Has plug and play solar now been passed, I see adverts?

[ericmark]

@morqthana link says:-
"UK wiring regulations effectively banned them without an electrician’s sign-off, but the government’s intervention changes all that." I have not seen any wiring regulations which stipulates what can be plugged in.

There may well be supply regulations which stop it, or HSE regulations, and we need to see exactly what is going to be changed, Plug and play basically points to a single item which plugs in, without any CT coils etc, at the meter. And what we want to know, is will those without the second MPAN number already, get something which allows them to be paid for export, and what will be the export limit?

 

[JohnW2]

.... Plug and play basically points to a single item which plugs in, without any CT coils etc, at the meter. ...

Probably true, but even if it did include clamping sensors onto meter tails, that's something which countless 'ordinary people' already do in the name of 'monitoring', isn't it?

And what we want to know, is will those without the second MPAN number already, get something which allows them to be paid for export, and what will be the export limit?

I suspect that it is not really 'intended' that these mini-PV thingies be used to export?

 

[Harry Bloomfield]

I suspect that it is not really 'intended' that these mini-PV thingies be used to export?

Isn't that inevitable, if the capacity exceeds the demand of the house? If I fitted one, our demand is 100 to 300w, an 800w panel, on a good sunny day would generate a surplus of 500 to 700w, where would that go, assuming no storage.

 

[JohnW2]

Isn't that inevitable, if the capacity exceeds the demand of the house? If I fitted one, our demand is 100 to 300w, an 800w panel, on a good sunny day would generate a surplus of 500 to 700w, where would that go, assuming no storage.

Well, my thinking was that the sort of things one bought from Lidl would probably rarely, if ever, produce anything like 800 W for appreciable periods in the UK and that many people's background demand is a lot more than your 100 W. Taken together, that suggested that, numerically, it was probably unlikely that there would be appreciable scope for significant export - in other words, as I wrote, they are "not really 'intended' to be used to export".

As for your "inevitable" suggestion, to respond to that in technical terms would require me to understand more than I currently do about these things. For example, do 'we' know what voltage the inverters produce?

 

[Harry Bloomfield]

if ever, produce anything like 800 W for appreciable periods in the UK and that many people's background demand is a lot more than your 100 W.

None-the-less, the times when they do produce the 800w, will be during the day, when many homes are empty, and so their base load will be at a minimum. I would suggest my 100 to 300w, is not far from normal, when a gas option is used.

As for your "inevitable" suggestion, to respond to that in technical terms would require me to understand more than I currently do about these things. For example, do 'we' know what voltage the inverters produce?

Obviously, to pick up the house load, the inverter would need to output at a slightly higher voltage than the mains voltage, otherwise it would not be contributing at all. Unless it were to somehow lead the mains sine wave slightly?

 

[JohnW2]

None-the-less, the times when they do produce the 800w, will be during the day ...

If they ever do (produce 800 W)!
If I know marketing people, a product labelled as "800 W" will just about be able to produce 800 W for a few minutes around midday GMT on the sunniest day of mid-Summer and with the panel optimally located and orientated - and probably, in practice in the real world, quite probably well under half that for most of the time. Given the international nature of the market, it's even possible that the quoted 'output' relates to Southern Europe, rather than UK

... when many homes are empty, and so their base load will be at a minimum. I would suggest my 100 to 300w, is not far from normal, when a gas option is used.

There will obviously be consdierable variation between houses/households but, for what it's worth ...

... although my house is large, I don't think it's appreciably different in terms of 'electrical loads' from any 'average house'. The below graph shows one fairly typical day in mid-Summer last year for the phase which covers the standard 'living areas' (ground floor) and, as you can see, the total demand was hardly ever significantly less than 300 W. [I presume that the nocturnal burst of usage was probably a dryer (rare in Summer) and the one around midday probably a washing machine or dishwasher]. I presume that most of my 'baseline load' (most often 300-500 W) is accounted for by a couple of fridges and a couple of freezers - things which obviously would be 'running' even when the house is unoccupied.
As above, I would suspect that that 300-500 W was probably at least as much as one could, in the real world, really expect to be getting for significant periods of time from an "800 W" panel.

Obviously, to pick up the house load, the inverter would need to output at a slightly higher voltage than the mains voltage, otherwise it would not be contributing at all. Unless it were to somehow lead the mains sine wave slightly?

As I said, without understanding more about these things, I would not attempt to comment on technicalities. However, in view of the above, that may be essentially unnecessary - since, if there is rarely a significant excess of PV generation over local demand, the technicalities of ex;port become moot.

 

[ericmark]

@JohnW2 reading match my own.
I look at my own system

and it seems multiply the size in kW by 1000 gives the kWh per annum, so 800 watt = 800 kWh per annum. So looking at £96 at 12p/kWh or £200 at 25p/kWh depending on if stopping import or exporting.

And it does seem most the adverts are working on these figures. My baseline is 200 to 500 watt, with 4 freezers running, most people can work with one freezer, so will have half that baseline, so at 800 watts we can expect half the energy to be exported.

Of course, we don't know if 800 watt, if 800 watt with 16 amp outlet looking at 650 watt with a 13 amp outlet. If 800 watt limit is because of back feed into grid, then likely be 800 watt.

So we are at the moment no idea of what will be permitted, and one assumes neither do the manufacturers, only if it matches some other country will there be a fast appearance in the centre aisle. More to the point we are already seeing sales, before we have any idea what will be permitted.

 

[JohnW2]

Could you perhaps explain the arithmetic of that?

My baseline is 200 to 500 watt, with 4 freezers running, most people can work with one freezer, so will have half that baseline, so at 800 watts we can expect half the energy to be exported.

Similar to my baseline then, and for similar reasons - as I said, I have two fridges and two freezers on that phase.

 

[ericmark]

Could you perhaps explain the arithmetic of that?

6 kW panel produces approx 6000 kWh per year, so 1000 kWh per kW panels size, so 0.8 kWh should give around 800 kWh per year.

Similar to my baseline then, and for similar reasons - as I said, I have two fridges and two freezers on that phase.

I would say most people don't have 4 refrigeration machines running, you and me are unusual.

I could buy plug in solar, and I would get paid for export, as no one would be able to show which solar array it was coming from. But this plug in solar is not aimed at you and me, it is aimed at people who can't for what ever reason fit what we have.

And I can see many people being disappointed unless payment for export is permitted.

Theory is great, we can get units which monitor export, and once over 100 watts use it to heat the domestic hot water, but these units cost nearly £300, so in real terms not worth it for an 800 watt panel. The same applies for battery units,

cheapest only designed to be used with a 200 watt, panels. Double the size £400 and still only 400 watt of solar they are designed for camping not balcony solar.