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Renewable Energy: Quote comparison

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    • CommentAuthorniallcook
    • CommentTimeAug 3rd 2015 edited
     
    Anyone like to comment on these three quotes for a 4kW PV system I've recently received:

    Quote 1:
    16 x JA Solar 250w Mono Modules
    Ginlong Solis 3.6kW Dual MPPT Inverter
    £4,630.00 inc VAT

    Quote 2:
    16 x Jinko JKM-250P Poly Modules
    Solax SL-TL 3600T Dual MPPT Inverter
    £3,999.00 inc VAT

    Quote 3:
    16 x UpSolar 250w Poly Silver Modules
    Fronius Primo 3.6 Inverter
    £5,382.46 inc VAT

    Thanks in advance
    •  
      CommentAuthorSteamyTea
    • CommentTimeAug 3rd 2015
     
    Quote 2, it is 600 quid cheaper.
    What is your projected energy output per year?
    • CommentAuthorniallcook
    • CommentTimeAug 3rd 2015
     
    Simple logic suggests the lower quote, but wasn't sure if the spec was somehow inferior. Energy output estimates for each:

    Quote 1: 3,800 kWh
    Quote 2: 3,844 kWh
    Quote 3: 3,812 kWh
  4.  
    Polycrystalline used to be a bit less good than mono-, but there's so little in it nowadays, and in fact yours claims there higest output anyway!
    • CommentAuthorringi
    • CommentTimeAug 3rd 2015
     
    What the warranties on the Inverters?
    • CommentAuthorniallcook
    • CommentTimeAug 3rd 2015
     
    Warranties as follows

    Quote 1:
    Panels – Product 10yrs; Performance 90% 10yrs, 80% 25yrs
    Inverter – 10 yrs

    Quote 2:
    Panels - Product 10yrs; Performance 90% 12yrs, 80% 25yrs
    Inverter – 10 yrs (installer says a 20 yr extended warranty can be purchased direct from manufacturer for about £80)

    Quote 3:
    Panels - Product 10yrs; Performance 6 trigger points to 80% at 25yrs
    Inverter - 7 yrs
    • CommentAuthorringi
    • CommentTimeAug 3rd 2015
     
    See if you can find the performance for the panels and inverts when there is not much light, e.g. winter. They may effect you more in real life then peak performance.
    • CommentAuthorniallcook
    • CommentTimeAug 3rd 2015
     
    OK. Any idea what info I should be looking for on the product sheets in order to determine that?
    •  
      CommentAuthorSteamyTea
    • CommentTimeAug 3rd 2015
     
    I would not worry too much about low light performance, you may get jack all extra of very little.

    Generally, PV equipment, especially inverters, fail early (SMA had a huge batch that failed, but they replaced them pretty quickly).
    The one thing that does affect the module ageing process is shading, but if you are shade free or only shaded at very low light levels, then nothing to get concerned about really.

    There is really nothing much different in your quotes, almost down to the salesman commission levels.

    If you really want to look at data, the the temperature and power curves tell you a tiny bit about your modules.
    For inverters it is the cut in voltage and MPPT curve. They are all pretty similar really though.
    This is because they all work the same way, use the same basic components and connect to the same grid.
    Your local grid voltage variation can have as large an effect on performance as just about anything else (except the weather).
    •  
      CommentAuthordjh
    • CommentTimeAug 3rd 2015
     
    I'm with ringi, low level performance matters. Check out Ed Davies' blog.
    •  
      CommentAuthorSteamyTea
    • CommentTimeAug 4th 2015 edited
     
    Posted By: djhCheck out Ed Davies' blog.
    Would that be Ed's bit about comparing PV and ST in low light levels?

    http://edavies.me.uk/2012/01/pv-et-flat/
  12.  
    They look like cheap quotes to me. I didn't get anything this low in London!
    • CommentAuthorniallcook
    • CommentTimeAug 4th 2015
     
    I think we are an installers dream really so I would expect a keen quote. Single storey 35º south facing roof. No shading at all throughout the year. One end of array will be directly above the garage where there is already a consumer unit with two spare RCDs, so minimal electrical work. Looking at the quotes, the difference is mainly in labour and ancillaries – the cost of the panels and inverter is roughly the same.
    • CommentAuthorborpin
    • CommentTimeAug 4th 2015
     
    I'd be going back to all 3 and asking if that is their final offer!
    • CommentAuthorniallcook
    • CommentTimeAug 4th 2015
     
    Quote 1 definitely is, as it's a council-run collective buying scheme (already discounted, supposedly).

    Already gone back to Quote 3 to get them to look at their installation costs which are over £1,000 more than Quote 2.

