DNO limited export, oversize array storage options - Solar Immersion Diverter or battery

Hi,

Just after some practical advice please as i'm struggling to find info online.

Our export with the DNO is limited to 3.68kwh. we are a large family and would like a bigger array, so am wondering what options there are to store excess.

We're proposing an 8kw array (all on the same orientation) that would be clipped to 3.68kw export, if we're generating over 3.68kwh what storage options are available that could use the pre clipped energy on the DC side?

Is there an immersion diverter that will use this? e.g. if the array was generating peak circa 8kwh and we were self consuming the inverted AC 3.68kwh, could the immersion diverter use the remaining output? or would it be lost without a battery?

I understand that a hybrid inverter with battery could be used that would store in DC, we dont really want to go down that route at the moment as we have a 500 litre unvented cylinder that has potential.

Thanks 

Replies

  • DougMLancsDougMLancs Forumite
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    With that size of array I would be wanting to apply to the DNO for a larger export limit
  • QrizBQrizB Forumite
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    rc28 said:
    We're proposing an 8kw array (all on the same orientation) that would be clipped to 3.68kw export, if we're generating over 3.68kwh what storage options are available that could use the pre clipped energy on the DC side?
    If you wish to store on the DC side, you're looking at a hybrid inverter (or an add-on DC battery that achieves the same result).
    I understand that a hybrid inverter with battery could be used that would store in DC, we dont really want to go down that route at the moment as we have a 500 litre unvented cylinder that has potential.
    You can get hybrid inverters that monitor your export (after any house loads are satisfied) and clip accordingly. This would let you heat your cylinder withour eating into your export limit. I think Reed_Richards has one.

    N. Hampshire, he/him. Octopus Go elec & Tracker gas / Voda BB / Virgin mobi. Ripple WT2 member.
    2.72kWp PV facing SSW installed Jan 2012. 11 x 247w panels, 2.5kw inverter. 28MWh generated, long-term average 2.6 Os.
    Kinda busy right now but I try to pop back to the forum every so often. Drop me a PM if you need me!
  • ispookie666ispookie666 Forumite
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    The tech has come a long way and you can just limit export to 3.68 and have unrestricted generation.  It can be any variant DC, AC or hybrid. 
    Export limitation would be usually G100, I would look for inverters which are already certified for G100. 
    “Don't raise your voice, improve your argument." - Desmond Tutu

    System 1 - 14 x 250W SunModule SW + Enphase ME215 microinverters (July 2015)
    System 2 - 20 x 330W Jinko Panels + Enphase IQ7+ microinverters (Jan 2022) + Givenergy AC Coupled inverter + 2 * 8.2KWh Battery (May 2022) + Mitsubishi 7.1 KW and 2* Daikin 2.5 KW A2A Heat Pump
  • rc28rc28 Forumite
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    QrizB said:
    rc28 said:
    We're proposing an 8kw array (all on the same orientation) that would be clipped to 3.68kw export, if we're generating over 3.68kwh what storage options are available that could use the pre clipped energy on the DC side?
    If you wish to store on the DC side, you're looking at a hybrid inverter (or an add-on DC battery that achieves the same result).
    I understand that a hybrid inverter with battery could be used that would store in DC, we dont really want to go down that route at the moment as we have a 500 litre unvented cylinder that has potential.
    You can get hybrid inverters that monitor your export (after any house loads are satisfied) and clip accordingly. This would let you heat your cylinder withour eating into your export limit. I think Reed_Richards has one.

    Perfect thanks, sounds like i need to research that specific type of hybrid inverter. Am finding it a bit of a minefield (new to solar pv) as were sourcing the components ourselves for a self build there's no point of contact to ask questions.

    Batteries may be an option for the future, for now immersion storage seems like the most economical thing.


