The Low Power Solar Water Pump

A project supported by Caritas, iDE, SDC and ennos

Lessons Learned from the Introduction of a

Technical Innovation

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It all began in 1987…

… with what is said to be the toughest solar car race in the world – the World Solar Challenge. In friendly

competition with others, teams from all over the world participate in this race from Darwin to Adelaide across the

Australian outback. For its first edition in 1987, Prof René Jeanneret and his students from the Bern University of

Applied Sciences (BUAS) developed a revolutionary solar racing car called Spirit of Biel.

Despite a comparatively small budget, the Swiss team

dominated the solar racing sector for many years – driving

to podium positions and breaking several world records.

The Spirit of Biel became a legend and Switzerland

one of the leading nations in the field of solar energy.

Prof René Jeanneret with the Spirit of Biel

Spirit of Biel

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This pioneering spirit still can be felt…

… at BUAS. It was clear that with the maximum power point tracker, the brushless motor drive and the permanent

magnet motor used for the Spirit of Biel, the BUAS had a range of innovative technologies at hand and vast

experience in the field of solar energy that could be used also for other solar applications.

In 1997 Dr Hari Sharan, an Indian engineer working in the

field of sustainable energy solutions, suggested to use

BUAS expertise to equip rickshaws – a very popular

means of transport in Asia – with a hybrid drive. In a

project sponsored by SDC and CEDT, Prof Andrea Vezzini

and his students developed a prototype of a hybrid

rickshaw which was tested at the same time as LPG gas

rickshaws were introduced in India. The hybrid rickshaw

was more effective in CO2 reduction than the gas

rickshaws but required a higher investment. The gas

rickshaws immediately became very popular in India. Due

to this strong competitive pressure, the hybrid rickshaw

project was not pursued at that point. Newspaper article in The New Indian Express, 9 April 2003

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From solar racing to solar pumping…

The project team, however, identified another solar application that could

serve many people in the developing world: water pumping.

Inexistent or unreliable electricity grids are a reality for most people in

the developing world. The electricity under-supply, among others,

negatively affects the water provision of urban households. This led to the

idea to use solar energy to guarantee a continuous water flow.

Practically speaking, a solar pump was to be installed to lift water into a

tank on the roof of a multiple-family house and to cover the daily water

consumption of its inhabitants.

In 2004 Prof Vezzini and his students developed the first prototype of the

solar pump in collaboration with RV College of Engineering in Bangalore.

In 2007 ennos GmbH (ennos is the German word “Sonne” meaning “sun”

spelled backwards), was created as spin-off company of BUAS to promote

the proliferation of the solar pump.

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The need for irrigation…

Still today, many smallholders in the developing world rely on

traditional low productive agricultural practices and on

rainfall to cultivate their few acres of land. Due to a lack of

knowledge and financial means to access irrigation

technologies, those families are exposed to a high risk of

crop failure.

The solar pump is well suited to cover the needs of those

smallholder farmers as it is an affordable irrigation

technology for individual use that combines environment-

friendliness and low maintenance costs with income,

productivity and labor-saving benefits. Prototype of small-scale solar pump developed by BUAS

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While the operating costs of a solar pump are minimal compared to a fuel-powered pump, the high upfront

investment (about USD 500 for an 80W system) are a major hurdle for small farmers and poor families. To

overcome this hurdle, leasing and renting systems will be studied and the possibility to use a carbon finance

mechanism is being investigated.

Solar pumping on the rise…

In view of rising diesel prices and non-existing or unreliable electricity grids in many developing countries, solar

power has become an increasingly attractive energy source.

Many governments are now promoting the use of solar energy and are subsidizing highly expensive, large-scale

solar pump projects with a water delivery similar to large diesel or electric engines. Those projects, however,

require extensive subsidies to make them attractive and often are out of reach for smallholder farmers. The

downsized solar pump developed by BUAS, on the other hand, has been developed specifically to cover the

water needs of those farmers.

