This Solar-Powered Pipe Desalinates The Water That Flows Through It
It’s called ‘The Pipe.” And if it works, it could change the calculus of our water problems.
After a massive, billion-dollar desalination plant opened near San Diego eight months ago, it won an award for its efficiency. But even with the latest technology, the plant—which turns ocean water into clean drinking water for about 7% the county—uses enough electricity every day to power 28,500 homes.
But a new conceptual design shows how a desalination plant can run on solar power instead, while doubling as public art and a place for visitors to soak in salt baths.
Unlike the San Diego plant, which uses reverse osmosis to blast seawater through filters with microscopic holes, the new design, called “The Pipe,” says it would use a magnetic field to pull salt out of water. “We’re just addressing the salt,” says Abdolaziz Khalili, part of a team from Khalili Engineers that created the design. “Regular ocean water has about 3% salt, so we’re calling that 3% of salt out of the water rather than pushing the 97% that’s water.”
That saves a corresponding amount of energy. It also eliminates the need for moving pumps—which can quickly rust in ocean water—and filters that also need frequent replacement.
In a design for the Land Art Generator Initiative, a competition that calls for new energy infrastructure that looks like art, the engineers mocked up what the plant could look like off the coast of Santa Monica. The designers plan to build a prototype and prove that their technology is actually effective at desalination.
“We’ve created this as a pipe because it’s a good metaphor—pipes bring us water,” says architect Puya Khalili. “We need quite a lot of length to achieve this process, so we needed something long. We also need the surface to accommodate all of the solar cells.”
The pipe would stretch about 600 meters, and would sit on top of an existing breakwater in the Santa Monica Bay. Inside, the plant would send drinking water back to the city—roughly 4.5 billion liters a year, or half of the city’s needs—and use the salinated water in indoor swimming pools. As visitors float in the salt baths, they could listen to the waves and watch the surrounding ocean.
“It’s letting people get in touch with this new technology, which is very friendly,” says Abdolaziz Khalili.
The Pipe’s designs show it covered in flexible solar panels on the south and west. The technology can run directly on the current from the solar cells, rather than converting (from D/C to A/C) like most equipment; this helps it run even more efficiently.
Typical desalination plants can harm marine life when brine is dumped back in the ocean. But the new design, placed over the ocean, can use ocean water to dissolve the brine as it’s slowly released.
The design is a finalist in the competition. Though it’s just a concept now, the Land Art Generator Initiative plans to work with cities around the world to pursue implementing some of the most practical ideas. In California, as the drought continues, there’s likely to be interest. Los Angeles is considering another large desalination plant now; more than a dozen others have been proposed up and down the coast. But if the pipe works, there might be a simpler solution.