FINAL REPORT Evaluation of Seawater Desalination Projects ...

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EVALUATION OF SEAWATER DESALINATION PROJECTS PROPOSED FOR THE MONTEREY PENINSULA referred to as Older Dune Sand Aquifer, or coastal aquifer, or in permeable offshore marine sediments. Because the intake for the seawater is below the sea floor, it is assumed that there are no potential impacts from impingement or entrainment resulting from seawater withdrawal. Conclusion The Sand City Desalination Project would include either an array of horizontal directionally drilled (HDD) or radial collector wells for seawater collection (feedwater source) located along the coastal beachfront of Sand City. Because the intake for the seawater is below the sea floor, it is assumed that there are no potential impacts from impingement or entrainment resulting from seawater withdrawal. For brine discharge, the project would utilize either HDD wells along the coastal portion of former Fort Ord north of Sand City, or the outfall from the regional wastewater treatment facility north of the Marina. The Board Review Draft EIR stated that the HDD wells option would have less-than-significant environmental impacts on Monterey Bay aquatic resources. Discharge to the outfall would be subject to the regional facility’s NPDES permit. The Board Review Draft EIR includes a summary of environmental impacts and mitigation measures for the proposed project. Many of these environmental impacts are deemed to be significant and would have considerable accompanying mitigation measures. 7.4 Seawater Desalination Vessel (SDV) Schedule Project proponents have stated that water delivery will commence three years after contractual agreements are signed. In our opinion, this seems optimistic given the uncertainties in the permitting process. No other scheduling information was provided. Environmental Impacts or Environmental Documentation Air Quality Permitting Requirements With respect to air quality issues, the Water Standard Company has provided conceptual project information on the Seawater Desalination Vessel (SDV), such as its approximate age, construction, equipment and configuration, approximate location, hours of operation, and water product transfer options. The materials also note potential emission sources such as gas turbine engines (main but not auxiliary), fuel mix (biodiesel capability), power supply, and pumps. The information provided features the “green” nature of the technology used for the SDV but downplays the air permitting issues that may correspond with construction and operation of the plant. In addition, some optional scenarios (e.g., a seabed pipeline versus shuttle vessels for transfer to mass storage) appear intermittently in the materials and would Monterey Peninsula Water Management District 7-15
EVALUATION OF SEAWATER DESALINATION PROJECTS PROPOSED FOR THE MONTEREY PENINSULA be expected to have greatly varying air quality requirements. Most of the information needed for an adequate air quality permitting assessment is not compiled specifically for that purpose; rather, it is scattered throughout the materials. The proponents acknowledge that more detailed information will be made available once costs and other feasibility concerns are sorted out. While it is reasonable that air emissions controls can be achieved through this proposal, it is also recommended that a legal and regulatory analysis of air quality requirements be conducted when the project is described more clearly. For example, file materials prepared by PBS&J suggest that air permits for construction of the treatment vessel and docks and piers will not be an issue. Other materials explain the basis for this assumption—the treatment vessel will not be refurbished locally, and docks and piers will not be necessary. Nevertheless, the materials do not discuss the potential construction permitting requirements for laying a seabed pipeline that may include air quality emissions from barges and drill rigs. These construction-related emissions were considered in a Minor New Source Review air permit application to EPA Region IX for a proposed deepwater port near Ventura, California called “Cabrillo Port.” In addition, the assumption that terminal storage for water needs to be constructed appears in the Water Standard Company “Proponent’s Statement,” dated April 11, 2007, but is not considered part of the proposed alternative package. Proponent’s supplied materials indicate that no permanent mooring or turrets will be constructed; but these assumptions are not carried forward to the Proponent’s Statement 62 . Each of these components would need to be clarified to assess construction-related air emissions and permitting requirements. In addition, Section 30253(3) of the California Coastal Act requires that an off-shore vessel operating within 24 nautical miles of the California coast must be “consistent” with requirements imposed by Air Resources Board (state) and the local air district, in this case, Monterey Bay Unified Air Pollution Control District (MBUAPCD). The 2006 PBS&J letter to the CPUC does not directly address the air quality impacts listed in the original NOP for the Moss Landing Desalination Plant/Coastal Water Project, although some may continue to apply in the SDV alternative. In addition to construction-related permitting, a key issue will be related to power generation for the SDV. The materials generally explain that the GE LM2500 gas turbines will power the equipment on-board. These engines are used routinely on cruise ships and commercial aircraft, which are regulated as mobile sources of air pollution. Nevertheless, it would be appropriate to obtain a legal opinion on the applicability of certain stationary source requirements (including federal New Source Performance Standards) to the gas turbines and the on-board equipment drawing power from the turbine while it is operating at a location fixed by mooring or satellite. To complete the SDV 62 Proponent’s comments on the draft GEI/B-E report include: “For clarification, at the time the PBS&J report was prepared, seabed pipelines were not an option and dynamic positioning was the preferred alternative. Switching from barge delivery to pipeline has occurred during discussions with Monterey over the past year. WSC will be in full compliance for seabed construction. Monterey Peninsula Water Management District 7-16
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