Load Shedding Downtime Loss Log Worksheet
Frequent power interruptions are a daily reality for manufacturers in several African countries, but few plants know what they cost per line. This log records each event and converts it into lost units, lost contribution and generator diesel.
| Date | Line or cell | Outage type | Hours stopped (h) | Hours on generator (h) | Units per hour | Contribution per unit | Diesel per hour (L) | Lost units | Lost contribution | Diesel used (L) | |
|---|---|---|---|---|---|---|---|---|---|---|---|
300 | R 11,400 | 0 | |||||||||
150 | R 900 | 36 | |||||||||
480 | R 18,240 | 0 | |||||||||
42 | R 17,220 | 0 | |||||||||
300 | R 1,800 | 54 |
Diesel cost is shown in litres so you can multiply by your current price. Use the contribution per unit (price less variable cost), not the full selling price, so the loss is not overstated.
Capture downtime from the shop floor
Optional: we can show how outage reasons feed ERP production orders.
Optional. The tool and every export work without this. No spam.
How to use the log
Add a row for each outage or generator event. Enter the line, the hours it stopped, the hours it ran on generator, its normal output per hour, the contribution per unit and the generator's diesel burn per hour. The sheet calculates lost units, lost contribution and litres used. Review weekly and export to Excel for management reporting.
- Use actual stop and start times from the shift report
- Record generator hours separately from stopped hours
- Use contribution margin, not selling price
- Tag the cause so you can compare grid and equipment faults
Method
Lost units are hours stopped times the normal rate. Lost contribution multiplies that by the contribution per unit, which is selling price less variable cost. Diesel used is generator hours times consumption per hour. The summary divides total lost contribution by total stopped hours, giving a cost per stopped hour that you can compare against the cost of running a generator or installing solar and storage.
Reading the result
In the sample data, the press line and the CNC cell account for most of the lost contribution even though packing is stopped more often, because contribution per hour differs. Prioritise backup power on the lines with the highest contribution per hour, not simply those with the most interruptions.
Common mistakes
Plants often count partial hours loosely, ignore the restart and warm up time after an outage, or value lost output at full price. Where scrap or rework follows an abrupt stop, record it separately in your quality system. In an ERP, outage events can be posted as downtime reasons on production orders for later analysis.
Frequently Asked Questions
How is lost contribution calculated?
Hours stopped times output per hour times contribution per unit. Contribution is price minus variable cost, so fixed overhead is excluded and the loss is not overstated.
Does it include diesel cost in money?
It shows litres, so you can apply your current diesel price. This avoids baking an out of date price into the log.
Can I use it for non-African plants?
Yes. Any plant that suffers power interruptions can use the same method. The title refers to load shedding because that is how many African plants describe the problem.
Can I share it with my team?
Export to Excel or CSV and share the file. The page itself does not store your data.
If you want outage and downtime reasons captured from the shop floor into your ERP automatically, Netray can discuss how to wire that in.
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