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solar PV system

  • 08-08-2019 11:43pm
    #1
    Registered Users Posts: 210 ✭✭ pjwhite99


    a solar PV system do you really save 70% on your electricity bill ?

    Anyone get one did they save much?


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Comments

  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,874 CMod ✭✭✭✭ unkel


    No you won't save anywhere near 70% on your electricity bill. Unless you go for a battery storage system. But these are mostly very expensive.

    It's not all about money though. You can get a basic PV install that will give you much better returns than money in a savings account. And you will be doing the world a favour. It's not all about money. We need to tackle climate change, if we aren't already too late.

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Registered Users Posts: 210 ✭✭ pjwhite99


    unkel wrote: »
    No you won't save anywhere near 70% on your electricity bill. Unless you go for a battery storage system. But these are mostly very expensive.

    It's not all about money though. You can get a basic PV install that will give you much better returns than money in a savings account. And you will be doing the world a favour. It's not all about money. We need to tackle climate change, if we aren't already too late.

    Hot water is a big factor dose the pv give you hot water al year round?


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,874 CMod ✭✭✭✭ unkel


    No. You can install an immersion diverter that will send all the electricity that you aren't using to heat the water. This will be a big help in summer, on many days heat your water if you have a large PV setup. But it won't do much in winter unless you have a very sunny day.

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Registered Users Posts: 210 ✭✭ pjwhite99


    unkel wrote: »
    No. You can install an immersion diverter that will send all the electricity that you aren't using to heat the water. This will be a big help in summer, on many days heat your water if you have a large PV setup. But it won't do much in winter unless you have a very sunny day.

    Ok thanks is it worth the money to get in?

    It’s taking around 7500 for my home that’s with the grant and battery’s

    Don’t know if it’s a good idea or bad

    This is the cheapest I can find

    https://nextgenpower.ie/homes/


  • Moderators, Society & Culture Moderators Posts: 31,294 Mod ✭✭✭✭ Gumbo


    pjwhite99 wrote: »
    Ok thanks is it worth the money to get in?

    It’s taking around 7500 for my home that’s with the grant and battery’s

    Don’t know if it’s a good idea or bad

    This is the cheapest I can find

    https://nextgenpower.ie/homes/

    They done mine.
    I’ve a 3kw system with no battery over 2 years now. I want a battery but saving up and awaiting for a better set up to work with existing infrastructure.

    It wasn’t about pay back periods etc, I had my roof stripped and scaffolding in place for an attic conversion so it made sense to get it done.


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  • Registered Users Posts: 210 ✭✭ pjwhite99


    kceire wrote: »
    They done mine.
    I’ve a 3kw system with no battery over 2 years now. I want a battery but saving up and awaiting for a better set up to work with existing infrastructure.

    It wasn’t about pay back periods etc, I had my roof stripped and scaffolding in place for an attic conversion so it made sense to get it done.

    Did you see your electricity bill come down any?


  • Closed Accounts Posts: 3,364 ✭✭✭ rolion


    Is this that kind of "green and free sponsored electricity promo" joke !?


  • Registered Users Posts: 5,412 ✭✭✭ Charlie-Bravo


    I myself have a bit of a dilemma and need some guidance of what other people think without being pushed by the sales agents for a PV panel company.

    I have 4 thermal panels taking up the best area on a West facing roof (slightly more South than North). I only have enough space left for 4PV panels giving me 1.2kW on that side. The other side which is east-facing I have much more space and could get in 6-8 panels giving me upward of 2.4kW, or even more if I went with bigger 400W panels.

    So the question is, should I take out the thermal panels and Max out my better West-facing plane, or stick to an East-West split? If I get an array with over 2kW I might as well get a hybrid battery setup to maximise the use, a separate question whether I'd get the use out of it.

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  • Registered Users Posts: 791 ✭✭✭ reklamos


    astrofluff wrote: »
    I myself have a bit of a dilemma and need some guidance of what other people think without being pushed by the sales agents for a PV panel company.

    I have 4 thermal panels taking up the best area on a West facing roof (slightly more South than North). I only have enough space left for 4PV panels giving me 1.2kW on that side. The other side which is east-facing I have much more space and could get in 6-8 panels giving me upward of 2.4kW, or even more if I went with bigger 400W panels.

    So the question is, should I take out the thermal panels and Max out my better West-facing plane, or stick to an East-West split? If I get an array with over 2kW I might as well get a hybrid battery setup to maximise the use, a separate question whether I'd get the use out of it.


    I have not seen any 400W panels on sale in Ireland but that might have changed in last couple months. You need to take into account that 400W panels will be big in size ~1x2m, so depending on your roof area you may not have space to fit many of them on your roof. I think one advantage of PV is that you can get electricity and hot water(with diverter) out of them. But then you probably looking at 4kW system with battery or drop the battery. You need to do some calculations on your average usage and usage patterns and size based on that.


