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PV panels / Wind turbines

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  • 10-07-2010 10:03pm
    #1
    Electrisco-pops
    Registered Users Posts: 49 ✭


    Is there a system in which if you have either PV panels / Wind turbines that you can connect to the grid by having an additional meter?

    Obviously you would be billing esb as well as them billing you. I know its all in place over in the UK but I haven't heard of it over here.


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    #2
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,558 Mod ✭✭✭✭2011


    Yes, check out coolpower.ie

    My opinion is that PV panels are not financially viable. Look at the investment required to generate 1 unit (about €0.20) of electricity per day! I don't think your investment will break even in 20 years. Hopefully their cost will reduce over time and then they will make sense.

    The carbon footprint in manufacturing these cells is pretty horrific too! I did look into this, perhaps someone can post figures to prove me wrong.


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    #3
    Electrisco-pops
    Registered Users Posts: 49 ✭Electrisco-pops


    Yes well if you were wrong more and more people would be doing it. I'm doing a small essay on them at the moment and I'm mostly stateing the negatives. Cheers for the feedback!

    Anything to say about wind energy or domestic hot water panels?


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    #4
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,558 Mod ✭✭✭✭2011


    Sorry to come across as so negative. I would like to see these systems perform effectively. As technology improves I am sure they will become more cost effective. "Lean engineering" is the thing now. Making systems run more efficiently.

    Solar panels that heat hot water seem to make far more financial sense than PV.

    Wind turbines are only cost effective when they are over a certain size; this requires a large investment and even then suffer from massive mechanical wear due to the extream forces they are subjected to. Ireland generates less than 4% of it's power requirements from wind turbines.

    I think that if you want the biggest bang for your buck spend your money on insulating your home!


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    #5
    Electrisco-pops
    Registered Users Posts: 49 ✭Electrisco-pops


    Yes that seems to be the best solution alright. I think that people who invest in these sources and actually know how long the investment takes to pay off are just trying to encourage other people to save to environment, and have disposable income.

    Roll on the price drops!


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    #6
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    jamesekeenan wrote: »
    Is there a system in which if you have either PV panels / Wind turbines that you can connect to the grid by having an additional meter?

    Obviously you would be billing esb as well as them billing you. I know its all in place over in the UK but I haven't heard of it over here.

    Well the esb have meters that can measure the output onto their grid if a turbine is producing surplus, they just dont buy surplus units at pesent i dont think? But a meter could be installed by the installer to meter what the turbine is producing, fitted between the grid tie inverter and the connection to the clients mains.


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    #7
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    2011 wrote: »
    Sorry to come across as so negative. I would like to see these systems perform effectively. As technology improves I am sure they will become more cost effective. "Lean engineering" is the thing now. Making systems run more efficiently.

    Solar panels that heat hot water seem to make far more financial sense than PV.

    Wind turbines are only cost effective when they are over a certain size; this requires a large investment and even then suffer from massive mechanical wear due to the extream forces they are subjected to. Ireland generates less than 4% of it's power requirements from wind turbines.

    I think that if you want the biggest bang for your buck spend your money on insulating your home!

    I dont think its all that negative, realistic probably. Wind turbines are probably not too bad, just very expensive.


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    #8
    Kippure
    Closed Accounts Posts: 1,186 ✭✭✭Kippure


    jamesekeenan wrote: »
    Is there a system in which if you have either PV panels / Wind turbines that you can connect to the grid by having an additional meter?

    Obviously you would be billing esb as well as them billing you. I know its all in place over in the UK but I haven't heard of it over here.

    I done a theies on PV panels. I desigened a off grid system just to run the lighting in my home.

    I was running 1827 watts of lighting, got it down to 264 watts.

    I used 2 PV panels 700 to 800 watt pv panels, 17 to 24 volt output.

    One 12 volt regulator

    15 12 volt 40 ampere hour batteries, 600 ampere hour capacity.

    One 500 watt inverter, 1 kw peak.

    Thats 230 volt, 2 amp peak, 460 peak watt load.


    The set up is 5 year pay back.


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    #9
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Kippure wrote: »
    I done a theies on PV panels. I desigened a off grid system just to run the lighting in my home.

    I was running 1827 watts of lighting, got it down to 264 watts.

    I used 2 PV panels 700 to 800 watt pv panels, 17 to 24 volt output.

    One 12 volt regulator

    15 12 volt 40 ampere hour batteries, 600 ampere hour capacity.

    One 500 watt inverter, 1 kw peak.

