Desalination, With a Grain of Salt: A California Perspective

Desal Response GroupAquarium of the Pacific

October 2006

Background• Seawater desalination is widely and

successfully used in parts of the world.• Interest in seawater desalination is growing.• Understanding the real costs and benefits is

critical to avoiding costly mistakes. • The Pacific Institute was asked to prepare an

independent California assessment: funded by Packard and the California Coastal and Marine Initiative.– Cooley et al. 2006. http://www.pacinst.org/reports/desalination

Findings

• Potential benefits of seawater desalination are great.

• But the economic, environmental, and social costs of wide commercialization remain high.

• Alternatives can provide these benefits at lower cost, with fewer environmental and social impacts, especially for California.

Economic Questions

• There are some economic advantages that are poorly understood or quantified.– Reliability; ecosystem water; independence of supply

• Actual costs are neither as low nor dropping as fast as claimed. – subsidies, interest rates, plant size, energy costs,

salinity of the source water, etc.

• Despite cost reductions in recent years, desalination remains more expensive than other California water supply and demand management options.

Energy Intensity of Water Sources in San Diego County

Source: Wolff et al. 2004

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

ColoradoRiver

Aqueduct

State WaterProject

Groundwater ReclaimedWaste Water

SeawaterDesalination

BrackishWater

Desalination

Ocean-TowedWater Bags

En

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y In

ten

sit

y (

Eq

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ale

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Water Supply Diversity and Reliability

• Largely independent of weather conditions

• Offers local control

• Source diversity

Source: USGS website

Source: DWR website

Report describes a method to quantify the economic value of these benefits based on financial portfolio theory.

Water Quality

• Desalination produces high-quality water (low TDS).

• But there are uncertainties about blending with existing water distribution systems.

• Desalination can introduce contaminants from corrosion or from source water.

• New standards may be needed.

Environmental Risks and Benefits

• Desalination offers environmental advantages:– Source displacement

• And environmental risks:– Water intakes (impingement and entrainment)– Brine discharge– Energy use

Marine Mammal Center

U.S. Fish and Wildlife Service

Climate Change

• California is especially vulnerable to climate changes, particularly along the coast. Issues to be addressed include:– Future sea-level (intake, outfall, design)– Storm frequency and intensity– Implications of high energy requirements

Source: USGS

Siting and Operation

• Coastal development and land use issues are unresolved.

• Privatization concerns must be addressed.

• Co-location offers advantages and disadvantages, but have been poorly assessed.

• The regulatory process should be clarified.

Source: USGS

Conclusions

• Desalination is likely to play an important role in California’s future water portfolio.

• The future isn’t here yet.

• Current proposals fail to adequately address the complicated costs and benefits associated with seawater desalination.

• Decision-making process must be open and transparent, and it isn’t yet.

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