Rare Earth Magnet & Motor Materials worked example

Energy Cost at 58% on-load duty: a worked example in rare earth magnet & motor materials

Here is what the math looks like when conditions slip. We hold every other input steady and drop on-load duty to 58%, then walk the calculation through step by step. Estimate the electricity and utility cost of sintering, annealing and magnetizing rare earth magnet and motor materials.

The inputs for this scenario

  • Sintering furnace runtime: 120 furnace-hours (held at the documented default)
  • Electricity rate: 38 $/kWh-equiv hr (held at the documented default)
  • On-load duty: 58 % (the input this scenario stresses; the baseline uses 80)
  • Vacuum and chiller base load: 600 $ (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Total energy = furnace-hours x power rate x on-load duty + base load.
  • Total energy cost works out to 3,245 $ at these inputs, and this is the headline figure for the scenario.
  • Energy cost per unit works out to 27.04 $ / piece at these inputs.
  • Variable energy cost works out to 2,645 $ at these inputs.
  • Fixed energy cost adder works out to 600 $ at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where on-load duty sits at 80% and the headline result is 4,248 $, this scenario comes in 23.62% below the baseline at 3,245 $.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to on-load duty, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It treats on-load duty as a single average percentage, so furnaces with sharply peaked ramp-up draw or utility demand charges will read differently than this linear model.

Results at a glance

  • Total energy cost: 3,245 $ (headline result)
  • Energy cost per unit: 27.04 $ / piece
  • Variable energy cost: 2,645 $
  • Fixed energy cost adder: 600 $

Run it with your numbers

  • To rerun this with your own numbers, open the live Energy Cost calculator, set on-load duty to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.