    Thats 230 volt, 2 amp peak, 460 peak watt load.


    The set up is 5 year pay back.

    Are you not going to use a charge controller for charging the batteries?


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    #10
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,558 Mod ✭✭✭✭2011


    The set up is 5 year pay back.
    Really? Can you post the figures? I would like to know:
    1) How many hours of sunlight you based your calculations on

    2) total cost

    3) How long do you expect the batteries to last. They are only good for a certain amount of charges/discharges. Also the cost of battery replacement and disposal.

    4) Does your system sync with the grid?

    5) Any other facts/ figures would be good

    Thanks!


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    #11
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    2011 wrote: »
    Really? Can you post the figures? I would like to know:
    1) How many hours of sunlight you based your calculations on

    2) total cost

    3) How long do you expect the batteries to last. They are only good for a certain amount of charges/discharges. Also the cost of battery replacement and disposal.

    4) Does your system sync with the grid?

    5) Any other facts/ figures would be good

    Thanks!

    I was just thinking some of them questions myself. I would`d say its grid tied if its using bateries, grid tied would seem a better option and meter the power the panels are supplying to the house.
    The batteries should last a fair while with that many of them, but not indefinite.


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    #12
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Two 800 watt panels probably would of made a decent water heating setup maybe. Especially in the summer.
    Anyway 264 watts of lighting for 5 years even with the lights on 24 hours a day is 1600 euro or so. That seems cheap for a solar setup of 1600 watts anyway.


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    #13
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,558 Mod ✭✭✭✭2011


    I guess the other big question is how many units a day would thus system generate?


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    #14
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    2011 wrote: »
    I guess the other big question is how many units a day would thus system generate?

    Yea i think the solar panels will only give out the rated watts in direct sunlight, and half that on a cloudy but bright day. Or something like that. So in mid winter there would be a far lower daily units output i would imagine, just when the highest lighting requirement is, although 1600w solar panels might cover it, its hard to know really is`t it.


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    #15
    Stoner
    Moderators, Home & Garden Moderators, Technology & Internet Moderators Posts: 10,952 Mod ✭✭✭✭Stoner


    jamesekeenan wrote: »
    Yes well if you were wrong more and more people would be doing it. I'm doing a small essay on them at the moment and I'm mostly stateing the negatives. Cheers for the feedback!

    One advantage of a PV system on a development is that it is standalone. There are other options for example a heat pipe/panel arrangement that can produce 4-5 more energy at source. However some of them need to interface with an existing or new heating heating system, so plant rooms need to be changed around, more work on the building management system etc. The PV panels can be placed on the roof of a development and the electricity they produce is simply sold to a service provider, if they breakdown the heating systems still work.

    Sometimes planning conditions require an element of renewable energy as part of the application, the requirement may not state a % or amount it's just a condition that its there, in some areas of some countries rain water harvesting may tick a box. PV systems have been used to simply tick a box in a cost effective way, their lack of impact on traditional heating systems needs to be taken into account on a payback calculations.


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    #16
    Kippure
    Closed Accounts Posts: 1,186 ✭✭✭Kippure


    2011 wrote: »
    Really? Can you post the figures? I would like to know:
    1) How many hours of sunlight you based your calculations on

    2) total cost

    3) How long do you expect the batteries to last. They are only good for a certain amount of charges/discharges. Also the cost of battery replacement and disposal.

    4) Does your system sync with the grid?

    5) Any other facts/ figures would be good

    Thanks!


    I done a theis on this, dont want to give out to much info yet.

    System is off grid



    I have attached the price chart
    and lighting table.Attachment not found.


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    #17
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Kippure wrote: »
    I done a theis on this, dont want to give out to much info yet.

    System is off grid



    I have attached the price chart
    and lighting table.Attachment not found.

    I assume the 12v regulator is to connect from the panels to the batteries, but i dont think 12 volts will charge them up fully, a charge controller is whats used which just switches from the batteries to a dummy load or alternative load when the batteries reach 12.8v or so. And switches back to the batteries when they discharge to a certain level. That was my thinkingon it anyway.


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    #18
    Electrisco-pops
    Registered Users Posts: 49 ✭Electrisco-pops


    Incidentally, if possible can someone post up reasonable price list of sandard domestic PV panels?

    The prices I saw when I googled it were absolutly outrageous and seem like they would take nearly 30 years to pay themselves off!

    5 years dose not seem to bad, could be onto something there.

