at what cash level are west north west solar panels not completely mad?

esperluette

hello all you great folks and helpers!
this is a question for the more extreme PV ers!
I have had my first visit and the salesman nearly didn't come in at all when I told him I absolutely didn't want panels on my east/ south east front in Leicester.I told him I was thinking of future proofing more than money making and sweet chatted him into looking at the rear roof, which is not shaded by any trees and has no dormer windows etc.That's the good bit of the news.
The bad bits are
1.the slope is 45 degrees
2. the orientation is 155 degrees from south.
that gives a kk factor from the table for zone 6 ( midlands ) of 481.
( at this point I got it confirmed it would be TWICE that if only I had the panels on the front).
3.the roof can take 12 panels of 1.6 by 1.05 meters
4. the end of the house can only take 2 panels which wouldn't fire the string and would have tree shading.
Thanks to all of you I could ask him to quote for standard 250 w (seraphim all black )panels and higher 330w (BenQ) ones. He duly went through the calculations .
The basic price quoted by this large company ( they do lots of other home improvements so probably will be around) for
12 panels, inverter etc ( iboost extra 345) was
GBP 5895 for normal seraphim black S4, solis 3k-2G inverter
add GBP 120 for slightly smaller all black prettier seraphim 250W panels=6015 GBP
add GBP 1620 for Benq 3330 panels and Tranergy PVI 4000tl inverter. total for the latter is therefore= GBP 7515.
To be fair he said he didn't think the higher price was worth it.He wasn't at all pushy and answered all the questions I threw at him.( I think he thought I was mad to even think of PVs on the back roof!)
Here are the production and cash savings projections ( rounded off):
( I currently use 3300KWh per annum,gas heated water, unvented cylinder, gas boiler)
for the seraphim3kWp system:
3kWp x kk481=1443 kWh per year
annual FIT 180, export 35, reduced bill 120
=335 annual savings for outlay of 6k. will produce half what I use if I can manage it!I am retired and at home when not abroad!

for the benq 3.96 kWp system
3.96kWp xKk 481= 1904 kWh per year ie two thirds of my current consumption.
annual FIT 238, export 46, reduced bill 158=
442 annual savings for outlay of 7.5 k.

I boost extra at 345 GBP.
I know these quotes are on the high side as I have a preliminary quote from very small company for 16 panels installed etc of 250W solarworld at GBP 5250.they are coming tomorrow.

What I want to know is ( if anyone is prepared to guess)
1. am I totally/ mostly mad to even consider it ( with any company)?
2. if I do go for it, should I go for the higher spec, with another company perhaps?the salesman warned that non 250 w panels may be more difficult to replace and that some companies had already stopped making them.
3. whats the max price I should pay?( I know, how long is a piece of string)
3.at the FIt return is so low, should I take a chance and see what happens next year to the prices?
4.I thought of doing it now with a view to use the new storage systems that are hopefully coming in eg TESLA in 4/5 years when they have improved both in spec and in price.The main motivation is a the planet and b having an edge against future price increases.
I plan to be in this house for 20 years ( if i live).
the Salesman had the view that big companies were increasing prices as clients wanted the safety of the big names whilst small companies likely to fold post FIT drop were dropping theirs.They had fitted 200 systems last week!

Thank you all for past help and also in advance !
esperluette

EricMears

esperluette wrote: »

.He wasn't at all pushy and answered all the questions I threw at him.( I think he thought I was mad to even think of PVs on the back roof!)

I know these quotes are on the high side as I have a preliminary quote from very small company for 16 panels installed etc of 250W solarworld at GBP 5250.they are coming tomorrow.

What I want to know is ( if anyone is prepared to guess)
1. am I totally/ mostly mad to even consider it ( with any company)?
2. if I do go for it, should I go for the higher spec, with another company perhaps?the salesman warned that non 250 w panels may be more difficult to replace and that some companies had already stopped making them.
3. whats the max price I should pay?( I know, how long is a piece of string)
3.at the FIt return is so low, should I take a chance and see what happens next year to the prices?
4.I thought of doing it now with a view to use the new storage systems that are hopefully coming in eg TESLA in 4/5 years when they have improved both in spec and in price.The main motivation is a the planet and b having an edge against future price increases.
I plan to be in this house for 20 years ( if i live).
the Salesman had the view that big companies were increasing prices as clients wanted the safety of the big names whilst small companies likely to fold post FIT drop were dropping theirs.They had fitted 200 systems last week!

