Solar-powered borehole pumping is one of the most useful applications of solar energy in Kenya. A properly designed solar borehole system can provide water for homes, farms, livestock, schools, commercial properties, institutions, irrigation projects and remote locations where grid electricity is unavailable, unreliable or expensive.
A solar borehole system uses photovoltaic panels to convert sunlight into electricity, which is then controlled and supplied to a borehole pump. The pump lifts groundwater from the borehole and delivers it through a pipe to a storage tank, water tower, irrigation system or direct-use point.
Unlike a normal household solar installation, solar water pumping must be designed around both electrical and hydraulic requirements.
The installer needs to understand how much water is required, how deep the water is, the pump's operating conditions, the required flow rate, the total pumping head, the borehole yield, the pipe diameter, the storage arrangement and the available solar resource.
Simply connecting several solar panels to a borehole pump is not a professional solar pumping installation.
The PV array, pump, controller, protection equipment, cables, borehole pump, pipework and water-storage system must operate as one coordinated system.
For solar borehole installation, pumping-system design and related electrical work in Kenya, contact 0723763173.
HOW SOLAR PUMPING WORKS
The basic energy flow is:
SUNLIGHT → SOLAR PANELS → PUMP CONTROLLER → BOREHOLE PUMP → WATER STORAGE
The solar panels generate DC electricity.
The controller regulates the electrical supply to the pump.
Depending on the pump technology, the controller may supply controlled AC or DC power to the motor.
The pump then converts electrical energy into mechanical energy and moves groundwater through the delivery pipe.
The water can be pumped into:
- Elevated storage tanks
- Ground-level storage tanks
- Water towers
- Irrigation reservoirs
- Livestock trough systems
- Household storage tanks
- Commercial water-storage systems
- Industrial water-storage systems
The storage tank is particularly useful because it allows water to be stored when solar energy is available and used later when solar production is low or unavailable.
WHY USE SOLAR?
Solar pumping can be attractive because the pump can operate using energy generated directly from sunlight.
A properly designed system can reduce dependence on:
- Grid electricity
- Diesel generators
- Petrol generators
- Manual pumping
- Unreliable power sources
Solar pumping can be especially useful in areas where extending grid electricity to a borehole would be expensive.
It can also reduce the operating costs associated with fuel-powered pumping.
However, the economics depend on the borehole depth, pumping requirements, solar-resource conditions, equipment costs and water demand.
START WITH THE BOREHOLE
The solar installation should not begin with the panels.
It should begin with the water source.
The installer needs information about the borehole.
Important borehole information includes:
- Total borehole depth
- Static water level
- Dynamic water level
- Borehole diameter
- Pumping water level
- Borehole yield
- Recovery rate
- Casing diameter
- Existing pump
- Existing delivery pipe
- Water quality
- Required pumping rate
This information is essential for selecting the correct pump.
A pump that is too small may fail to deliver the required water.
A pump that is too large may exceed the sustainable yield of the borehole or consume unnecessarily large amounts of energy.
BOREHOLE DEPTH
Borehole depth is not the same thing as pumping head.
A borehole might be drilled to a certain total depth, but the water level may be much higher.
The pump does not necessarily need to lift water from the absolute bottom of the borehole.
The actual pumping requirement depends on the water level while pumping and the elevation of the delivery point.
This is why pump selection should not be based only on total drilling depth.
STATIC WATER LEVEL
Static water level refers generally to the water level when the borehole is not being pumped.
This provides useful information about the groundwater condition.
However, the water level can fall when pumping begins.
The installer therefore needs to understand the dynamic water level as well.
DYNAMIC WATER LEVEL
Dynamic water level is the water level while the borehole is being pumped at a particular rate.
It can be significantly deeper than the static level.
This is important because pump selection must account for the actual operating water level.
Using only the static water level can result in incorrect pump sizing.
BOREHOLE YIELD
Borehole yield describes how much water the borehole can sustainably provide.
This is critical.
