Solar Quote

[bob the builder 2]

Hi All

 

Just received a quote for a 10kw, all black, standing seam solar install.

 

Any thoughts appreciated

 

Bob 

 

-----------

 

26x JA395 all black panels 

1x SolarEdge 3phase 10kw inverter 

Excludes scaffolding 

 

£13,250 - no VAT on new solar installs at the momen

[Nickfromwales]

About £8,500 worth of kit if NOT optimised, so ~£4,500 - £5,000 installation costs ( not labour costs ). A bit heavy tbh as a standing seam ‘on roof’ is a pretty simple install if all on a single mono pitch elevation?

[nod]

I’ve said it many times before 

Won’t the PV need replacing by the time you have eventually recouped the initial layout 

The projected saving on our previous build was about £250 per year 

Probably more than double that now 

Still a lot of years before it pays for itself 

[bob the builder 2]

Hi All

 

Just to add the panels have individual optimisers given the shading around the site.

 

Scaffold is still up so the cost is ex scaffold.

 

Many thanks

 

Bob  

[joth]

It will be hard to self-consume those 10kW in summer.

 

Does the install include MCS certificate? To get paid export.

Do you have a v2 smart 3phase meter? To ensure you get net billing across phases.

Have you considered adding a battery (or two) now? They're only VAT free if bought with the PV.

 

[Nickfromwales]

2 hours ago, nod said:

I’ve said it many times before 

Won’t the PV need replacing by the time you have eventually recouped the initial layout 

The projected saving on our previous build was about £250 per year 

Probably more than double that now 

Still a lot of years before it pays for itself 

The ‘premium’ panels we use ( Solarwatt ) have a 30 year performance guarantee. That states that they will still be a MINIMUM of 87% efficient 3 decades from now or they’ll be replaced for free. That warranty + guarantee is underwritten by BMW ( as they own Solarwatt ), eg “worth the paper it’s written on”. So my panels will still be up in the 90th percentile in 30 years from now or they’ll be replaced for free. I expect my panels will still be putting out around at least 50% in a half century from now.

The longevity is attributed to the glass-glass design, where the solar element is hermetically sealed away from atmosphere, bonded between two layers of glass ( laminated ). It’s the only panel I know of that can go coastal without any degradation, whereas “others” will state not to install them within 12 - 15 miles of the coast. 
 

For a lot of installs the RoI will just get better and better; as the price of electricity goes up, your break even comes down. All the surveys we do allow 50% or more redundancy in the purchase price of electricity, ( IIRC that assumes 17p/kWh ) so a) the breakeven point ( RoI ) is actually much better than we state, and b) the self-consumption figures we state are based on 50%, whereas most are using a lot more “in-house” and managing / minimising their export far more scrupulously, FURTHER reduced the breakeven point.

The year that you’d break even would be just into double-digits in most scenarios, if you’ve a straightforward  mono-pitch single array, with prices going up by around £1k if the array(s) are fragmented over a couple / few elevations ( so have to be multiples of strings and all optimised ), but as electricity prices go up, your breakeven point comes down. That will continue to get better and better as time goes by. 
 

Time for you to dust of what you think is a poor investment old boy     

[SteamyTea]

24 minutes ago, Nickfromwales said:

That states that they will still be a MINIMUM of 87% efficient 3 decades from now

That is 87% of the stated peak power output of the module at standard testing, which is not the same as as what they actually tested at when new.

That makes it very possible that over a decade you will see a quite large drop off in performance of the total system.

Edited February 1, 2023 by SteamyTea

[Nickfromwales]

32 minutes ago, joth said:

It will be hard to self-consume those 10kW in summer.

But very easy to consume the residual ~2kW in winter, that which the 10kW system will then only provide. Or less. Or none. If you want winter generation you have to max out and accept the export in winter, it’s just a matter of finding the “sweet spot”. Economy of scale says it’s cheaper to put more on when you’ve mobilised a company and paid for scaffolding etc, so I’m an advocate of this policy, and with EV’s on the horizon, or already owned, you cannot have too much PV afaic.
 

If you have “his and hers” EV’s then leaving one routinely tethered during the day, whenever possible, is a great way of deleting a domestic battery from the capital expense, and absolutely maxing out on self-consumption.

