Replacing data with more reliable sources

Maybe I’m the only person with this issue, but I thought I’d put it out there for discussion.

I can get data from my electricity supplier on my household consumption. It comes in 15 minute granularity, but with a day’s delay. I.e. I can never see my instantaneous consumption with this method.

I also have a ZigBee device attached to my electric meter (a Linky with a Lixee ZigBee device on the data port) that gives me data instantly (well, once per minute).

My problem comes from wanting to combine these two data sources.

  1. The day delay is annoying, but the supplier’s data is the gold standard, but it’s in 15 minute chunks.
  2. The ZigBee data can be more finely grained in time, but the physical layout of my property means the signal is very weak and occasionally I get no data at all for hours, or only one data point every hour or so. I have limited opportunity to improve the wireless link as the distance between the meter and the nearest place I can locate a repeater is fixed at about 15 m through two brick/concrete walls.

Is there a way I can combine these two sources of data without double counting the consumption?