A pump capable of moving a large volume of water does not automatically mean the borehole can supply that volume continuously.
If the pump extracts water faster than the borehole can recover, the water level may fall significantly.
This can lead to:
- Pump dry-running
- Reduced water output
- Pump overheating
- Motor damage
- Borehole stress
- Unreliable water supply
The sustainable borehole yield should therefore be considered during pump selection.
PUMPING TEST
A pumping test can provide useful information about the borehole.
Depending on the project, testing can help establish:
- Pumping rate
- Drawdown
- Recovery
- Sustainable yield
- Dynamic water level
- Borehole behavior
For larger agricultural, commercial or institutional installations, proper borehole testing is particularly important.
WATER DEMAND
After understanding the borehole, determine how much water the customer needs.
A home may require water for:
- Drinking
- Cooking
- Bathing
- Cleaning
- Laundry
- Toilets
- Gardening
A farm may require:
- Irrigation
- Livestock
- Greenhouses
- Dairy operations
- Poultry
- Cleaning
- Domestic use
A commercial property may require:
- Sanitation
- Cleaning
- Hospitality
- Manufacturing
- Processing
- Landscaping
The required daily water volume determines the pumping strategy.
FLOW RATE
Pump flow is commonly expressed in litres per minute, litres per hour or cubic metres per hour.
For example:
1 cubic metre = 1,000 litres.
If a system needs to deliver a certain volume of water every day, the pump must be capable of meeting that demand within the available pumping hours.
However, the required flow rate should not be chosen independently of the borehole yield and pumping head.
PUMPING HOURS
Solar pumping systems typically have a useful pumping window during daylight.
The exact operating period varies with solar conditions.
The pump may start when sufficient solar power is available and reduce or stop when available power becomes inadequate.
Instead of requiring water immediately at every moment, many installations pump water into storage.
This is one of the most practical ways of using solar energy.
WATER STORAGE
Water storage is extremely important in solar borehole projects.
The system can pump water during daylight and store it for use later.
For example:
Morning → pump begins operating
Midday → strong solar production and high pumping potential
Afternoon → continued pumping
Evening → pump stops as solar falls
Night → property uses stored water
The water tank therefore provides a form of operational storage.
WATER TANK SIZE
Tank size depends on:
- Daily water demand
- Pump capacity
- Solar availability
- Borehole yield
- Irrigation requirements
- Required reserve
- Number of users
- Expected cloudy periods
A larger tank can provide greater water autonomy.
However, an unnecessarily large tank may increase project cost.
The storage requirement should therefore be calculated from actual demand.
TOTAL DYNAMIC HEAD
One of the most important technical concepts in pump selection is total dynamic head.
The pump must overcome the vertical lift and the resistance created by the pipework and fittings.
Total head can include:
- Vertical elevation
- Water-level depth
- Tank elevation
- Pipe friction
- Valves
- Bends
- Filters
- Other fittings
- Pressure requirements
The pump must be selected to deliver the required flow at the required total head.
PIPE FRICTION
Water flowing through a pipe experiences friction.
The amount of friction depends on factors such as:
- Pipe diameter
- Pipe length
- Flow rate
- Pipe material
- Internal roughness
- Fittings
A small pipe can create significant pressure losses at high flow rates.
Using an appropriately sized delivery pipe can improve pumping efficiency.
PIPE DIAMETER
The pipe should be selected based on the required flow and pressure conditions.
An undersized pipe can increase friction losses.
An oversized pipe may increase installation costs without providing sufficient benefit.
The correct diameter is therefore a hydraulic design decision.
BOREHOLE PUMP TYPES
Solar boreholes can use different pump arrangements.
Common technologies include:
- Submersible pumps
- DC solar pumps
- AC submersible pumps
- Solar-compatible AC pumps
- Variable-speed pumping systems
The appropriate pump depends on the borehole and the solar system.
SUBMERSIBLE PUMP
A submersible pump is installed inside the borehole below the water level.
It pushes water upward through the delivery pipe.
Submersible pumps are commonly used because they are designed for deep-water applications.
