serviced and whether the space is sufficient for both to be serviced without restricted access.

Do they do anything other than a Tesla 3? I'd be keen to speak to them and research their reviews.

I may be reading this incorrectly, but it does appear that there is some previous advice shared that may be slightly inaccurate.

1) Enphase Microinverters or SolarEdge Optimizers are two types of devices to help reduce generation losses from substantial shading, achieved by isolating heavily shaded panels. They are not capable of generating additional power and can be overkill for minor shading. BTW, I have optimizers on my roof as I have heavy shading from a chimney and 3 roof aspects spread across SSE/ ENE/ WSW. 

2) The Powerwall 3 is not compatible with Enphase Microinverters or SolarEdge optimizers. It can be used as a AC coupled battery but this less efficient from a power and cost standpoint. 

3) Did Octopus Energy visit your property for a survey? I suspect not. The reason I ask is, very often shading is minor enough for the panel's own bypass diodes to mitigate. The PW3 has three built in strings, which means that the panels exposed to winter shade can be isolated from the rest of the system using clever system design, effectively achieving a similar result at a substantial savings.

4) Counterintuitively, it may benefit your heat pump to have the PW3 installed alongside it, as the PW3's heat exhaust may be captured by the heat pump to heat your home. This will make a negligible difference, but I know several homeowners who have installed both side by side.

I always recommend keeping an open mind, letting a quality installer visit your property to design a correct system and then deciding on the best option, once presented to you. Hope this helps! 

1)

I'll give an example of my understanding to help me communicate my thoughts, I'm happy to be corrected as that's far away from what I do for a living, the numbers are random I don't know the actual outputs:

Let's say I have 10 panels in a string configuration, 9 can produce 10amps, and the 10th is shaded and produces 5amps. It's my understanding that the output would be 10x5amps= 50amps, NOT 9x10amps +1x5amps = 95amps

Having a microinverter will allow me to isolate that 5amps panel (decentralise), so the rest can still produce whatever they can. I also understand if a panel fails completely, the current will continue to flow, it's not an emergency that needs fixing. I can live with one down panel (which is a very important requirement for me, living mostly on electricity).

I also understand that optimisers are a string configuration, not a modular one.

Again, if any of this is wrong, I'm happy to be challenged, it's important for me to understand what I'm buying.

2) that makes the tesla less attractive option despite the bigger capacity and better performance.

3) No we're not at the stage where Octopus come and have a look, I took some pictures at 2pm on Wednesday where the building next door (block of flats) shaded the whole roof. My property is on a hill and they're above mine. Admittedly, there's probably 10m distance between my property and theirs, so light would still reach, just not direct sunlight.

Re:PW3 having 3 strings, I only have two sides, I'd imagine they'd string the south together, and the north together, which does mean if south fails, north will continue, but that's a loss of 10/11 panels. I'm looking for a configuration that would give me a high confidence that my house will run on solar power except in rare circumstances if the battery gives up.

Thanks for your time, again, I'm open to speak to them and see if my requirement for a fault-tolerant system can be met.

squirrelpie

I have Enphase microinverters and yes they behave as you describe. When I had snow covering just two panels (for some strange reason) not only did I get output from the rest of my panels but I also received an automatic email from Enphase warning me that two of my panels might have failed. Another benefit is that the voltage on the roof and in the cable leading down from the roof is normal mains voltage and there's only any voltage there if there is already a live mains supply below. (this was important to us, because the panels were installed before the house was finished building). So no special DC voltages to deal with.

That also means you will need an AC-connected battery.

I have trees that shade my panels during part of the year and the difference in output is very noticeable.

Each panel will generate at its own individual power, which you can see on the web console for your system. I believe you'll get significantly less output from north-facing panels so be sure your installer tells you exactly what is predicted for each group.

QrizB

Note that Enphase microinverters top out at ~380 watts (I think?) so am array of ten 500-watt.panels under standard conditions will have a maximum output of 3800 watts. That's rather less than the nominal output of 5000 watts, and less than you'd get with a conventional string inverter.

Depending on exactly how big a shading problem you have, you might find that the Enphase system has a lower total output (in terms of kWh per day/week/year) despite the theoretical advantages it gives you.

Jemma01

squirrelpie said:

I have Enphase microinverters and yes they behave as you describe. When I had snow covering just two panels (for some strange reason) not only did I get output from the rest of my panels but I also received an automatic email from Enphase warning me that two of my panels might have failed. Another benefit is that the voltage on the roof and in the cable leading down from the roof is normal mains voltage and there's only any voltage there if there is already a live mains supply below. (this was important to us, because the panels were installed before the house was finished building). So no special DC voltages to deal with.

That also means you will need an AC-connected battery.

I have trees that shade my panels during part of the year and the difference in output is very noticeable.

Each panel will generate at its own individual power, which you can see on the web console for your system. I believe you'll get significantly less output from north-facing panels so be sure your installer tells you exactly what is predicted for each group.

Thanks for your experience, I appreciate it. Imagine the panels failing in the middle of winter when you need them the most 😭. 

QrizB said:

Note that Enphase microinverters top out at ~380 watts (I think?) so am array of ten 500-watt.panels under standard conditions will have a maximum output of 3800 watts. That's rather less than the nominal output of 5000 watts, and less than you'd get with a conventional string inverter.

Depending on exactly how big a shading problem you have, you might find that the Enphase system has a lower total output (in terms of kWh per day/week/year) despite the theoretical advantages it gives you.

Very interesting point. Thanks for pointing that out. I've checked the quoted model and it is 360-366 😑, not impressed. But I believe newer models support 480. I'll ask octopus about it. I doubt the panels will produce maximum capacity but I still want the support if it so happens.

But that's the thing, unless someone knows exactly how much sun and shading my roof gets, it's difficult to know. I should go out every hour tomorrow and take a picture of the roof and see what happens 🤔 or beg the block for their CCTV footage 😅.