Solar Water Pumps
Windmills still dot the countryside in rural areas, but today using the sun to power water pumping is making its own history. There are over 10,000 solar powered water pumps in use around the world. They are practical for agriculture anywhere and are especially used in remote villages in developing countries.
As with other solar used for agriculture and at remote locations, solar water pumping is a cheap alternative to extending hydro lines. It is used primarily for three purposes:
- Watering livestock: since water resources can be scattered over a wide area and can be expensive to transport, ranchers and farms use solar powered pumps to channel the water through pipelines or other means, to get it to livestock.
- Irrigation: solar power is used to pump water into a tank, where gravity will redistribute it over time. Sometimes a battery backup will be used instead.
- Water for homes, villages and more. Similarly, water is pumped for storage, using the power of the sun.
Getting an idea of the cost
Figure out the wattage you will need and multiply by $10. You will need to oversize your system slightly, as PV does not consistently put out as much power as it is rated for. Solar PV panels and arrays generally cost about $10 per watt.
Up for some math? Here's a quick guide to calculating the wattage needed: watts (W) are equal to the height (H) in feet of your storage tank multiplied by the gallons per day (GPD) multiplied by 19. This factor is then divided by your pump efficiency percentage. There are usually energy losses that result in efficiency being slightly less than 50%. You can enter "50" as the last value (Eff %) to get a safe estimate.
The whole formula:
W = (H X GPD X 19) / Eff
$Cost = W x $10.