How does exporting work with meters ?

[andycee]

As part of my research before pulling the trigger on a small 2.4Kw grid tie system, I'm looking to confirm what actually happens in a grid export situation.

 

I have an old analogue spinny meter that I've hung on to for dear life. Am I correct in assuming that in an export situation this will run backwards ?

 

The clarify, this will be a non-MCS self install system, provided by Midsummer, cabled up and roof/kit install by myself and system design/final connection/commissioning/tests by a spark.

 

I'm aware that such a system should not really be exporting, and will ensure self consumption with an immersion diverter. I'm just trying to establish what will happen if, lets say the diverter accidently gets turned off 😄

 

TIA

[tonyshouse]

You might mean kW 

 

the meter I knew about only ran the units backwards not the tens 

[SteamyTea]

Most of the newer, dial meters had a ratchet to stop them running backwards.

Think it was the very, very old ones that could run backwards.

Post a picture of it up and I am sure someone will know which model it is.

 

I think it is illegal to tamper with a meter, and that included winding it backwards by any means, without agreement.

[Ronny]

As far as I know the feed in tariff from the suppliers will only work with a smart meter. They need exact readings as the FIT payments are very small compared to the unit rate you pay.

[TonyT]

I have a spinning disk meter and get FIT payments have done since 2011.

no requirement to fit ‘smart’ meter

[Conor]

Your electric supplier will (via the DNO) install a new digital meter for you when you apply for a contract to get export payments. Mine was swapped the other day. 

[joth]

7 hours ago, TonyT said:

I have a spinning disk meter and get FIT payments have done since 2011.

no requirement to fit ‘smart’ meter

 

FIT was disconnected in 2017 and replaced with SEG which does require a smart meter to be paid for export. (It's literally what the S in SEG stands for).

But this is irrelevant to the OP as they're not getting an MCS install so won't get paid anyway

[JohnMo]

As self install or non MCS install, you will not get paid for export, so doesn't really matter what occurs during export.

 

With a 2kW array and I assume an immersion diverter, you would be very unlikely to export, except for a few weeks per year if no-one is home during the day.

 

If you hoping for export payment, you need an MCS certificate to be eligible.

[joth]

9 minutes ago, JohnMo said:

so doesn't really matter what occurs during export

Well it does if the meter goes backwards, as you'd be breaking the law, but ultimately you're only going to confirm that by installing the solar and finding out. 

[TonyT]

You then inform the DNO once and only once and let them change the meter in due course.

[ProDave]

As we are talking of a DIY install you will not be eligible for export payments.  That needs an MCS install and when you compare the cost difference you will realise you will never recoup the MCS premium with the export payments in your lifetime.  So forget that.

 

BUT even with a DIY install you have to notify it to the DNO and perhaps that will make them look at the installed meter and if it is a spinner, replace it.  And unfortunately now, any replacement will be a smart meter.

[andycee]

TY all. Really helpful.

So G98 notification to my DNO is still required for a non-exporting installation ?

On the whole meter backwards thing, I'm sure my parents meter does so (10+y old MCS install). I need to check if they were mistaken....

JohnMo mentioned "With a 2kW array and I assume an immersion diverter, you would be very unlikely to export, except for a few weeks per year if no-one is home during the day." - thats just the issue, even with a small system, most generation will be during sunlight hours and most usage outside of this, so exporting would still happen (well, only when immersion is up to target temp.). Can mitigate this somewhat by running some high loads during the day but I also have a lot of kit that runs 24/7.

 

Have done plenty of number crunching, and even this £1800 2.4kW system will have an ROI of 1.8 years (at expected prices coming in October). But of course thats presuming 100% solar usage.

Immersion diverters are fine, but not that efficient as all you are saving on is the gas you would have used to heat the water, and gas is way cheaper for heating things.

 

So really its either this solution or going the storage route, but then the battery investment is considerable and will ruin the ROI further. Its such a shame - we already have access to a giant battery - the National Grid.

 

I wouldn't be comfortable waiting longer than 2 years for ROI - this is primarily a cost saving exercise for me personally.

 

 

Edited April 15, 2022 by andycee

[ProDave]

I manage to self use most of what my 3.68kW system produces just by time shifting the big appliances to the middle of the day and the immersion diverter for any left over.  Heating your hot water by the immersion may not be the best use of it, but it is certainly way better than export it for no payment.

 

I will be mighty impressed if you can self use £1000 per year from a 2.4kW system, I doubt mine even generates that much (but I do have shading issues)

[joth]

2 hours ago, TonyT said:

You then inform the DNO once and only once and let them change the meter in due course.

Nit: inform the supplier (unless in NI?). The DNO don't have anything to do with the meter and won't give a fig which direction it is turning.

 

Technically after informing supplier you'd have to leave the PV disconnected until they fix the meter, as at that point you've admitted to then you're knowingly breaking the law by causing it to run backwards.

 

[Dillsue]

1 hour ago, joth said:

Technically after informing supplier you'd have to leave the PV disconnected until they fix the meter, as at that point you've admitted to then you're knowingly breaking the law by causing it to run backwards.

 

Having posted on an internet forum the suspicion that the meter may run backwards, Id hazard a guess that knowingly exporting anything through a backward running meter from now on would be fraud????