Solar Irrigation Pump (SIP)

Summary

The solar irrigation pump (SIP) is a low-cost, low throughput pump consisting of a 50-watt photovoltaic solar panel powering a 12-volt pump, which can move 1,300–2,600 litres per hour. SIP is relevant where rainfall is unreliable and traditional pumps are impractical, and can mitigate the risk of rain-fed agriculture for high value crops to provide off season income. Successful testing has been conducted at small scale in Malawi.

Challenge/Problem

Irrigated cropland is twice as productive as rain-fed agriculture (World Development Report 2008), but many smallholder farmers do not have access to irrigation infrastructure, including a nearby water source and power to move the water to and through their fields. Combining drip irrigation kits, newly affordable photovoltaic panels and off-the-shelf, 12-volt pumps can result in a cost-effective system for supplying water for irrigation. Solar-powered irrigation has the potential to increase incomes dramatically, particularly for the most remote producers.

Women in many countries are responsible for collecting and carrying water and cultivating small horticulture plots for consumption or the market. Therefore, it is likely to positively impact gender equity and empowerment, relieving women of this time-consuming burden. Finally, as SIP will displace or eliminate the need for electrical or fossil-fuel-driven water pumps, it will have positive environmental effects, benefits reinforced by the decreased need for chemical fertilizer.

Solution

The SIP is a 50-watt photovoltaic solar panel that can power a 12-volt pump to move 1,300–2,600 liters per hour. Standard plastic fittings and half-inch piping connect these elements to a water saving tank of 500–1,000 liters. A sturdy stand should be built for the water tank to provide gravity flow, and a frame should also be constructed to provide the best angle for the solar panels. Multiple filters are needed to protect the life of the pump and minimize clogging in sprinkler emitters and tubes. A solar pump combined with affordable drip irrigation kits can be used with a wide variety of high-value crops to increase water efficiency, minimize fertilizer loss, and irrigate hilly terrains. Solar irrigation can increase incomes dramatically, particularly for remote producers with inconsistent access to electricity or fuel. Solar pump irrigation also reduces labor for water delivery.

This innovation targets smallholder farmers who do not have the need or the resources to use the larger volume higher-priced pumps. Water pumps are used globally for agricultural production, and the market is accordingly very large. Basic components for the pump are typically available from local suppliers at low cost and include: 
 

- Solar panels & frame

- 12V water pump and electric wire

- Water level switches

- PVC piping, connectors, valve

- 500L water storage tank and stand

- Filters

- PVC cutter

- Irrigation tape or tubing

This solution was developed under the Feed the Future Horticulture Innovation Lab, implemented by the University of California, Davis.

Results

- An Innovation Lab researcher deployed the pump to villagers in Malawi, and a visit from our evaluation team after three years found the pumps still in use and being highly valued for their utility.
 

- Cheaper, more reliable, and comes with a pressure switch that can stop the pump if there is no water. The pump provides 12 liters a minute at sufficient pressure for micro sprinklers or drip irrigation. 
 

- Assuming a total cost of $200 for a unit, the cost is at the edge of feasible for the target market, but the savings in terms of labor (women and children hauling water for irrigation) is substantial, and the benefits in terms of potential improved plant growth through directed and regular water delivery are also substantial.

Lessons Learned/Potential for replication

Outside of the US, SIP has only been tested at small scale in Malawi and could benefit from piloting in other countries, though in theory the addressable market for it is large. Local assembly and construction is possible, but sourcing the panels, pumps, filters, and putting them together could provide a profitable role for a commercial partner. This approach could generate employment opportunities or a small-business opportunity for an entrepreneur providing inputs to the growers.

Next Steps

The Innovation Lab is able to provide technical support to implementers, remotely, if needed. But as a next step, the unit could be integrated into a local private business and sold for broad dissemination.
 

- Education: Continue to provide training through the Horticulture Innovation Lab Regional Centers and our network of partners.
 

- Research: Test components available in partner countries to find the most effective and affordable combinations.
 

- Partnerships: Work with the Horticulture Innovation Lab’s network of partners to provide training, consulting and extension services to small-scale fruit and vegetable growers.