Seawater Greenhouse Brings Agriculture to World's Harshest Environments

To riff on an old proverbial phrase: When life gives you a hot, punishing climate and nary a drop of fresh water for irrigation, why not make ...

OK, there’s literally nothing you can make — or grow, in this particular instance — with those things. Not lemonade, not tomato salad, not a banana and strawberry smoothie. Nada.

However, British theatrical lighting designer-turned-inventor Charlie Paton has devised an agricultural workaround that enables some of the most arid, drought-stricken communities in the world to successfully grow and harvest crops by harnessing the two things that parched coastal regions happen to have in spades: sunshine and saltwater. As a result, residents of fresh water-starved locales like Somaliland, Oman, Abu Dhabi and bone-dry South Australia are finding that they can indeed grow lemons — and make delicious lemonade — along with a variety of other crops that would be otherwise impossible to grow in harsh environments where water insecurity is a pressing issue.

Revolving around a technology first developed and piloted in Spain’s Canary Islands in the early 1990s, Paton’s company, Seawater Greenhouse, specializes in just that: solar-powered greenhouses where crops are grown using saline water, which in normal circumstances is a plant killer (save for salt-filtering mangroves and a few other plants, most of which aren’t fit for human consumption.)

The two-step technology is rather straightforward. "The idea is so simple that it’s rather insulting," Paton tells Wired U.K. in a profile of Seawater Greenhouse’s latest endeavor in Somaliland, an autonomous region of Somalia that's home to 4 million-some residents who have long struggled with crippling drought and famine. "People say, 'If that’s going to work then somebody would have done it before.'"

First, seawater is pumped to the greenhouse installation.

Then, the seawater is used to cool and humidify the hot desert air drawn into the structure’s growing area using fans before going through an evaporation process that distills saltwater using solar heat, transforming it into fresh water.

Voila! A relatively low-cost, integrated desalination process ideal for areas where agricultural efforts, large or small, would otherwise be a nonstarter.

Some more nuts and bolts — also discussed in the below video — on the process:

The innovation utilises the cooling and humidifying power of water vapour produced from evaporating salt water. Using modeling and simulation techniques developed in collaboration with our partners at Aston University, we are able to process local climate data to predict greenhouse performance and inform the design. The combined effect of reducing temperature and increasing humidity, together with providing a protected environment for crops, results in up to 90 percent reduction in evapotranspiration. This to greatly reduced irrigation requirements, which can be provided by desalination, and improved growing conditions.

Speaking to the Guardian, Paton, a graduate of London's Central School of Art and Design, explains how the idea first came to mind while on his honeymoon in Morocco (not too far from the Canary Islands) in the 1980s:

I was on a bus and it had been raining outside. People were getting on with wet, steamy clothes, and condensation ran down the windows. I started thinking about using heat to make water, specifically in hot, arid countries like the one I was sitting in. I knew that using seawater was the answer, because it's abundant, but it's generally poisonous to plants, and even by distilling it, plants need more water than we could easily provide. The trick was working out not just how to create water, but how to create an environment where plants don't need nearly as much of it, yet grow better; the answer was using seawater to cool and humidify the climate.

Growing crops with sun and saltwater Down Under

The nearly 62-acre Seawater Greenhouse operation in Somaliland, located near the port city of Berbera on the Gulf of Aden, may be first project of its kind in the woefully water insecure Horn of Africa. But as mentioned, the Seawater Greenhouse has been transforming saltwater into fresh water for agricultural purposes in other arid regions for some time now. With each new project, the company has improved and expanded upon its original pilot project in the Canary Islands.

In 2000, Paton worked alongside industrial engineer Dr. Philip Davies of Aston University in Birmingham, England, to develop a "lighter, stronger, simpler" greenhouse that was piloted on Al-Aryam Island in Abu Dhabi. Four years later, Paton and his team collaborated with researchers from Sultan Qaboos University to pilot another greenhouse near the Omani capital of Muscat that "showcased the potential of the technology in extreme desert environments."

