Transcript Desalination, With a Grain of Salt: A California Perspective

Desalination, With a Grain of Salt:
A California Perspective
Desal Response Group
Aquarium 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.
4,500
Energy Intensity of Water Sources in San
Diego County
Energy Intensity (Equivalent kWh/AF)
4,000
3,500
3,000
2,500
2,000
1,500
1,000
500
0
Colorado
River
Aqueduct
Source: Wolff et al. 2004
State Water
Project
Groundwater
Reclaimed
Seawater
Waste Water Desalination
Brackish
Ocean-Towed
Water
Water Bags
Desalination
Water Supply Diversity and Reliability
• Largely independent of weather conditions
• Offers local control
• Source diversity
Source: DWR website
Report describes a method
to quantify the economic
value of these benefits
based on financial portfolio
theory.
Source: USGS website
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.
What’s the first thing to do to a leaky bucket?
$
$
$
$
$
$