Updated: Oct 3, 2022
WHAT IS THE TAP PROJECT?
It’s well known that Africa’s water insecurity issue poses a large threat to its inhabitants especially as desertification and droughts increase in intensity and duration. According to the UN, about 45% of Africa is affected by desertification, the process through which fertile land becomes arid and desert-like, with about 55% at high risk of further desertification. Rainfall, now more than ever due to climate change, is a volatile variable and cannot be factored into the clean water equation. Although there are existing technologies that could help mitigate the issue, acquiring adequate funding for policymakers and engineers to create and maintain green infrastructure is the largest hurdle that governments face. The Sahel region of sub-Saharan Africa consists of the area between the Sahara desert and the savannahs of Sudan. It stretches from coast to coast, including countries such as Mauritania, Burkina Faso, Mali, Chad and Niger. With rapidly rising temperatures due to climate change, the issue of water insecurity only grows more pressing each day.
The Trans Africa Pipeline (TAP) is a proposed non-profit water project that would provide fresh water to over 28 million people across the Sahel region in 12 countries. It would span 8800 kilometers, a distance almost halfway around the world, through pipes made of prestressed concrete and would consist of 10 reservoirs along the way, flanked by 2 solar desalination plants on the coasts of Mauritania and Djibouti. The project was created in Toronto, Canada and works with the 11-country Pan African Great Green Wall (PAGGW) agency.
On average, according to the TAP report, a human needs 3-5 liters of water per day to survive; however, including water for sanitation and other daily activities, this number rises to 30-50 liters per day. To offer a shocking comparison, the average American uses approximately 375 liters of water daily. Within sub-Saharan Africa, the irrigated regions are not enough to counteract severe and extended droughts. Although modern drip irrigation is now common in many places, it’s sustained using underwater reservoirs and rivers, which are not options for the Sahel. The TAP project gives a more detailed report into how much water is required per hectare of crop and how it would affect harvest levels.
Currently, the International Desalination Association says that about 100 countries are implementing a desalination process, and half of this freshwater output is in the Middle East and North Africa. There are approximately 15,000 plants in operation now and they are growing steadily to meet increasing demand. The largest of these desalination plants to date is located in Saudi Arabia and cost $3.4 billion USD, pumping out over 800,000 liters of clean water a day. TAP is proposing to operate in a similar mechanism using two plants: one located in Mauritania and the other in Djibouti.
How are they planning on powering such massive plants?
The Sahel has a tropical, semi-arid climate and is consistently hot, dry, and windy all year long. Although less extreme than the Sahara Desert to its North, it has very low cloud cover and high duration of sunshine; the number approaches 2500 to 3000 hours of sun per year. For reference, Miami, Florida receives approximately 3000 hours of sun per year whereas Los Angeles, California pulls slightly ahead with a whopping 3300 hours of sun yearly.
The desalination plant in Saudi Arabia mentioned earlier uses solar desalination, a technique that utilizes heat from the sun to boil seawater where the evaporating steam is captured and then condensed into fresh water. The amount of solar energy available in the Sahel region is more than enough to power desalination plants. The team plans on building the water pump systems in remote desert areas, using either windmill farms along the ocean or solar farms if the land and infrastructure is available. Based on the projected costs of those of the Saudi Arabia project, the total costs for the all pump stations would come up to about $1.73 billion USD; this is considering that the power needed for all pump stations is 345 MW and for the TAP project, and for the pump stations the estimated cost per watt is $5.
In terms of freshwater distribution and storage across the Sahel, the TAP used an arbitrary allocation of half the water for the human population and the other half towards agriculture and employment. According to the TAP report, the minimum amount of water needed for about 28 million people over 12 countries is around 600 million liters per day. The demand and necessity for water is high, especially as temperatures rise, and so although the TAP project seems to cover infrastructural designs and costs, contingency plans are also necessary. If the solar desalination plants are down for any reason, the plan is to build artificial reservoirs in place that contain 30 days worth of freshwater supply as a backup. Finally, in order to avoid contamination or excess evaporation of the reservoir supply, the organization designed floating covers to sit on the water.
WHAT ABOUT ALL THE SALT LEFT BEHIND?
One of the largest concerns that comes up in the global conversation surrounding desalination plants are their byproducts and how to dispose of them. Disposing of the brine, highly saturated salt water, into local water bodies is a huge disruption to the ecosystems and the homeostasis of the organisms inhabiting the area.
TAP’s proposed solution is to utilize salt ponds. This is a contrast to the Al-Jubail solar desalination plants in Saudi Arabia whose concentrated brine water goes back into the Arabian Gulf; however, they are looking to pursue a similarly proposed solution. By mass producing salt as a byproduct of solar desalination, TAP would get rid of the disposal issue as well as provide a stream of income that can be redirected into funding for the plants. Solar generated salt is considered higher quality than other salt due to the size of its crystals and the organization estimates that around 10.7 million tons of salt could be extracted per year, per plant.
The financial return is theorized to be $2.53 billion USD per year of salt from the plants, thereby reducing the fees paid by other countries to the project. This financial return is enough to offset plant operation costs. As a bonus, lithium, whose cost has been steadily rising over the years, could also be extracted from the saltwater, increasing the financial opportunities presented by the TAP.
WHAT IS IT GOING TO COST?
The costs as a whole are no small feat. For the plants themselves, the pipeline, pumping stations, reservoirs, solar power farms for the plants and the pump stations combined, the
total TAP cost comes up to $20.11 billion USD. The majority of the costs come from the pipeline and its construction ($10.24 billion USD) as well as the plants and their construction ($4.96 billion USD).
TAP is an ambitious endeavor, with the potential of great failure on a myriad of fronts: political, climate disaster related, financial, and more. However, the ROI on this project for both investors and the surrounding community would greatly outweigh the downsides of the project. If executed smoothly, it would revolutionize water access across Africa, and serve as a precedent for the rest of the world in terms of sustainable energy, community-driven action, and humanitarianism.