The pump motor and hydraulic assembly must be correctly matched to the borehole diameter and operating requirements.
DC SOLAR PUMPS
Some solar pumps are designed to operate directly from DC power.
These systems can have specialized controllers designed for photovoltaic input.
Advantages can include efficient direct solar operation and suitable variable-speed control.
The specific pump/controller combination must be checked carefully.
AC SOLAR PUMPS
AC pumps can also be used in solar pumping systems.
In such installations, a solar pump controller or variable-frequency drive may convert and control the available power so that the pump can operate correctly.
This can be useful when a suitable AC pump is already available or when a particular pump specification is required.
VARIABLE-SPEED CONTROL
A solar pumping controller may adjust pump speed according to available solar power.
When solar energy is strong, the pump can operate at a higher output.
When available solar energy falls, the controller may reduce the pump speed.
This can allow the system to make use of changing solar conditions rather than simply switching the pump fully on or fully off.
The exact behavior depends on the pump controller.
MPPT PUMP CONTROLLER
Many solar pumping controllers incorporate MPPT technology.
Maximum Power Point Tracking allows the controller to extract useful power from the solar array under changing irradiance conditions.
Because solar voltage and current change with weather, temperature and time of day, MPPT can help the controller operate the PV array more effectively.
SOLAR PANEL SIZING
The PV array must be sized to provide enough energy for the pumping requirement.
The calculation depends on:
- Pump electrical power
- Daily pumping hours
- Required water volume
- Solar resource
- Pump efficiency
- Controller efficiency
- Cable losses
- System losses
- Seasonal conditions
A pump's rated electrical power is only one part of the calculation.
EXAMPLE
Suppose a borehole pump requires approximately 2.2 kW under its operating conditions.
The customer wants to pump water for several hours during the day.
The solar array cannot simply be selected as exactly 2.2 kW without considering the rest of the system.
The designer needs to consider:
- Available solar irradiance
- Pumping hours
- Controller requirements
- System losses
- Starting behavior
- PV operating voltage
- Panel string arrangement
- Required daily water volume
A suitable PV array may therefore have a capacity greater than the nominal pump rating.
The exact design must follow the pump and controller specifications.
PANEL VOLTAGE
Solar panels must be connected in a configuration compatible with the pump controller.
The controller may require a particular DC voltage range.
The installer must check:
- Maximum PV voltage
- Minimum operating voltage
- MPPT voltage range
- Maximum PV current
- Maximum PV power
The string arrangement should remain within those limits.
SERIES CONNECTION
Connecting panels in series increases voltage.
For example, if several modules are connected in series, their voltages add while current remains approximately that of the string, subject to module and operating conditions.
Series design is useful for achieving the voltage required by the pump controller.
However, maximum cold-weather open-circuit voltage must also be considered.
PARALLEL CONNECTION
Parallel strings increase available current.
A system may use multiple strings in parallel where the controller permits the resulting current.
The installer must check the controller's maximum input current.
Incorrect series/parallel design can damage equipment or prevent the system from operating correctly.
CABLE SIZING
Solar borehole systems often have long cable runs.
The distance between the PV array, controller and pump can create significant voltage drop.
Cable sizing must therefore consider:
- Current
- Cable length
- Conductor material
- Installation method
- Allowable voltage drop
- Temperature
- Electrical standards
An undersized cable can result in excessive voltage drop and heating.
PUMP CABLE
The submersible pump requires an appropriate electrical cable designed for the installation environment.
The cable must be suitable for:
- Voltage
- Current
- Submersion
- Temperature
- Mechanical conditions
- Water exposure
Connections must be properly insulated and protected.
CABLE JOINTS
Pump cable joints are critical.
A poorly made joint can allow water ingress and eventually cause insulation failure or motor problems.
Appropriate submersible cable-jointing methods and materials should be used.
A pump cable should never be joined casually.
PROTECTION
Solar borehole installations require appropriate electrical protection.