 

My philosophy on the “bigger is better” approach is as so; 

For all the electricity you then don’t buy in summer, plus the hot water you don’t heat, plus then the increased longevity of your boiler / ASHP ( from it going into ‘hibernation’ for around 6 or more months of the year ) all added together goes into a hypothetical glass jar. So you have made yourself energy rich in the summer months / times of discernible generation. You then take that saving and use it to off-set your wither heating costs / inevitable draw from the grid during times of poor generation and reliance on the grid. That ‘pot’ is as good as cash, so can go towards either gas or electricity based heating systems. After that ‘pot’ has been exhausted, only then do you go back to absolute grid reliance ( less the 0 - 25% winter solar generation ) making for a very wise investment, imho. Factor in the few quid for export, which can be improved via Agile etc, and it’s a no-brainier to go large’. 
 

Further consider that the PV will go much further in winter if it’s diverted into a heat pump, so that residual ~2kW could then be producing as much as 8kW of heat energy. 
 

If the pockets are deep enough, “go large”. 
 

Amen. 

[Conor]

In our first 9 months we've self consumed 70%, even at that, the payback with current energy prices is just 4 years. Down from the original 7 years estimate. We also get paid 8.5p per unit export, which is basically the same as our overnight economy 7 import rate. So we even have the option to use appliances and heat hot water overnight on the cheap rate and just export during the day - which I think works out better as never guaranteed when running a dishwasher or dryer during the day that you will ONLY be using PV. And heat pump heating water on economy 7 is far better value than immersion running on excess PV. 3x better "return"

[billt]

1 hour ago, SteamyTea said:

That is 87% of the stated peak power output of the module at standard testing, which is not the same as as what they actually tested at when new.

That makes it very possible that over a decade you will see a quite large drop off in performance of the total system.

But then again you may not.

 

These panels nearly 10 years old, bought in March 2013. The top lines are nominal 280W per panel and the lower lines are nominal 220W per panel. The 280W panels managed a peak of 297W and the 220W panels a peak of 225W.

 

 

 

[SteamyTea]

9 minutes ago, billt said:

These panels nearly 10 years old, bought in March 2013. The top lines are nominal 280W per panel and the lower lines are nominal 220W per panel. The 280W panels managed a peak of 297W and the 220W panels a peak of 225W.

That is because of the testing methodology, they have have been tested for output with an input of 1000W.m^-2, at 25°C, which would be the point that they deliver at least the stated output.  They may well have produced 10% more for during the test.

Modules that just fail the STC would be relabelled to a lower output i.e. failed at 330 W_p, relabel as 310 W_p.  Even of they are just 1 W_p below the level.

 

So the trick is to not buy the highest output modules, but the ones below, if there is a decent enough price difference.

 

If you find a local weather station that has a W.m^-2 sensor on it (kWh/day is no use here), you can take a random selection of dates, but pick the same 3 times each day i.e. 10 AM, 2 PM and 4PM, then correlate the output of your system to the irradiation levels, then see how the performance has changed over the years.  You can even adjust for different ambient temperature.

Edited February 1, 2023 by SteamyTea

[Radian]

33 minutes ago, SteamyTea said:

You can even adjust for different ambient temperature.

If measuring output from the AC side of the inverter then the operating temperature of the inverter can have a significant effect. Taking measurements from the DC side is the only reliable way to assess the module performance.

[SteamyTea]

8 minutes ago, Radian said:

If measuring output from the AC side of the inverter then the operating temperature of the inverter can have a significant effect. Taking measurements from the DC side is the only reliable way to assess the module performance.

Just add in the standard error and it will be close enough.

[Radian]

4 minutes ago, SteamyTea said:

Just add in the standard error and it will be close enough.

What do you mean by standard error?

[SteamyTea]

9 minutes ago, Radian said:

What do you mean by standard error?

Standard Error of the Mean.

Allows you to infer how accurate the results are within pre agreed limits.

 

When looking at something like PV output and Solar Power, there is no need to work at the 1W level, 50 W bins would be accurate enough.  Would be the same as a P-Value of 0.05.

Edited February 1, 2023 by SteamyTea

[Mr Blobby]

12 hours ago, bob the builder 2 said:

Hi All

 

Just received a quote for a 10kw, all black, standing seam solar install.

 

Any thoughts appreciated

 

Bob 

 

-----------

 

26x JA395 all black panels 

1x SolarEdge 3phase 10kw inverter 

Excludes scaffolding 

 

£13,250 - no VAT on new solar installs at the momen

 

No GSE frames in the quote?

What's the standing seam made of?  Zinc, aluminium? 

Integrating the panels in GSE frames will not only look better but will save money on the standing seam.  Just make sure to put some ventilation underneath.

[nod]

3 hours ago, Nickfromwales said:

The ‘premium’ panels we use ( Solarwatt ) have a 30 year performance guarantee. That states that they will still be a MINIMUM of 87% efficient 3 decades from now or they’ll be replaced for free. That warranty + guarantee is underwritten by BMW ( as they own Solarwatt ), eg “worth the paper it’s written on”. So my panels will still be up in the 90th percentile in 30 years from now or they’ll be replaced for free. I expect my panels will still be putting out around at least 50% in a half century from now.

