Solar vs. Generator for Water Pumping: A Cost Comparison

If you're pumping water from a borehole, you're paying for energy, either through diesel, grid electricity, or a solar investment. Let's compare the real costs.

The Setup

We'll compare costs for a typical Kenyan scenario:

• Borehole: 120m deep, SWL at 60m
• Daily demand: 5 m³/day (enough for a large household or small farm)
• Pump required: ~0.75 kW submersible

  Option A: Diesel Generator

• Generator: 3kVA diesel genset
• Running: 4-5 hours/day to pump required volume
• Fuel consumption: ~1.5 litres/hour

  Option B: Solar Pump System

• Pump: DC solar submersible (0.8kW)
• Panels: 3 × 350W solar panels
• Controller and accessories included

  Year 1 Costs

  Cost Item	Generator	Solar
  Equipment purchase	KES 45,000	KES 180,000
  Installation	KES 10,000	KES 35,000
  Fuel (365 days)	KES 365,000	KES 0
  Maintenance	KES 15,000	KES 2,000
  Year 1 Total	KES 435,000	KES 217,000	Even in year one, solar is cheaper. The fuel cost of a generator is devastating. 5-Year Costs	Cost Item	Generator	Solar
  Equipment (incl. replacement)	KES 90,000	KES 180,000
  Fuel (5 years)	KES 1,825,000	KES 0
  Maintenance	KES 100,000	KES 10,000
  5-Year Total	KES 2,015,000	KES 190,000

  After 5 years, the generator has cost over 10 times more than the solar system. And the generator will need replacing while the solar system is still going strong.

  10-Year Costs

  Over 10 years, a generator will cost approximately KES 4 million in fuel and maintenance alone. The solar system's 10-year cost remains under KES 200,000 (the initial investment plus minimal maintenance).

  Beyond Cost: Other Advantages

  Reliability. Solar pumps run unattended. No fuel runs, no starting procedures, no noise complaints from neighbours.

  Environment. A diesel generator pumping 5 m³/day produces roughly 4 tonnes of CO₂ per year.

  Maintenance. Generators need oil changes every 200-300 hours, fuel filters, air filters, and eventual overhaul. Solar panels just need occasional cleaning.

  Resale value. Solar systems retain value. A used generator is worth very little.

  When Generators Still Make Sense

  - Very high flow rates needed 24/7 (processing plants)

  • Temporary construction sites
  • Backup for critical systems during extended cloudy periods

    For most Kenyan residential and institutional water pumping, solar is the clear winner.

    Get Your Solar Pump Quote

    Use our free configurator to see exactly what a solar pump system would cost for your specific borehole and location.