How Much Does
Seawater Desalination
Cost?
Nikolay Voutchkov, PE, BCEE
Water Globe
Consulting
Presentation Outline
Overview of Current Desalination Cost
Trends
Low-Cost Bracket Desalination Projects –
Key Features
High-Cost Bracket Desalination Projects –
What Factors Drive the High Costs?
Key Cost Components
Main Factors Impacting Costs
Cost of Water of
Recent Desalination Projects
12
Cost of Water , US$/kgal
10
8
6
4
2
0
Costs of Recent US SWRO Projects
Project Status Capital Cost Annual O&M Cost of Water
(US$) Cost (US$/kgal) (US$/kgal)
0.6 MGD In Operation US$11.9 MM US$1.15/kgal US$2.91/kgal
Sand City, CA since 2010
25 MGD In Operation US$138 MM US$1.54/kgal US$3.48/kgal
Tampa Bay, FL since 2008
50 MGD In Financing US$350 MM US$1.75/kgal US$4.00/kgal
Carlsbad, CA
2.5 MGD In Planning US$59-64 MM US$3.94/kgal US$7.6-8.0/kgal
Santa Cruz, CA
2.5 MGD In Planning US$22.5 MM US$2.80/kgal US$4.38/kgal
Brownsville Demo
Project, TX
25 MGD-80 MGD In Planning US$180 MM - US$1.99/kgal US$4.47/kgal
Coquina Coast, FL US$560 MM (US$5.35-US$6.10
w/ conveyance)
Typical Cost and Energy Ranges
(Medium & Large SWRO Plants)
Classification Cost of SWRO System
Water Energy Use
Production (US$/kgal)
(US$/kgal)
Low-End Bracket 2.0 - 3.0 9.5 – 10.5
Medium Range 3.5 – 5.0 11.0 - 12.0
High-End Bracket 6.5 - 11.5 12.5 – 14.0
Average 4.0 11.5
Common Features of Low-Cost
Desalination Projects
Low Cost HDPE Open Intakes or Beach Wells;
Near-Shore/On-Shore Discharges w/o Diffuser
Systems or Co-discharge w/ Power Plant of
WWTP Outfalls;
Point of Product Water Delivery within 5 Miles
of Desalination Plant Site;
RO System Design w/ Feed of Multiple Trains
by Common High Pressure Pumps and Energy
Recovery Systems;
Turnkey (BOOT, BOO) Method of Project
Delivery.
Key Reasons for Cost Disparity Between
High-End & Low-end Cost Projects
(US$2.0 – 3.0 vs. US$6.5-11.5/kgal)
Desalination Site Location (NIMBI vs. Science Driven)
Costly Plants Have Overly Long Product Water Delivery Pipelines
• 120 MGD Melbourne Plant – Cost of Plant/Delivery + Power Supply Systems =
US$1.7 BB/1.1 BB (50 miles)
• 66 MGD Sydney SWRO Plant – Cost of Plant/Delivery System
= US$560 MM/US$490 MM (10 miles of underground tunnel under Botany Bay).
