From Excel exports to Power BI — 16× faster
The problem
Solar panels, weather sensors and energy devices write a reading every second — millions of rows a quarter. Analysis meant exporting to Excel and drawing charts by hand. With the energy worked out inside the report, three months took 21 minutes to load, and the full year the staff needed was estimated at over an hour.
What I built
- Power BI on the hub's own database: five energy reports, one per monitoring system, a report of sunlight against panel output, and an overview.
- The energy calculation moved into the database, so the report only adds up by the interval picked — one second to one day.
- Optimised SQL queries and DAX measures for spotting anomalies in the production data.
- Accuracy checks on the data flow, so the charts could be trusted against the raw readings.
Result
Three months of data, by hour
Time for the report to load. Bars to scale.
16×faster — the energy is now worked out in the database, not inside the report.
| Report | Before | After |
|---|---|---|
| 1 month, by minute | 3 min 50 s | ~50 s |
| 1 month, by hour | 4 min 50 s | ~70 s |
| 3 months, by hour | 21 min 40 s | ~80 s |
16× faster on three months of data. Built to requirements agreed with the hub, so its staff can analyse the data without Excel. Read the letter of recommendation from the team I built it for.
Relevant if your role mentions
Slow Power BI reportsSQL optimisationLarge datasets Time seriesIoT / sensor dataReplacing Excel reportingAre your reports slow to load? Tell me how big the data is and where it lives — two lines are enough.
Email me