I have 15-minute interval data for a client but it's just a massive spreadsheet of numbers. 35,000 rows. How do you turn this into something visual that helps you spot anomalies and also looks professional when presenting to the client?
Visualizing interval data — what tools?
Excel pivot tables and charts are your best friend. Create a pivot table with date on rows and hour on columns, then average the kW values. That gives you a heat map of usage by time of day and day of week. You'll immediately see patterns — like demand spikes at 8 AM on weekdays, or unexplained usage at 3 AM on weekends. For client presentations, a line chart showing daily peak demand over the year with the billing demand overlaid is extremely powerful. Clients can instantly see the gap between their actual peaks and what they're being billed for under the ratchet clause.
Good suggestions. I'd add that a scatter plot of kW demand vs outdoor temperature is very revealing. It shows you the building's weather sensitivity and helps identify anomalies — like high demand on a mild day when the building shouldn't be drawing much. For presentations, keep it simple. Clients don't need to see 35,000 data points. Three or four well-chosen charts that tell the story of where the money is being wasted are more effective than a 50-page data dump. Lead with the chart that shows the biggest finding and work backwards to explain how you discovered it.
The pivot table heat map is exactly what I needed. Just built one and I can already see that this building has significant load running from midnight to 5 AM every night. Nobody should be there. That's my next conversation with the facilities manager.