Solar pumping systems use the sun to generate power and run electric water pumps. The simplest system consists of a solar panel and a DC pump. Systems may also include batteries, sun trackers, and wind co-generators. Adding an inverter makes using an AC motor and pump possible, but this raises the costs substantially.

Solar water pumping systems are really not very different from modern wind turbine systems. Today, wind turbines can power electric pumps, too. Solar systems have some benefits over wind systems, but there are also some limits. As the well gets deeper, the number of gallons per minute pumped lessens. Pumping water from deep wells, or high volumes of water from shallow wells, means more powerful pumps. Stronger pumps need more power. Getting more solar power means adding more panels and this can get costly for high volumes or very deep wells. A possible choice for such conditions is an electric pump powered by a wind turbine.

There are many reasons to think about solar pumping systems over common windmills.

• Fewer moving parts and a pump that is easy to maintain means lower yearly costs. There are no wooden rods or leathers to keep up and no need for large equipment.
• In many areas the sun is more dependable than the wind, especially during the hot, dry periods of peak demand. Amarillo, Lubbock, Midland, El Paso, and Albuquerque are five of the top ten sunniest cities in the United States.
• A solar pumping system is easier to install from scratch than a conventional windmill.
• With some systems, it is possible to move solar panels from well to well, so it may not be necessary to buy a full set-up for each well.
• Some systems have float valves that turn the pump off when the storage area is full. This helps conserve water.
• Solar pumping systems are safer because there are no towers to climb.
• How well any one solar system works depends on the kind of system selected, how much water is required, the depth of the well, and the amount of sunshine at the site.

Livestock water use drops during cool or wet weather. However, some systems come with batteries that will pump when there’s no sun, and most can be hooked up to batteries. Most people would agree that it’s easier to haul batteries or a generator than water.

Solar pumping systems are only economical in remote areas where there are no power lines. The best time to think about a solar water pumping system is when a new well is being set up or when an existing windmill needs to be replaced. High upkeep costs on windmills drive some people to look for other answers. However, solar systems are not always the right solution.

Every pumping situation is different. You should seek expert help and consult more than one vendor before installing a new system. Even the people who sell solar systems agree that if you have a reliable windmill that meets your peak water demands, you should stick with it. There are many factors to consider when deciding what kind of system to install. Vendors should ask for the following kinds of information when you call about a system:

Water Source: Static water level, total depth of well, inside casing diameter, casing material, production, location, & age of well, previous use, including pump type, water quality conditions.

Water Requirements: Amount of water needed in a day, how water is used, pressure requirements, number & type of livestock.

Site Condition: Water destination, site information (shading, terrain, etc.), water storage (tank, trough, & pipe information).

Recommended Reading

1. Water Pumping: The Solar Alternative. by M. B. Thomas. Sandia National Laboratories. April 1987. Document No. SAND 87-0804.
2. Solar Water Pumping: A Handbook. by Jeff Kenna and Bill Gillett. 1985. Intermediate Technology Publications, London, UK.

Government Help

1. Oldham County Extension Office

• Box 380 / Vega, Texas 79092
• 1-806-267-2692

1. Governor’s Energy Management Center Texas Energy Extension Service

• P.O. Box 12428 / Austin, Texas 78711
• 1-800-643-SAVE