Updated on 12/08/24 by Shads_OVO
I’m very confident that it’s the Calorific Value. Meters measure gas volume and can’t know what the energy content is until the gas properties have been measured, which they are at many places across the country, every day. Provisional CVs for the day in progress are published by National Grid at 10:30am, at the same time as they publish what are usually the finalised values for the previous day. (My words, not theirs - very occasionally more than one revision is published, with the update coming around 4:30pm.) Gas suppliers generally use those numbers within a few hours, so if you see yesterday’s consumption before 10:30am, the supplier must be using a provisional value for CV, which may change. National grid keep all values available so you can, if so inclined, calculate for yourself how the usage in kWh will have varied as CV estimates change.
I’ve been on this journey, and a helpful trick is to remember that all these energy usage values in kWh are derived from gas meter readings in volume, which are exact multiples of 0.001 m^3
The national grid data can be queried here, and you’ll need to know which area you’re in ...
https://mip-prd-web.azurewebsites.net/DataItemExplorer/
have fun ;-)
