Egypt is facing a growing water crisis due to its arid climate, limited water resources and a rapidly growing population. The country with a population of 114 million depends largely on the world’s longest river, the Nile, used for freshwater. However, the increasing demand for water in Egypt, and the upstream users of the Nile water (such as the Greater Ethiopian Renaissance Dam in Ethiopia) meant that the Nile was no longer enough.
Chemical engineer Thokozani Majozi is part of a team that has built a new model of a wind energy reverse osmosis fading system. These use the energy from the remaining salt water to power the plants. The team found that the model could run well in windy coastal resorts. Such water supply systems are resilient to climate change. The water agency is currently lobbying for June, and South Africa is leading this year to put more money into building those funds.
How does seawater desalination help Egypt?
Renewable freshwater and rainwater in Egypt in the Nile have been declining for decades. The current annual water poverty threshold in the country is below 1,000 cubic meters. That’s just half what they need for health and well-being.
Climate change makes things worse. It disrupts rainfall patterns and exacerbates drought, thus reducing traditional water sources to be reliable.
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Fadeout provides promising solutions. By removing salt and impurities from seawater, desalination can provide a stable supply of clean water for alcohol consumption, agriculture and industry. For example, 3A, a Jubail desalination plant in Saudi Arabia, provides drinking water to 1.6 million people per day.
Desalination is very effective when using reverse osmosis. Reverse osmosis uses pressure to force seawater through a semi-permeable membrane. This removes all dissolved salts, contaminants and impurities, such as microplastics in dirt and water.
It has been considered particularly suitable for a vast coastal area away from the Nile.
How much energy does seawater desalination require?
Reverse osmosis fading requires a high pressure pump to force seawater through the membrane. For every cubic meter of fresh water produced per cubic meter, the process usually consumes between 3 kWh and 8 kWh of electricity. This is enough to power an average home refrigerator for 24 hours.
Therefore, producing 600,000 cubic meters of water will use the same amount of electricity as 600,000 refrigerators. In contrast, a typical (municipal) water treatment facility uses only 0.2 kWh to 1 kWh to produce one cubic meter of drinkable water.
Read more: Egypt and Ethiopia are finally reaching a water deal – what this means for other Nile countries
This energy demand makes it expensive to run the desalination plant. If a country’s electricity is generated by burning fossil fuels, such as coal, then running a desalination plant with this dirty energy will mean that desalination will have a negative impact.
Egypt aims to reduce its carbon footprint and transition to a more sustainable energy model. Therefore, desalination plants operated using renewable energy are crucial to the long-term viability of seawater desalination technologies in the region.
How can wind help?
Our study establishes a new model of wind energy reverse osmosis desalination systems.
Rather than converting wind energy into electricity, our new models use wind-powered pumps that provide the pressure required for reverse osmosis. When the wind speed is high, the system stores excess compressed air in a dedicated compressed air storage. This is caused during low winds. We found that this eliminates the need for traditional electrical infrastructure such as generators, motors and battery banks.
Our model shows that the salt water remaining after seawater desalination can also generate energy. Reverse osmosis uses high pressure to push seawater towards a membrane that removes salts and other impurities. This means that the salt water is always on the high pressure side of the reverse osmosis membrane. This remaining salt water is usually discarded.
In our system, we lower this high pressure to atmospheric pressure and then throw away the salt water. This provides additional pressure to help push new seawater through the membrane, thereby reducing overall energy consumption of the system.
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We tested the model in the laboratory using wind speed data from 20 coastal cities in Egypt. The results show that Helgada, a major resort city located about 500 kilometers southeast of Cairo, will be the most promising location. This is due to its favorable wind speed, which means the lowest total water cost and the highest annual water yield. The amount of potable water that can be produced depends on the size of the system – in other words, how much money can be used to build a larger sized desalination plant.
This concept is still in the developmental research stage. It belongs to a technology that has been called a long-term continuous energy storage solution (which can store renewable energy for more than 10 hours). Now it needs to be applied in practice.
What needs to happen next?
The next step should be the pilot program in windy areas such as Hurghada and the development of El Gouna, a specialized resort located about 25 kilometers of NAHUrghada.
The pilot project will verify the performance of the proposed system in real-life situations. This will allow scientists to see what these desalinated plants need in the case of years to operate.
We also need to test all the components that make up the system to see if they are durable, reliable and cost-effective.
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Egypt’s Science and Technology Development Fund and other national funding organizations often play a major role in funding these innovative projects. Partnerships between universities, engineering companies and local authorities are also crucial to building technical expertise and infrastructure.
A public awareness campaign should be held to gain community support and to listen to the community’s attention. Advocacy will also attract private investment by showing the environmental and economic benefits of wind-down.
By leveraging its abundant wind resources and coastline, Egypt can pioneer a new generation of decentralized low-carb infrastructure. The reverse osmosis system of wind energy can be used as a model for other blister countries in this region and in other regions.
(Professor Majozi is the Chairman of the South African Science Commission of S20 – an official participation group in the G20, which promotes science-based dialogue and provides policy advice).
This article is republished from the conversation, a non-profit independent news organization that brings you factual and trustworthy analysis to help you understand our complex world. It is by: Thokozani Majozi, Witwatersland University
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Thokozani Majozi received funding from the National Research Foundation (NRF) and the National Institute of Energy Development (SANEDI).
