The Desalination Treatment Cost Estimator calculates annual operating cost from product-water volume, specific energy consumption, electricity price, non-energy variable cost, and fixed annual expense. It is tailored to desalination because electricity intensity often represents a major operating component and is therefore shown separately.
The tool supports early-stage comparison of operating scenarios such as different recoveries, membrane conditions, energy prices, or plant utilizations, provided the user supplies the corresponding inputs. The unit-cost result is expressed per 1,000 gallons of product water. The estimate is intentionally transparent and limited: it does not automatically include debt service, depreciation, intake construction, concentrate disposal capital, membrane replacement schedules, or other ownership costs unless those amounts are translated into the fixed or variable cost fields.
Desalination operating cost
gal/yr
kWh/1k gal
$/kWh
$/1k gal
$ /yr
Result
—
Estimated annual desalination cost
Electricity cost—
Other variable cost—
Total unit cost—
1. Enter annual product-water volume Use the desalinated finished-water output expected over one year.
2. Enter specific energy use Provide electricity consumption per 1,000 gallons of product water.
3. Set electricity price Use the average price expected for the energy consumed by the plant.
4. Add other variable cost Enter chemicals, consumables, routine concentrate handling, and similar throughput-linked expenses.
5. Add fixed annual cost Include modeled annual fixed operating expense, then review the total and cost per 1,000 gallons.
Annual cost = Fixed cost + (Product volume/1,000 × Energy use × Electricity price) + (Product volume/1,000 × Other variable cost)
Where:
Product volume: desalinated water in gallons per year
Energy use: kilowatt-hours per 1,000 gallons of product water
Electricity price: dollars per kilowatt-hour
Other variable cost: non-energy dollars per 1,000 gallons
Fixed cost: annual dollars not directly tied to volume
Assumption: The model estimates operating cost only. Compare scenarios using the same cost boundary so technology differences are not distorted by inconsistent inclusion of capital or overhead items.
What the result means
The main result is a planning estimate derived directly from the entered operating assumptions and should be interpreted within the stated system boundary.
Use project-specific design criteria, equipment data, and applicable requirements before making final engineering or procurement decisions.
Result: $464,000 per year, or about $9.28 per 1,000 gallons.
The result shows how fixed expense and energy together shape the modeled product-water cost at this production level.
Why is energy use expressed per 1,000 gallons?
That basis connects plant electricity consumption directly to product-water output and makes the energy-cost term easy to scale with annual production.
Should intake and brine disposal costs go in variable cost?
Include only the portions that vary with production on a per-1,000-gallon basis. Fixed permits, contracts, or infrastructure costs are better placed in fixed annual cost if they belong in the model scope.
Can I compare reverse osmosis and thermal desalination?
Yes, but use technology-appropriate energy and other cost inputs and keep the cost boundary consistent. The calculator does not supply default technology benchmarks.
Why might unit cost fall as production increases?
With fixed annual cost held constant, spreading that expense across more product water reduces the fixed-cost contribution per 1,000 gallons. Variable and energy costs scale with volume in this model.
Does this estimate the selling price of water?
No. It estimates modeled production operating cost, not tariffs, profit margins, financing, taxes, or distribution charges.