It is official: California faces the third driest year on record and water utilities across the state are scrambling to prepare for another drought. Some communities plan to enact an alert system for rationing water, similar to the warning system announced across intercoms at airports. Others have set reduction goals based on the number of occupants in a residence or the type of industry. Still others are proposing creating water supplies through desalination.

The City of Santa Cruz and Soquel Creek Water District are currently operating a desalination pilot plant to provide secondary water supplies to the city during drought years. In the San Francisco Bay Area, Contra Costa Water District, East Bay Municipal Utility District, San Francisco Public Utilities Commission, and Santa Clara Valley Water District have joined forces to build and operate the Bay Area Regional Desalination Project, which is also in the pilot testing stage. The Regional project not only provides additional water during a drought, it would also supply emergency supplies, for example, in the event of an earthquake.

Most recently, the California American Water Company with oversight from the California Public Utilities Commission, has released a draft environmental impact report, which proposes a desalination plant for the Monterey area to supply the region with an ongoing water supply and preventing further pumping from the sensitive Carmel River. A long list of other desalination plants in operation currently considered or to be considered by the California Coastal Commission (CCC) indicates that desalination is a real possibility for California’s failing water supplies.

While providing much needed water, desalination as a water strategy could use some major improvement. The energy required to pump water from the ocean, conduct a reverse osmosis process, and then pump water out to the public is intense and the cost of that energy is highly variable.

According to a 2004 analysis conducted by the CCC, “for each one-cent difference in the price per kilowatt-hour of electricity causes about a fifty-dollar difference in the cost to produce an acre-foot of desalinated water” (Seawater Desalination and the California Coastal Act, March 2004). In a previous study by the CCC, they estimate that it takes anywhere between 2,500 to 29,500 kilowatt hours to produce an acre-foot of desalinated water. While every plant is different, assuming the average or median kilowatt hours needed to produce one acre-foot is 16,000 (kwh), and that the average U.S. household uses about 8,000 kWh and about half an acre-foot of water each year, a desalination plant is operating using twice as much energy as water in the cleaning process . 

Unless desalination plants are powered by solar and wind or natural gas supplies, thousands of greenhouse gases and air pollutants are being spewed into the atmosphere to create a new water supply for Californians. Desalination goes against California policies like AB 32, which requires reducing greenhouse gases emissions, not increasing them, and national policies like the Energy Policy Act of 2005, which seeks to increase energy efficiency, not ignore it.

It is vital that California has a portfolio of water supplies in times of drought and with a potential security or seismic threat hovering daily. There is also an argument to be made, and one that is presented in each of the environmental impact analyses of these desalination pilot programs: creating more water creates population growth.

Unless a smart growth plan is fully executed, more greenhouse gas emissions, more air pollution, more demand for water, and more energy is needed to support that growth. So regions need to reduce their emissions, expand only using low impact and smart growth designs, and create a new water supply.

One silver lining does exist:  when renewable energy supplies power to these plants, California is bringing renewable power infrastructure to communities across the state . Only under these conditions should desalination be considered a viable option. The need for water in California is immediate. So to is the need to cut emissions. Some serious policy development by key decision makers is absolutely necessary to balance California’s need for water, and reduce climate change contributions.