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Solar PV - is it worth it?

  • 25-02-2018 6:35pm
    #1
    Registered Users Posts: 2 CuriousDonkey


    I’m looked into option of getting a Solar PV system for installation onto my house, and I’m trying to determine if it’s a wise spend. It would be great to get some feedback from anyone that has had a system installed.

    The house is in the north east, SW facing with nothing obstructing sunlight to the roof. The house being a 70’s era semi-D concrete house, currently heated by oil-fired central heating.

    I’ve been recommended a 4kw setup with inverter and diverter (for heating water). Average electric units used per-year are about 7k units.

    I’m on the fence on whether solar is a good move right now. I like the idea of reducing our carbon footprint, and reducing our energy costs, (with young kids as they get older our energy use will increase), hence thinking solar might balance out additional demand.

    I do like the idea of the Sunamp heat battery technology running along with PVs, but I’ve no idea how feasible that is.

    Would it be better to invest the money you’d spend (on PV) towards replacing the oil fired central heating with an ‘air-to-water’ heat pump (like the daiken Altherma high temperature system)? I’m know there’s talk of grants in the future.

    As I don’t know anyone with real-world figures of what sort of benefit they’ve derived from having a solar PV installed into an older house. For example, if you had a 4 kw PV system, what sort of equivalent in units (KWhr?) could it generate? Granted it’s very much a ‘how long is a piece of string’ question.
    Would it be expected that the diverter could sufficiently heat water whilst having wife and kids at home during summer months?

    The more I dig into the subject, it seems to be that many people would be ‘exporting’ their generated power back to the grid for free..given FiT isn’t available anymore. With so many new houses being built with PVs, there must be quite a lot of surplus supply about? Does Eirgrid / ESB networks limit the number of houses with PVs to prevent general supply issues?


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Comments

  • Registered Users Posts: 21,364 ✭✭✭✭ Mad_Lad


    Solar PV is uneconomical in Ireland at current electricity costs, I pay 17 C day and 7.4 cent per Kwh night. No way solar PV is worth it.

    If a FIT existed then I would consider it but that's not likely for years.

    The Greatest Issue I have with Solar PV is the fact you have to divert a substantial amount to heating water you don't need and that's a complete waste. This is where you need the grid but without a FIT it makes it non viable. The Grid becomes your unlimited storage battery, sell to the grid and buy back when needed, the perfect solution and it could work but our grid is overwhelmed with commercial wind farms.

    A storage battery is too expensive and brings other problems , you haven't a hope to charge it fully in Winter and in Summer it will be charged too often and you'll still have to divert excess electricity or give it to the grid for free.

    Only in countries where there isn't such a large difference in Summer and winter daylight hours and countries that get a predictable amount of sunshine can you predict more accurately the size of the array and battery.

    One of the greatest way to reduce your carbon footprint and the greatest saving you'll make is to change to electric car, since doing this I'll never go back. savings over Diesel and maintenance is significant + electrics are so good to drive and getting into a warm car before you set off this time of the year is particularly great, no more scraping ice or waiting 10 minutes or more for heat, no more fogged up windows until the heater blows warm air etc.

    Electric cars can use any renewable energy on the grid and at peak production can be 65% of our total mix on the grid, 65% is the limit of renewable energy the grid can take, the rest gets exported or turbines get switched off + the more cars charging at night means a lot more wind energy can be used as energy demand significantly drops.

    Petrol and diesel has to be extracted from the ground, shipped to refineries and refined into petrol and diesel which consumes a lot of energy itself then it's burned in an internal combustion engine at only about 25-30% efficiency.

    Of course petrol and diesel cars emit far worse emissions than carbon, Co2 is a harmless Gas and the VW emissions scandal has made a lot of people including Governments finally realise the great mistake of promoting lower emitting Co2 cars as some kind of greener transport.

    As for heat pumps, forget it, unless you got a very efficient house to begin with you're talking a lot of money to insulate and make it air tight and possibly install of a heat recovery system also.

    In actual fact, the best thing you can do is insulate the bejesus out of the house and rely on as little energy as possible and get an EV.

    One of the greatest things I did was to block up the open fire chimney with a chimney balloon I got in the local hardware store, the heat loss and draughts caused by chimneys is enormous.


  • Registered Users Posts: 21,364 ✭✭✭✭ Mad_Lad


    By the way 7,000 units of electricity is a lot per year ?


  • Registered Users Posts: 2 CuriousDonkey


    Mad_Lad wrote: »
    By the way 7,000 units of electricity is a lot per year ?

    Thanks for the feedback!

    And your right 7k units is heavy, hence the look down the PV route. with two small kids the washing machine , dryer, dishwasher etc has been going non-stop over the winter months.
    I’ve switched out the lights to LEDs, from MR16’s (at 50w a pop they were hungry yokes)
    Replacing the dryer and dishwasher with A+ rated units would help with energy consumption, the other appliances have been done.

