Can desalination plants solve Africa’s water crisis?

For three years the population of Agadir, on Morocco’s southern Atlantic coast, has been struggling with a drought that has forced the authorities to divert water from dams meant for farm irrigation to residential areas in order to provide drinkable water to half a million people. Agadir’s agricultural heartlands were left reeling by parched fields and decimated crop yields when temperature monitors at Agadir Airport soared to 49 degrees Celsius in August, the Kingdom’s highest temperature on record. 

This summer’s heat wave also shattered records in Tunisia, while the UN warns that Madagascar is on the brink of its first climate-induced famine, after months without rain.

As water scarcity is forced towards the top of the political agenda, North African governments are investing in water desalination (desal) plants.

The Algerian government is implementing a new emergency plan that will focus on seawater desal in its drinking supply. Tunisia is ramping up production of multi-million dollar facilities, and Egypt’s sovereign wealth fund is building financial partnerships of up to $2.5bn to build, own and operate 17 new solar-powered desal plants by 2025. The Egyptian government has announced plans to invest $8.5bn by 2050 to build 47 seawater desal plants through public-private partnerships, increasing its desal capacity by 6.4m cubic metres a day (MMm/d).

“Egypt has been successful in harnessing solar and wind energy with above average yields, making the efficiency of plants quite attractive, which helped create a very low cost base for energy units, and those competitive rates are now becoming a solid base for enabling and powering more sustainable tech like desal, and this is the breakthrough,” says Ayman Soliman, CEO at the Sovereign Fund of Egypt.

ACWA Power, the Saudi Arabian energy and desal giant, say they are studying several opportunities for seawater reverse osmosis plants in North Africa, which will be powered by solar, wind, or a combination of both.

“Egypt presents a valuable opportunity for us to lead the energy transition and deliver water and power reliably and responsibly, and we’re excited to participate in the country’s development plans and transition to a greener future,” says Thomas Altmann, executive vice president for innovation and new technology.

Technology revolution

Most of the world’s 20,000 desal plants usually fall into one of two categories. Sea, waste, brackish and other water categories are heated to get a pure vapour that is cooled into liquid for safe drinking; or membranes are used to push water at great pressure through filters to draw out salt and other impurities. 

Desal businesses make a profit by supplying water to residential, commercial and government end-users, or provide water to government-owned distributers. Yet facilities are often expensive to build, energy intensive and environmentally damaging, as the waste by-product of desal is brine, which combined with other harmful chemicals used during the desal process can ruin ecosystems when pumped back out to sea.

The long-term prospects for desal as a key strategy in Africa’s water security mix have been boosted in recent years as renewable energy becomes more efficient, and the method of converting brine and other desal waste products into useful commodities like hydrochloric acid through standard chemical processes make facilities more cost effective. 

A development on membrane technology – reverse osmosis (RO) – requires less pressure and energy to filter water, further reducing operating costs. Efforts to combine RO and renewable energy are in their infancy, but developments in renewable energy storage systems – such as solar thermal energy storage facilities, using molten salts for long-duration reliable discharge, and lithium-ion batteries to manage short-term variability – are now motivating more governments to look into renewable desal.

More efficient pumps, membranes and energy-recovery devices mean plants now use a quarter of the electricity they did in the 1980s.

Egypt’s plans for renewable desal are in part motivated by schemes to create new cities away from the Nile valley. Desal water can be used to irrigate its agricultural land to grow more wheat, while it must also insure itself against possible consequences from the Grand Ethiopian Renaissance Dam project, which Cairo fears will threaten its water supply.

“This is a very forward-looking strategy, and it’s an attractive asset class for us to invest in long term,” says Soliman. “The market is wide open for developers since we know there is a growing sustained demand for desal capacities that are being built. Africa is super hungry for renewables and desal, and I think that presents an opportunity to create a supply hub for the rest of the Middle East and Africa, by localising the components of the desalination tech in Egypt.”

According to a report by Ventures ONSITE, a market research firm, 48% of the world’s water desal projects are being carried out in the Middle East and North Africa, in a market expected to reach around $4.3bn by 2022.

In Agadir, Spanish multinational Abengoa is constructing a $301m wind-powered seawater desal facility, which will have a total production capacity of up to 400,000 MMm/d. The Douira plant will meet the demand of water for domestic use in addition to irrigating 15,000 hectares of land, with local farmers chipping in to finance construction. 

“Using efficient reverse osmosis membranes and installing modern energy recovery devices, and a turbine to capture the energy of the effluent to take advantage of the plant height above sea level, the great capacity of the Douira plant makes it unique in the world, and opens the window for the use of this renewable water source to show the great agricultural potential in desert areas,” says Antonio Borrero Villalón, Abengoa’s business development director for Europe and Africa.

Beyond North Africa

According to the UN, more than 40% of the world’s population suffers from water shortages, with more than 700m people having no access to clean water, and nearly 2bn people living in river basins that need additional sources of fresh water.

In 2018, after years of anaemic rainfall, Cape Town’s local officials warned the city was approaching “Day Zero”, when municipal water supplies would be switched off to conserve water.

Jayant Bhagwan, executive manager at South Africa’s Water Research Commission, says South Africa’s slow uptake of renewables and its dependency on coal power means South Africa’s short- and medium-term strategy must focus on recycling wastewater, while promoting sensible water use and repairing existing infrastructure.

“Forty to fifty percent of water pressure issues are to do with wastage, so yes we’re pushing efficiency around water use in industry and in domestic agriculture. But I think in 10 to 15 years time the uptake of desalination will get accelerated, as part of a more permanent mix of water supply.”

In East Africa, Berlin based start-up Boreal Light have developed WaterKiosk, to supply solar powered desal systems to 23 Kenyan hospitals, providing over 1m litres of safe drinking water daily. The firm has installed additional systems in Tanzania, Madagascar and Somalia. 

Boreal Light’s CEO Dr Hamed Beheshti says a million undersupplied people in Africa get their provisions from WaterKiosk, which has sold carbon credits from 41 solar desal units to foreign firms.

As the world’s population is predicted to reach 9.7bn by 2050 – with about two thirds of that growth taking place in Africa – additional water technologies will be needed.

“There’s a means to create a more sustainable technology so maybe not only desal. There are other emerging technologies that use water vapour in the air to create water, so those tech-based solutions could be emerging to cater for the rest of Africa, and we’re very fond of those ideas,” says Ayman Soliman.