Load Shedding Cost Calculator for Manufacturers
Rolling outages hide their cost across the fuel invoice, the wage bill and missed deliveries. This calculator adds them into one monthly figure so you can compare options such as a bigger generator, solar with batteries, or shift changes.
Your numbers
Many plants cover lights and compressors but not the largest machines.
Your results
Planning estimate. Generator fuel burn varies with load and machine age; use your own meter readings where you have them.
Monthly outage cost vs outage hours per day
Sweeps Outage hours per working day from 0 to 12, holding your other inputs fixed.
Downtime reporting from your ERP
Tell us how you log stoppages and we will suggest a reporting layout over your ERP data.
Optional. The tool and every export work without this. No spam.
How to use it
Start with the real average of outage hours per working day from your last three months. Enter the share of load your generator carries and its fuel burn at that load, taken from the fuel log or the nameplate curve. Idle workers and contribution per hour describe the uncovered part. Contribution is price minus variable cost for one hour of normal output on the bottleneck, not average profit.
- Use a bottleneck hour, not the plant average.
- Check whether staff are redeployed rather than idle.
- Update diesel price monthly.
The maths
Generator cost equals outage hours times the sum of fuel per hour times price plus maintenance per hour. The uncovered hours are the outage hours times one minus coverage. Idle labour is uncovered hours times people times loaded wage, and lost contribution is uncovered hours times contribution. Total adds the three. Cost per outage hour divides total by outage hours and is the figure to compare against capex quotes.
Reading the result
If cost per outage hour exceeds what it would cost to cover another block of load, extending coverage pays back. Watch the sweep chart: when contribution is high the line is steep, which signals that raising the covered share matters more than saving diesel. A low slope means fuel is the main cost and efficiency or solar is the lever.
ERP and planning links
Feed outage windows into finite capacity planning so the schedule does not promise capacity that will not exist. Record downtime reasons on the shop floor so lost hours are measured instead of estimated. Track overtime after outages because recovery shifts add labour premium that this tool does not include.
Frequently Asked Questions
What load does the generator really carry?
Read the generator's load percentage on its panel during a normal shift or compare fuel use to the manufacturer's curve. Many plants overestimate coverage because some large drives trip or are kept off.
Should I include overtime to catch up?
Overtime premium is a real extra cost. Add the premium hours to the loaded labour figure or include a catch-up allowance in contribution lost per hour. Leaving it out understates the true cost of an outage.
What is a bottleneck hour's contribution?
Price minus variable costs for the output of one hour on the constraint machine. Using average plant profit understates the loss because a lost bottleneck hour is lost for the whole line.
Does this cover solar?
Not directly. Use the output as the baseline cost of outages, then compare a solar plus battery quote by how much uncovered load and diesel it removes per month.
If you want outage losses reported straight from your ERP and shop floor data rather than a spreadsheet, we can scope that with you.
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