Depending on system architecture, this may include:
- DC isolators
- DC surge protection
- AC protection
- Overcurrent protection
- Motor protection
- Dry-run protection
- Overvoltage protection
- Undervoltage protection
- Overload protection
- Short-circuit protection
- Earthing
- Lightning/surge protection
The exact protection arrangement depends on the system design and applicable standards.
DRY-RUN PROTECTION
Dry running is one of the major risks to borehole pumps.
If the water level falls below the pump's safe operating condition, the pump can operate without adequate cooling and lubrication conditions.
A suitable controller or sensor arrangement can detect low-water conditions and stop the pump.
This can protect the pump from damage.
WATER LEVEL SENSOR
Some systems use water-level sensors to monitor conditions inside the borehole.
The sensor can help determine whether sufficient water is available.
The system can then stop the pump when necessary.
This is particularly useful for boreholes with variable water levels.
TANK SENSOR
A tank-level sensor or float switch can prevent unnecessary pumping.
When the tank reaches the desired level, the pump can stop.
When the water level falls, the system can restart if sufficient solar power is available.
This creates an automatic pumping cycle.
OVERFLOW PROTECTION
Tank overflow wastes water and can damage surrounding structures.
A properly designed system should include an appropriate control strategy.
This can involve:
- Float switches
- Level sensors
- Controller logic
- Overflow pipes
- Automatic pump shutdown
The exact configuration depends on the installation.
SOLAR PUMPING DURING CLOUDY WEATHER
Clouds can reduce available solar energy.
A solar pump may therefore produce less water during heavily overcast conditions.
A variable-speed controller may reduce the pump speed.
The pump may continue operating at reduced output if sufficient power is available.
If available PV power falls below the required operating threshold, the pump may stop.
This is normal behavior.
RAINY DAYS
Rain does not mean that solar pumping must completely stop.
If sufficient light reaches the panels, the system can continue operating.
However, heavy rain and dense cloud can reduce solar production substantially.
Water storage becomes particularly important because water pumped on earlier sunny periods can remain available during poor solar conditions.
BATTERY OR NO BATTERY?
Many solar borehole pumping systems do not need a large battery.
Instead, they use:
Solar energy → pump → water tank
The water itself is stored.
This can be more economical than storing electricity in batteries.
However, batteries can be appropriate where water must be pumped at night or where a constant pumping schedule is required.
The correct approach depends on the application.
WATER AS ENERGY STORAGE
A water tank can effectively act as an alternative to electrical storage for many pumping applications.
Suppose the property requires water at night.
Instead of operating the pump from a battery after sunset, the system can pump water into a tank during daylight.
The stored water can then be used overnight.
This can reduce battery requirements.
BATTERY-BASED PUMPING
Some installations may use batteries.
A battery can allow the pump to operate when solar production is low.
However, the battery must be sized for:
- Pump power
- Pump operating hours
- Starting requirements
- Battery chemistry
- Depth of discharge
- Efficiency
- Required autonomy
High-power pumps can require substantial battery capacity.
DIRECT SOLAR PUMPING
Direct solar pumping means the PV array supplies the pump controller and pump without relying primarily on battery storage.
This arrangement is often attractive for agricultural and water-supply applications.
The main requirement is to have sufficient water storage to accommodate periods when the pump cannot operate at full capacity.
FARM IRRIGATION
Solar borehole systems are widely applicable to irrigation.
Water can be pumped into:
- Storage tanks
- Elevated reservoirs
- Irrigation reservoirs
The irrigation system can then distribute water when needed.
This separates the timing of water pumping from the timing of irrigation.
DRIP IRRIGATION
Drip irrigation can be combined with solar pumping.
The solar pump fills a storage tank or supplies the irrigation system.
Drip lines then deliver controlled quantities of water to crops.
This can improve water-use efficiency.
The irrigation system itself should be designed separately from the electrical system.
GREENHOUSE FARMING
Greenhouse operations can use solar borehole pumping for irrigation.
