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Demystifying Solar-Powered Water Pumping

Solar pumping is the trendiest technology in rural water supply today. Much of the interest in solar pumping is motivated by the Sustainable Development Goal to increase water service levels in the most remote areas. A more compelling driver is that rural water users are willing to pay for service that is accessible near or within their homes. There is currently no more promising technology for meeting these expectations in off-grid settings than solar pumping.

Despite this high interest and the fact that solar pumping technology has been around for decades, a great deal of misinformation is being propagated. This article aims to address a few of the most common misconceptions.

For an overview of solar pumping, see this recent World Bank publication: Solar Pumping: The Basics

Solar-powered water pumping in Peru.

Myth #1: Solar pumping is too complicated and not appropriate for remote, rural settings

The most common barrier to adoption of solar pumping is misunderstanding of its complexity and applicability. The technology is often avoided because of perceived technical and management challenges which are in fact common to any rural water supply system. In reality, the design and installation processes associated with solar pumping are no more complicated than other motorized pumping schemes. Operation and maintenance is more straightforward than with handpumps and generator powered schemes which likely leads to higher functionality and reliability rates (see recent evaluations by UNICEF and the Global Solar and Water Initiative).

The high capital cost of solar pumping equipment often brings its large-scale applicability into question. However, the life-cycle cost benefits of solar pumping are well documented and are on the lower end of IRC WASHCost benchmark ranges. Solar pumps have no fuel cost, and their long functional lifespans and lack of moving parts greatly reduce maintenance expenses. Furthermore, the cost of solar modules, the most expensive element of a solar pumping scheme, continues to decrease at a rapid rate.

Click here to read about the advantages of solar pumps compared to alternative technologies commonly utilized in remote, rural settings.
Click here
to read about the advantages of solar pumps compared to alternative technologies commonly utilized in remote, rural settings.

Solar-powered water pumping in Indonesia.

Myth #2: All solar-powered water pumping equipment is created equal

Equipment manufacturers have taken advantage of demand, flooding the market with solar pumping products of all varieties and price tags. Unfortunately, many are poor quality and likely to fail in a fraction of the lifespan of higher priced, higher quality equipment, which creates higher maintenance costs and failure rates in the long term. This results in solar pumping schemes which were expected to function for years failing and being abandoned after a few months in operation. Using brands that have a proven track record for durability and reliability, such as Grundfos pumps and SolarWorld modules, can guard against this, even if the upfront cost is higher. Verifying a product’s adherence to internationally recognized certification and testing standards is another important step.

Furthermore, the private sector can positively influence product quality. By providing local dealers with exclusive access to advanced training and support networks, major manufacturers can incentivize sales of quality equipment.

Solar-powered water pumping in Puerto Rico.

Myth #3: Scaling up solar powered water pumping will lead to widescale depletion of groundwater aquifers

There is concern that solar pumps, because they can operate automatically whenever the sun shines, could pose a long-term threat to groundwater resources. It is true that exploitation of groundwater paired with low or misunderstood aquifer recharge can lead to potentially irreversible depletion, and there is a deficiency of good hydrogeological data in countries where the most interest is being placed on solar pumping. However, abstraction technology is just one of many factors that influence aquifer sustainability and solar pumping should not be devalued because of potential risks which can be mitigated.

Actions that can be taken to mitigate the risk of groundwater depletion include:

  • Proper borehole development and pump sizing to safe yield – Ensures solar pumps are physically incapable of depleting aquifers (see RWSN/UNICEF’s valuable guide). Simple control measures such as float valves and switches can help prevent wasting.
  • Better groundwater monitoring – Alerts authorities to potential risk areas. Many countries successfully employ remote monitoring systems (see, for example, the USGS’s National Groundwater Monitoring Network). Read more here.
  • Water pricing in the form of tariff collections and abstraction charges – Enables sustainable and equitable allocation of groundwater resources, but requires sound management built on transparency and accountability. Prepaid water metering technologies may also play a role.

Solar-powered water pumping in Uganda.

Further resources

Resources are available to equip rural water professionals with knowledge and skills and stop the spread of misinformation about solar pumping. Of note:

Learn more about Water Mission’s approach to solar-powered solutions.