SOCAL Considering the Promise of a Project that Provides Desalinated Water AND … Renewable Energy

The contraption, reminiscent of Rube Goldberg, would produce two of Southern California’s most precious and essential resources: water and electricity.

The electricity would be renewable. And the drought-proof, desalinated ocean water could prove more environmentally friendly — and cheaper — than the water produced from three other desalters proposed for Southern California.

The idea, developed by Silicon Valley-based Neal Aronson and his Oceanus Power & Water venture, caught the attention of the Santa Margarita Water District. The agency quickly saw the project’s viability to fill a void.

“Somebody looked at a problem differently than anybody has in the past,” said district General Manager Dan Ferons. “It’s really creative and got us excited about it. … It could become a primary source of water for south Orange County.”

While Oceanus’s proposals at locations in Mexico and Chile have advanced to the preliminary engineering phases, it remains in the conceptual stage for a plant in northern Camp Pendleton.

But because south Orange County is almost entirely dependent on imported water — and vulnerable to shortages during droughts and earthquakes that can disrupt imported flows — the Santa Margarita Water District last summer signed a non-binding memorandum of understanding with Oceanus for possible participation.

“You don’t want to have just one source of water,” Ferons said, noting that the district is also interested in desalted water from two other plants proposed for the region.

“We thought, ‘Here’s another opportunity to increase our resilience.’ It made sense to encourage and support the project while they pull it together.”

How it works

The Oceanus process begins by pumping water from the ocean to a reservoir some 1,000 feet above sea level, using solar and wind energy to power the two-way pump turbines during daylight hours when those renewable sources are plentiful. During the evening and early morning, water would be released to run downhill, most of it churning through turbines to create electricity when solar and wind energy are unavailable.

Additionally, a portion of the downhill water would be diverted into a desalination operation, where gravity would force it through reverse osmosis membranes that remove the salt.

Relying on gravity rather than electricity to push water through the filters is key to making it cheaper than the water that someday could be produced at desalination plants proposed for Huntington Beach, Dana Point and El Segundo.

Meanwhile, the salty brine byproduct would be mixed with the other outward-bound seawater, greatly diluting it before entering the ocean. Concerns linger among some environmentalists about the harm that the brine would inflict on marine life at other proposed plants, something that would be minimized by the Oceanus approach.

“No one has done this type of project anywhere in the world,” said Oceanus CEO Aronson, whose background is in real estate development and renewable energy projects. “It’s climate resilient. And we’re not planning to use any energy beyond pumping water from the ocean. … I’m a huge believer in the value this integration can bring.”

Inspiration and invention

The idea of creating energy by releasing water to drive turbines is hardly a new one — that’s how hydroelectric dams work. Even the idea of pumping water into reservoirs when electric rates are low and releasing it when they spike — a process known as pumped-storage hydroelectricity — has been used for over a century, Aronson said.

He recalled seeing such plants while vacationing with his parents in Switzerland and France as a child.

Neal Aronson, CEO of Oceanus Power & Water. (Courtesy of Oceanus Power & Water)

And then, in 2014, while developing a solar farm project near the San Luis Reservoir in Merced County, he sized up his project sitting in the shadow of the reservoir and began imagining future sites for pumped-storage hydroelectricity.

Solar and wind are great but what do you do at night?” Aronson said. “Chemical batteries aren’t the right solution for large-scale energy storage.”

While batteries increasingly are being used in California to store solar and wind energy for use during off hours, Aronson points out that those batteries have a limited life span, are still expensive, and can have negative environmental consequences as they have a carbon footprint and are not yet recyclable.

After Aronson began thinking about pumped-storage hyrdoelectricity plants, his focus sharpened to the possibility of building such plants along the coast, using ocean water — something that was only being done in Japan.

Next, the desalter portion of the plant clicked into place.

“In conversations with engineers, one kind of flippantly said, ‘If you’re going to stick a straw in the ocean and suck water out, why don’t you desalinate it while you’re at it,’ ” Aronson recalled. “And we figured out, yeah, you can do that.”

Next steps

Oceanus, founded in 2015, is farthest along with its plans in Chile, where Aronson said he may have all permits necessary to break ground within two years.

The proposal in Sonora, Mexico, on the Sea of Cortez sounds more tentative. While Oceanus has a site, a feasibility study is still underway by the Binational Desalination Work Group. If the U.S.-Mexico entity decides to go forward, Oceanus would likely compete with other bidders. The water would go to both Mexico and to southernmost U.S. states that depend on increasingly uncertain water supplies from the Colorado River.

Camp Pendleton is farther off still. Aronson said he has had talks with the base, the Navy and the Department of Defense, but the decision to go forward has not yet been made. A selling point for the military is that the plant could help the base become more resilient and self-sufficient in terms of water and electricity, which is of particular interest to the Department of Defense, Aronson said.

“The first step is to get them to draft and issue a solicitation for something like this, and we would bid into it,” Aronson said. He declined to speculate on how long it might take for the project to get off the ground, but Santa Margarita Water District’s Ferons estimated a minimum of five years.

While Aronson envisions building a solar farm to power a plant in Sonora, he said a Camp Pendleton plant would likely use power from the state electrical grid during hours when it’s being fed by renewable sources.