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Just had approval from DNO
Just had approval from DNO.
20kw export limitUsage here is around 13000kwh annual.
Roof in question is 15deg slope.
190deg orientated
No shading.
HR8 2LN
No Ev as yet.
Winter we use 60 to 70kwh
Plenty of roof space available hence large array.
Originally agreed to 25kw inverter, with 38kwp array with 36kwh of battery.
Now we always planned on using the clipped solar in the summer to Dc charge battery.
But with a export limit of 20kw do we reduce the amount of panels or look at it as originally did to wipe out as much winter import as possible and accept that some summer sun will be lost.
And have the option in the future to add batteries to capture lost summer power.
Tried signing up for Gary does solar to use the modeling tool. But won’t let me.
Thanks
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20 Replies
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Presumably you have quite a large amount of usage if you are looking at installing a 35kWp array? Or were you expecting to become a mini power plant and just sell to the grid?
Depending on the orientation of your panels, shading issues and location, you may never generate your max amount of 35kW.
If your usage is significant, the likelihood is that you will be using a lot of what you generate, and will therefore be unlikely to exceed the export limit.
If you tell me you address and postcode, and the yearly amount of electricity you use, I can tell you what your peak export is likely to be
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What’s the layout of your panels? How much kWp facing each orientation?
A 20kW export limit is still massive, so personally I’d stick with the original design.
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Big inverter
Max the roof
Batteries to suit daily load
Sorted
Better to worry about clipping than lack of winter power
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Just wondering, in winter, with low solar, how much will it cost to charge your battery? Maybe hurry to get that EV?
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Do NOT reduce the number of panels. Panels are cheap and will be very useful in winter.
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Not that impressive or surprising as you have a 3 phase supply and all export limits are “per phase”.
So you have been given a 6.67kW single phase export equivalent.
But still decent. It’s all about the local network infrastructure.
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with 65kWh winter use I’d definitely max the PV especially as at a shallow 15 degrees it will be even less effective than a steeper pitch in the winter. You’ll clip bundles in the summer so investigate a 3 ph solar enabled DC charger for some electric vehicles or put an high power solar enabled AC charger invisible to the inverter. Or as you say more storage.
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The batteries you choose will have a significant cost impact on the overall installation cost. Fogstar batteries would give you very good value for money.
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Battery storage, even a small amount, will cover you. Remember it’s 20 kW, so that’s a theoretical export of 480 kW a day. Wouldn’t change your setup 1 iota, as that 36 kWh (okay, effective discharge of 30-33, as you shouldn’t discharge to empty, so check the DoD figure) will cover those few hours when you’re getting more than 20kW around peak summer midday (you might want to force discharge in the morning at that time of year to make room).
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Looking at a similar set up (presumably you are a farm with shed rooves too?). Still waiting to here from DNO, but inclined to max panels to get as much as possible in winter.
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yes we are farm.
That was what my original thinking was.
And thinking on it since replied to the comments here. It’s probably carry on as planned.
Don’t cost much more to put extra panels whilst they are on the roof installing.
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is this a 3 phase install as I thought the maximum inverter size for single phase was around 17kw
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What inverter? My mistake was installing a 10kw inverter in my 3 phase house believing it was 3 phase compatible…it is, but needs 3 inverters to use all 3 phases.
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we’re at the very early stages of looking at a similar setup also on a farm in herefordshire. would you mind telling me how much this is looking to cost and who is doing the installation?
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unfortunately no one local. The original set up cane in at £31k. + vat if applicable
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I’d say depends on the cost difference and what amount will he clipped , if it’s on one south facing roof then Pro good idea to reduce the panels if on ,2 different orientation then they may not produce much more than 20kw at any given time and you can just charge batteries at those peak products times to stop clipping.
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Think its going to be best off stick with set up and change the inverter
Had a fairly sharp price on the set up.
Reducing panels may not be reflected like i originally thought.
Set up is all South ish facing with no shading.
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If you havnt done already get yourself ordered a 3 phase smart meter, takes ages if not already installed and can’t then use the 3 phase for tou tariffs..I take it this will come under domestic so get yourself on a good supplier such as octopus, eon and do overnight charging of batteries at 7-8pkwh and export 100% of solar generation at 12-16pkwh, using batteries for day load only.
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yeah got smart meter.
Took 2 years to get us changed over.
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Nobody has ever said I wished I got fewer panels lol
Get as many as you can as we can get long winters.
EV is a no brainier.
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