Solar PV Advice Please

edited 30 November -1 at 1:00AM in Green & Ethical MoneySaving
21 replies 4K views
Chris_WisemanChris_Wiseman Forumite
27 Posts
edited 30 November -1 at 1:00AM in Green & Ethical MoneySaving
Hi all
Looking for a bit of solar advice. I’ve been investigating systems for a while but only got into our own house nine months ago and aware of the diminishing FIT incentives.

I own a large 3 bedroom house, relatively new build so good efficiency. I own a Nissan Leaf and home charge most days between 5-15kwh.

I’ve spoken to a few providers and have options from a local installer.
We have a main roof facing SE and a secondary garage roof facing SWW. We can fit 15 panels on the main roof and 6 on the garage roof.

I have approx. prices for systems as follows:
Just house - 4.5kw @ £5.4k (JA Solar) or 5.1kW @ £6.3k (LG 340)
Including garage – 5.46kw @ £5.5k (Perlight), 6.3kw @ £6.2k (JA Solar) or 7.14kW @ £7.6k (LG 340)

Wondering what is likely to work for us in terms of ROI. I have an expectation we will get a second EV within the next three years and I am also looking to add battery storage in the near to medium future when reasonable capacities become viable.

Any initial advice would be greatly appreciated.

Thanks

Chris
6.3kW system in Loughborough. 15 JASolar 300w panels on main roof SSE (no shading) with 4.2kW Growatt Inverter. 6 JASolar 300w panels on garage roof WSW (some winter shading) with a 1.65kW Growatt Inverter. Running a Nissan Leaf 24kW and considering battery storage :)
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Replies

  • Martyn1981Martyn1981 Forumite
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    Hiya and welcome.

    First off, I think all those prices look good, so you're straight off to a nice start, not one of the folk coming on who've been quoted £12k for 4kWp .... or so.

    Also, in my head, my fantasy PV system would be SE and SW, giving the best combination of good annual gen, good daily gen (throughout) and a good winter gen, so I'd certainly keep those WSW panels in the plan, especially as late afternoon demand is hard to avoid, such as cooking tea etc.

    I think with a big system, and EV's, a big battery (10kWh+) is a great idea, but they are so expensive at the moment, quite frustrating.

    Are you aware about DNO (distribution network operator) rules limiting output from the inverter(s) to 3.68kW without prior permission? As you are considering big systems, and they will overlap a lot with their generation profiles, you will really want to get permission for something in the 4-6kW region, depending on which package you finally go for.

    So, initial advice/thoughts, you are on the right path, and look good.
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
  • Thanks for that Martyn, I'll have a chat with the installer re: DNO rules, but my initial thinking is to try and go as big as possible whilst keeping it economical.

    Do you have any thoughts on the panels? The option with garage and JA Solar 300w panels seems to be the best option based on cost per KW and the potential to get ROI. The LG option taking it above 7kw would be nice but looks to me to be too much of a premium?

    Thanks
    Chris
    6.3kW system in Loughborough. 15 JASolar 300w panels on main roof SSE (no shading) with 4.2kW Growatt Inverter. 6 JASolar 300w panels on garage roof WSW (some winter shading) with a 1.65kW Growatt Inverter. Running a Nissan Leaf 24kW and considering battery storage :)
  • Martyn1981Martyn1981 Forumite
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    I think I'm with you on the economics, that the extra kWp is costing a bit too much. But, and this gets tricky to explain, but if you need, or can make use of that extra capacity and the generation it will provide, then you need to remember that revising it later won't be possible, or will cost a hell of a lot more.

    But (again) with the small(!) system coming in at 6.3kWp and probably around 6,000kWh's pa, I'm not sure it matters so much whether you go super size. It would be far more important if you were considering 3kWp or 4kWp, not 6.3kWp or 7.14kWp ..... IYSWIM.

    I think you are safe with all those options, but I'd massively favour the twin aspect solutions for that late afternoon generation, I added some a year later, which proportionately was much more expensive.
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
  • ZarchZarch Forumite
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    Any shading to consider? Are these quotes for a Solar Edge based solution with power optimisers? Or are they putting the different aspects on separate strings?
    17 x 300W panels (5.1kWh) on a 3.68kWh SolarEdge system in Sunny Sheffield.
    4.8kWh Pylontech battery storage system with Lux AC controller
    Creator of the Energy Stats UK website and @energystatsuk Twitter Feed
  • HeedtheadviceHeedtheadvice Forumite
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    Just a small addition....


    Given that you wish to charge cars then (unless it is in periods of low generation) you benefit a lot from having a system that generates much of that charge rather than buying off the grid i.e. at time you will charge your cars for free.


