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Solar Power - Garden Office/Workshop

Discussion in 'off topic' started by jagdesign, Dec 1, 2021.

  1. molee

    molee pfm Member

    I would be very skeptical about the more optimistic posts above and echo those that are pointing out the difficulties. First thing any electrician will ask when surveying a new build garden building is 'How do you intend to heat it' even a poxy little fan heater draws significant amps/watts not sure which. My partner is an architect specializing in sustainable development and just happens to be having pvs installed on her house, garden office this week. If you are near Oxford you are welcome to come have a look, she will talk you senseless about the whole thing. One thing to point out- she has a ruled out battery storage after a lecture we both attended at Oxford University by industry and academic leaders in the field who trashed the idea of batteries in a domestic setting.
    Richard Lines and Tony Lockhart like this.
  2. gingermrkettle

    gingermrkettle Deep vein trombonist

    Given our experience with a Powerwall and solar panels, there would appear to be some variance between their theory and our practice.
  3. molee

    molee pfm Member

    I suppose it would depend on the basis on which they were trashing the idea as opposed to the basis on which you appear to be supporting them. They were looking at the issue from a strategic national electricity generation/ storage perspective taking into account the needs of millions of people, materials supply in the longer term and environmental impact amongst other things. From what perspective are you assessing the issue of battery storage? May I be so bold to suspect it may be an individualist one. Apologies if I have misjudged the thrust of your statement.
  4. gingermrkettle

    gingermrkettle Deep vein trombonist

    From a demand/eco point of view, we have virtually eliminated all demand at peak times and, with the exception of what goes into our car, effectively run off grid for about half a year. In the winter we effectively timeshift our demand from high CO2 generation to low overnight generation (check something like the Western Power Carbontracer app for more on that).
  5. molee

    molee pfm Member

    Bully for you. Scale that up to 70 odd million people and see if it still works.
    Durmbo likes this.
  6. cubastreet

    cubastreet Espresso Fiend

    Great idea, you could run the whole island off solar and wind.
    gingermrkettle likes this.
  7. sam_cat

    sam_cat C'est Crounchifique!

    Insulate, Insulate, Insulate... That and air tightness. Makes keeping your garden office/workshop cool/warm easier.
    Go grid tied, but also cover it in solar panels.. This way your making use of the 'free' energy and are offsetting some when your using more than you are generating.

    If you are a competent person you can self install the solar, wire it all up, get a sparky to test and sign off the circuit (get them around before you start for a conversation, solar needs to be a dedicated circuit/have its own breaker.. You could run a small consumer unit in home office so you have circuits out there for solar, lights, sockets and anything else that needs separating such as fridge/freezer etc). G98 form to DNO to inform them of a solar install (if its the first solar at this address, otherwise it gets more complex). Or pay a firm to cover the roof of the house AND the workshop/office in solar.
    martin clark and jagdesign like this.
  8. sam_cat

    sam_cat C'est Crounchifique!

    If self installing you can get panels from Bimble solar, or ebay/facebook marketplace etc... 250-300W normal sized panels can be had for £80-90 each.
    DONT get cracked/crazed ones that are super cheap, not worth the hassle (they WILL fail eventually)

    We use Growatt inverters, work really well and nice web interface to monitor/check from.
    martin clark and Mark Grant like this.
  9. molee

    molee pfm Member

    In a word, this. Bravo
    martin clark and sam_cat like this.
  10. sam_cat

    sam_cat C'est Crounchifique!

    You can get higher density solar panels, but they cost more (per watt), but IMO higher density gets my vote IF you have limited roof...

    On MOST days and for MOST of the day you wont produce the panel MAX (eg 250w), so if you need 500w for most of the day you dont want just 500w of panels..

    EG my 2kw SW facing system at shallow angle (15 degree) mounted on our verandha...

    Does this - mid august (day picked at random):

    And a day earlier

    And yesterday:

    Its shaded (by the house) until about 11am, hence the sudden jump.

    You can use the calculator at PVWatts ( to get a very good idea of average/expected generation by date/date etc... This will give you some idea of what your dealing with.

    We run 2kW of panels into a 1.65kW inverter, on the very best of days at peak it maxes out at 1650w but was quite a bit cheaper. DNO have limited us to 16a (3.68kW) of INVERTER capacity... But we are aiming to ultimately have around 5500W of panels..
    For most of the rest of the year we will be ahead of if we had installed 3.68kW of panels, All we lose is the very top on the very best of days.