    So boosting the insulation & focusing on drafts, maybe upgrading the OFCH to a high-efficiency boiler might be a better investment.


  • Registered Users Posts: 9,070 ✭✭✭ Heroditas


    Mad_Lad wrote: »
    By the way 7,000 units of electricity is a lot per year ?

    Thanks for the feedback!

    And your right 7k units is heavy, hence the look down the PV route. with two small kids the washing machine , dryer, dishwasher etc has been going non-stop over the winter months.
    I’ve switched out the lights to LEDs, from MR16’s (at 50w a pop they were hungry yokes)
    Replacing the dryer and dishwasher with A+ rated units would help with energy consumption, the other appliances have been done.

    So boosting the insulation & focusing on drafts, maybe upgrading the OFCH to a high-efficiency boiler might be a better investment.
    You'd also get a good return if you got a day/night meter and switched your dishwasher, washing macine and dryer etc to night usage!


  • Registered Users Posts: 21,364 ✭✭✭✭ Mad_Lad


    Thanks for the feedback!

    And your right 7k units is heavy, hence the look down the PV route. with two small kids the washing machine , dryer, dishwasher etc has been going non-stop over the winter months.
    I’ve switched out the lights to LEDs, from MR16’s (at 50w a pop they were hungry yokes)
    Replacing the dryer and dishwasher with A+ rated units would help with energy consumption, the other appliances have been done.

    So boosting the insulation & focusing on drafts, maybe upgrading the OFCH to a high-efficiency boiler might be a better investment.

    I'd never have installed down lights all over the house, we have some in the conservatory but rarely use that in winter and if we do it's mainly a freestanding light with energy saver bulb of some sort. Each room is the same no nasty halogens.

    7K Kwh is just mental really. Time for a dual tariff meter. If you can manage to use the dishwasher and washing machine at night it would be a good start, most modern machines have a delay timer.

    Night rate starts at 11PM - 8am Winter and Midnight to 9 am Summer.

    It can be tricky to manage the clothes dryer, usually the washing machine does the wash at night and throw into the dryer during the day.

    We recently had to get a new Dryer and got a Bosch Heat Pump Dryer and it's fantastic, My Partner and my Mother gave it lots of praise particularly my Mother. It uses a lot less electricity but takes longer to dry. But "the clothes come out lovely" :-)

    You need to install an energy monitor, one that the sensor clips on the the ESB wiring in your meter box. They're a great way of monitoring and finding the energy eaters.

    Electric showers are notorious energy consumers and a lot of people don't realise that they're wasting all the hot water heated by the central heating system. Replacing with pumped only showers will make a big difference, in Summer you can use the immersion on night rate to heat the water. Pumped showers are also far nicer.

    Perhaps your a "drink a glass of water and put the glass in the dishwasher immediately" kind of family ? If I'm home all day I use the one cup and glass, rinse them out after use. Less dishes mean less times the dishwasher has to run.

    We're in the house nearly a year and probably got the new meter about a 3 weeks to a month after and this is our meter reading since last March.

    Total = 681 Kwh

    Total Day = 3125 Kwh

    Total Night = 3685 kwh

    So as you can see we use significant energy at night saving a lot of money !

    This is also to drive an electric car ! I have work charging so with the old car I used to charge at work and at home so half my Commute was free, this time I have a larger battery and charge less at home.

    I also work shift so for 7 Night shifts a month I have to charge the car at peak rates but as I say with the new car I charge less at home now.

    So anyway my point being that you need to seriously look at your energy consumption because there's no need to throw money at Solar PV when you can possibly greatly reduce your energy requirements and also use a lot during the night.

    Again, with solar PV you won't be able to use the energy at the time you need most of the time and will have to divert it, diverting it is just another term for throw it away because diverting means sending energy somewhere you really don't need.

    Until a FIT is introduced in Ireland solar PV really makes no sense.


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  • Registered Users Posts: 3 BobEmmet


    Mad_Lad wrote: »
    Solar PV is uneconomical in Ireland at current electricity costs, I pay 17 C day and 7.4 cent per Kwh night. No way solar PV is worth it.

    If a FIT existed then I would consider it but that's not likely for years.

    The Greatest Issue I have with Solar PV is the fact you have to divert a substantial amount to heating water you don't need and that's a complete waste. This is where you need the grid but without a FIT it makes it non viable. The Grid becomes your unlimited storage battery, sell to the grid and buy back when needed, the perfect solution and it could work but our grid is overwhelmed with commercial wind farms.

    A storage battery is too expensive and brings other problems , you haven't a hope to charge it fully in Winter and in Summer it will be charged too often and you'll still have to divert excess electricity or give it to the grid for free.

