Access to a safe, sustainable water supply is a growing concern in every region of the world. In many communities, groundwater is being pumped by diesel fueled systems, which are both expensive and can be difficult to maintain. In communities where electricity is scarce, solar can be a part of the solution.
The highest demand for solar pumps is among rural off-grid areas, currently underserved, or served by costly fuel-driven pumps. Solar pumping is most competitive in regions with high solar insolation, which include most of Africa, South America, South Asia, and Southeast Asia; but the technology can operate successfully in almost any region of the world.
“Things are changing; new technologies are coming up. You can’t resist good technology that offers you cheaper costs for what you need.” said Jackson Mutazamba, assistant director of operational planning in the Ministry of Water and Irrigation in Tanzania, when asked about the use of solar pumps for water supply.
Echoed by Mamun from the Sohagpur village in Dhamrai, Bangladesh, “With the solar pump installed, we are getting sufficient water with lower monthly bills than we spent on buying diesel to run the generator”, he said.
In order for solar to be successful, however, this technology needs to be understood and appreciated by water practitioners around the world.
To provide a clear and concise introduction to solar water pumping, my colleagues and I have developed a handbook – Solar Pumping: The Basics, which offers an overview of the various aspects of solar water pumping.
Let’s take a deeper look.
Over the last 7 years, things have changed dramatically. Solar photovoltaic (PV) panels, which power the pumps, have dropped significantly in price, while the technology has improved and is now able to pump higher volumes of water and reach even deeper sources of groundwater.
While the initial acquisition of equipment is more costly than other pumping alternatives, the operation and maintenance costs are low. Particularly compared with diesel pumping, solar is not only more energy efficient, but with a lifespan of over 20 years, the financial benefits vastly outweigh the costs.
A solar pumping system is simple and includes the solar panel itself, the pump, and a power conditioner. The new systems are flexible and can work in tandem with a back-up generator and the electrical grid.
Considerations for designing a solar pumping system include various parameters including: water demand (volume), water storage, water depth (head), location of PV panels, and solar irradiance among others. Fortunately, modern software provides a free and user-friendly tool that enables engineers to easily design and size solar pumping system.
Finally, once the system is up, running, and secured, long-term maintenance is critical. This includes warrantees on equipment and maintenance contracts to ensure the water keeps flowing clean.
This handbook is part of a larger package on solar pumping produced by the World Bank Water Global Practice, which includes a comprehensive knowledge base, video tutorials, case studies, and more. While solar pumping may not be the silver bullet for every community, it is important that this technology is made accessible and available as an option for those who wish to benefit from it.