Hey @Firedog,

Some interesting questions raised here, I’ve asked one of our experts to see if they can shed some light!

@Firedog 

Have you tried comparing the 30 min data pulled from ovo vs that from https://www.n3rgy.com/

Is each 30min slot data the same in both data sources every day? 

Hey @Firedog,

Received a very in depth response from one of our experts to your first question:

This query is high level and complex, and it depends on the tariff the customer is on, but we are only billed ‘Distribution Use of Systems’ costs at the level the supply point (meter) is traded.

So we'd only be billed on Half Hourly readings data if the tariff and meter type is, what is known as, ‘Elective Half Hourly’. If they are not Elective then they will be billed on the Register Readings from the Billing Registers. The billing register reads will never directly align exactly to the Half Hourly profile reads for many reasons, the offset being one, the time the snapshot is taken and a few other bits.

But the amount of energy split out will always be within a permitted tolerance, noting the Half Hourly Profile is a record of the energy using in each Half Hourly period that is then posted to a table. The Billing Registers have an Offset applied and record the energy used in a set period as per the tariff they are on.

It is nearly impossible to align the Billing to the Profile data though due to the in built offset required by National Grid to protect the demand switching.

So, to confirm, the usage used for billing is taken from the configurable Billing Registers. The Half Hourly Profile data is the amount of energy recorded to have passed through the meter every half hour. The source of the data streams is the same, but the recording triggers differ.

I don’t know about ‘every day’, but I’ve never come across any discrepancy. Here are yesterday’s figures:  
 

oMany rows all with zero difference removed]

So, spot on.

The OVO figures are taken from the API, not the (2-digit) entries on the Usage page. There is a fault there, documented elsewhere, which has until yesterday moved the last hour’s data to the top of the table. This won’t be a problem now BST’s behind us.

My E7 offpeak period is 00:00 - 06:59 GMT, so adding the 14 Hh amounts to the midnight reading should produce a figure equal to the next reading. It does, but not exactly.

Here are two different recent midnights, just to show that this isn’t anything to do with the BST/GMT variation (so long as you pick the right figures to add up!):

Brilliant, thanks very much - also to the expert ‍♂️

That’s what I guessed: “the daily difference amounts to about 4 minutes consumption, so that could be linked to the random offset of the switching time between peak and offpeak.“

This appears to suggest that while usage during the switch-on offset time is recorded on the peak register, the offpeak register will stop clocking precisely at the start of the peak period. In other words, every consumer on this type of tariff will be diddled out of the difference between peak and offpeak rates for a few minutes’ consumption every day¹. As I said, neither here nor there for the customer, but a nice little windfall for OVO.   

OK, that’s what I expected. In this case, then, the 2kWh or so that the meter recorded but didn’t make it to DCC will nevertheless be billed to me² by virtue of the closing read taken by the engineer before he pulled the plug on the old meter - less any fraction of a kWh, of course. OVO will still miss out a little bit, so I’ll let them off for pinching a smidgeon at midnight every day 
  

1. Keeping my pedant’s hat on, those few minutes’ worth of difference will be at the same draw as before the switch, not the potentially much higher draw (and cost) that the switch might lead to, e.g. if a load of storage heaters are fired up.  
    
2. Billing is still on hold for me, so what this month’s statement will look like is going to be interesting. Last month’s used a completely arbitrary estimated closing reading from a meter that was probably still in the back of the engineer’s van at the time. We’re fast approaching the five- or six-week deadline by which time everything should have fallen into place following a new meter installation. 
    

Hey @Firedog if it exceeds the 6 week deadline let me know and i’ll get Forum_Support to reach out.

Thanks for the offer. Check your PMs