Home Solar...?

Discussion in 'The Guru's Pub' started by BLEH!, Jun 15, 2022.

  1. BLEH!

    BLEH! Ancient Guru

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    Hi Gurus!

    Been thinking of investing in a small (initially), but modular home-solar-storage system to offset some of our power use given the current (alarmingly high) costs of electricity. Home (UK) is 1930s build but fairly well insulated and had new windows fitted about 6 months ago; the challenge is we have no south-facing roof (basically east-west facing, the east-facing has trees at the end of the garden), but we do have a two-story south-facing wall. We're covered by a garden on 3 sides (end of a road) so there's the potential for mounting things at ground level if needs be. I've got a couple of old 12 V leisure batteries (~ 110 Ah each) that could be used for storage, I keep these maintenance charged just in case. So I'm thinking we can at least offset our base power usage with ~500 W of solar panels, with the option to expand later. It's also quite windy where we are, so I could throw in a wind turbine as a booster...

    Have any of you guys done home solar/storage? Any tips you can throw my way? I know Hilbert did an article on this waaaaaaaaay back, makes me wonder how that's holding up!

    Cheers

    BLEH!
     
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  2. D1stRU3T0R

    D1stRU3T0R Master Guru

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    I'm really interested in this too. Is there any UE fund (sorry my UK guy :p) to help with this?
     
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  3. BLEH!

    BLEH! Ancient Guru

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    Err I think there used to be funding for it here, but nowadays it's more the case of "if you want it, pay for it yourself). The feed-in tarrif (price you get for selling back to the grid) is also crap compared to what it used to be (we're on about 20 p/kWh these days, the reverse price is about 3 p IIRC), AND there's a standing charge of ~ £1.day just to be connected to the grid...
     
  4. mbk1969

    mbk1969 Ancient Guru

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  5. Tat3

    Tat3 Ancient Guru

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    I have 22 solar panels on the roof. No batteries for storage. I have tried to calculate how much it would cost and what the benefits are for storage, just not worth it atm. Excess power is sold to the power grid.

    My house is kinda "T" shape, panels are to south-east and south-west. Some trees at south which I'll take care of next winter. Power production was around 5000kwh last year. Panels were covered in snow the whole winter so nothing from that. This is in Finland. Panels were ordered by the previous owner and I have been happy with those.

    Call your solar panel seller and ask for estimate how much those would produce in your case and how long it would take for that investment to pay itself back. There might be calculators on the company website where you tell the location and so.
     
  6. Truder

    Truder Ancient Guru

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    vivaldi_pukKKfUjBA.png
    Lel
     
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  7. BLEH!

    BLEH! Ancient Guru

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  8. Mufflore

    Mufflore Ancient Guru

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    Careful if you place panels away from the house, thieves/vandals may like that!
     
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  9. BLEH!

    BLEH! Ancient Guru

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    All of our land is fenced off, thankfully, so that should be less of an issue.
     
  10. allesclar

    allesclar Ancient Guru

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    Where to start?

    We have a 1930s house like you but are more fortnuate to have a good level of sunshine throughout the year and our roof has the right facing sun all of the day (part from night ;))

    My first Q, as i am in a simliar predicament as yourself is why do you want them?

    We have 12 x 330W panels so therefore roughly a 4kW solar panel system. Feeds straight onto our Consumer unit via a AC inverter, no direct feed in tariff or connection to a battery storage solution. Throughout the year, even cold winter days, during negligable electrical load, we see little to no draw from the grid and our panels do most of the work.

    We have gas only for heating and this is where you notice the solar panels struggle.

    Our thoughts is to go alone with a further 12 panel x 330W panels to increase our generation, but also we want to look at some form of energy storage.

    This storage mainly is to remove the load draw we take off the grid overnight.

    We are looking currently at two options, either a GroWatt or Tesla Powerwall solution. Both are more than capable but have their advantages / disadvantages etc.
    We will be getting an EV charger and will be connecting it directly to GRID but also with the option for the solar panels (maybe even battery storage depending on size) to trickle charge during the day.

    Our loads (Electrical) are typically;

    Low - 300W (night time)
    Med - 800W (During the day/evening, with no solar support and/or general house usage)
    High - 4kW (Cooking etc, will go as high as 10kW but very rare, taken the 4kW as average).

    We want to save money and not rely on the GRID for good prices.

    Rough calculations for discussion but generally speaking;
    • Taking currently 20p per KWH is a good rate at the moment (This is only going to go up and the days of 14p per KWH are gone for now (if not good)
    • A Tesla Powerwall can store roughly 13.5kWH, say 12kWH usable, you can even daisy chain them etc to your needs.
    • A Tesla Powerwall installed and supplied say is £12k all in;
    Uses a full cycle of Powerwall charge per day at 12kWH, will save you £2.40 in electricity per day when charge by solar. A 4kW solar array should have no problem in fully charging a power wall on a good sunny day. More panels, the quicker it will charge, in a nutshell.

    It would take approximately 14 years to get payback on the Tesla power wall. £12k / £2.40 (per day) = 5000 days or 13.7 years.
    This doesnt take into account the cost of panels (we have them so I have excluded this) but it also doesnt include the fact you can get more than 12kWH of energy out of the solar panels in a day, and or use it via a battery storage system. For example if we are doing alot of heavy usage, cooking for example, we could use almost all of it in a couple of hours. Be fully charged by the end of the day, to be used again over night etc. So in theory here we could save two losts of £2.40.

    For me, if we can get a good system £6k ish, which can support our house over night and a little during the day, that will be perfect, and this for us is where the GroWatt system has the advantage over Tesla Powerwall.

    But as with all things electrical, you will have efficiencies and deficiences everywhere, sun levels, energy usage, battery degradation etc.....

    Will be watching this thread with interest, apologies for the messy all over the place post but thought i would share some thoughts.....
     

  11. Loobyluggs

    Loobyluggs Ancient Guru

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    The thing that stands out is that it increases the resellability of your property.

    If a property comes with free energy, that makes it sell faster - but will not necessarily increase the value for an identical property next door, for example.

    Buyers are fickle, but free energy is free energy.

    Thought about hydrogen? You could use any unused solar power to create hydrogen through electrolysis of collected rainwater. It could be used for heating and cooking, like natural gas is, and of course hot water.
     

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