Solar-Powered Water Pumping (SolarMUS)

This project has wiped away our sweat and quenched our thirst“’ – A villager from Tallo Chisapani, Nepal.

What is a SolarMUS?

This is a system where a solar-powered water pump lifts water from the source to a reservoir above a community. The water is then distributed to tap-stands near households in the community through a gravity powered system. The MUS refers to the ‘Multiple Use Water System’ meaning that the water system is designed to be used for multiple purposes such as domestic use (drinking and cooking), sanitation, and agricultural and productive end uses.

Where is it appropriate?

We use a SolarMUS system in the mountainous regions of Nepal, where communities often live far above their nearest water source. Unlike our Hydram projects (which require a high volume of water), a SolarMUS system can be used in areas where the water source is low in quantity but high in quality, such as a naturally occurring spring. This is because we are able to cap the source and lift all the available water up to the community.

Why is SolarMUS innovative?

  • It uses solar radiation, a freely available resource.
  • The water can be released and shut off on demand by the community members, meaning each household can take what they need, when they need it.
  • The time women save on water collection can instead be spent on more productive activities; they can start their own business, grow more crops and pursue education. It also empowers women to play a larger role in the household decision-making process because of their increased income.
  • Greater quantities of water mean that crops can be grown outside of the normal growing season, when they will fetch a better price.
  • The MUS infrastructure is constructed with local materials and labourers, and this simple technology, integrated with the solar system, provides water for domestic use and for micro-irrigation.

Where have we used it?

We have installed SolarMUS systems in Nepal’s Central and Western Development Regions, and are currently expanding the programme into the Mid and Far Western Regions of Nepal. Typically a tap has been shared between 3-4 households, however we are now moving towards a ‘one house, one tap’ policy, ensuring that each household has their own individual tap stand. Communities are using the pumped water for domestic as well productive end uses.

This improved access to water brings many benefits, such as: drastically reducing the time and drudgery required to collect water, increasing child school attendance, increasing household income by selling vegetables, improvements in health and nutrition.

A community-owned clean energy solution

Each solar water pumping system is owned and managed by the community. A tariff is charged for water use and this money is collected in a community bank account. These funds can be used for any future maintenance or replacements, and ensures the long-term sustainability of the project.

Community members are also trained in maintenance, financial management, business development, and agricultural practices. This ensures that they are equipped to gain the maximum benefit from their improved access to water.

Kavre District

Interviewer: “What will you do with the time saved from water carrying?

Kavre District Villager: “I’ll spend more time on my children. I’d like to train for a skilled job, motivate the community, and grow vegetables to earn a little income.

In Nepal’s Kavre District, SolarMUS systems now provide safe and accessible water for drinking and irrigation. This frees women and children from the burden of water collection and allows crops to be grown out of season.

Working with these communities has also given us the opportunity to work with marginalised local households. We help them to claim their full financial entitlements from the government, including solar pumping subsidies.

How does it work?

A solar PV array generates electricity as DC from the sun’s light. This electricity drives the motor in the pump and brings the pump into operation. The pump lifts water, from the source, up to a storage tank located above the community. A gravity fed system then distributes the water down to individual tap stands, outside homes and within easy reach of fields.

  • A collection tank is constructed near the water sources to collect the water from different sources.
  • The pump is submersed under the water in the collection tank (if the pump is a submersible type) or near the collection tank (if it is a surface mounted type). Solar panels are erected close to the collection chamber, ensuring that the solar array gets as many hours of sunshine as possible. The solar PV array generates the electricity as DC.
  • The electricity generated from the solar PV array passes through the cable to drive the motor, and motor operates the pump. If an AC pump is used, an inverter is required to convert the DC to AC.
  • The pump draws water from the collection tank and delivers it to the storage tank through a delivery pipe. The storage tank is constructed at the top of the village and the size of the tank is designed to allow at least 3 days of autonomy (i.e. it will be made large enough to hold 3 day’s worth of water). This means that even if there are 3 consecutive days of cloudy weather, when the pump is not in operation, there is still sufficient water for distribution.
  • A distribution pipe carries the water from the storage tank to a series of taps and outlets at various locations in the community.
  • Water can be released on demand by community members.

Our Solar MUS programme is proudly supported by The Big Lottery Fund.

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Bibliography

McLoughlin, Fintan, Duffy, Aidan and Conlon, Michael. 2013. Solar Photovaltaic Pumping for Multiple Use Water Systems (MUS) in Nepal [pdf] Dublin Institute of Technology.

Banner image photo credit: Kristin Lau

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