Maybe not 'pushy' but certainly not unbiased !

NOT 'mad to consider it' but make sure you get a good estimate of likely generation (use the pvgis page; don't rely on a salesman's figures) then work out the annual receipts as a %ge of installation cost. If it's better than keeping money in bank (likely to be this year but have a stab at what you think interest rates might be in ten years time) then well worth considering; if not keep it in bank (or find another investment e.g. property).

His company may not be keen on 330W panels but I doubt everyone would discontinue them - indeed, expect to see even bigger ones in a few years time.

You would indeed be mad to think of choosing a big company now that he's told you they're increasing their prices without a valid reason. Nothing wrong with small companies per se (indeed the better ones will probably go on to become big companies) or indeed anything to worry about if installer crashes - providing you get an insurance backed warranty (several thousand times safer than even the biggest company's own assurance).

But just what is the objection to having panels on the front of the house ? You won't see them from inside the house or even from the back garden and just how long in an average day do you spend looking at the roof anyway ?

Good luck - enjoy the sales pitches (and feel free to laugh at the silly ones).

esperluette

dear mr Eric mears
I agree with you that one doesn't spend much time looking at the panels.But I m just stupidly fussy about the "looks of the house"and I suspect that I wouldn't be allowed to put them at the front even if I wanted to, as the1995 house is in a conservation area anyway ( albeit in cul de sac).
I'll listen to the small company chap carefully!
ill give the pvgis page a go but might need help!
many thanks
esperluette

esperluette

the value given on the PVGIS site for my post code is 2.99 for optimal inclination.
How do I convert this into estimated production using , I presume the panel wattage and numbers and roof details ( inclination and and slope figures ? KK value?) please?I couldn't see this on the main FAQ section?
many thanks
esperluette

EricMears

esperluette wrote: »

the value given on the PVGIS site for my post code is 2.99 for optimal inclination.
How do I convert this into estimated production using , I presume the panel wattage and numbers and roof details ( inclination and and slope figures ? KK value?) please?I couldn't see this on the main FAQ section?
many thanks
esperluette

Assuming you follow the link from our FAQs page
http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php#
you should arrive at a page with a map on left hand side and a questionnaire on right. Typing postcode into search box on left page is a lot easier than trying to zoom in on map and place the pointer yourself (you still have option of dragging the pointer a short distance if you're in a big postcode area).

Once you've done that, just answer a few questions on right hand page - there are a lot you can ignore but make sure you fill in 'installed peak power' with your (proposed) system size, 'slope' (of your roof) and 'azimuth' (the note in small red letters explains what that is) but just accept defaults or leave blank for rest. Then click on calculate.

You should then get a pop-up window (or may have to tell browser to accept one !) with a table of monthly expectations. All you're really interested in at this stage is the annual total of the Em column (but come back to it after installation to get individual monthly predictions).


HTH

esperluette

the values I got after finding the link on the excellent ( thanks Martyn1981) FAQ ( section 5)were slightly lower than the ones quoted by the salesman
for 3 kWh system 1. 3 rather than 1.4
and for 4kWh system 1.8 rather than 1.9.
many thanks.
shall quiz the next ones as to their method of calculation!
esperluette

EricMears

esperluette wrote: »

the values I got were slightly lower than the ones quoted by the salesman

Quelle Surprise !

Actually my main surprise is that your figs are only slightly lower. Your salesman was probably only slightly dishonest Make a note of your own result then use it to evaluate the reliability of your 'advisors'; laugh at them & send them packing if there's a big discrepancy.