Large-scale (8.6kW) solar pump in the North of Bangladesh

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A solar-powered water pump for smallholders…

In 2007 the first ten prototypes of the solar pump were produced and tested in India, Bangladesh and Switzerland.

What followed was a period of technical refinements based on the first test results.

In 2011-2012 Caritas Switzerland, iDE with the support of the Swiss Agency for Development and Cooperation SDC,

and ennos GmbH tested 200 solar pump units around the world, mostly in Honduras, Ghana, Nepal, Bangladesh

and the United States.

Bangladesh 80 pump systems

tested

Nepal 14 pump systems

tested

Denver 2 pump systems

tested

Ghana 13 pump systems

tested

Honduras 18 pump systems

tested

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The handling of the technology as major challenge…

As always when a technology is taken from the lab to the field, technical “teething”

problems appear. Several of them had to be addressed during the filed testing – for

example problems related to the filter, the electronics and the clutch.

A major challenge in the field was the handling and operation of the solar pump.

Until the field testing, the solar pump always had been installed and used by engineers

in a laboratory setting. Now, they were used by farmers under real conditions in the

field.

The goal of the field testing was not only to test the functionality of the pump but also

to involve a broader set of stakeholders (e.g. end users and distributors) and to learn

about the suitability and acceptance of this innovative technology.

The main lesson learned was that the installation and handling of the solar pump

tended to be difficult for the farmers. Therefore, the pump had to be made more user-

friendly. Moving parts, connections or failure points needed to be reduced in order to

make the pump easy to install, operate, maintain and repair.

Solar pump installed in Ghana

Solar pump installed in Honduras

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Solar pump not a one-to-one replacement of existing technologies…

When introducing a new technology, special attention has to be given to training and

local capacity building. Local technicians have to be trained to solve problems on

their own. This, again, underlines the importance of user-friendliness and simplicity if

a new technology is to be disseminated.

When testing the solar pump under real conditions and comparing it to fuel-powered

irrigation technologies, it became clear that a solar pump cannot be a one-to-one

replacement of existing technologies. Compared to a powerful diesel pump, the

solar pump with its 0.5 inch diameter outlet has a comparatively small discharge rate.

Over a longer period of time, however, it can pump considerable amounts of water.

The amount of water pumped with a 120 Watt vane pump over 6 hours is comparable

to the amount pumped with a 4 HP diesel pump in 1 hour.

This, in turn, means that one cannot afford to waste a single drop of water and that

the water distribution system must be optimized to increase the crop production

per unit of irrigation water applied.

Pumping uphill in Honduras

Solar pump installed in Bangladesh

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The use of water needs to be optimized…

To make full use of the advantages of the solar pump (independence from fuel

and electricity, constant flow of water, considerable amount pumped over a

longer period of time), it has to be used in combination with a water storage

technology (e.g. water bag). This allows to store the water that is pumped

over the course of the day and to apply correct doses to the field whenever it is

needed. Ideally, the solar pump is also combined with an application

technology (e.g. drip irrigation or shower hose) to make efficient use of the

water.

This, however, stands in sharp contrast with current irrigation practices in

many countries. Farmers, e.g. in Bangladesh, still practice very wasteful flood

or furrow irrigation. Often they do not know that they reduce productivity by

over-irrigating their fields.

Hence to reach those farmers and to teach them more efficient and

economical irrigation practices is a major challenge of the project. Drip irrigation

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The difficulty of changing behavior…

It has been proven that the benefits of a water application technology (e.g. drip irrigation) outweigh its costs:

farmers enjoy improved profitability by increasing crop yield and quality. Still, farmers are very reluctant when

it comes to changing irrigation practices. In order to achieve the necessary behavioral change on the side of the

farmers, innovative irrigation technologies need to be explained and demonstrated and there has to be

extensive support and training.

If I had asked people what they wanted,

they would have said faster horses.

