Saudi Arabia Pushes to Use Solar Power for Desalination Plants

With photovoltaic costs dropping, oil states turn to solar power to desalinate their water

3 min read
Photo: Chip Hires/Gamma-Rapho/Getty Images
Drink Up: A desalination plant in Al Khafji, Saudi Arabia, is powered by fossil fuels. A new, solar-powered desalination plant is now being built in the city.
Photo: Chip Hires/Gamma-Rapho/Getty Images

It seems like a natural fit for desert dwellers: Use the sun to scrub salt from groundwater or seawater and make it suitable to drink.

Armed with oil money, the Saudi government’s Saline Water Conversion Corp. (SWCC) has already built the world’s most extensive network of desalination plants. However, like many facilities in Saudi Arabia, those plants are powered mostly by fossil fuels.

Thanks to a steep drop in the cost of photovoltaics (PV), solar power is now starting to look like a tantalizing replacement. As of press time, desalination expert Thomas Altmann of ACWA Power was expected to argue that solar power is turning the industry “on its head” at a conference in Paris in April, according to a session description.

But a 2015 attempt by SWCC to commission a 15-megawatt solar PV–⁠powered desalination plant at Al Khafji, in Saudi Arabia, is behind schedule. When it does come on line, the solar power and desalination components will likely operate separately, insiders say. Another solar desalination plant, in Morocco, has also failed to integrate the two parts.

Energy costs make up 40 to 50 percent of the cost of desalination, estimates ­Carlos Cosín, CEO of Almar Water Solutions, in Madrid. Industry leaders in Saudi Arabia, Abu Dhabi, and Chile are particularly interested in using solar power to run reverse-osmosis desalination, which uses electricity to pump saline water through membrane filters.

Despite the missteps, a Middle Eastern country will still be first to operate a commercial solar desalination plant, predicts Cosín, who worked on the Al Khafji site. He estimates such a plant could open in 2021 or 2022.

The countries in the region have lots of sunlight and stand to gain from cheaper freshwater, given the dearth of local sources. Switching to solar also means they could export more oil for US $65 a barrel, instead of selling it to desalination plants for subsidized prices.

Renewable energy “actually is cost competitive” for some remote desalination plants, says engineering researcher John Lienhard, of MIT. But for others, that calculation depends on the type of solar power used and the kind of desalination that occurs there.

Concentrated solar power (CSP), which uses circles of mirrors to direct sunlight toward a solar tower filled with thermal salts, generates electricity more consistently. It can also store heat for several hours, which certain types of desalination plants can use to evaporate saltwater.

PV is less than half the price of CSP during the day, but it produces only electricity—not heat. That makes PV a better fit for reverse-osmosis desalination than for evaporation techniques.

However, the Persian Gulf and the Red Sea are so saline that desalting seawater may drive up electricity costs for reverse osmosis. In such places, evaporative desalination paired with CSP might be best because the costs of evaporation do not increase with salinity.

In fact, the Saudi government announced plans a few years ago to build 25 gigawatts of CSP capacity by 2032, and a 2015 study concluded that combining CSP with evaporative desalination could make sense in the Middle East and in the U.S. Southwest. But nobody has put any solar technology into commercial desalination practice.

The original contractor on the Al Khafji site, which was designed to perform reverse osmosis using solar PV, narrowly avoided bankruptcy. SWCC divided the project into parts, handing the solar-PV component to one contractor and the desalination part to another. In the end, the desalination plant might run on the grid instead of on solar.

The setback has not fazed the Saudi government. In March, King Abdullah Economic City, in Saudi Arabia, broke ground on its own solar PV–powered desalination plant, which will also lean on the grid.

This article appears in the May 2018 print issue as “Oil States Try to Turn Sunlight Into Freshwater.”

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Smokey the AI

Smart image analysis algorithms, fed by cameras carried by drones and ground vehicles, can help power companies prevent forest fires

7 min read
Smokey the AI

The 2021 Dixie Fire in northern California is suspected of being caused by Pacific Gas & Electric's equipment. The fire is the second-largest in California history.

Robyn Beck/AFP/Getty Images

The 2020 fire season in the United States was the worst in at least 70 years, with some 4 million hectares burned on the west coast alone. These West Coast fires killed at least 37 people, destroyed hundreds of structures, caused nearly US $20 billion in damage, and filled the air with smoke that threatened the health of millions of people. And this was on top of a 2018 fire season that burned more than 700,000 hectares of land in California, and a 2019-to-2020 wildfire season in Australia that torched nearly 18 million hectares.

While some of these fires started from human carelessness—or arson—far too many were sparked and spread by the electrical power infrastructure and power lines. The California Department of Forestry and Fire Protection (Cal Fire) calculates that nearly 100,000 burned hectares of those 2018 California fires were the fault of the electric power infrastructure, including the devastating Camp Fire, which wiped out most of the town of Paradise. And in July of this year, Pacific Gas & Electric indicated that blown fuses on one of its utility poles may have sparked the Dixie Fire, which burned nearly 400,000 hectares.

Until these recent disasters, most people, even those living in vulnerable areas, didn't give much thought to the fire risk from the electrical infrastructure. Power companies trim trees and inspect lines on a regular—if not particularly frequent—basis.

However, the frequency of these inspections has changed little over the years, even though climate change is causing drier and hotter weather conditions that lead up to more intense wildfires. In addition, many key electrical components are beyond their shelf lives, including insulators, transformers, arrestors, and splices that are more than 40 years old. Many transmission towers, most built for a 40-year lifespan, are entering their final decade.

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