California needs to invest in environmentally sustainable desalination
California is in the midst of a four-year long drought, and the arid climate shows no signs of letting up. The drought is so extreme that reservoirs and wells are drying up, and the state is looking to new sources of water to sustain its agriculture and its residents. Even though California’s Western side lies along the pacific ocean, the high salt content of ocean water makes it unusable unless the salt is removed through a process called desalination. Desalination is costly, and has historically been an impractical solution to water shortages in California; until now.
San Diego county has invested $1 billion to build a desalination plant capable of making 50 million gallons of sea water per day salt-free and potable. When completed, the New York Times reports that the San Diego plant will be the largest desalination plant in the Western Hemisphere. The region greatly needs the water that the plant will provide, but many are concerned over the environmental damage of the new plant.
Even when using improved technologies, desalination is a highly energy intensive process. Globally, most desalination plants meet those high energy needs with fossil fuel power. “Desalination plants in Qatar consume around 1.54 billion kWh of electricity annually, which roughly translates to around 680,000 metric tons of CO2 equivalents per year” (Saif 2012). In oil rich countries like Qatar, desalination is affordable because of the country’s vast oil reservoirs. The San Diego plant will use a reverse osmosis process that requires high amounts of energy. Proponents of this technology argue, however, that improvements in materials make the process cost efficient. Israel recently constructed 4 desalination plants that supply 40% of its water, expected to increase to 50% by 2016.
Analyses of cost efficiency, however, do not take into account the costs of environmental degradation and of pumping millions of tons of CO2 into the atmosphere. In the context of a drought made worse by global climate change, fossil fuel powered desalination seems like a counterproductive response to a serious issue. Instead of making communities water independent, conventional desalination methods force them to rely on a shrinking and expensive supply of fossil fuels that, when burned, contribute warming gases into the atmosphere. In other words, they will make droughts worse, and provide only a temporary solution to decreased at best.
One company in California is taking a sustainable approach to desalination. WaterFX, a self-described “independent water producer”, has designed a desalination plant that runs entirely on solar energy. The plant was designed in conjunction with California’s Panoche water district and is being used to reclaim water laden with salt and other minerals collected from agricultural runoff. The plant does have the capacity to remove salt from sea water. Currently, the plant’s is generating 65,000 gallons of freshwater per day. 65,000 gallons is far below the 50 million gallons per day that the San Diego plant is expected to produce, but WaterFX representatives claim that their plant can be scaled to meet the needs of a major urban population.
If desalination is one of the solutions to meeting the compounding crises of increased demand for water and severe drought, more states need to invest in sustainable desalination technologies like solar powered processes. Some scientists are also experimenting with wave-powered energy systems that could help power desalinization plants. If as many resources were devoted to improving sustainable technologies as is devoted to building fossil fuel powered systems, sustainable desalinization systems could be scaled to meet global demand.
Relying on fossil fuels to solve a drought made worse by global warming will make the problem worse in the future.
We need to make a commitment to sustainable technologies now, so that they are ready to meet the climate needs of the future.