Weekly column by Barbara Hirsch
To be sure, desalination has been a hot topic in California and other drought stricken parts of the globe. Fresh water supplies are always limited to less than 1% of all water on the planet. Needs increase with the population while more droughts threaten existing resources. In the last 5 years, desalination capacity, globally, has increased 57%.
The Middle East could be a model for this, now and into the future. Home to 6.3% of humanity with only 1.4% of the water supply, they generate over half of the desal water available on the planet at the moment. But that water is costly, using more than ten times more energy (and their precious export resource, fossil fuels) than needed for pumping well water. A renewable energy company in Abu Dhabi is working on possible alternatives that could be a boon to a thirsty planet.
Closer to home, another model could be Santa Catalina Island, a popular tourist spot off the coast of LA, sort of a miniature California water wise, except they are not getting water diverted from other places. It all comes from their drying up reservoirs, wells and some desalination, 10%. All of their water is controlled by Edison. Residents and businesses pay more – 5 to 18 times more - than anywhere else in California. Few relaxed showers and little car washing goes on there. Their entire economy is severely threatened right now.
To reactivate Santa Barbara’s decommissioned plant, completed at the end of the last serious drought in 1991 and used only briefly, would cost nearly $30 million, so no one is in a rush to do it. This coming rainy season will determine how quickly that goes forward. We are fortunate in that currently most of the area’s water supplies are gravity fed and so of low energy use. Desalination requires pumping the water from the ocean to the plant, high pressure pumping through reverse osmosis membranes and further processing.
Environmental challenges in the process are: a higher percentage of energy and associated emissions needed for water supplies; potential harm to sea life at the intake; treatment and disposal of the briney waste. Let’s hope that the plants of the future most certainly needed, will manage these well.