Christian M. 10 min read

Flood the Sahara for Hydropower!?

No, we haven’t lost our marbles. This is a feasible mega-project that may just start piquing interest soon, so keep your eyes on the news! In this article, we give you the great, the not-so-good, and the potentially ugly consequences of flooding a huge part of the Sahara desert.


😲 Flood the Sahara!?

That was our first reaction too. Why would anyone want to “flood the Sahara” for hydropower? It sounds like a massive undertaking when you could simply dam a river, right?

Well, it turns out the benefits go far beyond just producing green energy, and it’s not as complex as it appears. Consider the Qattara Depression in Egypt – a vast basin lying below sea level in the Sahara that is merely 55km in a straight line from the Mediterranean Sea!

Covering 19,600 square kilometres, it’s nearly as large as Wales. Can you picture creating a new sea the size of Wales in the heart of the Sahara? It’s an ideal, albeit surreal, location for a gargantuan Run-of-the-river hydro scheme, capable of seawater desalination and kick-starting a flurry of thriving activities that a freshwater source would catalyse in this new coastline.

Introducing aquatic life would revitalise this new habitat, fostering fishing, fish farming, algae breeding and harvesting, and sparking local economies. A deep canal could further facilitate shipping to this region, connecting it to global markets. Not to mention, leisure vessels could navigate the canal, bringing tourism to this area. 🛳️

Moreover, everything could be designed with carbon-neutral values in mind—powered solely by the abundant green electricity produced, with zero reliance on fossil fuels. 🌍

And the cost? All is going well, much less than some would expect, and with various means of auto-financing itself… but more of this is in the sections below. 💸

🤔 Hasn’t anyone thought of this before?

A Reddit user simulated how the Qattara depression would look like when flooded. (Credit: Reddit)

This isn’t a new concept. The idea of flooding vast tracts of the Sahara was first proposed by renowned French geographer François Élois Roudaire.

His ideas were the inspiration behind Jules Verne’s final novel, “Invasion of the Sea”, and in collaboration with Ferdinand de Lesseps, the mastermind behind the Suez Canal, they planned to execute this vision at the Chott el Djerid depression in Tunisia, until politics and war ultimately shelved their ambitious plan. 📚

During that era, colossal mega-projects were in vogue as the Industrial Revolution provided the means for humans to manipulate nature at unprecedented scales.

Take, for instance, the Panama and Suez Canals—both built during this period. Their construction required the shifting of millions of tons of soil and rock over many years to massively boost global shipping, and they certainly succeeded! 🚢

We digress; in 1927, British surveyor Dr John Ball mapped the depression and proposed the concept of harnessing it for hydroelectricity. He even made initial feasibility calculations. But with the world in turmoil—including events like the Suez crisis and WW2—the idea was swiftly sidelined yet again. 🌍

Then, the Americans stepped in. As part of their “Atoms for Peace” program, they floated the idea of using nuclear bombs to carve out the canal. For evident reasons, this idea was also shelved…💣

In the ensuing decades, several propositions were made, but none came to fruition. However, with humanity now racing against climate change, the time might be ripe to escalate our efforts. This could very well be the most consequential mega-project out there. 🌿

💡 What is the latest plan?

Summary of the different canal routes proposed so far. (Credit: Wikipedia)

The map above illustrates the historically proposed routes for a tunnel or canal to fill the Qattara Depression. Each route has its pros and cons—some avoid topographical challenges like hills, while others traverse softer rock that’s cheaper to excavate for a canal.

Shoving specifics aside, the main innovative development is that of Elon Musk’s Boring Company. Their goal is to reduce the cost of tunnelling to $10 million USD per mile, which they plan to achieve by streamlining the process, reducing tunnel sizes, concurrently drilling and reinforcing the structure, and reusing the waste material as construction material. 🚇

Assuming the Boring Company achieves their technical spec and prices, and considering the shortest route of 55km between the Mediterranean and the depression, the cost of a single tunnel could be around $300 million US dollars, a rather affordable sum considering the subsequent benefits of a new sea, such as the increased land value and new economic activity.

