[Mortimer]

Hi,
As an absolute idiot when it comes to electrics, I need some help.
I have just had a 12 month bill for £12,500 from EON on a 3-phase supply. Usage is calculated at 45Mwh over that 12 months.

However I have solar panels and the app for those show that we have:
Produced 16.2Mwh
Fed to Grid 2.5Mwh
Consumed 27.5Mwh
From Grid 13.9Mwh

How do I find out which is correct. The implication is that I put in £25,000 of panels with absolutely no reduction in usage if the EON meter is correct. If it is incorrect, I have been overpaying for years possibly or just since solar went in, in May 23.

Any help gratefully received.

[retrotecchie]

@Mortimer

Absolutely, the meter is likely not net reading because it simply cannot! That said, it may be an older Atlas with a newer version of the software installed. If you press the Display button it should cycle through a set of registers each time you press the button.

If you see one that says 'sIg' followed by a number, then its an AMI version of the meter with an obsolete GSM module. Not smart, but capable of being read remotely by a mobile phone. If you see a display that says 'iPt', that is your total import which is what you are being billed on.'ePt' is your export (if the meter is capable). But only if it's the AMI capable software version.

[retrotecchie]

@Mortimer

Are you a domestic or a business customer?

Why are you only getting 12 monthly bills? Are your meters smart or do you submit regular bill readings?

Do you have FiT or SEG for your solar panel installation?

SEG or FiT for your exported energy is paid back to you separately from the bills so how much have you received in export payments since your solar went it?

[Mortimer]

Thank you for the speedy reply.

We are a business. We have two meters and tbh as I was paying the one by DD, I had not noticed that EON had not taken money for the other meter and therefore neither paid, nor submitted a reading. The meter used to update the previous supplier and I again assumed it was doing this time - my mistake.

We are supplying back to grid, but have no tariff arranged. It was said at the time that we would not get such a good deal on the tariff ie it would be clawed back one way or another.So we have not received nor are we due any export payments.

Does this make sense?

I want to be sure that we are getting the correct usage, it seems as if we are paying the same as we did before the Solar went in and a completely differnt reading to the Solar app. The installer says that a 1-2% difference would be normal.

[retrotecchie]

Originally Posted by Mortimer

We are supplying back to grid, but have no tariff arranged. It was said at the time that we would not get such a good deal on the tariff ie it would be clawed back one way or another. So we have not received nor are we due any export payments.

Does this make sense?

It makes no sense at all to me, If you export to the grid you will get paid for your export via the SEG scheme. That is completely separate from any tariff you may or may not get with your supply. The two are completely separate.

However, you will always pay more for imported electricity per kWh than you get for exporting surplus, so I'd make sure, in the first instance, that you use everything you generate rather than export anything if you have the ability to adjust your system to not export.

Those numbers on your app. Are they total figures since the system was installed?

Produced 16.2Mwh
Fed to Grid 2.5Mwh
Consumed 27.5Mwh
From Grid 13.9Mwh

Your total generation was 16.2MWh. You exported 2.5MWh of that leaving a balance of 13.7MWh. If you add your grid import to that, the total is 27.6MWh so that's within a gnats whisker of your consumption, give or take rounding errors.

There are two possible reasons off the top of my head why the figures from your solar system app don't tally with the meter readings.

One is the difference between real power (KWh) and apparent power.(kVAh) which will depend on the power factor of your installation. Inductive or capacitative loads (motors, fluorescent lighting, etc.) can make quite a difference depending on whether or not your system is properly balanced and has power factor correction (PFC) mitigation in place but if your meters are measuring kWh and your solar is metered in kWh then I don't see that as a problem.

The other issue may be that your three phase meter is one of those models that cannot correctly handle export power and erroneously adds your export onto the import to generate a net figure, rather than subtract export from the total consumption.

Certain Landys and Gyr meters are notorious for this issue.

Does your meter have a menu function that allows you to read your export register and how does that tally with your solar app?

I know this is a nuts thing to suggest when the sun is shining, but I'd be tempted to take a full set of meter readings, shut down the solar for a 24 hour period, and then take another set of readings and see what has changed with regards to meter readings.

Any export register should stay the same and the import registers will increment. The following day, re-enable the solar and do a similar set of meter readings. Again, see what's changed. The export should rack up a bit and (assuming your usage is fairly consistent), the import should reduce accordingly. If the change in import is an increase in roughly the same amount as the solar has produced, I would be inclined to suspect that the meter is not capable of handling export properly and should be swapped out. This had happened to a few folk I know, especially with L&G meters.

If that is the case, then what can be done to correct the situation retrospectively I'm not sure. But if the export is being added to the import on the meter and you are effectively being charged for what you've exported, the meter readings should allow an adjustment to be recalculated without too much difficulty.

In any case, you would need to contact the Business part of E.On Next and have that conversation. hellobusiness@eonnext.com by email or 0808 501 5699 on the dog and bone.

[Mortimer]

If this image shows, is it of any help?

[retrotecchie]

@Mortimer

That looks like an EDMI Atlas Mk10 polyphase meter which doesn't have any smart capability so how it sent readings to the previous supplier, I know not.

I'm also thinking, if that's the version of the meter I think it is, that it technically doesn't have an export register, so really isn't suitable for solar grid-tied applications. But I could be wrong. Hard to tell without seeing the logo just to the top left of the case next to the left of the display.

[Mortimer]

I hope this is better.

[retrotecchie]

Originally Posted by Mortimer

I hope this is better.

That'll do. It was the EDMI Atlas Mk10 - the D suffix just means it has remote disconnect but it's not a smart meter in any way, shape or form. It does have connectivity to a BMS system via RS485 or ModBUS but I can't see any such connection to the meter.

It also doesn't have capability for measuring your export, so it's not the right meter for use with any kind of solar system.

That's why the installer said not worth going for SEG....your meter isn't actually compatible! If your solar PV system is trying to drive power backwards through the meter, that will likely explain why you are still seeing large bills.

[Mortimer]

All of this is really useful information and I am very grateful.

Does this explain the huge difference between what the EDMI meter and the solar app?

The app shows the consumption from the mains as being far less than the actual meter. (excluding any feedback).

Is it still possible that the meter is not 'nett' reading?

I hope this make sense - I just don't understand the system.