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Please check my parents Solar plans

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I'm hoping the MSE hive mind can do it's thing and check my parents solar plans. I confess to not knowing much about the market or technology. But a quick google of their proposed new supplier Social Energy linked them to an installer with a poor record of over promising and under delivering and over charging - Project Solar ... so thought I'd just check. 


5.76 kWp system
2 x 5.8 KW batteries
Total Cost including Installation & VAT = £11,500

My parents estimated usage now is 3200 kWh / annum, likely to increase to close to 4500 in the next 2 years.

Supplier costs
Peak Rate - 14.97
Standing Charge - 21.6

Lines that gave me pause:
- Your guaranteed minimum solar energy output in units of energy will be 3,952.80 KW’s in the first year and your warranty is 90% of this by year 25
- This gives you up to £620.79 in electricity bill savings if you were to use all the energy but we have projected you are only using around £40 per month at the standard day rate of 15p per unit and more from the smart battery totalling £528.05 smart battery return. 

Comparative quotes from other installers were about £2,500 less ... but as far as my dad explains it he's paying that to be able to join social energy and make it back between £500-600 per annum.



  • l.tobiasiewiczl.tobiasiewicz Forumite
    5 posts
    Ninth Anniversary Name Dropper First Post Combo Breaker
    Can't edit and forgot to say that I've got anonymised copies of the proposals with full details I can share but MSE doesn't let me post links. So let me know what info is missing / that you need.
  • Martyn1981Martyn1981 Forumite
    11.6K posts
    Part of the Furniture 10,000 Posts Name Dropper Photogenic
    You lost me at Project Solar.
    Try this thread for an introduction to why that's the one company not even worth considering/discussing.

    Project Solar Quote Advice

    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.
  • DolorDolor Forumite
    515 posts
    500 Posts Name Dropper
    My wife and I are seniors and we installed PV solar and a battery 5 months ago. I chose a local installer with an excellent reputation as, given my age, I wanted to know that my wife would know where to go if there was an issue with the array/battery.  I am with Octopus Energy and when my battery needs a charge it does so at 5p/kWh overnight. My SEG export payment is 5.5p/kWh.  

    I am not sure why your parents think that they need to pay £2000 more to join a particular energy company? I should add that to get SEG most suppliers will insist on a MCS Certificate; DNO sign off of the final installation and they will want to fit a smart meter to record import and export. The supplier will apply to the DNO for an export MPAN for the meter. Octopus has an excellent smart meter team.

    Finally, does the proposed annual export figure include any export limitation set by the DNO? I have a 7kWp array which has a 5kW export limit. In truth, this limitation has little effect as my panels are arranged in two arrays which pick up the sun for longer than a single array on one roof. I also have SolarEdge to offset shading.

  • EctophileEctophile Forumite
    5.1K posts
    Ninth Anniversary 1,000 Posts Name Dropper
    Some quick calculations:
    £11500 / £528.05 = 21 years
    So if they actually save £528.05 per year, then they will have reached the break-even point after 21 years.  That's assuming all the kit keeps working that long.  Check how long the battery warranty is - it might be only 10 years.
    There are far better ways of investing that amount of money.

    If it sticks, force it.
    If it breaks, well it wasn't working right anyway.
  • ABrassABrass Forumite
    452 posts
    Part of the Furniture 100 Posts Name Dropper
    Not good.
    The total kWh they're predicting is very low for a 5.8kW system. On the other hand it's not far off a 4.2kW system, which is what the inverter will cap them at. Are they very far north or are they pointing in an odd direction?

    The total return quoted is probably much higher than they're ever going to see. During the summer months they'll produce more power than they can use or store so they'll be exporting lots and during the winter it won't be enough to meet use.

    Ectophiles has shown even using supplied numbers there's a 21 year return, I'd be amazed if it was less than 25.

