Desalination Energy Calculator Formula
Understand the math behind the desalination energy calculator. Each variable explained with a worked example.
Formulas Used
Daily Energy Required
daily_energy = daily_kwhDaily Energy Cost
daily_cost = daily_kwh * elec_rateAnnual Energy Cost
annual_cost = annual_kwh * elec_rateCost per 1000 Gallons
cost_per_1000_gal = kwh_per_1000_gal * elec_rateVariables
| Variable | Description | Default |
|---|---|---|
volume_gal | Daily Water Volume(gallons) | 100000 |
kwh_per_1000_gal | Energy per 1000 Gallons(kWh) | 12 |
elec_rate | Electricity Rate(USD/kWh) | 0.1 |
daily_kwh | Derived value= volume_gal * kwh_per_1000_gal / 1000 | calculated |
annual_kwh | Derived value= daily_kwh * 365 | calculated |
How It Works
How to Calculate Desalination Energy
Desalination removes salt from seawater to produce fresh water, requiring significant energy.
Formula
Daily Energy = Volume (gal) * Energy Rate / 1,000
Energy Requirements (kWh per 1,000 gallons)
Worked Example
A small RO plant producing 100,000 gal/day at 12 kWh/1000 gal with $0.10/kWh electricity.
- 01Daily energy: 100,000 * 12 / 1,000 = 1,200 kWh
- 02Daily cost: 1,200 * $0.10 = $120
- 03Annual cost: 1,200 * 365 * $0.10 = $43,800
- 04Cost per 1,000 gal: 12 * $0.10 = $1.20
Frequently Asked Questions
How much energy does desalination require?
Modern reverse osmosis uses 10-15 kWh per 1,000 gallons of fresh water produced. This is down from 25+ kWh two decades ago due to energy recovery devices and improved membranes.
How does desalination cost compare to tap water?
Desalinated water costs $2-5 per 1,000 gallons versus $1-3 for conventional treated water. The gap is narrowing as technology improves and freshwater sources become scarcer.
Can solar power run a desalination plant?
Yes. Several solar-powered RO plants operate worldwide. The combination is logical since areas with water scarcity often have abundant solar resources.
Ready to run the numbers?
Open Desalination Energy Calculator