Solar Water Pumping for Farms in Kenya: A Planning Guide

Solar water pumping can help farmers in Kenya supply water for irrigation and other agricultural needs. Planning a suitable system requires understanding daily water demand, pumping height, pipework, water source conditions, and the compatibility of the pump and solar array.

Solar equipment should be selected to match your actual requirements and the manufacturer’s specifications. Use this guide as a starting point and confirm product details before purchasing.

Start With Daily Water Demand

Begin by estimating how much water your farm needs each day and when it is required.

Irrigation requirements vary depending on several factors, including:

Crop type and water requirements
Season and weather conditions
Soil characteristics
Irrigation method
Size of the cultivated area
Timing and frequency of irrigation

Estimating daily water demand helps determine the flow rate and pumping schedule your system must support.

Where possible, prepare an estimate of the daily water volume required during different growing seasons. This will help you communicate your needs when requesting a quotation.

Understand Total Dynamic Head

Total dynamic head (TDH) is an important factor when selecting a solar water pump. It accounts for the vertical lift and relevant friction losses as water moves through the pipework.

Borehole depth alone is not enough to determine the pump requirements. You also need to consider:

Pumping water level: The level of water in the borehole or source while pumping.
Delivery height: The height to which the water must be lifted.
Pipe diameter: Pipe dimensions affect friction losses.
Pipe length and route: Longer pipe runs can increase resistance.
Required flow rate: The volume of water that must be delivered over a given period.

Accurate information about total dynamic head helps ensure that the selected pump can deliver the required water volume under the expected operating conditions.

Match the Pump, Controller and Solar Array

The solar pump, controller, and photovoltaic array must work together as a compatible system.

When selecting equipment, consider:

Required water flow rate
Total dynamic head
Pump power requirements
Solar array voltage and power
Controller specifications
Expected daily pumping hours
Operating conditions at the water source

The system should be designed to deliver the required water volume under the available solar conditions.

Consider Water Storage

Water storage can separate pumping time from water-use time. For example, a system can pump water when sufficient solar energy is available and store it in a tank for irrigation or other farm activities later.

The required storage capacity depends on daily water demand, pumping schedules, and how the water will be used.

Consider Water Quality and Site Conditions

Water source characteristics and installation conditions can affect pump selection, equipment life, and maintenance requirements.

Before installation, assess:

Water quality and sediment levels
Potential corrosion risks
Water source reliability
Dry-running protection requirements
Access for inspection and maintenance
The installation environment

Follow the manufacturer’s recommendations for installation, operation, and maintenance. Select equipment that is suitable for the water source and expected operating conditions.

What to Prepare Before Requesting a Quote

Providing accurate information helps a solar supplier assess your farm’s pumping requirements.

Prepare the following details:

Water source: Indicate whether you use a borehole, well, river, or other source.
Pumping water level: Provide the known water level while pumping, if available.
Daily water demand: Estimate the volume of water required each day.
Vertical lift: Explain how high the water must be raised.
Pipe route: Provide the approximate pipe length, diameter, and delivery route.
Intended use: Explain whether the water is for crop irrigation, livestock, or another agricultural purpose.
Installation area: Describe the available space for the solar panels, pump equipment, and water storage.

These details help the supplier evaluate the pump, controller, solar array, and storage requirements before preparing a quotation.

Frequently Asked Questions

Do solar water pumps need batteries?

Not necessarily. Many solar pumping systems operate when sunlight is available and store the pumped water in a tank for later use. Batteries may be appropriate in some designs, depending on the required operating schedule and system configuration.

What are the most important details when sizing a solar water pump?

Daily water demand and total dynamic head are key inputs. The water source, required flow rate, pipework, solar availability, and operating conditions must also be considered.

Can a solar pump draw water from a borehole?

Solar pumps can be used for suitable borehole applications, but the pump must be selected according to the pumping water level, required flow rate, total dynamic head, water conditions, and manufacturer’s specifications.

Is a water storage tank necessary for solar pumping?

A storage tank can help ensure water is available when irrigation or other farm activities require it, even when the pump is not operating. Whether a tank is needed, and its appropriate capacity, depends on the farm’s water demand and system design.