  • Registered Users Posts: 210 ✭✭ pjwhite99


    Got a price any one know what battery is best here?

    5.6kwh GivEnergy

    Or

    3.5kwh BYD

    One system is 7600 after grant that’s 5.6 battery and 3.25 on the roof

    Other is 3.5 battery and 4kw on roof 7050

    What’s better?


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  • Registered Users Posts: 791 ✭✭✭ reklamos


    pjwhite99 wrote: »
    Got a price any one know what battery is best here?

    5.6kwh GivEnergy

    Or

    3.5kwh BYD

    One system is 7600 after grant that’s 5.6 battery and 3.25 on the roof

    Other is 3.5 battery and 4kw on roof 7050

    What’s better?
    The way I look at it, it is much easier to add battery to the system later,
    compared to adding new panels on the roof(unless you're roofer). Also ideally you'd want panels to be same as previous ones. I would get as much kW on the roof as possible.


  • Registered Users Posts: 210 ✭✭ pjwhite99


    reklamos wrote: »
    The way I look at it, it is much easier to add battery to the system later,
    compared to adding new panels on the roof(unless you're roofer). Also ideally you'd want panels to be same as previous ones. I would get as much kW on the roof as possible.

    Thanks for that is that 3.5 battery still an ok size?


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,874 CMod ✭✭✭✭ unkel


    3.5kWh is a very decent start. Have you the spec sheet of the battery?

    How useful it is depends on more than the capacity. The maximum charge and discharge rate is important too. The market leader is probably Pylontech and their 3.5kWh battery can charge / discharge at 37A

    I'm with reklamos here. Get as much PV on your roof as you can first and don't spend too much on the battery.

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Registered Users Posts: 210 ✭✭ pjwhite99


    People one more thing

    I’m now thinking is it worth getting in as my bill for 2 months is only 140 or so

    I have been chatting to a few and is it worth with such a low bill any way???

    Lot off money to pay out €7k


  • Moderators, Society & Culture Moderators Posts: 31,294 Mod ✭✭✭✭ Gumbo


    pjwhite99 wrote: »
    Did you see your electricity bill come down any?

    Yes. I’ve noticed that I am more in credit year on year. I pay the same amount by EFT every fortnight (payday) and my ESB bills are accessible online from throughout the years.

    Tbh, To notice a big drop in your bill you’d need a big array with a big enough battery to get you through the night.

    I’m noticing that my gas boiler is off for 6 months of the year now too as I have a divertor so I don’t need to boost the water for an hour or 90 mins a day.


  • Registered Users Posts: 210 ✭✭ pjwhite99


    Could I get some info on what use think?

    I can get a 4.2 system on the roof with a 4.5 Solax battery and 4kw solax pv inverter

    After grant for 6700

    But I have been told this is way to big for me as I only spend around 900/1000 a year on my bill

    Would you think the same?

    Some other companies say this is better for me.

    2.1 on the roof with no battery after grant around 4000

    Don’t know what to do? Some help would be great thanks


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,874 CMod ✭✭✭✭ unkel


    That's a good price for the big system. And no, it's not too big. Your electricity consumption will probably grow over time and we are likely to see a feed in tariff where you will be paid say 5c/kWh for any electricity you send to the grid. Your large system got €3,800 subsidy

    The pay back period for the large system with the battery will be shorter than that of the smaller system with no battery, and it only got €1,400 subsidy

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Registered Users Posts: 5,412 ✭✭✭ Charlie-Bravo


    That's interesting unkel about payback period with grant. I'm not in a position to get any grants so looking at maybe investing in a smaller system in East/west split with no battery, say 1.6kw on West with 2kw on east. Would love to know what a good average generation is for an e/w split over the year of that size.

    If deciding to go for a battery and hybrid inverter, yes maybe that would make sense of there's no FiT coming, but seeing as there is, when is the crossover point for having a battery v using FiT?!

    -. . ...- . .-. / --. --- -. -. .- / --. .. ...- . / -.-- --- ..- / ..- .--.



  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,874 CMod ✭✭✭✭ unkel


    astrofluff wrote: »
    East/west split with no battery, say 1.6kw on West with 2kw on east. Would love to know what a good average generation is for an e/w split over the year of that size.

    I'd guess around 2.7-2.9MWh per year in a good location (i.e. Dublin area)
    astrofluff wrote: »
    If deciding to go for a battery and hybrid inverter, yes maybe that would make sense of there's no FiT coming, but seeing as there is, when is the crossover point for having a battery v using FiT?!

    If you can't get the grant, don't even think about going for a battery. It will never pay for itself unless you get it more or less for free.

