If  you need to supply water within the range that grid cannot provide, solar energy can solve the problem. (Photovoltaic) solar pumps are an alternative to combustion engines, windmills and hand pumps. There are thousands of solar water pumps in operation all over the world. They perform best when the sun is full when the sun demand is greatest.

Photovoltaic (PV) modules (that is, solar panels) use silicon cells with no moving parts to generate electricity from sunlight. They have been in mass production since 1979. They are so reliable that most manufacturers offer a 25-year warranty, and their life expectancy is well over 30 years. They work well in cold or hot weather. The solar water pump is specially designed to use the direct current generated by the photovoltaic module. The pump must work under low illumination conditions, when the power will be reduced, and will not stall or overheat. The small volume pump uses a positive displacement (volume) mechanism to seal the water in the cavity and push it upward.

Even if pumping slowly, the lifting capacity can be maintained. These mechanisms include diaphragm pumps, vane pumps and piston pumps. These are different from conventional centrifugal pumps that require rapid rotation to work effectively. Centrifugal pumps are used where greater flow is required. Surface pumps are pumps installed on the ground. The ground pump works well when sucking water through a suction port less than 10 or 20 feet. A submersible pump is a pump that is lowered into the water. Most deep wells use submersible pumps. The pump controller (which is a linear current intensifier) is the electronic device used by most solar pumps. It acts like an automatic gearbox and helps the pump start and prevents it from stalling in weak sunlight. Some controllers also have other functions, such as providing terminals for float switches to shut down the pump when the tank is full, and provide overvoltage protection. When the sun is moving in the sky during the day, solar trackers can be used to tilt the PV array. This can increase daily energy gain by as much as 55%. If there are more hours of peak sunshine, smaller pumps and power systems can be used.

On a sunny day, the tracking effect is best. In cloudy weather and shorter winters, the effect is not good. However, in recent years, the cost of solar panels has dropped so much that adding more solar panels is usually more cost-effective than adding trackers. In addition, because the tracker has moving parts, it often needs repairs after a few years. Storage is very important. Depending on the climate and water usage, storage time of three to ten days may be required. Most systems use storage tanks for simplicity and economy. In other cases, batteries can be added to the system. The electric energy generated by the solar module is stored in a deep-cycle battery, so the pump can be operated on non-sunny days. 

Add a float switch to the system, when the water tank is filled with water, the pump can be turned off to prevent overflow. The windmill, used to pump water in the old days, can still be seen in many fields of view. Recently, in water pump applications, solar pumps have replaced windmills. Facts have proved that small solar systems are cheap and easy to install and maintain. Solar panels also provide a more stable water supply; they can be installed in valleys and forest areas with insufficient wind. The PV array can be placed at a certain distance from the pump itself. Even distances of several hundred feet (100 m).