Waste-to-Energy Equipment worked example

Feedstock Moisture Impact at 40% excess moisture fraction: a worked example

This worked example runs the feedstock moisture impact numbers for a tougher week than the baseline: 40% excess moisture fraction instead of the typical 55%. Estimates the cost penalty of wet feedstock from throughput, per-tonne drying penalty, excess moisture fraction, and a fixed grate derate allowance.

The inputs for this scenario

  • Wet Feedstock Throughput: 60,000 tonnes (held at the documented default)
  • Drying Penalty per Tonne: 6.5 $/tonne (held at the documented default)
  • Excess Moisture Fraction: 40 % (the input this scenario stresses; the baseline uses 55)
  • Grate Derate Allowance: 35,000 $ (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Total = wet tonnes x drying penalty x (excess moisture รท 100) + grate derate allowance.
  • Total feedstock moisture impact cost works out to 191,000 $ at these inputs, and this is the headline figure for the scenario.
  • Feedstock moisture impact cost per unit works out to 3.18 $ / piece at these inputs.
  • Variable feedstock moisture impact cost works out to 156,000 $ at these inputs.
  • Fixed feedstock moisture impact adder works out to 35,000 $ at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where excess moisture fraction sits at 55% and the headline result is 249,500 $, this scenario comes in 23.45% below the baseline at 191,000 $.
  • Use it when negotiating fuel supply contracts, sizing a pre-drying investment, or explaining why steam output fell during a wet-weather delivery run. A result at this level usually justifies acting on the stressed input before touching anything else, because every other figure in the table is downstream of it.

Results at a glance

  • Total feedstock moisture impact cost: 191,000 $ (headline result)
  • Feedstock moisture impact cost per unit: 3.18 $ / piece
  • Variable feedstock moisture impact cost: 156,000 $
  • Fixed feedstock moisture impact adder: 35,000 $

Run it with your numbers

  • To rerun this with your own numbers, open the live Feedstock Moisture Impact calculator, set excess moisture fraction to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.