Costs

Costs of Seawater Desalination

A comparison of Energy costs per acre foot between the various water supply options looks like this... An acre foot of Poseidon desal water requires nearly fourteen times more energy than water recycling, an option which has not yet been seriously implemented in Cambria.   Energy costs should make ratepayers think very carefully before allowing ocean desalination to replace groundwater extraction or water conservation in their future water supply options. Desalination works best in places like Saudia Arabia – where oil is free. The following graph appears at The Oil Drum: Desalination-Energy Down the Drain.

Cambria’s CSD relies on information from the Affordable Desalination Collaboration. The Affordable Desalination Collaboration (ADC) is a group of desalination industry advocates and many California water agencies interested in seawater desalination. The organization is chaired and managed by industry advocates and leaders in promoting desalination. ADC indicates the cost seawater desalination ranges from around $800 to $1,000 per acre-foot of fresh water produced.

According to ADC’s CEO and Managing Director, the engineering assumptions, such as optimum membrane feed pressures for the different membranes tested, were based on a pilot project with tests conducted in Port Hueneme, California in 2005 and 2006.  The remainder of the cost figures in the ADC projections were not based on an actual operating facility but instead were estimates and projections.   CCSD Engineer Gresens is fond of quoting ADC in cost projections for Cambria.

A review of ADC’s website costs analysis for their theoretical 50 MGD facility found many fundamental flaws with the cost projections and associated assumptions.

                                 Energy Cost is underestimated                                  Inaccurate financing assumptions 
                                 Energy requirement is underestimated                   Cost estimates not complete           
                                 Intake water salinity underestimated                      NO environmental mitigation estimated
                                 Water production overestimated                              NO environmental monitoring estimated
                                 O&M costs underestimated                                       Capital costs are underestimated

LET’S GET  REAL ON COSTS

An Investigation of the Marginal Cost of Seawater Desalination in California

There is much interest, but little clarity on the cost of desalinated seawater in California and how it compares to other urban water management options. To address this issue, Fryer's investigation collected general information along with costs and production records and cost projections for many prominent seawater desalination facilities and proposed projects in North America and California. Along with many others, this included Tampa Bay, Carlsbad, Santa Barbara, and Marin. These four projects are described and evaluated as case studies in Fryer's paper.

Seawater desalination for $800 to $1,000 per acre-foot?

Some advocates of seawater desalination (including Cambria’s CSD) suggest marginal costs of $800 to $1,000 per acre-foot are now possible in California. However, despite a thorough investigation, Fryer's study found no evidence of seawater desalination facilities in North America producing water in that cost range.  His study also found no credible evidence that new seawater desalination projects in California, given local conditions, could produce water in that cost range. 

Given the best presently available technology, Fryer's investigation found realistic estimates of the marginal costs for seawater desalination in California will range from a minimum of about $2,000 to $3,000 or more per acre-foot of water produced.  This compares to typically much lower marginal costs of well under $1,000 per acre-foot for most urban water conservation measures.  Water recycling for urban areas typically costs between $300 and $1,300 per acre-foot.  Both water conservation and recycling appear to be far from fully utilized in California.

Water Recycling:                                                                                                                           $   300 -  $1,300 per Acre Foot
Water Conservation:                                                                                                                                     $1,000  per Acre Foot
Seawater Desalination in California                                                                                            $2,000 - $3,000  per Acre Foot