Desalination exists within California as a small production source, producing between .002 to 0.600million gallons per day. These plants are used for industrial processes. In 2002, the California Legislature passed Assembly Bill 2717 (Directing the department of water resources to establish a desalination task force to make recommendations related to potential opportunities for the use of seawater and brackish water desalination. The desalination task force established that desalination could only contribute to less than 10% of California’s water supply needs. Nine years after Assembly Bill 2717 passed, private corporations and municipal water agencies have proposed new desalination plants. There currently are over twenty large-scale desalination plants proposed throughout California (ranging in capacity from .40 MGD to 80MGD). The technology that is projected within desalination plants is Reverse Osmosis; a little insight on the inefficiency of this technology is displayed in the cost breakdown below:
- Provides reliable drought-resistant water supply to California
- Improve water quality compared to existing sources
- Lessen the demand on northern California’s water supply by developing a local alternative for Southern California.
- Can add harmful chemicals and metals into the water it produces
- Intake waters could contain: Pharmaceuticals, algal toxins, and endocrine disruptors depending on water supply source
- Desalination is extremely energy intensive, requiring 30% more energy than existing inter-basing supply system and the energy expense is 50% of the plants operating cost
- Desalination also would indirectly cause more GHG emissions (greater dependence on fossil fuels)
Desalination plants within California were indirectly withdrawn when coastal power plants once- through cooling methods ( seawater intakes and use the seawater for cooling from the power plant). In 2010, the California State Water Resource Control Board passed a policy to phase out the use of once-through cooling because of the impact on marine life. There were 20 desalination proposed to use open seawater intakes to withdraw water and ten of these will likely co-locate with existing power plants in order to share the intake pipes. Only 13 of those 20 projects are moving forward.
Alternatives to Current and desalination water supply systems:
- Urban water conservation
- Stormwater Capture/ reuse
- Water Recycling
- Groundwater Desalination requires less energy than seawater desalination because the water is less saline.