    I understand the economic statement about the larger power installation but it might be worth considering those economics in light of what you would pay to charge your cars as well as home use and generation FIT and including that in your rate of return calculation.
  • butakobutako Forumite
    8 Posts
    MoneySaving Newbie
    Hello,
    Those are good prices, may I ask which company quoted them please? And where abouts in the country approximately? Thanks
  • Zarch wrote: »
    Any shading to consider? Are these quotes for a Solar Edge based solution with power optimisers? Or are they putting the different aspects on separate strings?

    No shading to consider - the SE facing roof is shade free until mid/late afternoon, the WSW facing roof remains shade free.

    The quote is not based on Solar Edge, though I'm not sure it would add much based on this setup - thoughts?

    The different aspects are remote from each other so they will be on seperate inverters. The garage is around 30m externally detached from house on a shared courtyard.

    Thanks
    6.3kW system in Loughborough. 15 JASolar 300w panels on main roof SSE (no shading) with 4.2kW Growatt Inverter. 6 JASolar 300w panels on garage roof WSW (some winter shading) with a 1.65kW Growatt Inverter. Running a Nissan Leaf 24kW and considering battery storage :)
  • butako wrote: »
    Hello,
    Those are good prices, may I ask which company quoted them please? And where abouts in the country approximately? Thanks

    Bespoke Renewable Solutions - I'm based in Leicestershire
    6.3kW system in Loughborough. 15 JASolar 300w panels on main roof SSE (no shading) with 4.2kW Growatt Inverter. 6 JASolar 300w panels on garage roof WSW (some winter shading) with a 1.65kW Growatt Inverter. Running a Nissan Leaf 24kW and considering battery storage :)
  • Just a small addition....


    Given that you wish to charge cars then (unless it is in periods of low generation) you benefit a lot from having a system that generates much of that charge rather than buying off the grid i.e. at time you will charge your cars for free.


    I understand the economic statement about the larger power installation but it might be worth considering those economics in light of what you would pay to charge your cars as well as home use and generation FIT and including that in your rate of return calculation.

    Thanks for this. At the moment, we'll benefit mostly at weekends and a contribution late afternoon with the EV, due to working hours. When we move to being a two EV household, this will change in favour of more charging taking place earlier in the day.

    For this reason I've been focusing on worst case for returns - FIT income. Then factoring in current use without future electricity price increases. Any usage saved above this, increases in energy prices saved and potential savings from battery storage slightly further down the line are all bonuses in my view.

    In the short-term, have people seen good returns from solar diverters?

    Thanks
    Chris
    6.3kW system in Loughborough. 15 JASolar 300w panels on main roof SSE (no shading) with 4.2kW Growatt Inverter. 6 JASolar 300w panels on garage roof WSW (some winter shading) with a 1.65kW Growatt Inverter. Running a Nissan Leaf 24kW and considering battery storage :)
  • CoastalwatchCoastalwatch Forumite
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    Thanks for this. At the moment, we'll benefit mostly at weekends and a contribution late afternoon with the EV, due to working hours. When we move to being a two EV household, this will change in favour of more charging taking place earlier in the day.

    For this reason I've been focusing on worst case for returns - FIT income. Then factoring in current use without future electricity price increases. Any usage saved above this, increases in energy prices saved and potential savings from battery storage slightly further down the line are all bonuses in my view.

    In the short-term, have people seen good returns from solar diverters?

    Thanks
    Chris
    Hi Chris, I've followed your thread with interest but, being a newby to Solar panel installation haven't been able to offer any sound advice above that already posted.

    I'm not sure what you mean by "Solar diverters" but if it is the system in general then we seem to have a lot in common!

    Like you when trying to work out an ROI, I ignored any future potentional price increases focusing solely on what is known today. With thanks to the advice received on here we had installed the largest array our property would take which worked out to be 8.85 kWp and haven't regretted for one minute doing so. As for ROI, the forecast was 14.3 years when giving the go ahead in April.

    We purchased a Nissan Leaf in July and had a Zappi installed to charge it from. As you say getting "free" lecky for this and adding battery storage at a later date for further savings are all bonuses. We've not regretted for one minute taking the plunge as, for us it was the only sensible way forward into the future. Without fit and export payments we couldn't have made a case for it, similarly if you have to borrow in order to allow it to happen then you will possibly have additional calculations to make! Putting it into perspective, if you invested £6 or £7k pounds in a bank or building society today you'd be lucky to see it doubled(ROI) in thirty years!
    By coincidence our system just passed the 6 MWh's since installation. As we all know it's been something of an amazing summer and not typical of what to expect in future but the fit & export payments will total something very close to 4% of our initial investment.
    East coast, lat 51.97. 8.26kw SSE, 23° pitch + 0.59kw WSW vertical. Nissan Leaf plus Zappi charger and 2 x ASHP's. Still waiting for V2H and home storage to become available at sensible cost.
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