Smart Meter Reading Confusion

tfspark

I have a Kaifa MA120 smart electricity meter. I also have a 2kw solar panel system producing electricity when the sun shines.

The meter reports the reading to Octopus every month but I'm confused about the actual reading they use.

For instance, on 8th March the Octopus app shows a reading of 3309 used for billing. Today. 9th March the meter readings are,

+A = 3700

-A = 722

It also shows T01(day) = 3324 & T02(night) = 376  (total 3700 which is the same as +A)

I would have thought the reading used should be +A - -A, or 3700 - 722 = 2978. That will be slightly high as the reading was taken yesterday and I read the meter today.

Looking back at my history the meter was installed on 30th December 2022 with a reading of 0.

Grateful if anyone has any ideas.

Mark_d

+A appears to be your total import.  This is why it equals the sum of your day and night rate registers.

-A appears to be your total export.  This is when the energy consumed in your property is less than the amount generated, and hence you are exporting electricity to the Grid.

Import and export are not combined because they are treated separately in terms of industry processes

Scot_39

Depending on how you are set up - you may be subject to different per kWh unit rates on day / night on import and on excess kWh solar export to grid.

Breakdown as post above.

So they cannot simply be added - not for billing purposes anyway - but if you want to know your net drain in energy terms fine but you cannot estimate bill costs based on 2978 alone.

(You appear to have a multirate meter - two registers - most typically E7 these days.  

But if those figures are correct - only using about 10%  on night rate (376 in 3700).

Are you still on an E7 style tariff with more expensive day vs cheaper night - relative to single rate billing ?)

Reed_Richards

It appears that you have exported 722 kWh of electricity since your smart meter was installed, that's electricity generated by your solar panels that you didn't use to power your house.  If you are on the right tariff with Octopus they will pay you 15p per kWh exported so you could have been paid up to £108.30 for that exported electricity. 

tfspark

Thanks for all the comments.

I, maybe naively, thought it was a case of simple maths.

I knew that +A is import and -A is export.

I am on a single rate tariff, Octopus Tracker, which changes the unit cost at midnight every night.

Although I have solar panels I have never been paid for export.

I thought it would be the case where I had imported 3700kWh and exported 722kWh (since the meter was installed) so one minus the other would give me the total. ie the billing meter reading. After all the meter reading shown is actual kWhs.

I'm still not sure I understand why that won't be the case.

Scot_39

I dont have solar, but from posts here as I understand it.

Some older panels were registered under a FIT (feed in tariff) scheme - closed to new reg - 4+ years ago.

Sone even got paid based on nominal panel ratings and assumed not metered output.

Others now get an export meter reading dependent payment per kWh under a newer scheme called smart export guarantee SEG -  or an export tariff (this link says normally linked with import tariff) 

https://solartogether.co.uk/blog/seg-fit-and-export-tariffs-explained


Some suppliers used to pay well below 10p from posts here  - even when import over 30p per kWh -  Octopus have again been said to have some of the best deals - like the 15p mentioned above  - but even that used to be 7.5p. 

Whereas on Tracker you might now be paying c18p for import (rough ave in SE last few months from quick google spread c15-20p on old rate formulae ?)

So ovverall billing - excluding SC - could be something like if those rates applied over year.

3700 total x18p (tracker rate) - 722x15p (export rate) if kWh based.

Obviously the 3p+/-  per kWh difference (variable) matters - which is why you cannot simply add meter readings. Edit and for those on a defaul tariff - it would be c4x that - and with the wrong supplier - maybe over 20p difference per kWh

Your actual solar system might actually also have its own meter that tells you how much it has actually generated - as the export is normally only the excess generation - that generated power you haven't used from the solar panels.

So you used 3700 imported from grid
Exported 722 from panels to grid.
But would have used say 3700+xxxx actual energy
And panels generated 722+xxxx actual energy.

You need to register panels - with DNO or with supplier if have MCS ? - to get paid for export -  and their can be several weeks delay - have you got that parperwork / registration for your property  ?

(Is it per property or do you have to register again as individual if buy with solar pe installed - so personal ?   someone with solar ? )

And then I guess choose SEG / export tariff with a supplier and register with them  - from posts here Octopus seem to pay the most historically - they even appear to have dynamic export pricing if fancy the gamble. 

QrizB

tfspark said:

I thought it would be the case where I had imported 3700kWh and exported 722kWh (since the meter was installed) so one minus the other would give me the total. ie the billing meter reading.

I'm still not sure I understand why that won't be the case.

What you are describing is "net metering", a billing model that is applied in some countries but not the UK.

In the UK, you are billed for the kWh you import and can be paid for the kWh you export. The rates of payment are however different (usually, but not always, being charged more for an imported kWh than you are paid for an exported kWh). To be paid for export, you need to have your system registered with an energy company (not necessarily the same one you use for import).

When were your solar panels installed? What paperwork did you receive with them?

tfspark

Thank you Scot_39 for such a comprehensive reply. It's all a bit clearer now.

My solar system is a small 2kW system of eight panels. They were installed in 2016 on an out building and were DNO registered, certified and notified to LBC. They are not MCS registered hence no export payments.

TLDR - since installation my neighbour has planted fairly quick growing trees not too far from my panels. They now partially shade my panels in the late afternoon. The way they are growing the shading will only get worse. Not much point in doing anything with them as their efficiency is only going to get worse.

Obviously irrelivent to this thread.

Reed_Richards

tfspark said:

My solar system is a small 2kW system of eight panels. They were installed in 2016 on an out building and were DNO registered, certified and notified to LBC. They are not MCS registered hence no export payments.

Octopus have changed their terms and conditions for export payments fairly recently.  If your solar installation is DNO registered that may be sufficient to make you eligible for export payments, even though your panels are not MCS registered.  I see no harm in applying to Octopus.  But any payment would not be retroactive; you won't get paid for the 722 kWh you have already exported since your smart meter was fitted.

Scot_39

tfspark said:

Thank you Scot_39 for such a comprehensive reply. It's all a bit clearer now.

My solar system is a small 2kW system of eight panels. They were installed in 2016 on an out building and were DNO registered, certified and notified to LBC. They are not MCS registered hence no export payments.

TLDR - since installation my neighbour has planted fairly quick growing trees not too far from my panels. They now partially shade my panels in the late afternoon. The way they are growing the shading will only get worse. Not much point in doing anything with them as their efficiency is only going to get worse.

Obviously irrelivent to this thread.

Could you ask or even insist they cut the trees back ?

tfspark

Scot_39 said:

tfspark said:

Thank you Scot_39 for such a comprehensive reply. It's all a bit clearer now.

My solar system is a small 2kW system of eight panels. They were installed in 2016 on an out building and were DNO registered, certified and notified to LBC. They are not MCS registered hence no export payments.

TLDR - since installation my neighbour has planted fairly quick growing trees not too far from my panels. They now partially shade my panels in the late afternoon. The way they are growing the shading will only get worse. Not much point in doing anything with them as their efficiency is only going to get worse.

Obviously irrelivent to this thread.

Could you ask or even insist they cut the trees back ?

Thanks to all who took the trouble to reply.

I did have a conversation with my neighbour last year regarding the tree shading. He agreed they were growing tall quickly and said he would get round to trimming them some time.

His FIL came round yesterday and they did get trimmed down a bit. Not sure it'll make a huge difference but we'll see once they come into leave. I'm also not sure I could have insisted.

I'll check out Octopus' solar tariffs. Thanks Reed_Richards for the suggestion.