To fill the Depression—which doesn’t necessarily need to be filled to the top—multiple tunnels would be needed, but these could be gradually implemented.

In terms of hydropower, the scheme would have to be a Run-of-the-river hydro project that generates electricity from the perpetual filling of the depression that is constantly losing water due to rapid evaporation rates. This is uninterrupted

A single tunnel with a diameter of 3.5m could theoretically generate 40-50MW of continuous hydropower that isn’t subject to the intermittencies of wind and solar power. If ten tunnels are built that work 90% of the time, this would amount to 380-450MWh of power, approximately an eighth of the power output of the Drax power station. 🌊

This might not seem like a lot, but it would be a cost-effective electricity source suitable for desalinating water to support new inhabitants and potential agriculture. Remember, Australia produces 15% of its tomatoes using seawater greenhouses in the desert! 🍅

Factor in any capacity from floating solar panels—which would also help reduce evaporation—and the power output could become colossal. Costs could be further reduced if the electricity is used locally, eliminating the need for long transmission lines. However, if there’s an international market that could use any surplus electricity, an international interconnector between energy-intensive Turkey and Europe could become viable. 💡

💭 How crazy is the idea actually?

It’s been quite a while since the world has witnessed a mega-project of this scale. Surprisingly, for its colossal magnitude and impressive utility, the project’s cost appears rather affordable…

The initial investment, which includes utilizing The Boring Company‘s technology, constructing the hydro plant, and setting up desalination plants, is roughly estimated at 5 billion US dollars.

That’s less than the revenue Egypt earns from the Suez Canal alone! Given that a considerable amount of this cost could be recouped merely by selling the land adjacent to the new coastline, it’s quite surprising that no one has jumped at the opportunity.

Perhaps what we need is for Elon Musk to demonstrate that the success of Tesla and Starlink can be extended to drilling holes. If he can do this, the confidence needed to undertake such a project might be there! 🚀

🚧 It can’t be just positives, though…

Current rainfall map of Egypt. This would dramatically change with an interior coastline, likely leading to regional and even global weather changes. (Credit: Pavel Konecny)

There isn’t a single project on Earth devoid of side effects. The larger the project, the bigger the repercussions.

Most people might view ‘greening’ the Sahara as a good thing, turning a largely inhospitable area into a habitable space for plants, animals, and humans. However, this transformation could undoubtedly trigger knock-on effects on the climate, effects which are near impossible to model and extend far beyond the borders of Egypt.

Let’s begin with the ‘least significant’ yet immediate impact: Local ecology. Introducing a seawater environment into a desert ecosystem could be catastrophic for native desert flora and fauna. It would invite invasive species at all levels, from tiny bacteria to fish, disrupting existing food chains 🌱🐠.

That’s not even mentioning the high salinity of this new sea, caused by the elevated evaporation rates and constant water desalination. There are very few complex organisms that can survive in high-salinity environments like the Dead Sea 🌊.

Then there are the weather systems. Earth’s climate systems would need to balance this change and would rapidly adapt to an increase in moisture in the Sahara. It could potentially make Northern Europe colder by drawing the Gulf Stream southwards or just fully disrupt the already extreme weather of India and Pakistan to the East ☔🌵.

Also, consider that the entire project would take at least a decade or two in the most optimistic scenarios. There are hundreds of kilometres of tunnelling, constructing a hydropower station and desalination plant, and then waiting for the depression to fill. In our exponential world, a lot will happen during this time ⏰.

Political instability in Egypt could bring the project to a halt. Or advancements in Fusion Energy could recoup financing away, or even worse, Egypt could go to war. Just consider the impact of the Suez Canal on international politics-the consequences are still being felt many decades afterwards 🏦⚔️.

There’s clearly no reward without risk, but is further engineering Earth the true answer to our environmental challenges? Some believe we should strive to maintain the environment as close as possible to its early 20th-century state before the Industrial Revolution allowed us to have such a large impact on our planet 🌲💡.

In any case, here it is, probably the most realistic mega-project!

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