Clocks changing in October- What about the smart meter?

  • 23 September 2023
  • 12 replies

Will the smart meter readings and the usage chart on the OVO website both go back an hour at the end of October?


Best answer by BPLightlog 23 September 2023, 20:04

View original

12 replies

Userlevel 7
Badge +5

Hi @Sukicat , most smart meters are on GMT and don’t change 


Are the OVO website Usage charts GMT all year too?

So when the Path to Zero challenge time slot is 4 til 7, is that GMT too? Is it GMT now, or BST?

Userlevel 7
Badge +5

I think the usage charts do change - otherwise people would get confused. (Someone can confirm)
We’re current on BST, changing to GMT when the clocks change back. 

That’s what I suspected-meters don’t change, but the charts do. 

So what happens to the Path to Zero Challenge 4-7pm? Is that BST now?and will still be 4-7pm after the clocks have changed to GMT?

Maybe the ‘Path to Zero Challenge Time Slot’ should be marked on the usage chart, to make it clear?

Userlevel 7

It apparently depends on the meter, but as the industry as a whole works on GMT all year round, you can expect to see an hour’s shift at the end of summer time. You can see what happened at the last time zone change on 26 March: Your energy use - OVO Energy  (scroll below the chart to see the table of timed usage):

These are the usage figures I see from my Secure Liberty 110 meter:


There are other oddities lower down, too, because they have to make sure that each calendar day has 48 half-hours’ worth of figures. It all comes right the following day. 

The same happens with meter readings: they are taken at 00:00:00 GMT all year round, so they are in fact recorded at 00:01:00 during summer time.  

Although I’ve not seen it confirmed anywhere, I’m sure the Power Move time slot will stay in local time. Once summer time ends, 4-7PM will mark the high peak of daily consumption. Just now, it’s around 5-8 PM. Here’s a chart I posted elsewhere a couple of days ago which shows this apparent offset:


Come 30 October, the two lines will stay put while the coloured bars all shuffle two clicks to the right, so the ‘target zone’ neatly covers the high peak of demand.


Userlevel 7

Hey @Sukicat,


Great question!


With Power Move, the times will change with the clock change. I’m just finding clarity about the usage graphs but I’d assume they also change.

Userlevel 7

I’m just finding clarity about the usage graphs but I’d assume they also change.


The graph shows just the same as the table, with an hour missed at the start of BST and one added at the end. Here’s last March’s:


No usage shown for 01:00 to 02:00. In October, there are two pairs of bars for this hour.


Userlevel 7
Badge +2

Hey @Sukicat,


Great question!


With Power Move, the times will change with the clock change. I’m just finding clarity about the usage graphs but I’d assume they also change.

Did you ever get clarity about the usage graph @Emmanuelle_OVO 

Userlevel 4

Hi @Emmanuelle_OVO , @Sukicat and @Jeffus 

Clocks went forward at 01:00 GMT at the weekend so any idea why there is 24 hours of data since there were only 23 hours in the day?

I understand the smart meter records based on GMT (UTC) so I have compared the data from the OVO app with data downloaded from Glowmarket.

UTC_Date                    UK_Date                      Elec_kWh    OVO kWh
                                      31/03/2024 00:00:00                       0.10
                                      31/03/2024 00:30:00                       0.07
31/03/2024 00:00:00    31/03/2024 00:00:00    0.08            0.08
31/03/2024 00:30:00    31/03/2024 00:30:00    0.08            0.08
31/03/2024 01:00:00    31/03/2024 02:00:00    0.06            0.06
31/03/2024 01:30:00    31/03/2024 02:30:00    0.06            0.07
31/03/2024 02:00:00    31/03/2024 03:00:00    0.06            0.06
31/03/2024 02:30:00    31/03/2024 03:30:00    0.11            0.11
31/03/2024 03:00:00    31/03/2024 04:00:00    0.10            0.10
31/03/2024 03:30:00    31/03/2024 04:30:00    0.10            0.10

Why two sets of data for 00:00 and 00:30? The second set agree with Glowmarket, so where do the first two readings come from?

Userlevel 7

... where do the first two readings come from?


I haven’t checked the app (don’t like phones!) but on the web, this is evidence of a fudge in the usage data presented on the Day tab. The figures you see for 12:00am and 12:30am are actually the ones for the bottom of the table, following 11:30pm. 

I suspect this is because the page retrieves the (UTC) day’s worth of figures and presents them in BST. It’s not usually significant for most customers, whose usage doesn’t vary much from one day to another at that time of night. For those whose does, though, it can come as a shock: if you charged your EV after midnight on Thursday, yet see the spike in usage a day earlier, say.

It has been reported as a bug, but ‘they’ have clearly chosen not to do anything about it.

Userlevel 4

Thanks @Firedog . Strange how BST/GMT causes so much confusion. I guess if the 01:00 and 01:30 data is missing there would be comments on the forum re “where did my data go”.

Userlevel 7
Badge +5

One of the services I use is totally confused as to which time slot fits where ..

It will all shake out in the wash I guess