Solar water pumps: tips and things to know

Solar water pumps are fast becoming essential for farming in Africa and thanks to recent technological advancements they are much more affordable. Before the advent of solar energy, farmers in developing nations found it challenging to power machines without polluting the environment.

Today, providing a reliable water supply to the most remote locations is no longer a pipe dream (pun totally intended). It is now possible to irrigate our lands purely from the energy supplied by the sun, with little negative impact on the environment.

Zimbabwe and other African countries are likely to benefit immensely from solar water pumps due to the plentiful supply of sunlight. This article gives you the tips, benefits, limitations, and everything you need to know about solar water pumps.

How does a solar borehole pump work?

To better understand how a solar water pump works, you have to look at its components. A solar water pump system consists of solar panels, an electric motor, and a pump and more often than not a storage tank.

Essentially, the solar panels use photovoltaic cells to transform sunlight into electricity. Then, the electrical energy flows to the motor, enabling the pump to function. The pump will often be used to fill up a water storage tank.

What are the benefits of solar water pumps?

Solar borehole water pumps have numerous benefits. First, the pumps rely on the safe, clean, and renewable form of energy – solar energy. Luckily, this form of energy is readily available in Africa and other developing regions.

Secondly, the pumps are easily installable in remote and rural areas, which would otherwise take decades, if not centuries, for authorities to connect to the power grid, making commercial farming possible in rural setups.

Thirdly, solar pumps require little maintenance, operation costs are low and they can last for up to 25 years, which makes them a good investment for the long run.

Lastly, fuel-powered water systems have been polluting our environment. This pollution has accelerated climate change which is responsible for many national catastrophes today. For its part, solar energy is beneficial because it is environmentally friendly and helps to reduce pollution.

Limitations

If your pump is not connected to a backup battery, then it will only run during daylight hours. Many people counter this by adding a water storage tank to their system, which can gravity feed water at night. Extremely cloudy or rainy conditions will also impact the efficacy of your pump. In addition, investing in solar pumps may be unsuitable for short-term projects as their initial cost doesn’t make it viable. You can expect an entry level system to set you back at least US$500.

Bearing in mind the relatively high initial investment, solar water systems and their components can be a target for thieves. Be sure to take security into account when siting your pump.

When to use a Solar Pump

You can use solar pumps to:

• pump water from a borehole to above ground
• supply your farm animals with drinking water
• supply water for home consumption and kitchen purposes
• extract slurry and waste water
• irrigate farmlands and systems
• flow water during treatment
• amplify other pumps when pumping liquid substances over an extended distance

Factors to Consider when Buying a Solar borehole Pump

Climate

As stated earlier, solar pumps rely on sunshine. Although this may not be a big issue in most parts of Zimbabwe, it is an essential factor to consider. Solar water pumps may not work for you if your region experiences little sunlight throughout the year.

Initial costs

Although the price of solar pumps has gone down considerably over the years, they are still not cheap. So, depending on the intended use, you may have to dig deep into your pockets for a quality solar water pump that can cater to your needs.

Pump efficiency

As an investor, you need to put your money into a system that promises the best results and is devoid of wastage. An efficient pump will produce the best results and will not lose a lot of energy. Be sure to buy components from reputable dealers and beware of cheap knock-offs in the market.

Economic viability

You want your project to succeed, don’t you? As a result, you have to evaluate solar pumps’ investment potency compared other options. Also, examine the land size and slope, intended use (crop irrigation, livestock, or home use). Simply put, you will have to do a thorough cost-benefit analysis.

The other factors that you should consider are:

• Water management,
• Installation and operation costs and,
• Maintenance

Things to Consider when Installing a Solar borehole Pump

Sunshine exposure

When installing solar water pumps, ensure the panels get optimum sunlight exposure to achieve a higher quantity of solar energy. Therefore, you should avoid shadows from buildings, trees, or hills when positioning the solar panels.

Pump size and power needs

Ideally, you will need a system that pumps enough, if not excess, water for your needs. The pump manufacturers will specify the number of litres per hour a pump is capable of pumping together with the height, or head it is possible to pump. The amount of power used by the pump determines the size and number of solar panels needed. It is important to ensure that you get the right pump with well matched panels to suit your needs. Reputable solar companies will be able to advise the best setup to use. Have a look for solar companies in our directory for assistance with sizing your system.

Pump type

Depending on the use of your pump you may need either a submersible pump or surface pump. Submersible pumps are used primarily in boreholes to pump water to the surface or to pump slurry while surface pumps are usually used to transfer water from a storage tank to point of use.

Solar borehole Pump Maintenance

Solar borehole pumps have a simple and adaptable maintenance routine that involves:

• Surface pumps require regular cleaning of dust, debris, and any other material that may prevent the free turning of the motor.
• Solar panels in an agricultural environment tend to get very dusty. Remember that dust on the panels will decrease the efficiency of the pump. Regularly clean the panels with soapy water.
• Trim overgrown trees that surround the solar panels to maintain sunlight exposure.
• Switch off the borehole system if you see it start to pump very muddy water. That could be an indication that the hole is running dry. The mud in the water will damage the pump.
• Clear the area around the borehole, pump, and panels so they are clearly visible. This should discourage thieves.

Cost-benefit Analysis

Africa is highly underserved with power from the grid, especially in remote areas. Where electricity is available, it’s costly. The lack of a cheap and reliable electricity supply leaves farmers with no option but to look for other forms of energy. Unfortunately, the readily available diesel pumps are not environmentally friendly and have high operation and maintenance costs. 

Despite its relatively high initial cost, a solar water pump system has minimal maintenance costs and can work effectively for many years. Furthermore, solar borehole pumps are environmentally friendly.  With a projection of pocket-friendly solar borehole pumps on the horizon, in the coming years, the future of farming in Africa is all about solar energy.

In Conclusion

Africa has long complained of a lack of affordable energy and water. However, with the exponential growth of solar technology coupled with price drops, this could potentially be a thing of the past with the continent experiencing a sunny agricultural revolution. Solar energy is safe and renewable and cost-effective for many farming projects.

Those of you planning to set up a solar water pumping system, well, do your analysis, and you will realize that you should have set the system up yesterday.