Green Building Forum - Can PV Solar make your grid meter run backwards!?

Can PV Solar make your grid meter run backwards!?

JTGreen — Sun, 09 Sep 2012 15:02:39 +0100

Just doing my meter readings for The Carbon Account, and my electricity meter is reading lower now than at the start of August. Is it running backwards due to PV solar? Surely that's not how it is meant to work? (Since we also have generation meter for purpose of FiT.

Can PV Solar make your grid meter run backwards!?

tony — Sun, 09 Sep 2012 15:16:28 +0100

It can, you need a new meter!

Can PV Solar make your grid meter run backwards!?

jms452 — Sun, 09 Sep 2012 15:19:29 +0100

Officially you should let your electricity supplier know pronto as they won't be happy. By giving them a negative meter reading you are effectively letting them know!

Our PV installer advised us to let our electricity co know we were now generating so we couldn't be accused of 'stealing' electricity.

Some may suggest that you maintain the situation as it saves you cash but as our installer pointed out this might not be well received!

Can PV Solar make your grid meter run backwards!?

Beau — Sun, 09 Sep 2012 15:26:46 +0100

Yes your meter can run backwards.
My parents have a backwards spinner that they have reported to their supplier twice but nearly two years on nothing has been done

Can PV Solar make your grid meter run backwards!?

JTGreen — Sun, 09 Sep 2012 18:45:03 +0100

The electricity supplier knows we've had PV solar installed, because they are also our FiT provider (Ecotricity/microtricity). I'm sure it happens all the time, and presumably they are responsible for fitting a new meter if they require me to have one?

Can PV Solar make your grid meter run backwards!?

Seret — Sun, 09 Sep 2012 18:57:32 +0100

They probably aren't aware of what meter you have installed, so I wouldn't assume they it's running backwards. Give them a shout to avoid unpleasantness later.

Can PV Solar make your grid meter run backwards!?

JTGreen — Sun, 09 Sep 2012 19:54:31 +0100

Of course I'm going to let them know (first thing tomorrow when their customer service open) - but I'm wondering who is responsible for upgrading the meter - me or them?

Can PV Solar make your grid meter run backwards!?

dimengineer — Sun, 09 Sep 2012 20:29:37 +0100

Yes indeed. Older meter will run backwards. When I put in my appication, there was a check box on the form "does your meter run backwards". Which I ticked. That was a year ago.
However, my PV is only 1.7kWp, so it only runs backwards occasionally, and the meter reading is never negative, so I don't think the supplier is that fussed

Can PV Solar make your grid meter run backwards!?

mzthomps — Sun, 09 Sep 2012 21:00:06 +0100

Mine does also (meter dates to late 70s). I'm with Npower for supply and fit payments. On their application form there was also a tick box. I have also written to them by email asking if I needed to do anything. They said no and that it was now with their metering team. I believe that the local grid company do the work on their behalf - at no charge to end customer. I'm still waiting, but they did say it would take some time and it was no longer my responsibility. So far Npower fit team have been very good.

Can PV Solar make your grid meter run backwards!?

Nick Parsons — Sun, 09 Sep 2012 21:07:28 +0100

but I'm wondering who is responsible for upgrading the meter - me or them?

Them

Can PV Solar make your grid meter run backwards!?

JTGreen — Sun, 09 Sep 2012 21:24:25 +0100

That's a relief. I'm starting to dread every new expense associated with this house. Thanks, I'll inform ecotricity tomorrow and see what they suggest.

Can PV Solar make your grid meter run backwards!?

Gavin_A — Sun, 09 Sep 2012 21:47:20 +0100

Posted By: Nick Parsonsbut I'm wondering who is responsible for upgrading the meter - me or them?

Them

them.

Can PV Solar make your grid meter run backwards!?

Nick Parsons — Sun, 09 Sep 2012 21:53:39 +0100

Gavin_A. That's what I said - I just failed to put JT Green's words (''but I'm wondering who is responsible for upgrading the meter - me or them?'') in quotes!

Can PV Solar make your grid meter run backwards!?

nikhoward — Sun, 09 Sep 2012 23:16:32 +0100

Well with nights drawing in, you will produce less, and consume more, so i am fairly sure you will be spinning the correct way soon. Let hope they don't change the meter till the spring

Can PV Solar make your grid meter run backwards!?

owlman — Mon, 10 Sep 2012 08:12:42 +0100

Posted By: Seret They probably aren't aware of what meter you have installed, so I wouldn't assume they it's running backwards. Give them a shout to avoid unpleasantness later.

Surely, everything up to and including the meter is their responsibility. They have to be given access to it. So the question is; why should the householder have any input at all ? Why should the householder do their work for them, where did that creep in ?

What say you Gavin ?

Can PV Solar make your grid meter run backwards!?

tony — Mon, 10 Sep 2012 08:21:59 +0100

I think that it is the owners responsibility to tell them about the change, even itf it is the same supplier as the FIT, they almost certainly dont communicate with each other.

Can PV Solar make your grid meter run backwards!?

skyewright — Mon, 10 Sep 2012 09:22:11 +0100

Posted By: mzthompsMine does also (meter dates to late 70s).

I wonder what the (re-)calibration period is on those old meters?

Can PV Solar make your grid meter run backwards!?

JTGreen — Mon, 10 Sep 2012 09:50:19 +0100

Just to spoke to them, they will change the meter to one with a backstop. Hope it's smaller than my existing, as I've got a pull out coat cupboard on castors in front of the meter that is made to fit that space. Or perhaps they will put it outside?

There was talk of the billing dept working out a fair bill for that period where the meter was running backwards - not quite sure how that's going to work, as there is no record of what was generated when (just a cumulative total) and we were out of the house for a period (therefore for not using much energy from the grid - the builders must have used some - but also exporting pretty much all we generated).

