A research group's report outlining the high energy costs and impacts of operating a desalination plant underscores local efforts to control the potential costs of California American Water's proposed facility.
The report from the Pacific Institute, an Oakland-based nonprofit organization that conducts research and analysis with a focus on global and regional freshwater issues, concludes that desalination is so energy intensive — consuming more energy per gallon than most other water supply and treatment options — that it replaces water reliability risks with energy price risk.
The report, released this week, noted that desal plants not only require additional energy to produce water, but also to deliver the water and dispose of the brine and other waste.
In addition, the report found that desalination plants can cause an increase in greenhouse gas emissions, thus "running counter to the state's greenhouse gas reduction goals" as expressed in legislation such as AB 32, which requires the state to reduce emissions to 1990 levels by the end of this decade. It suggested a few ways to reduce emissions, including cutting a desal plant's total energy requirements, powering a plant with renewable energy and purchasing carbon credits.
The report, "Key Issues for Seawater Desalination in California: Energy and Greenhouse Gas Emissions," is the third in a four-part research series on desalination by the institute. The report can be seen online at www.pacinst.org/reports/desalination_2013/energy.
The report comes as Cal Am's Peninsula water supply project, a $400 million proposal that includes a desal plant north of Marina at its core, is under environmental review through the state Public Utilities Commission. A draft environmental impact report, due this summer, is expected to address energy demand and use issues.
The project is designed to provide a new water source to offset the impending loss of a major portion of the Peninsula's supply due to a state-ordered cutback in pumping from the Carmel River that takes full effect starting in 2017.
"There's no question that desalination is an energy-intensive technology and that energy use is a large contributor to desal costs," said Cal Am spokeswoman Catherine Bowie.
But Bowie said the Peninsula's options "are very limited" because of the level of conservation the community has already achieved, limits on groundwater pumping, and the regulatory and permitting hurdles related to building new dams. She suggested that "most experts would agree that desalination has to be a part of our future water supply."
Efforts to cut costs
Bowie said Cal Am representatives are working on a couple of fronts, in cooperation with local officials, to try to minimize energy costs and the plant's carbon footprint.
First, the proposed water project could include a groundwater replenishment element backed by the Monterey Regional Water Pollution Control Agency that would enable Cal Am to build a smaller desal plant, capable of producing 6.4 million gallons per day instead of 9.6 million. The groundwater replenishment project uses about six times less energy than the desal plant would, Bowie said.
In addition, the water project includes the use of aquifer storage and recovery, backed by the Monterey Peninsula Water Management District, which is designed to bank water for later use and allow the desal plant to operate on a steadier basis, thus avoiding the energy use spikes and dips associated with residential and commercial water demand.
At the same time, Bowie said Cal Am has approached Pacific Gas & Electric Co. about the plant's power demands and is working with the water project governance committee on an analysis of available alternative energy sources, including landfill gas power from the Monterey Regional Waste Management District at the Marina landfill.
The Peninsula mayors' water authority has called for requiring Cal Am to seek the lowest available power rates for the plant, as one of the authority's conditions for supporting the project, by agreeing to purchase electricity from a municipal utility, generating on-site power or seeking other low-cost power sources.
Finally, Bowie said Cal Am expects desal plant energy-recovery technology to continue to improve, offering increased power savings in the future.
Jim Johnson can be reached at 753-6753 or email@example.com.