California is suffering through its worst drought in decades, and it has gotten so bad that officials announced that 17 communities across the state are in danger of running out of water within 60 to 120 days. But what if the solution to California’s water crisis is as simple as sunlight – a resource the state has in abundance? That’s exactly what California-based startup WaterFX is proposing with its solar-powered desalination system. Renewable desalination could solve water scarcity issues not just in California but in other drought-stricken and desertified areas across the world.
WaterFX’s system cleans water with a Concentrated Solar Still (CSS), which collects the sun’s thermal energy and transfers it through pipes filled with heat transfer fluid to a heat pump. The heat is then used for the distillation process, which evaporates freshwater out of the saltwater source. The condensate is then recovered as pure, fresh H2O. A thermal storage system holds excess heat for the times when the sun isn’t shining.
“If we roll out the technology … we could produce 8% of all the water used in California, with just the land that was fallowed during the last drought,” WaterFX Founder and Chairman Aaron Mandell recently told Forbes Magazine. “That’s enough water for over 7M acres of irrigated farmland. You would begin to change the economics and change the course of how water is used. The whole idea is to wean the State off of the Central Aqueduct and become water independent. The current system is unsustainable and unreliable.”
However solar desalination systems are not without their challenges – it takes a lot of energy to suck up large quantities of ocean water, and the process can capture local marine life as well. There’s also the issue of solar desalination’s byproduct – a salty sludge that can harm ecosystems if it’s pumped back into the ocean.
Other parts of the world working on renewable desalination include South Australia, where Sundrop Farms has installed a desalination plant near Port Augusta; Qatar, where the Sahara Forest Project is experimenting with a pilot system; and Saudi Arabia, where there are plans to build a solar-powered plant in Al-Khafji. Saudi Arabia currently uses the equivalent of around 300,000 barrels of crude oil a day for its desalination plants, so switching from fossil fuels to renewable energy could have a huge positive impact on climate change and sustainability.
“What we are trying to do is to develop a model that can be replicated. The problems in California are identical to those in many parts of the world. China is depending on delicate river systems to provide water for all types of economic growth that will not be sustainable. We could also do this in Saudi Arabia – they use an enormous amount of oil for water consumption, to evaporate or move water around the country,” said Mandell.
Via The Guardian
Images via WaterFX
The problems posed in this article concerning the use of solar desalination can be solved if the solutions are kept simple. For example, 1) Instead of pumping sea water into a desalinization plant, why not build solar desalinization plants on platforms on the surface of the ocean just like oil platforms are built now? 2) Instead of dealing with marine life entering pipes that suck water, why not lower big vats into the water from beneath the solar plant platform and allow these vats to be flooded with sea water? These vats would have a screen cover on top to filter out marine life. 3) The solar energy would be used to lift the sea water into the plant for treatment and to desalinate the water. 4)Much like ships now carry oil from oil platforms to the shore, desalinated water could be shipped to shore in the same way. At the shoreline, the water could then be hooked up to a pumping station and the water would be sent through to the local water treatment plant for chlorination, fluoridation etc. 5)The salty sludge left after the desalination could also be loaded on the same ships which would carry it ashore. It could be recycled to cities/government that want a cheap source of salt to be used for melting snow and ice on highways and roads in the winter.