    Dont just assume you can install more W of panels than the inverter label, check.. Some support more than others. Also be aware of working voltages and de-rating for temperature (and the reverse in cold weather)
    jagdesign likes this.
  11. Durmbo

    Durmbo not French

    To have sufficient scale I’m imagining Britain covered entirely in solar panels with wind turbines sprouted above & the population living beneath. :confused:
  12. sam_cat

    sam_cat C'est Crounchifique!

    Its surprising how little coverage is needed.

    This snip has no context without the above, but gives some idea
    Please bear in mind that onshore wind the ground under can still be utilised for crops, solar etc, solar farms can be used for rough grazing etc

    Solar at 2.1% isnt overly hard, as currently 1.4% of the total land surface is covered in buildings anyway... So retrofit where you can, make it a orequirement on new builds and then put it on landfill sites/areas hard to use for other purposes etc.

    This needs to be in tandem with a big push to reduce usage where we can, insulate and upgrade our stock of property (to reduce consumption), retrofit solar. New builds should be required to be near passivhaus with solar etc included (not the water down building regs that are currently applied, thats for sure!). Where buildings are not suitable for retrofitting/upgrading we have some harder questions.. Do we knock down and replace? Or just accept that some % of the housing stock is always going to be sub standard? or something else?

    Oh for a government with some ambition on these fronts!
  13. Tony Lockhart

    Tony Lockhart Avoiding Stress, at Every Opportunity

    So, no new builds allowed on the northern slopes of hills in Scotland?
  14. sam_cat

    sam_cat C'est Crounchifique!

    Ohh, the devil is in the details... :p
    Solar on rooftops where it would be beneficial... Some such thing.
    No point in putting solar of roofs that are heavily shaded, or north facing etc.
  15. molee

    molee pfm Member

    I must say I am skeptical about a strategic energy supply approach that is dependent, to a degree, on increasingly geriatric homeowners periodically scaling two stories on to rooves to clean bird doo doo etc off panels.
  16. Tony Lockhart

    Tony Lockhart Avoiding Stress, at Every Opportunity

    The rain keeps ours clean, just dusty at harvest time really.
  17. MikeMA

    MikeMA pfm Member

    I've only skimmed this thread but it''s pretty obvious even to me and from the comments made by others that what the OP really needs is not a collection of wussie solar panels but a small self-contained nuclear reactor, with a diesel stand by generator in case of core meltdown.
    Sue Pertwee-Tyr and Durmbo like this.
  18. gintonic

    gintonic 50 shades of grey pussy cats

    before long I am sure Karcher or some such will produce a gizmo on a pole
  19. Tony Lockhart

    Tony Lockhart Avoiding Stress, at Every Opportunity

    Most Poles have left the U.K.
  20. Richard Lines

    Richard Lines pfm Member

    I've been doing RE since 2008 and keep very much abreast of these things which is not to say I'm an expert....................

    The very simple answer here is ensure the new build is built to near passivehaus standard in the first place as this will be money much better spent than investing in sufficient Solar PV + battery storage etc. etc. to cover your needs.

    If you insulate it well enough there are some quite cheap A2A wall mounted "heat pumps" which will be provide more than sufficient heat.

    In very simple terms Solar PV will only return 10% of your expected output on average through December/ January.

    Battery storage - in most cases this doesn't make outright sense on a domestic scale. Believe me I have a Tesla PW2 and 12kW of Solar PV. In your first year a battery system will be 90% efficient at best and it will deteriorate at 3% a year to which you then add the 1% annual deterioration in your Solar PV panels. You'll need to ensure you are on the best TOU tariff you can find as most of the battery charging during the winter season will be by cheap overnight electricity. The gap between cheap and day rate on such as Economy 7 is going to reduce as more domestic heating goes over to electric and there is a greater number of EV's in the population which mitigates still further against any "logic" in installing a battery storage system (even, IMHO, allowing for any reasonable forecastable increase in electricity prices).

    Get a trench dug across from the house and lay a suitable SWA cable.

    If you want do something green then look to installing Solar PV on the house/ garage roof and install a more environmentally friendly heating system.


    Tony Lockhart, jagdesign and sam_cat like this.

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