Can PV Solar make your grid meter run backwards!?

SteamyTea — Mon, 10 Sep 2012 09:55:05 +0100

I thought they had to be changed every 20 years by statute, but I guess some get forgotten.
It was possible to 'stall' an old mechanical meter with an LCR circuit and this was outlawed a long time ago to stop it happening.
So how would the billing company calculate how much you have imported when all they have is how much you have generated and an import meter that is running this way and that. FIT is not set up to offset export with import, just to pay for your own generation.

Can PV Solar make your grid meter run backwards!?

JTGreen — Mon, 10 Sep 2012 10:06:44 +0100

Not sure, spoke to customer service frontline rather than billing, but I think they are proposing to measure our usage with the newly installed meter over a period (of a few weeks) and hypothecate it on that.

This creates an incentive to keep usage from grid as low as possible during that period (perhaps a good thing for reinforcing good habits). I don't think it will bear much relation to how much we actually exported/used (and hence how much the meter ran backwards) as the conditions for PV solar generation will be different (how much day to day variability is there?) and our consumption will be different (as now living in house).

Can PV Solar make your grid meter run backwards!?

windy lamb — Mon, 10 Sep 2012 11:19:42 +0100

We have Western Power for the DNO and they also do the meters for SSE. Told SSE about are generation and they said it would take months for a meter change. So I phoned Western Power-took them a week to change the meter, then came back and put in an export meter 8 weeks later. I'm happy!

Can PV Solar make your grid meter run backwards!?

JTGreen — Mon, 10 Sep 2012 11:26:09 +0100

Just looked at my meter - it was installed in July 1985! What's the legislation that says electricity supplier is responsible for making sure meter is fit for purpose/upgraded every 20 years?

Can PV Solar make your grid meter run backwards!?

JTGreen — Mon, 10 Sep 2012 11:26:45 +0100

Did you have to pay for your export meter?

Can PV Solar make your grid meter run backwards!?

SteamyTea — Mon, 10 Sep 2012 11:48:00 +0100

It is a problem with 'clock arithmetic' knowing what the time is tells you nothing about what has happened before, how the Enigma machines do the encoding.
So say you generate 10 kWh on Monday, you import nothing and export 6 kWh, your meter would show 6 kWh lower than the previous day, you have used 4 kWh in the house.
Now the next day you generate 12 kWh, still use 4 kWh in the house, your meter will show another reduction of 8 kWh
Wednesday is wash day and you use 15 kWh in the house, you generate 6 kWh, so you must be pulling in 9 kWh, so your meter will now be showing 5 kWh less than it did at the start of the period (call it Monday), your generation meter will show 28 kWh.
So I cannot see how they can work out that you actually used 9 kWh of imports as the meter will show -5 kWh.

Can PV Solar make your grid meter run backwards!?

SteamyTea — Mon, 10 Sep 2012 11:50:24 +0100

Posted By: JTGreenJust looked at my meter - it was installed in July 1985! What's the legislation that says electricity supplier is responsible for making sure meter is fit for purpose/upgraded every 20 years?

May be this one:
http://www.legislation.gov.uk/uksi/1998/1566/note/made

Can PV Solar make your grid meter run backwards!?

skyewright — Mon, 10 Sep 2012 12:50:17 +0100

Posted By: JTGreenThere was talk of the billing dept working out a fair bill for that period where the meter was running backwards - not quite sure how that's going to work

I think that's the sort of question that Ted would probabaly know the answer to, if anyone does?

Can PV Solar make your grid meter run backwards!?

JTGreen — Mon, 10 Sep 2012 12:57:31 +0100

Posted By: SteamyTea

May be this one:
http://www.legislation.gov.uk/uksi/1998/1566/note/made

Thank you! perfect.

Can PV Solar make your grid meter run backwards!?

SteamyTea — Mon, 10 Sep 2012 13:12:06 +0100

Posted By: JTGreenThank you! perfect.

May be a case of be careful what you ask for

They changed the electric meters in Uganda to and peoples 'metered usage' almost doubled, something to do with the old ones not being very good apparently.

Can PV Solar make your grid meter run backwards!?

JTGreen — Mon, 10 Sep 2012 13:22:59 +0100

Well, I don't have a choice - because my 1985 model is running backwards as we speak. There is a limit to how long I could let that go on for. Also, I do want to know how much grid electricity we are actually consuming (wrt CO2 emissions), so having an artificially low reading is not too good from that point of view even if it means I'm better of financially.

At least I can argue that it is the suppliers responsibility to ensure a properly certificated meter and that consequences of not having one (i.e. runs backwards when PV solar is installed!) should not be paid for by the customer (given impracticality of hypothecating grid import in absence of a properly certificated meter). We'll see.

Can PV Solar make your grid meter run backwards!?

ted — Mon, 10 Sep 2012 13:45:15 +0100

The relevant legislation as far as backwards running meters is concerned would be the Electrical Safety, Quality and Continuity Regulations 2002 - http://www.legislation.gov.uk/uksi/2002/2665/made

3.â€”(1) Generators, distributors and meter operators shall ensure that their equipment isâ€”
(a)sufficient for the purposes for and the circumstances in which it is used; and
(b)so constructed, installed, protected (both electrically and mechanically), used and maintained as to prevent danger, interference with or interruption of supply, so far as is reasonably practicable.

Any meter that is running backwards due to onsite generation is not "sufficient for the purpose". Any supplier that has been made aware that a meter is not recording usage correctly and does not expedite a change of meter has failed to discharge their duty under the ESQCRs and has no grounds for later charging for units on a calculated basis. Suppliers generally have a lease agreement with the meter owner if they don't actually own the meter themselves.