One of the most simple yet useful applications of solar energy is the solar powered water pump. This is essentially the same as a conventional war to pump, but the energy required to operate it comes from the sun instead of electricity from the grid.

As you would expect, these systems work much better in areas with a high solar irradiation index. This is because, despite technological advances, solar panels are still very inefficient in converting the sun's energy to electricity, with the current market average at around 15%. You also need to take into consideration that the sun does not shine all day long, and as such it is a good idea to purchase batteries which can store excess energy for the night time.

Using the data such as 15% efficiency and the latitude you are on, an engineer can determine the surface area required to be covered with solar panels to supply you with sufficient energy for your water pump. Taking as an example a standard house with four occupants, located within 30°of the equator, you could expect to need a surface area of solar panels of 3m to 4m squared and a battery pack as well. During the winter months, you should also expect to need to use a traditional electric backup.

The type of solar cells you will use are called photovoltaic, and are about 5 to 10 cm thick. They have an average lifetime of around 25 years, but their efficiency decreases substantially up to a period of about 15 years. However, the useful life time of the batteries is much less and is approximately five years.

If you are working out the potential savings and cost of a solar powered water pump compared to a normal water pump, it is necessary to take all of of these factors into account. Harnessing the power of the sun and using it for electricity is much harder than you might think. But if you do it right it is a great way to save yourself money whilst also doing something good for the environment at the same time.