EricMears

esperluette wrote: »

I suspect that I wouldn't be allowed to put them at the front even if I wanted to, as the1995 house is in a conservation area anyway

Planning Portal (sort of) confirms suspicions.
http://www.planningni.gov.uk/index/advice/advice_apply/advice_apply_homes/advice_home_work2/advice_home_solar.htm
But always worth popping along to town hall and having a chat with a planner - hard to believe a 1995 house is deliberately being 'conserved' and they may well tell you to submit a planning application which they'd be prepared to pass. The chats are free but you'd probably need to pay for a full application.

Martyn1981

esperluette wrote: »

this is a question for the more extreme PV ers!

1.the slope is 45 degrees
2. the orientation is 155 degrees from south.
that gives a kk factor from the table for zone 6 ( midlands ) of 481.
( at this point I got it confirmed it would be TWICE that if only I had the panels on the front).

Ouch! 155 from south and 45d, that's not promising. I checked PVGIS with a random pin in Leicester and got 459kWh/kWp. For -25 from south I got 918, exactly double.

Hmmmmm!

esperluette wrote: »

What I want to know is ( if anyone is prepared to guess)
1. am I totally/ mostly mad to even consider it ( with any company)?

Never mad to consider anything, otherwise you wouldn't find out what works and what doesn't. I'm hardly one to talk with WNW panels, but they are 'only' +110, and more importantly at 30d pitch so I get 679kWh/kWp.

I'm really torn, if the FiT gets slashed in Jan, then now's the only time to (consider) doing it, but it really doesn't sound too good. I'm also a little sceptical about the (my?) usual leccy saving guesstimate of £120. It shouldn't really be too hard for 2kWp+ systems with a south(ish) orientation, but I can't really guess what would happen for NNW, perhaps a steady background generation contributing to baseload, then afternoon and evening generation in the summer. I'm a little stumped, but far from confident on £120.

I think you've got to ask about planning permission for the front before you decide anything.

Mart.

esperluette

dear martyn,
many thanks for your detailed response.I know the front would give me twice the returns, but ( foolishly ) cant stomach the idea of panels there.
So my current plan is to see if I can get anything on the wsw hip- one installer said 4 X 285 panels ( wsw giving 1kw additional to 10 X 285 panels on wnw giving 1.7kw) and the other said only two so no go. let me see what the third one says on monday-the only one prepared to go and measure the roof!
I also thought now or never...and hope that storage will improve...
may be father xmas will bring 2000 watt minipanels in a few years time, which ill hide on the front....
I know you are telling me the unvarnished truth and thank you.
Do you feel that another 4 panels on the wsws hip ( S +56)would make it worthwhile?or less "mad"?I must say i jumped at the possibility and am now keen to explore it.
excellent work, cannot thank you & co pvers enough.
esp

Martyn1981

esperluette wrote: »

Do you feel that another 4 panels on the wsws hip ( S +56)would make it worthwhile?or less "mad"?I must say i jumped at the possibility and am now keen to explore it.
excellent work, cannot thank you & co pvers enough.
esp

Morning. 4 more WSW would certainly help. Hard to know where the point between less mad and worthwhile will be.

Hopefully the 4 extra panels will push up the generation average a bit, and pull down the average cost a bit. But hipped rooves are tricky things, and the extra scaffolding cost may range from zero to silly, so it'll all depend on the quotes you get.

You will also need a dual MPPT inverter, which will treat each roof as a separate system. The minimum voltage on a lot of dual MPPT inverters might struggle with 4 panels, as they may need 5 or 6. You will be able to find inverters that can cope, just a smaller range to choose from, but probably not a major concern, or deliberately choose panels that have higher voltages say 50V rather than 30V.

Looking optimistically for a cheap quote, say £5k, would an income of approx £400 work for you? I'm simply boosting your original 3kWp FiT + export guesstimate by 25%, and assuming a better chance of £120 leccy savings with a 4kWp system and some WSW generation.

[Edit: I was trying to be a bit conservative with that £400 figure, as I appreciated that the WSW work work better, however, having checked with PVGIS, it works much better, as the steep roof pitch doesn't make much difference for southish panels. So perhaps the total would be nearer £450 pa. One last check though, what is the roof pitch of the hipped roof (it may be different to the front/back rooves, and also would the hipped roof need PP, what are the rules, is it something like 'rooves facing the front/main road', 'visible from the front'? M.]

Mart.