    Will let you know final outcome. Plan is to offset some of the additional running costs of our recently-installed Ochsner GSHP system, so the lower the cost the better (without compromising on output obviously).
    •  
      CommentAuthorSteamyTea
    • CommentTimeAug 4th 2015
     
    Also worth remembering that with all the changes that Amber Rudd is putting in place, many installers may decide to leave the PV market. So installers warranty or guarantees will be worthless.
    • CommentAuthorniallcook
    • CommentTimeAug 4th 2015
     
    Surely RECC's Deposit and Workmanship Warranty Insurance scheme (or equivalent) will protect customers from that?
    •  
      CommentAuthorSteamyTea
    • CommentTimeAug 4th 2015
     
    :rolling:

    Try finding someone that has successfully claimed.
    • CommentAuthorniallcook
    • CommentTimeAug 4th 2015
     
    Not quite sure what point you're making. Are you saying there's no point even bothering installing the system because every installer's workmanship warranty will be worthless if they go out of business?
    • CommentAuthorowlman
    • CommentTimeAug 4th 2015
     
    Have you done a check on their standard of work on previous jobs? We've seen pics. in the past on this forum of some pretty crappy work.
  21.  
    Id want to know about the mounting systems they propose.
    • CommentAuthorCWatters
    • CommentTimeAug 4th 2015
     
    +1 to that.
    • CommentAuthorniallcook
    • CommentTimeAug 4th 2015
     
    @owlman Was planning to take a look at some installations once we've got a preferred quote.

    @bot de paille What would you be looking for/not looking for in their mounting system?
    • CommentAuthorowlman
    • CommentTimeAug 4th 2015 edited
     
    Posted By: bot de pailleId want to know about the mounting systems they propose.



    Plus the detail and fitting of the support hooks under tiles, and cable routing through tiles etc..
    • CommentAuthorniallcook
    • CommentTimeAug 4th 2015
     
    That's helpful, thanks. Definitely the kind of detailed questions worth asking once we've decided on a preferred quote. Possibly less important when deciding between these three quotes though, right (all three are reputable local companies with plenty of installations under their belts, so I'm happy to make an assumption that they do things properly.
  26.  
    Posted .

    @bot de paille What would you be looking for/not looking for in their mounting system?


    A complete and integrated mounting kit supplied by a reputable company like Schuco or similar.
    • CommentAuthorniallcook
    • CommentTimeAug 5th 2015 edited
     
    Quote 2 (£3,999) has confirmed that they use either a Schuco or Renusol mounting system. The tile is pushed up, rafters located, roof anchor screwed to rafter, tile pushed back down and bottom row of anchors grinded to fit flush if visible. Cable route is under a tile and tacked to the inside of a rafter to the fuse board.

    On top of that, they will handle our planning application (listed building) from start to finish at no extra cost.

    When I started my research a few months back, I never thought I would be able to get 4Kw for under £4k, but I'm thinking I should be biting this company's hand off right now!
    • CommentAuthorwoodgnome
    • CommentTimeAug 5th 2015
     
    What are the current FITs you will get once installed?
    I'm trying to decide if PV is still worth the money with the FITs reducing.
    • CommentAuthorniallcook
    • CommentTimeAug 5th 2015 edited
     
    Because we'll have to wait for planning permission, we're likely to get the Q4 FIT rate which for our property will be 12.47p/kWh. Assuming 3,844 kWh generated, that's a FIT payment of £479.35, an export payment of £93.22 and potential electricity savings of £230.64 (assuming 50% and 12p/kWh) = £803.21 per year, only £17 a year less than at the current FIT rate.

    Without factoring inflationary rises in payments, we're looking at payback on a £4k system towards the end of year 5, then another £12k or so in payments over years 6–20. As the house is occupied during the day and we have a GSHP, we're hoping we'll end up using some of the 50% deemed to be exported back to the grid.

    Hope my maths is right, but I'm sure someone will be along to correct it if not.
    •  
      CommentAuthorSteamyTea
    • CommentTimeAug 5th 2015
     
    Posted By: woodgnomeI'm trying to decide if PV is still worth the money with the FITs reducing.
    Quite easy to work out.
    If your 4 kWp system can deliver 3,500 kWh/year, costs £4,000 and last 10 years, then it is:

    4000 (£) / 10 (y) / 3,500 (kWh) = 0.114
    So 11.4p/kWh

    If it lasts 20 years
    4000 (£) / 20 (y) / 3,500 (kWh) = 0.0.0571
    So 5.7p/kWh

    30 years
    4000 (£) / 30 (y) / 3,500 (kWh) = 0.0381
    So 3.8p/kWh

    40 years
    4000 (£) / 40 (y) / 3,500 (kWh) = 0.0285
    So 2.9p/kWh

    Now if you invested that money at 3% over the same time periods, then you would earn:

    After 10 years
    5375 - 4000 = 1375
    £1,375

    After 20 years
    7224 - 4000 = 3224
    £3,224

    After 30 years
    9709 - 4000 = 5709
    £5,709

    After 40 years
    13048 - 4000 = 9048
    £9,048

    If imported electricity increases by 3% a year, and you have halved the average imports (so saving 1,900 kWh/year) and you currently pay 14p/kWh, then:

    After ten years you will have saved 190,000 kWh at 12p + 3% annual increase.
    £3,064

    20 years
    £4,117

    30 years
    £5,534

    40 years
    £7,437

    The big unknowns are interest rates, inflation and units saved.

    I can see why they are almost certainly going to drop the FiTs soon, there is just about price parity with imported energy.

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