Henry Ford

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One technology, multiple applications…

There are two different models of the solar pump available, covering solar

input power up to 160W and 320W respectively. A system can be easily

upgraded by adding a solar panel. The solar drive can also be adapted to

various pump systems. Currently it is operated with a high efficiency, well-

priced vane pump. Other pump systems (e.g. progressing cavity pump) are

currently being tested and could be an option for future solar pump systems.

The solar drive can also be mounted to existing manual pumps which can be

“solar-electrified” at a low price.

The solar pump project team always has been curious to explore new

applications of the technology and combinations with other solar

technologies – the solar light for example.

Solar drive adapted to treadle pump in Nepal

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Combination with the solar light…

BUAS, in a joint project with Antenna Technologies and Caritas

Switzerland, also developed the OOLUX solar power kit. The heart of the

OOLUX system is the Powerbox, an intelligent battery with two USB

ports, which allows not only to use two very powerful LED lamps, but also

to charge cell phones and to power a variety of USB-enabled devices,

such as small radios or fans.

The Powerbox includes a micro-finance management system. This

allows the customer to pay off the OOLUX kit over several months

through installments amounting to what has been paid for kerosene

before.

The solar radiation over the course of a day follows a curve. To make best

use of the expensive solar panel, one could use it in the morning and

evening to charge one or several power boxes and to power the solar

pump during the rest of the day. This would provide the owner not only

with water but also with light and entertainment.

Oolux solar power kit

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Application “Water Access for a School or Hospital”

In this scenario, a solar pump system is installed at e.g. a school or hospital, meaning a public building that needs access to water for washing, cleaning or drinking water purposes. A reference case is the Kilela Balanda project in DCR (see: https://www.youtube.com/watch?v=Yv_AMyqztZc). There, a solar-powered water distribution system enables the supply of running water to one hospital and two boarding schools. Before the pump was installed, water had to be carried up a steep hill from a water source about 250 meters away from the hospital. Now, the water can be pumped into two 5000 liters PVC tanks to cover the daily water needs.

Hospital in Kilela Balanda Getting water at the source

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Application “Drinking Water Kiosk”

In India, for example, there are many hand pumps (e.g. Taradev) installed but not used anymore. The idea is to put

those pumps back into use and “solar-electrify” them. An adapter and the solar drive are mounted on the existing

hand pumps which still can be operated manually if necessary. The water pumped could then be purified, filled into

bottles/canisters and sold to the people living nearby.

Water kiosk in Zambia

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Application “Smallholder Irrigation”

The solar pump will also be promoted as a an environment-friendly, CO2-neutral, fuel-free, reliable and

affordable alternative to diesel or electric pumps. Due to the small size of the pump system, it is transportable, can

be protected from stealing and is appropriate for the needs of a smallholder family. To give an example: drawing

from 4 meters, one 80 Watt system could provide enough water to irrigate a plot of about 1500 square meters (40

liters/min * 60 min/hr * 6 hours = 14400 liters, divided by 10 liters/m2/day = 1440m2/day).

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Application “Irrigation Service Provider”

Another option for a solar pump owner is to launch an irrigation micro business by selling the pumping service to

neighboring families. Due to its small size, the pump can be easily transported by bicycle or motorcycle. The pump

can be installed for one day and pump water into a tank (e.g. water bag) which covers the water needs of the

farmers for several days. There is also a possibility to charge a battery and take it – instead of the fragile and

expensive solar panel – to the field to power the pump. Two 12V 60A batteries (preferably solar batteries) would be

sufficient to power an 80W system for about 5 hours.

Service provider transporting solar pump on motorcycle 18

Costs…

Cost wise, a solar pump has the advantage of minimal operating costs compared to a fuel-powered pump –

especially in view of rising diesel prices. The high upfront investment, on the other hand, is a major hurdle for

smallholder farmers and poor families. This means that some sort of renting or leasing system has to be put into

place. Carbon finance is another option that will be further investigated.