The longevity is attributed to the glass-glass design, where the solar element is hermetically sealed away from atmosphere, bonded between two layers of glass ( laminated ). It’s the only panel I know of that can go coastal without any degradation, whereas “others” will state not to install them within 12 - 15 miles of the coast. 
 

For a lot of installs the RoI will just get better and better; as the price of electricity goes up, your break even comes down. All the surveys we do allow 50% or more redundancy in the purchase price of electricity, ( IIRC that assumes 17p/kWh ) so a) the breakeven point ( RoI ) is actually much better than we state, and b) the self-consumption figures we state are based on 50%, whereas most are using a lot more “in-house” and managing / minimising their export far more scrupulously, FURTHER reduced the breakeven point.

The year that you’d break even would be just into double-digits in most scenarios, if you’ve a straightforward  mono-pitch single array, with prices going up by around £1k if the array(s) are fragmented over a couple / few elevations ( so have to be multiples of strings and all optimised ), but as electricity prices go up, your breakeven point comes down. That will continue to get better and better as time goes by. 
 

Time for you to dust of what you think is a poor investment old boy     

According to Sap last time and this 

I would probably need the 30 years to realize my initial outlay 😂

 

[Nickfromwales]

3 hours ago, SteamyTea said:

That is 87% of the stated peak power output of the module at standard testing, which is not the same as as what they actually tested at when new.

That makes it very possible that over a decade you will see a quite large drop off in performance of the total system.

If a 4kWp system is generating less than 3.48kWp at year 30 it will be replaced. It is very simple. There is no grey area, just facts. No smoke and even fewer mirrors. 

The situation is; the panel ( manufacturers ) won’t let this happen. Underwritten by a company which doesn’t want provoke disgruntlement, or have to run around replacing thousands of systems at their own cost.

 

[Nickfromwales]

3 hours ago, nod said:

According to Sap last time and this 

I would probably need the 30 years to realize my initial outlay 😂

 

Big hairy load of bollocks. 
PM me your plans and a Google earth image showing north and I’ll work it out for you. Then, you will be buying the beers ma’ G.😎🍺

[SteamyTea]

12 minutes ago, Nickfromwales said:

If a 4kWp system is generating less than 3.48kWp at year

Totally missed the point I was making.

[joth]

9 hours ago, Nickfromwales said:

10 hours ago, joth said:

It will be hard to self-consume those 10kW in summer.

But very easy to consume the residual ~2kW in winter, that which the 10kW system will then only provide ...

 

 

Yes absolutely, wasn't trying to say exporting some in summer is an argument against buying PV at all / in those quantities, just flagging the OP should think now about strategies of what they'll do about it to make it acceptable when it inevitably happens. 

[Nickfromwales]

3 hours ago, SteamyTea said:

Totally missed the point I was making.

Likewise. 

[Nickfromwales]

1 hour ago, joth said:

 

Yes absolutely, wasn't trying to say exporting some in summer is an argument against buying PV at all / in those quantities, just flagging the OP should think now about strategies of what they'll do about it to make it acceptable when it inevitably happens. 

Yup. Hot water via diverter is numero-uno, EV second, batteries last if you can 1000% justify it. 

[Furnace]

On 01/02/2023 at 01:41, Nickfromwales said:

About £8,500 worth of kit if NOT optimised, so ~£4,500 - £5,000 installation costs ( not labour costs ). A bit heavy tbh as a standing seam ‘on roof’ is a pretty simple install if all on a single mono pitch elevation?

Nick,
Do you recommend GSE installations on standing seam roofs? My initial thoughts were that mounting the panels on clam brackets attached to the seams was fast and provided a cooling gap of 50mm. No danger of leaks and a more straightforward installation of the roof?

[Nickfromwales]

8 hours ago, Furnace said:

Nick,
Do you recommend GSE installations on standing seam roofs?

GSE would be in-roof, which means cutting into / interrupting the standing seam roof to suit. If a standing seam roof is below a certain pitch then the roof must remain continuous to stay weathertight. I've seen a couple done, but the roof installers were platinum level installers. I've seen one done badly where it was blown off. Going for the vernacular is often the safest / most sensible route tbh.

Cooling is academic imho, as even in-roof has a decent air gap behind it.

 

8 hours ago, Furnace said:

My initial thoughts were that mounting the panels on clam brackets attached to the seams was fast and provided a cooling gap of 50mm. No danger of leaks and a more straightforward installation of the roof?

Yup. You're spot-on.