The system may supply:
- Drip irrigation
- Nutrient delivery
- Cleaning
- Water storage
Because greenhouse crops may have predictable water requirements, the pumping system can be designed around a daily water schedule.
LIVESTOCK
Solar boreholes can supply water for:
- Cattle
- Sheep
- Goats
- Poultry
- Dairy farms
- Ranches
Storage tanks can provide water throughout the day.
For remote livestock locations, solar pumping can reduce dependence on fuel transportation.
DOMESTIC WATER
Homes can use solar borehole pumping for domestic water supply.
The system can pump water into an elevated tank.
A separate household plumbing system can then supply:
- Bathrooms
- Kitchen
- Laundry
- Toilets
- Outdoor taps
A pressure pump may be required if sufficient gravity pressure is not available.
WATER TOWERS
Elevated water storage can create pressure through gravity.
The higher the tank, the greater the potential static pressure at lower points, although actual pressure depends on elevation differences and system losses.
A water tower can therefore help reduce the need for continuous electrical pumping during household use.
COMMERCIAL WATER SUPPLY
Commercial properties may use borehole solar pumping for:
- Hotels
- Schools
- Apartment complexes
- Shopping facilities
- Farms
- Industrial properties
- Construction sites
The water demand can be significantly higher than a normal household.
The pump, PV array, storage and distribution system must therefore be designed accordingly.
HOTEL APPLICATIONS
Hotels can have substantial water demand.
Water is needed for:
- Guest rooms
- Bathrooms
- Kitchens
- Laundry
- Cleaning
- Swimming pools
- Landscaping
A solar borehole system can help provide water during daylight, while storage tanks provide reserve capacity.
SCHOOL APPLICATIONS
Schools may use borehole water for:
- Drinking
- Sanitation
- Kitchens
- Cleaning
- Gardening
- Dormitories
The system should be designed around peak and average demand.
Water storage is particularly useful because school water consumption can vary throughout the day.
INDUSTRIAL WATER
Industrial facilities may require borehole water for:
- Production
- Cooling
- Cleaning
- Processing
- Boilers
- Sanitation
- General operations
Industrial pumping can involve high flow rates and significant head requirements.
Detailed hydraulic and electrical design is essential.
PUMP STARTING CURRENT
Some motors require higher current during startup.
A solar system must be capable of handling the pump's starting characteristics.
Modern variable-speed pump controllers can help manage motor starting.
The exact requirement depends on the pump motor and controller.
VARIABLE FREQUENCY DRIVE
A variable frequency drive, or VFD, can control the speed of an AC motor by varying frequency and voltage appropriately.
Solar pumping systems can use specialized solar-compatible VFDs or pump drives.
A VFD may provide:
- Soft starting
- Speed control
- Improved matching to available solar power
- Motor protection
- Operational monitoring
The VFD must be selected for the specific motor and application.
MOTOR POWER
Pump motor power is normally expressed in watts or kilowatts.
Horsepower may also be used.
However, motor power alone does not tell you how much water the pump will deliver.
The pump curve is essential.
PUMP CURVE
A pump curve shows the relationship between:
- Flow
- Head
- Efficiency
- Power
The required operating point should be compared against the pump curve.
Selecting a pump solely because it has a certain horsepower can lead to poor results.
PUMP EFFICIENCY
Pump efficiency affects the required solar capacity.
A more efficient pumping system can move the required amount of water using less electrical energy.
Efficiency depends on:
- Pump design
- Operating point
- Motor efficiency
- Controller efficiency
- Pipe losses
- Hydraulic design
The entire system should be optimized.
BOREHOLE WATER QUALITY
Water quality should also be considered.
Some groundwater may contain:
- Iron
- Manganese
- Sediment
- Salts
- Other minerals
Water treatment may be necessary.
A water-treatment system can create additional electrical and hydraulic loads.
These should be included in the system design.
FILTRATION
Where filtration is required, the pressure drop across filters should be considered.
Blocked filters can increase resistance and reduce flow.
Regular maintenance is therefore important.