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Registered Users Posts: 1,835 ✭✭✭ garo


    I have a 4.8kW E/W system in Dublin. No issues with shade. These days I get 7kWh on a really bad day like last Wednesday and 20-22 on a good one which is way more than I need.
    On batteries, not having a grant certainly brings the economics into question but one benefit of even a small battery is that it covers you when a cloud passes over the sun. I am currently guesstimating a cost of 10c per kWh to get power into the battery and out which is lower than the day rate.
    Note that for a system without a battery you can get away with a simpler (and much cheaper) inverter.


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  • Registered Users Posts: 5,412 ✭✭✭ Charlie-Bravo


    garo wrote: »
    .... I am currently guesstimating a cost of 10c per kWh to get power into the battery and out which is lower than the day rate.

    Good to know this for running an approx calculation for RoI. FiT would definitely help in an over sized system. I've a few decisions to make and hopefully get this done soon.

    -. . ...- . .-. / --. --- -. -. .- / --. .. ...- . / -.-- --- ..- / ..- .--.



  • Registered Users Posts: 783 ✭✭✭ niallers1


    I have an E/W array. 1.8kw East and 2.4kw West .
    I just hit 3MWh today . I have them installed exactly 11 months and 1 week today.
    I should make 3.3MWh for the year.

    My estimated projection was just under 3.2MWh for the year so the projection was fairly accurate.


  • Registered Users Posts: 1,835 ✭✭✭ garo


    Obviously the number varies based on battery size and make and you need to include hybrid inverter costs over a normal inverter. And while batteries state they are good for 6,000 cycles the number could be higher or lower. But I think 6c on the lower end and 10c on the higher end is a good bound. It does mean that using a battery to charge at night rate does not make sense.

    My calculation was based on 1600€ for a 3.5kWh Pylontech installed. 80% DoD and 8k cycles and an additional 650€ for a hybrid inverter.


  • Registered Users Posts: 783 ✭✭✭ niallers1


    garo wrote: »
    My calculation was based on 1600€ for a 3.5kWh Pylontech installed. 80% DoD and 8k cycles and an additional 650€ for a hybrid inverter.

    I think those pylontech have a 90% DOD on them.


  • Registered Users Posts: 64 ✭✭ howman


    what kind of work is involved in retrofitting them to an existing house?

    Have a south facing site in countryside, space on roof or a sloping bank that would be ideal fro them, house was built in 2016 (with geo heat pump)

    I look at the sloping bank area as prime opportunity for PV but the thought of facing into construction work on house is majorly off putting


  • Registered Users Posts: 1,835 ✭✭✭ garo


    How man it is a relatively non-invasive procedure. Should take a day or less. The installers have to lift a few tiles to screw retaining brackets into your rafters and then put the tiles back on. They then put rails on the brackets and the panels on the rails.
    The other bit is to figure out where the wires go as you need to wire the panels to the inverter and the inverter to the fusebox.
    In any case do not let the construction work out you off. It should take 1-2 days max for a good installer.


  • Closed Accounts Posts: 3,364 ✭✭✭ rolion


    Again,is pointless to have a big huge PV generation figures if you cannot exploit and harvest the most and best of it.
    With a house normal consumption,an EV charging at night time and PV harvesting the photons,there were days when i consumed almost zero...

    489175.jpg

    489176.jpg

    489177.jpg


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,874 CMod ✭✭✭✭ unkel


    In a few years time, we might have a FIT, we might be able to use our EV as a home battery storage (provided the car regularly is at home during productive solar hours) and batteries are likely to become cheaper.

    If you are going to do a PV install without the subsidy, I would go as big as you can / what would fit on your roof. And not have a battery for now.

    You also don't have to replace your normal inverter with a very expensive hybrid one, you could have an independent battery on the AC side (that's how a Tesla Powerwall operates and that's what I am in the process of installing myself, a separate grid connected battery inverter plus a big batttery attached to it)

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Registered Users Posts: 360 ✭✭ TheWonderLlama


    On a slightly related note, I am thinking about pressing the button an a solar pv system, but I have nagging doubts.

    Is it possible to have a remote array and get credit onto your meter? It can be done for business, there is a transmission charge, i believe, but I have not heard of it being done for domestic.

    The idea would be that I erect a ground-mounted array away from the house with its own connection. it produces x kw over time.
    In the house, I use Ykw over same time. electricity provider allows me to offset x against y.

    Would work brilliantly for people in flats who use a lot of electricity.


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  • Registered Users Posts: 791 ✭✭✭ reklamos


    On a slightly related note, I am thinking about pressing the button an a solar pv system, but I have nagging doubts.

    Is it possible to have a remote array and get credit onto your meter? It can be done for business, there is a transmission charge, i believe, but I have not heard of it being done for domestic.

    The idea would be that I erect a ground-mounted array away from the house with its own connection. it produces x kw over time.
    In the house, I use Ykw over same time. electricity provider allows me to offset x against y.

    Would work brilliantly for people in flats who use a lot of electricity.
    Well this is how it work in many EU countries :)
    We're still waiting for FIT in here...


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