  • ispookie666ispookie666 Forumite
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    @rc28 without applying to DNO how do you know the export is limited to 3.68?
    “Don't raise your voice, improve your argument." - Desmond Tutu

    System 1 - 14 x 250W SunModule SW + Enphase ME215 microinverters (July 2015)
    System 2 - 20 x 330W Jinko Panels + Enphase IQ7+ microinverters (Jan 2022) + Givenergy AC Coupled inverter + 2 * 8.2KWh Battery (May 2022) + Mitsubishi 7.1 KW and 2* Daikin 2.5 KW A2A Heat Pump
  • rc28rc28 Forumite
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    Im not 100% it will be limited but 3 neighbours directly adjacent to me have 4kw systems (all installed many years ago). One of the neighbours said western power limited them to 4kw.

    I suppose i will have to apply to be sure.

    Thanks for the advice on the inverters, atleast i know it's possible to oversize (over export limit) and still use all generation.
  • ispookie666ispookie666 Forumite
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    I would probably go with the usual application process.  The outcomes could be 
    • Unrestricted export - Your full generation/Inverter output capacity
    • G98 limit of 3.68
    • Limited export - Any value depending on the local grid 
    • Zero export - Depending on your local grid.  
    I hope the DNO lets you export at least 3.68.  
    “Don't raise your voice, improve your argument." - Desmond Tutu

    System 1 - 14 x 250W SunModule SW + Enphase ME215 microinverters (July 2015)
    System 2 - 20 x 330W Jinko Panels + Enphase IQ7+ microinverters (Jan 2022) + Givenergy AC Coupled inverter + 2 * 8.2KWh Battery (May 2022) + Mitsubishi 7.1 KW and 2* Daikin 2.5 KW A2A Heat Pump
  • 70sbudgie70sbudgie Forumite
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    I would probably go with the usual application process.  The outcomes could be 
    • Unrestricted export - Your full generation/Inverter output capacity
    • G98 limit of 3.68
    • Limited export - Any value depending on the local grid 
    • Zero export - Depending on your local grid.  
    I hope the DNO lets you export at least 3.68.  

    I'm not sure the DNO can limit the export of a domestic property below 3.68kW? Because up to 3.68kW is G98 notification and you don't apply in advance for that.

    So I think your third possible outcome should be "Any value above 3.68kW, depending on the local grid."

    And the 4th outcome is not a possibility. 

    (This is only applicable if you are a domestic property. If you are a commercial property, ignore everything I just said and @ispookie666 's comment stands in full)
    Longi 360W panels: 2.52kW ENE, 1.8kW WSW, Solis Dual 3.6kW inverter. 41kWh Zoe. 540W Ripple Kirk Hill. Cheshire
  • ispookie666ispookie666 Forumite
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    Good point. I would not be surprised with a limit lower than 3.68 is applied by DNO. 
    G98 is notification after completion of works, I presume this does not mean automatic approval from DNO. 

    If I was DNO, with the scrutiny on finances and having to eat profit - I'd look at low hanging fruit a and domestic generation looks very appealing 🤐. 
    “Don't raise your voice, improve your argument." - Desmond Tutu

    System 1 - 14 x 250W SunModule SW + Enphase ME215 microinverters (July 2015)
    System 2 - 20 x 330W Jinko Panels + Enphase IQ7+ microinverters (Jan 2022) + Givenergy AC Coupled inverter + 2 * 8.2KWh Battery (May 2022) + Mitsubishi 7.1 KW and 2* Daikin 2.5 KW A2A Heat Pump
  • 70sbudgie70sbudgie Forumite
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    Good point. I would not be surprised with a limit lower than 3.68 is applied by DNO. 
    G98 is notification after completion of works, I presume this does not mean automatic approval from DNO. 

    If I was DNO, with the scrutiny on finances and having to eat profit - I'd look at low hanging fruit a and domestic generation looks very appealing 🤐. 
    This is why they are so heavily regulated. As long as you meet the prerequisites (like MSC cert, max 3.68kWhr inverter, safety cut out etc etc), then I don't think they are allowed to say no to G98. If they do, I would be having words with my installer as it means info is missing. I think they would also tell you why its been refused, so it can be sorted.
    Longi 360W panels: 2.52kW ENE, 1.8kW WSW, Solis Dual 3.6kW inverter. 41kWh Zoe. 540W Ripple Kirk Hill. Cheshire
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