Desal in SLO County closer to reality



Using desalinated ocean water to combat the impact of the state’s brutal drought on SLO County is slightly closer to actually happening.

The issue was the center of a lengthy discussion by the county Board of Supervisors on Aug. 25. The supervisors reviewed a detailed report on the county’s desalination prospects. The 538-page document laid out the advantages and challenges of such an undertaking.

“A regional desalination project may be an appropriate solution for San Luis Obispo County to address water supply issues when integrated with the communities’ goals and strategies,” a summary of the report stated. “However, the feasibility for a desalination project highly depends on the various needs by water managers, decision makers, and the general public.”

Supervisors also voted to direct county staff to work on planning the construction of a 7-mile-long pipeline that would carry desalinated water from the PG&E-operated Diablo Nuclear Power Plant to nearby Avila Beach. From there, the plan is to feed the water from Diablo into an existing distribution system for South SLO County. According to PG&E, Diablo Canyon’s desalination facility is one of the largest of its kind in the California, and can desalinate sea water at a rate of more than 450 gallons per minute. As of late May, the plant’s desalination operation was producing 40 percent of its total possible capacity to meet plant needs. The county entered into a water sharing agreement with PG&E in May to provide desalinated water to the Office of Emergency Services to reduce the use of local water in fighting wildfires. 

The desalination report also identified a number of other opportunities, including expanding existing desalination facilities in places like Morro Bay and Cambria and co-locating new facilities on existing industrial sites such as the Nipomo Mesa Refinery. The report also noted that such ambitions had challenges, including the amount of energy necessary for the operation and maintenance of current desalination technology.

“High energy use means high operating costs and, depending on the source of power, an increase in greenhouse gas emissions. In the case of seawater desalination, environmental impacts must be properly mitigated to avoid harming marine life,” the report stated.

While the county has dreams of pipes carrying desalinated water to its drought-stricken residents, the local chapter of the Surfrider Foundation, a nonprofit environmental group, said the report “barely scratched the surface” of desalination’s potential obstacles and asked supervisors to refocus on conservation and reclamation policies. 

“Existing policy, with effective measurement and management, will promote self-reliance and community ownership and resolution of local water supply problems,” stated a letter Surfrider sent to the county. “Our communities need help fixing leaking pipes and distributing recycled water—now.” 

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