In the heart of the Sahel, where the sun blazes and water is scarce, a Dutch researcher has proposed an innovative solution that could transform the region’s energy and water landscape. Maarten J. Waterloo, an expert from Acacia Water in the Netherlands, has developed a concept that combines photovoltaic (PV) energy systems with rainwater harvesting, offering a dual solution to the region’s pressing energy and water challenges.
The Sahel, a semi-arid and arid belt stretching across Africa, receives ample solar radiation year-round, making it an ideal location for solar power. However, the region also faces severe water scarcity, with precipitation amounts ranging from 150 to 850 millimeters annually. This is where Waterloo’s concept comes into play. By integrating rainwater harvesting with PV systems, the technology can address both energy and water needs, providing a sustainable solution for the region’s inhabitants.
Waterloo’s study, published in the journal ‘Water-Energy Nexus’ (translated as ‘Water-Energy Connection’), shows that a minimum precipitation of about 200 millimeters per year is needed to achieve a net rainwater harvesting yield surplus. This surplus accounts for evaporative losses, PV panel cleaning needs, and water required for hydrogen production. In the Sahel, this integrated system can yield up to about 800 millimeters of clean water annually. In regions south of the Sahel, such as the highlands of Guinea-Bissau, Guinea, Sierra Leone, and Ethiopia, the yield can exceed 1500 millimeters per year.
The implications for the energy sector are significant. For households with a Tier 4 energy supply (4.5 kilowatt-hours per day, which allows for electric cooking), fixed-tilt solar power system rainwater harvesting can provide 2–7% of unit household water demand. A PV-powered hydrogen production plant can provide up to 50% of water per kilogram of hydrogen produced in the Sahel. In regions south of the Sahel, these values can exceed 25% and 100%, respectively.
Waterloo emphasizes the potential of this integrated approach: “The combination of rainwater and photovoltaic energy harvesting can significantly increase the availability of both resources. This could be a game-changer for the Sahel, providing a sustainable path towards a hydrogen economy.”
The siting criteria for these combined systems include precipitation and water storage aspects, in addition to those for solar energy harvesting. This means that the technology can be tailored to specific locations, maximizing both energy and water yields.
The commercial impacts for the energy sector are profound. As the world transitions towards renewable energy, the Sahel could play a pivotal role. The region’s abundant solar radiation and the potential for significant rainwater harvesting make it an attractive location for investment. Moreover, the integration of hydrogen production adds another layer of opportunity, as hydrogen is increasingly seen as a key component of the future energy mix.
This research opens up new avenues for development in the energy sector. It challenges traditional approaches to energy and water management, offering a holistic solution that addresses multiple needs simultaneously. As the world grapples with climate change and resource scarcity, such integrated approaches will become increasingly important.
Waterloo’s work is a testament to the power of innovative thinking. By combining two seemingly disparate technologies, he has created a solution that could transform the lives of millions in the Sahel and beyond. As the energy sector continues to evolve, this integrated approach could shape the future of renewable energy and water management, paving the way for a more sustainable and resilient world.