Environmental Considerations
Complex Intakes & Diffuser Systems
Phasing Strategy
Intake and Discharge System Capacity;
Pretreatment & RO System Design;
Labor Market Pressures
Method of Project Delivery & Risk Allocation
Seawater Desalination Plant –
Construction Costs
RO System –
40 % to 60 % of
Pretreatment – Construction Costs
15% to 20 %
of Construction costs
Discharge – 5 to 15 %
of Construction Costs
Intake – 5 to 20 %
of Construction Costs
Intake Construction Costs
Key Factors
Very Dependent on Source Water Quality
Usually US$0.5 – 1.5 MM/MGD (up to 3.0
MM/MGD for Complex Tunnel Intakes)
Beach Well Intakes Are Usually Less Costly
Horizontal and Slant Wells Comparable to
Open Intakes
Infiltration Galleries Often are More
Expensive than Open Intakes
Pretreatment
Construction Costs
Very Dependent on Source Water Quality &
Type of Treatment Technologies
Usually US$0.5 – US$1.5 MM/MGD
High Quality Well Water Sources Require
Only Cartridge Filtration (Low Cost
Pretreatment)
Single-stage Granular Media Filtration
Usually is Less Costly than Membrane
Pretreatment
SWRO System
Construction Costs
Dependent on Source Water Quality & Target
Product Water Quality
Usually Between US$1.5-4.0 MM/MGD
Single-stage/Single Pass SWRO System is
Least Costly
Additional Costs for Two-Pass/Two-Stage
RO System May Vary Between 15 and 30 %
of the These of Single Pass/Single Stage
SWRO System
Concentrate Disposal
Construction Costs
Disposal Method Construction Cost
(US$ Million/MGD)
New Outfall w/Diffusers 2.0 – 5.5
Power Plant Outfall 0.2 – 0.6
Sanitary Sewer 0.1 – 0.4
WWTP Outfall 0.3 – 2.0
Deep Well Injection 2.5 – 6.0
Evaporation Ponds 3.0 – 9.5
Zero-Liquid Discharge 5.5 – 15.0
Typical O&M Cost Breakdown
Usual O&M Cost Range
US$1.5 – 4.0/kgal
Cost of Water Breakdown
RO/CF Other Costs
Replacement 9%
Project 6%
Eng. & RO System
Permittin Constr. Cost
g 30%
7%
Pretreatment
Constr. Cost
12%
Power Cost
26%
Intake &
Discharge
Constr. Cost
10%
Key Factors Affecting Costs
Plant Size – Bigger is Better
Source Water Quality - TDS, Temperature, Solids, Silt and Organics Content.
Product Water Quality – TDS, Boron, Bromides, Disinfection Compatibility.
Concentrate Disposal Method;
Power Supply & Unit Power Costs;
Project Delivery Method & Financing;
Other Factors:
Intake and Discharge System Type;
Pretreatment & RO System Design;
Plant Capacity Availability Target.
Desalination Plant Construction
Cost as Function of Capacity
Unit Construction Cost (US$ MM/MGD)
16
14
12
10
8
6
4
2
0
0.5 MGD 1 MGD 2 MGD 5 MGD 10 MGD 20 MGD 50 MGD 100
MGD
Product Water Quality & Costs
Target WQ Constr. O&M Cost of
Costs Costs Water
TDS/Cl = 500/250 mg/L; 1.0 1.0 1.0
Boron = 1 mg/L.
TDS/Cl = 250/100 mg/L; 1.15-1.25 1.05-1.10 1.10-1.18
Boron = 0.75 mg/L.
TDS/Cl = 100/50 mg/L; 1.27-1.38 1.18-1.25 1.23-1.32
Boron = 0.5 mg/L.
TDS/Cl = 30/10 mg/L; 1.40-1.55 1.32-1.45 1.36-1.50
Boron = 0.3 mg/L.
Where Future Cost Savings Would Come From?
“The Best” of Seawater Desalination
Present Status & Future Forecasts
Parameter Today Within 5 Years Within 20 Years
Cost of Water US$2.0-3.0 US$1.5-2.5 US$1.0-1.5
(2010 US$/kgal)
Construction Cost 4.5-8.0 4.0-6.5 2.0-3.5
(Million US$/MGD)
Power Use of SWRO 9.5-10.5 8.0-10.0 5.0-6.5
System (kWh/kgal)
Membrane Productivity 6,500-12,500 9,000-15,000 25,000-40,000
(gallons/day/membrane)
Membrane Useful Life 5-7 7-10 10-15
(years)
Plant Recovery Ratio (%) 45-50 50-55 55-65
Concluding Remarks
Seawater Desalination is Economical Today and
Will Become Even More Cost-Competitive in the
Future;
Typical Cost of Water is US$3.5 to US$5.0/kgal;
The Future of Seawater Desalination Is Bright – 20%
Cost of Water Reduction in the Next 5 Years;
Long-term Investment In Research and
Development Has the Potential to Reduce the Cost
of Desalinated Water by 80 % In the Next 20 Years.
Seawater Desalination Costs
Questions?
