Water Projects

Carlsbad 50 MGD Seawater RO Desalination Plant and Product Water Pipeline

Poseidon Water
Carlsbad, California
$537 million (Desalination Plant) and $159 million (Conveyance Pipeline)
Operational by end of 2015
Kiewit Shea Desalination
SDG&E Energy Showcase Champion Award

Butier Engineering, Inc. and GHD provided Owner’s Engineer services, including project management, permitting support, design review / development, cost estimating, value engineering, scheduling, field resident engineering, QA/QC field inspection, and start-up / commissioning and performance testing for the construction of the 50 MGD seawater reverse osmosis desalination plant. The project also included the construction of a 2.5 million gallon cast-in-place product water storage tank; product pump station; a 10-mile, 54-inch diameter conveyance pipeline system; and significant plant process and electrical systems. The project, which was developed through a public-private partnership between the San Diego County Water Authority and Poseidon Water, is the largest seawater desalination plant in the Western Hemisphere.

The power plant intake withdraws a minimum of 304 MGD seawater from the Pacific Ocean via the Aqua Hedionda Lagoon. The collected cooling seawater is pumped through the condensers of the power plant generation units. Approximately 200 MGD of warm seawater is discharged from the EPS condensers into a common enclosed discharge channel, which conveys the plant discharge to the Pacific Ocean through a jetty.

Approximately 104 MGD of the 304 MGD cooling water is diverted from the power plant discharge channel and pumped to the desalination plant, processed through a pretreatment system, and desalinated via seawater reverse osmosis. Seawater concentrate from the desalination plant is discharged into the existing cooling water discharge channel for blending with the remaining cooling water prior to its ultimate conveyance to the Pacific Ocean.

The 50 MGD of drinking water produced by the desalination plant is delivered to Poseidon customers in San Diego County by a water conveyance system that consists of a product water pipeline, several booster stations, and other service structures.