Can I access downloadable usage data for prior year?

You could try sites such as Glowmarkt (or their Bright App) or n3rgy - Unified access to smart energy data (who supply gas usage data in m3 rather than kWh). There are others as well. I’m sure others will chip in with their suggestions.

With Glowmarkt you will need to supply your MPAN number and may/might be able to get data going back up to 12 months depending on how long your smart meter has been logging data and the frequency of reading (daily or half-hourly). Data can be downloaded as a CSV file and then imported straight into Excel. If you link the data (rather than copy/paste) you should be able to simply refresh the data after each download.

Good luck!

Thank You BeePee and Firedog - I will be investigating these solutions.

I tried Glomarket, but that only returned a few months of data.

I’ve just looked at Firedogs solution and although I have some understanding of the concept, as you can only output one day at a time, I find copying and pasting the data direct from the individual day usage webpage into an EXCEL spreadsheet a lot easier. I strip out the kWh trailing digits using a text formula, and then periodically convert text to numbers so it becomes usable data. What a faff, shame OVO cannot share our own data with us in a usable format.

Hi @Phil225xe 

Glowmarkt and the Hildebrand smart app should be able to recover 12 months worth of data from the meter (assuming you have had a smart meter for longer than 12 months of course!). Have a read of

How to recover historical meter readings- Would this information be retained on the meter | The OVO Forum

which also links to

Energy usage data from third party Apps: Ivie, Loop and Hugo - my guide | The OVO Forum

I obtained a full 12 months from Glowmarkt for myself and a neighbour. It may also take a while to back-fill the data.

Glowmarkt/Hilderbrand support is very good and responsive should you have issues.

It would be nice to do this directly from OVO, however some suppliers are still in the dark ages. No facility to download at all and quarterly or half yearly statements which makes it a pain to see how much you owe (or are in credit) from day to day (my mother’s accounts).

When comparing data the weather is the critical factor. Comparing with the same date last years is pointless.

You need to somehow compare usage against outside temperature either on a daily (lots of scatter) or weekly basis.

You might be able to get local weather data from Met Office WOW - Home Page 

You can look up ‘degree days’ data for a nearby location.

Great!
  

RAF Wittering is only 19 miles away, the nearest to me in suburban Leatherhead is Kenley which is 20 miles away.

I had my tongue in my cheek when I posted that map. It just shows that I’m smack in the middle of a desert in so many respects - mobile masts, for example. Whenever I search for x near me on Google, x marks spots miles away.

I’ve used the historical data from RAF Waddington, which is my nearest Met Office station. It’s just not very easy to handle. Luckily, this doesn’t really have any meaning for me - heat pumps are just a pipe dream.
 

Thanks @Firedog for the tip on how to get daily JSON data. Am I right in thinking that the timestamps are always in UTC (or GMT as we know it)?

[for certain values of we!]
  

Yes. Have a look at the hours bit of the timestamp on the first entries on 26 October and 28 October. You should see 2024-10-2nT00:00:00.000 in both cases, so it doesn’t change with the clocks. This makes sense: there are precisely 48 half-hour buckets each day throughout the year.

Compare with the timestamp (“readingDateTime”) on the meter readings page smartpaymapi.ovoenergy.com/orex/api/meter-readings/nnnnnnn; you should see a one-hour shift popping up at the clock change. Times prior to this are local midnight, shown as 2024-10-2nT01:00:00.000. So while there are 48 half-hours’-worth of usage data on ‘27’ October, there are apparently only 46 half hours between meter readings. This of course plays havoc with anyone trying to align usage data and meter readings, and I’ve no idea how suppliers offering ToU tariffs cope with the difference. I expect with mixed success.
  

E&OE, as usual: it’s easy to go bog-eyed trying to make sense of this 🙂

I’m ashamed to say that I quite forgot about @MikeWilliams’ excellent little utility. It’s a long time since I tested it, but if you’re a Windows user, it might do just what you want in one fell swoop: Release Release 1.0.2 · MikeWilliams-UK/My-Ovo-Data · GitHub

Of course, the OVO devs keep changing stuff without telling anybody, but give it a go. 
 

MikeWilliams wrote:

I have just published my application which fetches your data and stores it in a local SQLite database on your PC. It can also export the data to CSV and Excel files, to allow easy anaylsis. Just download the zip file and unzip it’s contents to any folder, then run OvoData.exe
 

[cont.]

I just tried this version. It works, and it quickly produced a simple CSV file with every half-hour’s usage to three decimal places from the date my first smart meter was installed in 2017 to yesterday, 133,000 lines of data.

Once you’ve entered your username and password (and selected the appropriate account if there’s more than one), select a period. I went for All time just to see how much was retrieved. Then click Read. You’ll see a progress report as the utility fetches the data. Once it’s finished, select Export. I used the CSV option; it looks like the Excel option has some limitations I could do without, but by all means check what it produces.

In general, once the historical data are in place, it’s easy to grab a single day’s JSON data to keep the whole lot up to date.

I have just released V1.0.3 of my App to GitHub, this fixes the issue found by @HexhamUser when you have electricity with missing cost data.

Just download the zip file from https://github.com/MikeWilliams-UK/My-Ovo-Data/releases and unzip it’s contents to any folder, then run OvoData.exe

If you like my work, please consider donating at https://www.buymeacoffee.com/mikewilliamsuk

/Mike Williams