STORAGE TANK MAINTENANCE
The water tank should be inspected and maintained.
Issues can include:
- Sediment
- Algae
- Cracks
- Leaks
- Faulty float valves
- Damaged outlets
- Contamination
Clean water storage is part of a reliable borehole system.
SOLAR ARRAY STRUCTURE
The panels can be installed:
- On a roof
- On a ground-mounted structure
- On a dedicated steel frame
- On a solar canopy
For borehole pumping, ground-mounted structures are often convenient where sufficient land is available.
They can simplify maintenance and allow the PV array to be positioned appropriately.
GROUND-MOUNTED PANELS
A ground-mounted solar array requires:
- Strong foundations
- Appropriate steelwork
- Panel clamps
- Correct tilt/orientation
- Wind resistance
- Cable management
- Security
The structure should be designed for the site.
SECURITY
Solar borehole installations in remote locations may require security measures.
Possible considerations include:
- Strong mounting structures
- Tamper-resistant hardware
- Fencing
- Locked control cabinets
- Equipment monitoring
- Secure cable routing
The appropriate approach depends on location and risk.
CONTROLLER LOCATION
The pump controller should be installed in a suitable environment.
It should be protected from:
- Excessive heat
- Direct rain
- Water splashes
- Dust where relevant
- Unauthorized access
Adequate ventilation should be maintained.
ELECTRICAL EARTHING
Appropriate earthing is an important part of solar pumping safety.
The installation should have an appropriate earthing and bonding arrangement based on the equipment and applicable electrical requirements.
PV frames, metallic structures and electrical equipment may require bonding.
SURGE PROTECTION
Solar arrays and long outdoor cable runs can be exposed to transient overvoltage.
Appropriate surge protection should be considered.
The exact protection design depends on the installation, site exposure and electrical architecture.
LIGHTNING
Borehole sites can be exposed to lightning, particularly where equipment is installed in open areas.
Lightning and surge protection should therefore be considered during design.
Protection requirements should be evaluated by a qualified electrical professional.
MAINTENANCE
Solar borehole systems require maintenance.
The PV array should be inspected for:
- Dust
- Dirt
- Cracks
- Loose hardware
- Shading
- Damaged cables
The pump system should be inspected for:
- Abnormal noise
- Reduced water output
- Excessive current
- Controller faults
- Water-level problems
- Pipe leaks
MONITORING
A modern solar pumping system may provide useful operating data.
Monitoring can show:
- PV voltage
- PV current
- PV power
- Pump frequency
- Pump current
- Pump status
- Water level
- Tank level
- Fault conditions
This can make troubleshooting much easier.
REDUCED WATER OUTPUT
If the pump suddenly produces less water, investigate systematically.
Possible causes include:
- Reduced solar irradiance
- Blocked pipe
- Pump wear
- Falling water level
- Borehole yield reduction
- Electrical fault
- Cable voltage drop
- Controller problem
- Valve restriction
- Filter blockage
- Pump operating outside its intended point
Do not immediately assume the solar panels are faulty.
PUMP NOT STARTING
If the pump does not start, check:
- Solar irradiance
- PV voltage
- Controller status
- Fault codes
- Water-level protection
- Tank-level status
- DC isolator
- AC supply where applicable
- Motor connections
- Pump cable
- Controller configuration
A qualified technician should carry out electrical testing where required.
PUMP RUNS BUT NO WATER
A pump that runs without delivering water can have several possible causes.
Examples include:
- Water level issue
- Pump damage
- Incorrect pump installation
- Pipe disconnection
- Blocked pipe
- Valve problem
- Pump operating outside its hydraulic range
- Borehole condition
Professional diagnosis is recommended.
CLOUDY-DAY WATER MANAGEMENT
A solar borehole system should be designed with weather variability in mind.
During a sunny period, the pump may fill the tank.
During a cloudy period, the pump may produce less water.
During a very poor solar period, pumping may stop.
The stored water can then provide the necessary reserve.