In 2010, Seawater Greenhouse embarked on its first commercial-scale project outside of Port Augusta, a small port city on Spencer Gulf in arid South Australia. Originally 21,500 square feet, the Port Augusta operation has since grown to nearly 50 acres under the auspices of Adelaide-based sustainable agriculture operation Sundrop Farms. (The massive project, which is powered by a sizable solar farm, was initially a joint venture between the two companies although Saltwater Greenhouse later bowed out leaving Sundrop Farms in full control.) As noted by Wired, the Port Augusta greenhouse now supplies 15 of the tomato markets in Australia. That’s no small, um, tomatoes.

Creating a 'Horn' of plenty

Soon after the big-budget, headline-garnering Australian project was completed, Seawater Greenhouse was implored to bring the concept to the Horn of Africa, by far the most challenging environment yet — in terms of both the climate and the economic and political realities of the region.

As Paton explains to Wired, he initially balked at the idea, which has been three years in the making.

"It was just too expensive," he says noting that many of the elements that made the Australian greenhouse such a success would be difficult, if not impossible, to implement in Africa. "But then I went back to the drawing board, and realised it could — if I made it really simple, and stripped it back to the basics."

Despite the daunting logistics, it’s a good thing Paton did return to the drawing board as the Somaliand greenhouse is his company’s most revolutionary project yet. Earlier this year, the operation produced its very first harvest: lettuce, cucumbers, and, yep, tomatoes. Future crops trials will expand to include carrots, onions and beans.

"This new Seawater Greenhouse is not a typical greenhouse but rather a shade net system that retain core evaporative cooling elements developed from previous projects," explains the company. "Advances in our greenhouse modeling techniques have allowed us to simplify the design and drastically reduce its cost without sacrificing performance."

'A restorative approach to agriculture'

One element present in earlier greenhouses developed by Paton and the team at Aston University are fans, employed to push water vapor through the interior of the structure. To cut costs at the closed-loop Somaliland greenhouse, prevailing desert winds, not fans, do all of the pushing.

Per Wired, for every liter of seawater pumped through the system, 30 percent is converted into crop-friendly fresh water. There are plans to collect and sell the salt left over from the evaporation process at markets throughout Somaliland and Ethiopia. Normally, brine resulting from desalination is pumped back into the sea, an aquatic life-disrupting method that poses serious ecological concerns.

"Somaliland lies in the center of one of the world's most food-insecure regions," notes the company website. "With this latest project we will show that drought need not lead to famine, and through subsequent scale-up enhance self-sufficiency of the region as well as provide drought-resilient livelihoods to smallholder farmers."

That last part, providing a livelihood to local farmers, is still in the works as the Seawater Greenhouse team contemplates the most effective way to supply local markets with produce harvested at the nascent greenhouse. The company plans to erect an on-site training center for local farmers, with the idea that, thanks to the greenhouse’s modular design, they’ll eventually be able to tend to their own small individual plots. "A small family-run farm has the additional advantage of enabling the employment of women, who often make the best horticulturalists but are economically disadvantaged in the region," explains the project website.

"I am confident that output, quality and profitability will all go up as experience is acquired," Paton tells Wired. "For that reason, my primary focus, now that we have a fully functional site, is to arrange scale-up and training in parallel."

Last month, Seawater Greenhouse was named a regional finalist for Shell Springboard 2018, a competition that awards funding to U.K.-based low-carbon businesses. And despite being a for-profit operation party funded by InnovateUK, the company is seeking financial support from the big-hearted general public, noting the complex challenges that come along with launching an endeavor that's a world's first in several aspects: the Horn of Africa's first seawater cooled and operated greenhouse, the region's first solar-powered desalination plant and the first direct foreign investment in Somaliland by a U.K. company.

"Water shortages are a global crisis that is worsening dramatically," Charlie Paton tells BusinessGreen. "So is land degradation. This represents a scalable model that could be taken anywhere there is limited or no fresh water."