The solar pump designed by BUAS has been downsized to cover the needs of smallholder farmers or small

communities and to reduce the initial investment cost. In the range in which the solar pump operates (80-320W),

there are few or no alternative systems available on the market.

To finance the market testings in 2013 and 2014, solar pump “packages” (including hardware, installation, training

and support) will be sold to interested partners. As of current estimations, a package of 10 x 80W systems will

include the following costs:

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Costs for test package of 10 pump sets (80W)…

Pump, motor, electronics 10 x CHF 400 = CHF 4’000

Solar panels (100W) 10 x CHF 200 = CHF 2’000

Tubing, fittings 10 x CHF 100 = CHF 1’000

Shipping 1 x CHF 2’000 = CHF 2’000

Installation, training 1 x CHF 7’500 = CHF 7’500

Data logging, delivering performance data 1 x CHF 1’000 = CHF 1’000

(e.g. water flow rate/day, CO2 savings etc.)

Market study, delivering consumer feedback, Depending on the CHF 7’500 – 15’000

competition analysis, network of potential extent of the study

dealers and agents etc. ----------------------------------------------------------

TOTAL market testing of 10 systems: between CHF 25’000 - CHF 32’500

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Conclusion and outlook…

The solar pump as it exists today is the result of a long learning process that started in 1987. Driven by the vision to

give people in the developing world access to water – be it in the context of their home or for agricultural

production – the researchers of BUAS have steadily improved their technology and gained considerable experience

in the field of solar pumping. Following a human-centered design approach, the needs and aspirations of the

people in the developing world have been the focus of attention all along the learning process.

BUAS succeeded in downsizing the system to make it suitable for the needs of smallholder farmers and smaller

communities (e.g. schools or hospitals). The small size and the high system efficiency make the pump mobile and

affordable. In the solar power range up to 160W and 320W in which the pump operates, there are few to no

alternative products available on the market.

All this has been the result of an iterative trial-and-error process during which the project team had to reconsider

its basic assumptions and to adapt the technology to the reality on the ground over and over again. While there

have been comparatively few technical challenges, the socio-economic realities on the ground caused more

persistent problems. Especially the handling and operation of the pumps turned out to be difficult for the farmers.

This made it clear that the solar pump needs to be extremely user-friendly and simple.

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Conclusion and outlook…

Another major hurdle is the acceptance of this new technology and the behavioral change that has to come along

with the transition from traditional irrigation practices to less wasteful and more efficient solar pumping. In

consequence, demonstration of the technology and training of end users and technicians on the ground needs to

be a priority.

As of the next steps, another field test of 50 pump systems will take place in 2013. In 2014, it is planned to test 500-

1000 pumps in various locations and for the different applications defined before. The emphasis of this testing will

be on the market, not the technical testing. After this, the solar pump will be ready for mass distribution.

In the long run, the goal is to sell the solar pump to farmers or communities – instead of giving it out for free – in

order to create the motivation that comes with ownership. At a global level, a commercial enterprise is needed for

the dissemination of the pump. At a local level, commercial agents will have to be found which have the capacity to

sell or rent and to repair the solar pumps. By facilitating the creation of demand and developing an efficient supply

chain for the solar pump, the project shall contribute to the establishment of a demand-driven renewable

technology sector in various developing countries. Sources pictures: Antenna Technologies, Bern University of Applied Sciences, iDE, Karin Imoberdorf, Kilela Balanda Project, Larry R. Sweet, Nick

Jeffries, Raj GC, www.mpoweruk.com, www.wikimedia.org. 22

CONTACT

msd consulting GmbH

(markets, sustainability and development)

Muehlemattstrasse 45

CH- 3007 Berne

Switzerland

Email: karin.imoberdorf@msdconsult.ch

Mobile: +41 (0)79 415 28 04

Fax: +41 (0)31 372 68 31

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JULY 2013

AMRO TECHNOLOGY PVT