Report finds Poseidon desal location could be costly

Parimal M. Rohit

HUNTINGTON BEACH — A proposed desalination plant on the Huntington Beach coast is not economically viable, a panel of consultants, engineers and scientists stated at a public meeting on Aug. 27.

Poseidon’s plan to produce 50 million gallons of desalinated water daily at a plant just south of Huntington Beach Pier would feature an intake system on the seafloor but might prove too costly an endeavor for Orange County officials. Elements of the plan were studied by a six-member technical advisory panel “under the auspices of the California Coastal Commission and Poseidon Resources;” the results of the study were released online Aug. 17 and presented at the Aug. 27 public meeting at Huntington Beach Central Library.

The report specifically studied the feasibility of intake designs at Poseidon’s planned project in Huntington Beach. Members of the panel were selected from the fields of academia, consulting, engineering, environmentalism and science.

Poseidon’s proposed plant, which included plans for a seafloor infiltration gallery (SIG), would require more than 100 million gallons of daily water intake to support its planned product capacity of 50 million gallons per day. Initial plans estimated 127 million gallons of seawater would be processed daily to produce the 50 million gallons of desalinated water; Poseidon later reduced the estimated daily requirement to about 106 million gallons of seawater.

Installing an intake system on the seafloor raised concerns of how it would impact marine life. Poseidon officials reportedly claimed the intake system would feature an advanced screening system at the point of entry to protect fish and other marine life from being sucked into the plant. Environmentalists questioned whether a seafloor intake system would be effective.

Michael Kavanaugh, a panelist from Geosyntec Consultants, said SIG technology was preferred over open ocean or beach gallery intakes. It was later revealed, however, a SIG-equipped desalination plant would prove most costly.

Still, the panelist believed a seafloor intake system about 3,400 feet offshore and 42 feet underwater would be the least harmful and most effective way to feed saltwater into the desalination plant. Water would be sourced on the seafloor before traveling about 3,400 feet to a collection point onshore and then processed for desalination.

Kavanaugh added the advisory panel and California Coastal Commission regularly used the word “feasibility” to describe whether to advocate for or against any aspects of the planned desalination project.

One question asked, for example, was whether building and operating the proposed desalination plant would be economically feasible. Answering the question involved looking at the construction and operation costs, then determining whether an agency such as the Orange County Water District (OCWD) would be able to recover its investment without charging its customers too much for water use.

Similar feasibility questions were asked about environmental, social and technical aspects of the proposed plant. The panel acknowledged short-term environmental harms but added the negative impacts could be overcome in the long run.

Kavanaugh said feasibility studies ultimately came down to a cost-benefit analysis since the Coastal Commission did not offer any formal definitions of what qualified as “feasible.”

Complicating the cost-benefit analysis: using a technologically-advanced seafloor intake might be the preferred approach but also a tougher sell than other options.

Panelist and Florida Gulf Coast University professor Thomas Missimer said the Huntington Beach coast poses design risks, is unstable and filled with high energy. Kavanaugh added SIGs, compared to open ocean intakes, have a higher level of cost uncertainty.

Larry Dale of the Lawrence Berkeley Laboratory added open ocean intakes are more feasible to build and operate than SIGs right now. However, seafloor intakes could become more affordable or financially feasible down the line. Dale added hybrid alternatives could also become available soon, though not enough data is available to substantiate SIG-open ocean intake crossovers.

Negative impacts stemming from the construction and operation of the proposed plant, according to the study, include, “payments for loss of beach access or recreation opportunities by construction activities.”

The proposed desalination plant could also result in increased costs to mitigate the effects of an open ocean intake on the marine ecosystem.

“A range of environmental impacts would be generated, directly or indirectly, as a result of constructing and operating the different SIG construction options,” the technical advisory panel stated in its report.

Onshore and offshore construction of the plant could result in increased air and greenhouse gas emissions, degradation of coastal views and obstruction of recreational fishing opportunities, among other issues, the panel’s study also found.

Building and operating a desalination plant with seafloor intakes have never been tried in California. Pursuing such a project is, according to the panel, a high risk proposition. Panelists, however, forecast the economic costs of the plant can be diminished as production and output increases, therefore minimizing long-term risks. Environmental risks would be high during construction of the plant, though panelists believe such risks would also diminish over time.

A construction moratorium could be instituted to allow summertime recreational activities in and around Huntington Beach; construction activities, however, would be delayed if a summertime moratorium were in place.

No decisions were reached at the Aug. 27 public meeting. The public will be able to comment on the draft report through Sept. 10. Poseidon will later submit an updated report to the Coastal Commission for review and approval.

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