    It's a bad deal. Even at 2,500 less it's a pretty bad value for money install.
  • DolorDolor Forumite
    515 posts
    500 Posts Name Dropper
    In fairness to the OP’s parents, getting a RoI may not be the sole decision driver. My array and battery has an on paper RoI of 20 years based on a fixed tariff price; however, I know that I can purchase energy for less by using a time-of-use tariff such as Agile or Go. Part of our decision-making process was that it was ‘the right thing to do’ and like a new kitchen it might add resale value to our property should we need to sell. Part of my thinking to get solar/battery was based on my experience of selling a home with Evohome smart heating. It cost me £1800; saved me very little and kept me young sorting out various component and comms issues. My chosen Estate Agent set what I thought was a sale price on the high side. The first potential purchasers were so impressed by Evohome that they offered the full asking price as they walked out of the front door.

    All that said, it is great to generate 20kWhs on a sunny February day.
  • l.tobiasiewiczl.tobiasiewicz Forumite
    5 posts
    Ninth Anniversary Name Dropper First Post Combo Breaker
    Thanks for the replies so far:
    @Martyn - not from Project Solar ... just seems to be following the same style but thanks for the link :smile:
    @Dolor - I also have no idea ... Is there something that makes social energy's trading system better than Octopus Agile or just regular selling back to the grid? I'll ask about the export limitation. MCS certification is there, also split across 2 roofs
    @Ectophile - The aim is not a financial investment, rather one because they also want to look at the right thing to do as it were. Battery warranty is 15 years.
    @ABrass - I just realised the kWh prediciton is for a previous 4.2kW proposal, I'll get the new one. What would a good value cost be for an equivalent install with 5.76 kWp panel generation on 16 360W panels + 11.6KW of battery?

  • l.tobiasiewiczl.tobiasiewicz Forumite
    5 posts
    Ninth Anniversary Name Dropper First Post Combo Breaker
    ok, a couple of updates:
    The kWh prediction is actually just over 5000kWh per year. The aim is to store and use this energy as much as possible before then selling back to the grid from the stored battery power.

    2 remaining questions:

    1. Is there anything special or unique about the model of selling the electricity back to the grid than say selling through Octopus?

    2. Can someone tell me or direct me to someone who could give me a comparable quote / cost for the same spec system? Happy to do the legwork but really just want to check that they're not getting ripped off.

  • l.tobiasiewiczl.tobiasiewicz Forumite
    5 posts
    Ninth Anniversary Name Dropper First Post Combo Breaker
    1. This seems to be the answer ... 

    1) Using off peak energy at peak times

    The cost of energy you use on a daily basis is greatly reduced.  This is because the Social Energy storage system stores energy at off peak times when it’s cheaper, providing you with cheaper, renewable energy to use throughout the day or night.  And that’s not all. Each time you flick a switch in your home, electricity travels from a power station through national and local cables, pylons and substations. Your Distribution Network Operator charges your current utility for this, who then passes the cost to you via your bill. But when you use off peak energy the charge is much lower and depending on where you live, could even be nil, adding up to further savings.

    2) We sell to the Grid, you gain the reward

    As well as having access to cheap electricity, you earn as well as save via Fast Frequency Response (FFR). What’s FFR? When energy levels spike across the UK and the National Grid needs to meet demand, Social Energy sells any excess energy contained within its network of Social Energy batteries back to the Grid. This earning power is then delivered back to you as savings via your energy bill.  Social Energy is the only home energy trading solution to be fully compliant with National Grid’s dynamic frequency response service.

    3) Social Energy sells to other utilities – you reap the benefit

    Social Energy acts as an energy wholesaler, buying energy when it’s cheap and selling it to other utilities when it’s more expensive. Any profit made is invested back to you via savings on your energy bill.

  • Exiled_TykeExiled_Tyke Forumite
    507 posts
    Fifth Anniversary 100 Posts Name Dropper
    Personally I'd go with Octopus. It essentially achieves the same thing and benefits society in a similar way just without the nice title of 'Social'.  But most importantly it gives so much more freedom and flexibility in terms of choice of installer and future choices of partners to work with. 
    Install 28th Nov 15, 3.3kW, (11x300LG), SolarEdge, SW. W Yorks.
    Install 2: Sept 19, 600W SSE
    Solax 6.3kW battery
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