E7 active period differs from billing period

gorspenyans

While monitoring my energy usage I noticed that for the first 30 minutes my E7 (off peak) becomes active (Midnight - 00.30) I am being charged on the peak rate tariff not the off peak. As this is when all my appliances on off peak circuits start drawing power it's my highest cost of my E7 active period (Not tariff period). On raising this with octopus they say; yep, nothing wrong with that, it's just the way it is. Surely for that 30 minutes I am being overcharged, conversely I am being undercharged for the last 30 minutes of the E7 period (my lowest demand)

Octopus's reply has left me a little bewildered. Can I do anything (apart from change supplier)?

Octopus's reply to my concerns;

Hi Gary,

Thank you for your message and for sharing your concerns about the Economy 7 tariff timings.

I understand how important it is for your Economy 7 appliances to run during the off-peak period and for the timing to match perfectly with your tariff. With smart meters on Economy 7 tariffs, the off-peak period is fixed from 00:30 to 07:30 Coordinated Universal Time (UTC). During British Summer Time (BST), this shifts to 01:30 to 08:30. This timing is standard for smart meters and is not adjustable.

For traditional non-smart meters, the off-peak periods can vary depending on the meter type. For example, 5 Terminal (5T) meters typically have an off-peak period from 00:00 to 07:00, while 7 Terminal (7T) meters have multiple off-peak indexes, including 00:00 to 07:00 and additional off-peak times on weekdays and weekends.

Because smart meters operate on UTC and the tariff timings are fixed, there can be a difference of 30 minutes or so compared to traditional meters or appliance timers. Unfortunately, this means your appliances may start drawing power just before the smart meter's off-peak period begins, resulting in some usage being charged at the peak rate.

I appreciate this can be frustrating, especially when your appliances are designed to run on off-peak power.

If you have any further questions or would like assistance with your tariff or meter setup, please let me know. I’m here to help.

Best wishes,

-----

I'm hoping someone on the forum has an answer other that lump it or move supplier

gorspenyans

A quick screen shot of my usage for one day. As you can see the cost for that first half hour is over double the next, while the load is very similar.

QrizB

Are you on a traditional E7 tariff, billed on two sets of meter readings (registers)?

If so, check on your meter to see which register is active at midnight (or shortly after) when your storage heaters etc. start changing. It should be the cheap rate register.

If it *is* the cheap rate register, there's no problem with your billing.

Swipe

While there can be an offset delay to prevent all meters going onto off peak at the same time, your tariff price schedule should still match the time that your smart meter switches to off peak via ALCS (assuming you have a five port meter and not a 4 port wth an external contactor that does your switching). I'd raise this as a complaint and insist that they correct things so that the switching and tariff times match each other. If they still refuse, ask for a deadlock letter and tell them you'll go to the ombudsman who will side with you and also inform them that you'll be requesting bill recalculations for the off peak usage at peak rate price. Hopefully, you just spoke to someone at Octopus who doesn't properly understand how smart meters are meant to work on E7 and they are getting confused with how time of use tariffs which are billed via 30min buckets, can result in some overcharge compared to E7 ALCS switching. Please post a photo of your meter if you are unsure which type of setup you have.

WiserMiser

Octopus's use of AI has been less than an outstanding success.

QrizB

WiserMiser said:

Octopus's use of AI has been less than an outstanding success.

Agreed.

Whatever combination of artificial intelligence and natural idiocy was responsible for the reply quoted in the first post, it's more wrong than right.

gorspenyans

That reply from Octopus had my blood pressure up to say the least. It was the second of two, the first was no better, I quote their reply; "This setup is standard for smart meters on Economy 7 tariffs"?  Seriously? 

I am on an E7 tariff, have been since 14/02/2025, we were on Agile prior to that but having solar without a battery it became more expensive than an E7 fix. This problem appears to have been present since that switch.

Knowing how Agile works also makes me read the Octopus reply with disdain. If Octopus can charge me per 30 minute slot on Agile then surely they can do the same for an E7 tariff. 

Thank You to Swipe, I will give that a go.

gorspenyans

QrizB said:

Are you on a traditional E7 tariff, billed on two sets of meter readings (registers)?

If so, check on your meter to see which register is active at midnight (or shortly after) when your storage heaters etc. start changing. It should be the cheap rate register.

If it *is* the cheap rate register, there's no problem with your billing.

Yes, we are on a traditional E7 tariff. They are charging us peak for the first 30 minutes. This can be seen by the light and dark pink shading and blue line on the lower of the two graphs above. on 18 Dec between 23.30 to 00.00 our consumption was 0.144kWh, then on 19 Dec (The graph above) for 00.00 to 00.30 it jumps to 4.169kWh but remains on the peak tariff.

QrizB

gorspenyans said:

Yes, we are on a traditional E7 tariff.

Ok.

gorspenyans said:

They are charging us peak for the first 30 minutes. This can be seen by the light and dark pink shading and blue line on the lower of the two graphs above.

The pretty graphs are irrelevant for billing purposes.

The only thing that matters is which register is active during the period that your ALCS is active.

Your ALCS is unlikely to switch on a half-hour boundary due to the randomised delay built into every smart meter.

Swipe

Yes, as above, you need to stay up and check your meter to see which rate register is being written to for that first half hour after your E7 circuits energise. There might not even be an issue. If you have an in home display, that should show you the current tariff price in use but it's always wise to confirm it on the meter as well.

Scot_39

Swipe said:

While there can be an offset delay to prevent all meters going onto off peak at the same time, your tariff price schedule should still match the time that your smart meter switches to off peak via ALCS (assuming you have a five port meter and not a 4 port wth an external contactor that does your switching). I'd raise this as a complaint and insist that they correct things so that the switching and tariff times match each other. If they still refuse, ask for a deadlock letter and tell them you'll go to the ombudsman who will side with you and also inform them that you'll be requesting bill recalculations for the off peak usage at peak rate price. Hopefully, you just spoke to someone at Octopus who doesn't properly understand how smart meters are meant to work on E7 and they are getting confused with how time of use tariffs which are billed via 30min buckets, can result in some overcharge compared to E7 ALCS switching. Please post a photo of your meter if you are unsure which type of setup you have.

It should afaik make no difference whether you have a 5 port or 4 port with meter 2A relay controlled external contactor.

Why do you think its different ?

The behaviour is the same when meters configured properly.   

My tariff and my alcs loads are at least matched on my 4 port smets1 with proteus external.

When tariff times and alcs calander times matched. 

The op needs to know if register billed (pretty sure efen Octopus dont use 1=2 hourly)  which is the norm for e7 - and if register whether the correct register in use in his disputed 1/2 hr slots.  The preset meter offset is applied to both alcs and register based tariff timings as well - to keep both in sync. 

If wrong Octopus need to set alcs calander to match tariff times or vice versa.  The 2 must match for register based billing to work.

And looking at that 1/2 hrly kWh and cost chart - it looks like they could be out by 1/2 hour. 

But the OP likely isnt billed by 1/2hrly so needs to check day night registers in use at the time..

Which is easy on many ihds or meter types that show active tariff register or rate and on meters themselves some even alcs contactor status.

If OP posts meter model ... 

And their referring to things like appliance timers, or older meter behaviour,  when the OP has told them his restricted meter feed from the new meter is llive - just muddies the waters.