This is one of the strongest advantages of combining solar pumping with adequate water storage.
MULTI-DAY AUTONOMY
If a property requires water continuously through several poor-weather days, the storage tank may need sufficient reserve capacity.
For example, a property using a predictable daily volume may size its storage around one or more days of demand depending on the importance of the water supply and available backup options.
The exact reserve should be determined from the project requirements.
GENERATOR BACKUP
Some commercial or critical installations may include a generator.
If several days of poor weather occur and water demand remains high, the generator can provide backup energy where the system is designed for it.
This can be useful for:
- Hospitals
- Hotels
- Farms
- Industrial plants
- Remote commercial facilities
- Large residential properties
GRID BACKUP
Where grid electricity is available, it may be incorporated into the pumping system.
The system can be configured to use solar when available and grid electricity when necessary, subject to the selected equipment and design.
This can provide additional reliability.
SOLAR AND GRID COMBINATION
A hybrid pumping arrangement can use:
- Solar PV
- Grid electricity
- Battery where appropriate
- Generator where required
The controller or system controls the available energy sources according to the design.
This can be useful where water availability is critical.
AUTOMATION
Automation can improve the reliability of a solar borehole system.
Possible automated functions include:
- Tank level control
- Borehole low-water protection
- Pump scheduling
- Solar tracking
- Automatic restart
- Fault detection
- Remote monitoring
The automation strategy depends on the equipment.
REMOTE MONITORING
For remote boreholes, remote monitoring can be extremely valuable.
The operator may be able to check:
- Whether the pump is running
- PV power
- Water level
- Tank level
- Pump faults
- Daily water production
This can reduce unnecessary travel to inspect the equipment.
SOLAR PUMPING FOR CONSTRUCTION
Construction sites can also use borehole pumping systems where appropriate.
Water may be required for:
- Concrete works
- Dust suppression
- Cleaning
- Worker facilities
- General construction activities
The system must be designed around the temporary or permanent nature of the site.
SOLAR PUMPING FOR RANCHES
Large ranches may have water points far from the electrical grid.
Solar pumping can be useful because the PV array can be installed near the borehole and water can be transported or stored appropriately.
The system can operate automatically with minimal daily intervention.
SOLAR PUMPING FOR REMOTE HOMES
A remote home may benefit from a simple arrangement:
Solar panels → pump controller → borehole pump → elevated tank → household plumbing.
The tank supplies water even after the pump stops in the evening.
This can provide a practical off-grid water solution.
SYSTEM SIZING PROCESS
A professional solar borehole design can follow these steps:
STEP 1: ASSESS THE BOREHOLE
Determine depth, water levels, yield and diameter.
STEP 2: DETERMINE WATER DEMAND
Calculate daily and peak requirements.
STEP 3: CALCULATE TOTAL HEAD
Include vertical lift and pipe losses.
STEP 4: SELECT THE PUMP
Match the pump to the required flow and head.
STEP 5: SELECT THE CONTROLLER
Match the controller to the pump motor and PV array.
STEP 6: SIZE THE PV ARRAY
Determine the required solar capacity.
STEP 7: DESIGN THE PANEL STRINGS
Check voltage and current limits.
STEP 8: SIZE THE CABLES
Account for current, distance and voltage drop.
STEP 9: DESIGN PROTECTION
Include appropriate electrical and motor protection.
STEP 10: DESIGN STORAGE
Determine the required water tank capacity.
STEP 11: INSTALL
Install the PV structure, controller, pump, pipework and electrical equipment.
STEP 12: COMMISSION
Test the system under operating conditions.
COMMISSIONING
Commissioning should verify:
- Panel voltage
- Panel current
- Controller operation
- Pump rotation where applicable
- Pump current
- Flow rate
- Water pressure
- Tank level controls
- Dry-run protection
- Overload protection
- Cable connections
- Earthing
- Surge protection
- Automatic controls
The system should be observed under actual pumping conditions.
TESTING WATER OUTPUT
The installer should verify that the pump delivers the expected water volume under the actual operating conditions.