    I would like to convince other people that this is a good idea eventually as I would love to offer the service of fitting them as I am an electrician. I'm also currently doing a short course on "Domestic Hot Water Solar systems" and I'm doing a degree in "Environmental Energy Engineering"


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    #19
    Electrisco-pops
    Registered Users Posts: 49 ✭Electrisco-pops


    Oh apologies someone already did put up price's.

    Thanks Kippure!


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    #20
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,558 Mod ✭✭✭✭2011


    Based on 5 year payback and the current exchange rate your system would have to provide you with an average of 10 kilowatt hours (or units) of electricity a day. This is assuming that the batteries survive for 5 years. That is 1000 watts an hour for 10 hours on average per day through all of the seasons. Impressive!

    Are my calculations correct? I'm taking a unit to be 20 cent and £1 = €1.193


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    #21
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    2011 wrote: »
    Based on 5 year payback and the current exchange rate your system would have to provide you with an average of 10 kilowatt hours (or units) of electricity a day. This is assuming that the batteries survive for 5 years. That is 1000 watts an hour for 10 hours on average per day through all of the seasons. Impressive!

    Are my calculations correct? I'm taking a unit to be 20 cent and £1 = €1.193

    I think the off grid load being fed by the system was 260 watts of lighting was it , so it would never cover its costs in 5 years only supplying that load which would only be used for a fraction of the 24 hours. If the system can produce 10 kwh`s a day then it must be fully utilised to have a decent pay pack time. It looks good though if it was grid connected to the mains suppy as every watt produced would be used then and no batteries etc. 260 watts of lighting on 24 hours a day for 5 years is 2300 euro at 20 cent a unit. Off grid systems have good applications of course, but a lot harder to get a good payback time. Maybe im forgetting something somwhere? Interesting though.


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    #22
    Kippure
    Closed Accounts Posts: 1,186 ✭✭✭Kippure


    2011 wrote: »
    I guess the other big question is how many units a day would thus system generate?

    Dont forget to size your cables correctly,

    Between the 12 volt voltage regulator and the batteris you,ll need 35 square for over a 100 amps.

    Between the Batteries and invertor 40 amps use 10 square. Thats what i used on my system if you go by it


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    #23
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Kippure wrote: »
    Dont forget to size your cables correctly,

    Between the 12 volt voltage regulator and the batteris you,ll need 35 square for over a 100 amps.

    Between the Batteries and invertor 40 amps use 10 square. Thats what i used on my system if you go by it

    I assume its a charge controller/regulator being used rather than a pure 12 v regulator which will just give out a stable 12 volts?


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    #24
    Kippure
    Closed Accounts Posts: 1,186 ✭✭✭Kippure


    robbie7730 wrote: »
    I assume its a charge controller/regulator being used rather than a pure 12 v regulator which will just give out a stable 12 volts?

    Thats correct mate, Stable 12 volts.


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    #25
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Kippure wrote: »
    Thats correct mate, Stable 12 volts.


    Yes i was just wondering was it a pure 12v output voltage regulator or were you just calling the charge controller a regulator, as to fully charge 12 lead acid batteries they need to be brought up near 13 volts or so. A 12 volt regulator would allow the batteries to act like a sort of buffer but would`t fully charge them, i would of thought the large battery bank would want to be brought up to full charge for use at night and for more efficient use of the solar output.
    A charge controller monitors battery voltage and switches the solar output over to another load when batteries reach full charge voltage, and switches back to the batteries when they are down to a certain discharge level.

    They can be near discharged when at open circuit 12 volts. I dont do much with lead acid batteries but heavily involved with lithium polymer ones alright.


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    #26
    icbarros
    Registered Users Posts: 144 ✭✭icbarros


    What is your opinion about having PV panels to feed an electrical underfloor heating in a domestic installation with approx. 140 sq.m.?
    Does it make sense at all??


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    #27
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    icbarros wrote: »
    What is your opinion about having PV panels to feed an electrical underfloor heating in a domestic installation with approx. 140 sq.m.?

    I think that would require about 20kw or more of power to have it all on at the same time, ye would be doing well to get the house supply to power that, and would require solar pannels nearly the same area as the floor area being heated.


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    #28
    saibhne
    Registered Users Posts: 182 ✭✭saibhne


    Kippure wrote: »
    I done a theis on this, dont want to give out to much info yet.

    System is off grid



    I have attached the price chart
    and lighting table.Attachment not found.

    Hi Kippure,
    I think the PV panels you have included in your costing are solar thermal panels and not PV - the SunnySol Up is a Gasokol solar thermal panel. Unless there is another PV panel by the same name..


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