    Only in countries where there isn't such a large difference in Summer and winter daylight hours and countries that get a predictable amount of sunshine can you predict more accurately the size of the array and battery.

    One of the greatest way to reduce your carbon footprint and the greatest saving you'll make is to change to electric car, since doing this I'll never go back. savings over Diesel and maintenance is significant + electrics are so good to drive and getting into a warm car before you set off this time of the year is particularly great, no more scraping ice or waiting 10 minutes or more for heat, no more fogged up windows until the heater blows warm air etc.

    Electric cars can use any renewable energy on the grid and at peak production can be 65% of our total mix on the grid, 65% is the limit of renewable energy the grid can take, the rest gets exported or turbines get switched off + the more cars charging at night means a lot more wind energy can be used as energy demand significantly drops.

    Petrol and diesel has to be extracted from the ground, shipped to refineries and refined into petrol and diesel which consumes a lot of energy itself then it's burned in an internal combustion engine at only about 25-30% efficiency.

    Of course petrol and diesel cars emit far worse emissions than carbon, Co2 is a harmless Gas and the VW emissions scandal has made a lot of people including Governments finally realise the great mistake of promoting lower emitting Co2 cars as some kind of greener transport.

    As for heat pumps, forget it, unless you got a very efficient house to begin with you're talking a lot of money to insulate and make it air tight and possibly install of a heat recovery system also.

    In actual fact, the best thing you can do is insulate the bejesus out of the house and rely on as little energy as possible and get an EV.

    One of the greatest things I did was to block up the open fire chimney with a chimney balloon I got in the local hardware store, the heat loss and draughts caused by chimneys is enormous.

    Thanks. I had a quote of €11k for 4kw solar PV with storage battery. I'll pass.

    Astonishing that no pressure.is being put on Denis Naughten etc to introduce feed in tarrifs for solar PV. This would no doubt increase the uptake. Very frustrating for those willing to make the effort.


  • Registered Users Posts: 21,364 ✭✭✭✭ Mad_Lad


    11K for a 4 KwP system is a bit high alright but it does have a battery, did they give you the size of the battery in Kwh ?

    Did they give you a price without the battery ?

    Unfortunately I don't think battery storage would work well in Ireland due to the short daylight hours in Winter and the very long daylight hours in Summer, in other words , you'd struggle to fill the battery in Winter and would generate far too much to store in Summer.

    The only real solution is a feed-in-tariff , the Grid then becomes your unlimited storage battery but without the FIT it won't work. Sell the excess and buy it back when you need it.

    Priority will always be given to the big commercial companies in Ireland which is a shame because eventually they will start installing solar farms and it will require a lot of land but there's a lot of rooftops that can be used first.


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 89,734 Mod ✭✭✭✭ Capt'n Midnight


    If a lot of the energy is used for heating water for dishwasher and washing machine then look at more efficient machines or lower temps.

    Some will take feed from central heating, but beware they may only do it on high temp washes.

    Using PV to heat water is more expensive than doing it directly.

    Max out the insulation it's a 70's house, if you haven't already done so.


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,833 CMod ✭✭✭✭ unkel


    BobEmmet wrote: »
    Astonishing that no pressure.is being put on Denis Naughten etc to introduce feed in tarrifs for solar PV. This would no doubt increase the uptake. Very frustrating for those willing to make the effort.

    Indeed. Drive around anywhere in Germany, Belgium, the Netherlands these days and many, many houses are plastered with PV panels.

    Our solar power is at least as good as those countries (well it is anywhere in the East of the country), we should be plastering our houses with PV too. It's not that expensive to do it, but it makes no financial sense unless we get a reasonable feed in tariff

    Welcome to boards, by the way, BobEmmet :)

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



  • Registered Users Posts: 9 JB_Dublin


    Hi,
    I'm thinking of building an app which could allow you to make money from solar PV in Ireland. I'm interested in talking to anyone with existing solar installations or someone thinking about solar pv.


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  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,833 CMod ✭✭✭✭ unkel


    Nice thoughts, JB_Dublin and welcome to boards

    But how do you think you could get money to a solar PV owner?

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



  • Registered Users Posts: 37,534 ✭✭✭✭ the_syco


    BobEmmet wrote: »
    Thanks. I had a quote of €11k for 4kw solar PV with storage battery. I'll pass.
    Does that quote include any grants? Or are there still grants for this?


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,833 CMod ✭✭✭✭ unkel


    There are no grants for solar PV

    There is a grant for solar thermal (heating of your hot water)

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



  • Registered Users Posts: 9 JB_Dublin


    Thanks Unkel,
    I don't want to poison the thread by talking commercials, however, I want to trial a system that scoops up the solar spill, aggregates it and sell it as a virtual generator. If anyone is interested in hearing more/trialling it please PM me. I am trying to gauge demand. This will not make anyone millionaires however it might reduce the solar payback to a couple of years.

