Desalination & Membrane Water Treatment Equipment worked example

Water Production Cost at 92% share of variable cost included in scope: a worked example

This scenario runs the water production cost calculation on the strong side: 92% share of variable cost included in scope, with every other input held at its documented default. Use it when water production cost in desalination and membrane water treatment equipment is being put through a desalination and membrane water treatment equipment weighted-cost review.

The inputs for this scenario

  • Treated water volume produced: 100 m³ (unchanged)
  • Variable cost per m³ produced: 45 $ / m³ (unchanged)
  • Share of variable cost included in scope: 92 % (raised for this scenario; the documented default is 80)
  • Fixed plant or skid overhead: 250 $ (unchanged)

Working through the calculation

  • Applying the documented formula (Included variable production cost = treated water produced × variable production cost × production cost scope included) to the inputs above produces each figure below.
  • At this operating point the engine returns 4,390 $ for total water production cost, the number this scenario is built around.
  • At this operating point the engine returns 43.9 $ / piece for water production cost per m³.
  • At this operating point the engine returns 4,140 $ for included variable production cost.
  • At this operating point the engine returns 250 $ for fixed plant or skid cost.

How this compares with the baseline

  • Against the tool's baseline example, where share of variable cost included in scope sits at 80% and the headline result is 3,850 $, this scenario comes in 14.03% above the baseline at 4,390 $.
  • Use it when setting a water tariff, building a project pro forma, or comparing the production economics of different plant or skid options. Treat this as a target state: the delta against the baseline quantifies what the improvement is worth before you commit to chasing it.

Results at a glance

  • Total water production cost: 4,390 $ (headline result)
  • Water production cost per m³: 43.9 $ / piece
  • Included variable production cost: 4,140 $
  • Fixed plant or skid cost: 250 $

Run it with your numbers

  • Every input above is editable in the live Water Production Cost calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.