Field note
How we read a utility interval file without drowning in columns
Most interval exports from an electricity supplier are not written for a facilities director. They are a dump of timestamps, sometimes in UTC, sometimes in the building’s clock, with a column that may be average kW, accumulated kWh, or a code for estimated reads.
Before any chart is drawn, we print the first two days and the last two days. If the file starts at 00:00 on a Monday and the building was closed that week for a roof repair, the low numbers are not a mystery; they are a calendar fact.
Daylight saving is a regular snare. A doubled 01:00 hour or a missing 02:00 hour will tilt a daily total if you sum blindly. We mark those rows in the working copy and keep the original file untouched.
Units matter more than color. A column labeled “demand” is not consumption. Adding demand intervals as if they were kWh will invent a year that never appeared on the invoice. We always tie the monthly sum of intervals back to the billed kWh; a gap larger than the supplier’s stated estimate allowance goes into the caveats page.
The Packagegridbase desktop application can hold a local copy of these checked tables on a machine the client already uses. It does not fetch interval files from a utility, and it does not replace the written report.