    Jim


  • Registered Users Posts: 9,070 ✭✭✭ Heroditas


    JB_Dublin wrote: »
    Thanks Unkel,
    I don't want to poison the thread by talking commercials, however, I want to trial a system that scoops up the solar spill, aggregates it and sell it as a virtual generator. If anyone is interested in hearing more/trialling it please PM me. I am trying to gauge demand. This will not make anyone millionaires however it might reduce the solar payback to a couple of years.

    Jim

    Have you engaged with the regulator and the likes of ESB Networks regarding this?
    Edit: or more to the point, an energy supply company?


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,833 CMod ✭✭✭✭ unkel


    Interesting concept, tell us more!

    To me the future of the grid is clear. There will be a lot more renewable energy (mainly solar PV and wind) and there will be storage on the grid (for when there is overproduction) in the form of batteries, ideally using EVs that are connected to the grid and can be used for "mining" electricity at premium peak times. But also other grid attached batteries as they become cheaper

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



  • Registered Users Posts: 9 JB_Dublin


    I agree with your proposition. Have you read the Chris Goodall book - the switch? It lays out a similar future.
    Unfortunately Ireland as a nation is way, way behind the likes of Sweden, it's even been accused of "delaying" eu legislation that helps this future to become a reality.
    Feed in tariffs are on their way out in the uk and the rest of europe, I think we need to find other ways of making solar "stand on it's own two legs".


  • Registered Users Posts: 9 JB_Dublin


    Yes (to all)


  • Closed Accounts Posts: 844 H.E. Pennypacker




  • Registered Users Posts: 21,594 ✭✭✭✭ ted1


    JB_Dublin wrote: »
    Hi,
    I'm thinking of building an app which could allow you to make money from solar PV in Ireland. I'm interested in talking to anyone with existing solar installations or someone thinking about solar pv.
    Block chain ? https://www.siemens.com/innovation/en/home/pictures-of-the-future/energy-and-efficiency/smart-grids-and-energy-storage-microgrid-in-brooklyn.html

    Or aggregating a group of people to sell on the ISEM. That can be pricey unless you have a couole of MW


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  • Registered Users Posts: 21,594 ✭✭✭✭ ted1


    unkel wrote: »
    Interesting concept, tell us more!

    To me the future of the grid is clear. There will be a lot more renewable energy (mainly solar PV and wind) and there will be storage on the grid (for when there is overproduction) in the form of batteries, ideally using EVs that are connected to the grid and can be used for "mining" electricity at premium peak times. But also other grid attached batteries as they become cheaper
    Are you still using your illegal non grid compliant invertor?


  • Registered Users Posts: 3 BobEmmet


    the_syco wrote: »
    Does that quote include any grants? Or are there still grants for this?
    No grants included but they've requoted about €5k without the battery.


  • Registered Users Posts: 3 BobEmmet


    JB_Dublin wrote: »
    Thanks Unkel,
    I don't want to poison the thread by talking commercials, however, I want to trial a system that scoops up the solar spill, aggregates it and sell it as a virtual generator. If anyone is interested in hearing more/trialling it please PM me. I am trying to gauge demand. This will not make anyone millionaires however it might reduce the solar payback to a couple of years.

    Jim

    I won't be having solar PV installed unless the payback term is reduced by FIT or something like you suggest (not that I understand the technicalities!)


  • Registered Users Posts: 21,364 ✭✭✭✭ Mad_Lad


    Without a FIT forget solar PV.


  • Posts: 0 [Deleted User]


    ted1 wrote: »
    Are you still using your illegal non grid compliant invertor?

    It's
    A: not illegal (not insurable)
    B: grid compliant (G83/2)


  • Closed Accounts Posts: 1,997 gally74




  • Registered Users Posts: 1,097 ✭✭✭ freddyuk



    This is irrelevant while the EU has a minimum price control in place limiting any reduction in imported solar module EU prices from China or anywhere else if they feel inclined.


  • Registered Users Posts: 9,070 ✭✭✭ Heroditas


    gally74 wrote: »

    Won't make a blind bit of difference unless some sort of FIT is introduced. Ireland intends meeting future renewable targets via large scale wind and also through some large scale solar.


  • Moderators, Society & Culture Moderators Posts: 31,256 Mod ✭✭✭✭ Gumbo


    JB_Dublin wrote: »
    Hi,
    I'm thinking of building an app which could allow you to make money from solar PV in Ireland. I'm interested in talking to anyone with existing solar installations or someone thinking about solar pv.

    PM me please
    Interested in what options you have
    Currently have a 3kw system that I give back to the grid on a daily basis.


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


    kceire wrote: »
    PM me please
    Interested in what options you have
    Currently have a 3kw system that I give back to the grid on a daily basis.

    Why PM me !?
    Let's hear it here now what kind of app can make PV more viable ... :)


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