A pump that runs does not necessarily mean that the installation has been correctly designed.
The final test should evaluate both electrical performance and water delivery.
DOCUMENTATION
The customer should receive useful information about the system.
Documentation may include:
- Panel specifications
- Pump model
- Controller model
- Wiring information
- Protection arrangement
- Operating instructions
- Maintenance requirements
- Pump depth
- Pipe specifications
- Tank capacity
- Warranty information
This information makes future maintenance easier.
COMMON INSTALLATION MISTAKES
Some common problems include:
- Choosing a pump based only on horsepower
- Ignoring dynamic water level
- Ignoring borehole yield
- Undersizing the PV array
- Incorrect PV string voltage
- Undersized cables
- Poor pump cable joints
- No dry-run protection
- Poor tank control
- Inadequate surge protection
- Poor earthing
- Insufficient water storage
- Ignoring pipe friction
- Ignoring future demand
- Using incompatible controllers
- Poor mounting structures
These problems can reduce system performance and equipment life.
WHY PROFESSIONAL DESIGN MATTERS
Solar pumping combines several technical disciplines:
- Solar PV engineering
- Electrical engineering
- Motor control
- Hydraulic engineering
- Borehole knowledge
- Pipework
- Automation
- Water storage
A person may understand solar panels but still lack the hydraulic knowledge needed to design a borehole pumping system correctly.
Likewise, a person may understand pumps but not know how to design the PV array and electrical protection.
The best results come from treating the entire installation as one integrated system.
PRO-LOGIC TECHNOLOGIES LIMITED
Pro-Logic Technologies Limited provides solar and electrical solutions for residential, commercial, agricultural and specialized applications in Kenya.
For solar borehole projects, the installation should be designed around the actual water requirements and electrical characteristics of the site.
The project can include assessment of the solar array, pump controller, electrical protection, cabling, inverter or pump drive where applicable, automation, water-storage arrangements and system commissioning.
The objective is not simply to install panels.
The objective is to provide a reliable water-pumping system.
For solar installation, borehole solar pumping, pump control, solar electrical systems and related services in Kenya, contact:
0723763173
FINAL ANSWER
Installing solar for a borehole water pump requires much more than connecting solar panels to a pump.
The borehole must first be assessed.
The installer needs to understand:
- Borehole depth
- Static water level
- Dynamic water level
- Borehole yield
- Required water volume
- Required flow rate
- Total pumping head
- Pipe length
- Pipe diameter
- Pump efficiency
- Motor power
- Pump controller requirements
- Solar resource
- PV array size
- Cable distances
- Protection requirements
- Water-storage capacity
The basic system normally follows this arrangement:
SOLAR PANELS → PUMP CONTROLLER → BOREHOLE PUMP → DELIVERY PIPE → STORAGE TANK → WATER USERS
The solar panels provide electrical energy during daylight.
The controller manages the electrical supply to the pump.
The pump lifts groundwater and delivers it to the storage tank.
The tank then provides water when the pump is not operating.
One of the major advantages of this arrangement is that water can be stored instead of relying entirely on batteries. In many applications, pumping water during daylight and storing it in a tank is more practical than storing the same energy in a large battery bank.
Cloudy weather can reduce solar pumping performance because less irradiance reaches the panels. However, a properly designed system can continue operating at reduced output when sufficient light is available. Adequate water storage can compensate for periods of reduced solar production.
For farms, ranches, homes, schools, hotels, institutions, commercial properties, irrigation projects and remote sites, solar borehole pumping can provide a practical alternative to conventional grid- or fuel-powered pumping.
The most important principle is correct sizing.
A large solar array does not automatically make a poor pump design work.
A powerful pump does not automatically provide the required water.
A large battery does not automatically solve a low-yield borehole.
Every component must match the actual hydraulic and electrical requirements of the project.
For professional solar borehole pumping installation, solar pump systems, borehole pump control, solar PV installation, water-storage systems and related electrical services in Kenya, contact 0723763173.