Here we look at some of the basics of remote water pumping and provide some very understandable information to allow you to decide which option suits best.
Off Grid Water Pumping.
So, you want to pump water in a remote area? Well this information is to give a brief but broad over view of off-grid water pumping in remote areas. It will be best used as a signpost to point those who which to explore solar and water powered pumps, in the right direction and where they are best to start their investigations.
My main experience is in providing stock water for farmers in the areas of their farms where mains power is unavailable (and unaffordable to install), as well as humanitarian projects that involved getting water for villages in third world countries. Both can be very challenging.
I have hands on knowledge of a number of water powered pumping systems that include; Hydrobine, High-Lifter, Glockemann, Powerspout PHP, and solar powered pumps that include the React Surface Pump (previously known as the Triplex) and the Aquatec Submersible pumps.
Water powered pumping.
The major limiting factor in water powered pumps is of course that you need flowing water and some degree of head pressure to drive the pump. You either need high flow and low head, low flow and high head, or some combination of the two. These quite specific parameters have shown, in my experience, that the options for these pumps is very limited.
The other issue I have found is the reliability of water powered pumps (with the exception of the High-Lifter). For a pump to operate 24/7 all year round is a significant ask and I have experienced first hand the complexity of choosing not just the correct site but also the exacting and specialised nature of the install.
The major benefit with water powered pumps is that they will pump and day and all night regardless of weather, this can give you some significant quantities of water over a 24hr period and makes no difference what season it is.
Basic data needed for analysing a water powered pumping solution.
- How much flow and fall (head) are available at the water source?
- How high do you need to lift the water, and over what distance?
- What is the delivery pipe size?
- How much water to you require each day?
With all water powered pumps it is crucial to stick religiously to the guidelines (near enough is seldom good enough), install it exactly to the manufactures’ specifications and remember the laws of physics cannot be broken. It will only do what it can do.
Solar powered pumping.
The major limiting factor in solar powered pumps is obviously the sun needs to be shining and the pump and panels need to be located in a place where they have good access to the sun. In most situations that will mean you can expect days when the pump will deliver little or even no water, and in the winter, you can expect significantly less water than in the summer.
The way to mitigate the inconsistencies of the sun is to pump more water per day than you need to a storage tank or reservoir. This allows you to have a bank of water in the system that can accommodate the down days. This is crucial and the tank/reservoir effectively acts as a battery would, allowing storage during the good times and delivery in the poor times.
The major benefit with solar pumping is the site you pump from can be either flowing water or still water, which opens solar up to all water sources, and solar pumps in my experience are very reliable, mainly I suspect because most have been around for a long period of time which means the weak points have been eliminated.
Basic data needed for analysing a solar powered pumping solution.
- What is the water source, and where is it located?
- What distance (closer the better) will the PV panels be from the pump?
- How high do you need to lift the water, and over what distance?
- What is the delivery pipe size?
- How much water to you require on average each day in summer, and winter?
As with the water powered pumps it is crucial to stick religiously to the guidelines, install it exactly to the manufactures’ specifications and have a reasonable expectation of what it can do. With the best will in the world, if there is not enough sunlight, it won’t pump.
Below are some points to consider when looking at off-grid pumping.
- If you have access to mains power it makes sense to use it, you will virtually always be better off both environmentally and financially.
- Recognise the limitations. Solar-powered; no sunlight - no water. Water powered; no flowing water - no water.
- It's just physics, you can’t get something for nothing. Energy in and energy out.
- Accurate data is essential. The old saying, wrong information equals wrong result is unfortunately very true.
Off grid pumping can and does deliver significant benefits. Do your homework, follow the rules and you can expect a great result.