A breakthrough has been achieved in simple and affordable solar irrigation for farmers in developing countries. This presentation was given at the FAO International Forum on Solar Technologies for Small-scale Agriculture & Water Management, April 2018.

1. SMALL-SCALE SOLAR IRRIGATION
IS NOW AFFORDABLE
John DeMarco, Consultant in rural development
12 April 2018, Rome

2. OVERVIEW OF EVENTS AND INITIATIVES
• who & where we are
• what we do
• activities in the field
• priorities
• enhancing capacities
• looking ahead

3. OVERVIEW OF EVENTS AND INITIATIVES (2)
• who & where we are
An individual with collaborators in Cameroon,
Senegal, Burkina Faso, Malawi, Canada
• what we do
On a mission since 2013 to make solar pumping
affordable to small farmers
• activities in the field
- Developing, testing and demonstrating simple,
low-cost solar pumping systems for irrigation
- Starting to put in place commercial distribution

4. OVERVIEW OF EVENTS AND INITIATIVES (3)
• priorities
Make low-cost solar pumps available to farmers
on a commercial basis
• enhancing capacities
- Training has started, much more is needed
- These pumps do not require ‘experts’ to set up
and use
• looking ahead
- Make the pumps widely available
- Improve the systems to be more cost-effective,
reliable, accessible

5. This presentation
• PART A: THE TECHNOLOGY
• PART B: AFFORDABILITY AND COST-EFFECTIVENESS
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6. The challenge and the opportunity
• Solar panels have at last become cheap and
accessible – a major opportunity to replace human
energy with solar energy!
• But commercial, specially-made solar pumps remain
expensive, especially at small scale.
• In 2013, we set out to fill this gap by developing
simple, low-cost solar pumping systems using
available components.
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7. First field test, 2013 Senegal
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• Uses 12V,
4000 gph
marine bilge
pump,
no battery,
no controller
• 5000 ℓ/h @ 5m head
• Irrigates 0.5ha
• Cost under US$1000

8. Big step forward: using a single solar panel
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• 24V, 220W bilge
pump works
directly with one
standard solar
panel of 250-
270W
• Complete system
retail cost $400,
not including
pipes (Cameroon)
• Irrigates 0.5ha

9. 250W system in operation, Cameroon
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10. Another step forward: smaller, more
affordable systems
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• Small, brushless DC pumps cost <$30 in China
• Useful output obtained with panels of 60W and up
• Many models available, more to be tested

11. Low-cost, entry-level system < US$200
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• Complete irrigation
system (60W panel,
pump, cable, hose)
costs US$160 retail
• Pumps 1000ℓ/h @ 4m
head; irrigates 1000m2
• Higher flow and head
with bigger panels
• Scalable by adding
more pumps

12. 60W system in operation, Cameroon
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13. PART B: Affordability and cost-effectiveness
• Cost of small solar pumping systems
• Potential revenue
• Comparison to other productive investments of small
farmers
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14. Lowest entry point: 60W solar irrigation system
ITEM COST US$ (Cameroon)
Brushless DC pump, ZKSJ DC50B-24130S $64
Solar panel, 60W $60
Hose, cable and fittings $34
TOTAL SYSTEM COST $158
Typical pump performance 1,000 ℓ/h @ 4m head
Potential water volume pumped per day 8,000 ℓ/day
Potential area irrigated (highly variable) 1,000 m2
POTENTIAL NET REVENUE, 1 CROP SEASON
(based on $3,000/ha for high value crop)
$300
Payback period < 1 irrigation season
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15. Scaling up: 250W solar irrigation system
ITEM COST US$ (Cameroon)
Marine bilge pump, Seaflo 3700 24V $82
Solar panel, 250W $250
Hose, cable, fittings, wheelbarrow $94
TOTAL SYSTEM COST $426
Typical pump performance 3,500 ℓ/h @ 5m head
Potential water volume pumped per day 28,000 ℓ/day
Potential area irrigated (highly variable) 3,500 m2
POTENTIAL NET REVENUE, 1 CROP SEASON
(based on $3,000/ha for high value crop)
$1,050
Payback period < 1 irrigation season
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16. Solar pump compared to other investments (1)
=
16
60 Watt system 4 sheep

17. Solar pump compared to other investments (2)
=
17
250 Watt system

18. Solar pump compared to other investments (3)
=
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2x 250 Watt systems Motorcycle taxi $900

19. Solar pump compared to other investments (4)
=
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60 Watt system Cheap gasoline
pump

20. Conclusions
• Simple, low-cost solar pumping systems are now
affordable for small farmers.
• A small solar pump can be a viable business
investment, with or without subsidies or institutional
credit systems.
• One pump can create one job (while replacing the
physical work of one or more people).
• Effort is needed to get the information out and make
the pumps available where needed.
• More can be done to make the pumps better and
cheaper.
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21. * Key recommendations *
Financing (institutional or informal) will come easier if we
can do the following:
• Identify and continue to improve the most affordable,
cost-effective and easy-to-use solar pumping solutions –
if it is attractive enough, users will adopt it voluntarily.
• Get the information out through pilot projects,
demonstrations, training, media..
• Development partners can accelerate the process of
adoption through active promotion of the best
technology, without necessarily subsidizing the
purchase or financing of pumps.
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THANK YOU!
John DeMarco
demarcojohnf@gmail.com