Did you know that hydroelectric power is the most widely used renewable energy source in the world today? Worldwide, it accounts for approximately 16 percent of all electricity production. Much of the same technology used for massive hydroelectric plants can be used in powering your home.

Micro–hydro generators can use average water flows to generate electricity. The reason hydro power often surpasses solar and wind power in side-by-side comparisons is that water can generate power constantly, unlike sun and wind. If you’ve ever seen images of areas that have been flooded, you immediately understand the power of water.

Although most commercial hydroelectric power plants use a dam, for residential power generation you will typically use a pipe to collect water from a stream or river. The water from the pipes increases in power or energy as it flows downhill from the source to the turbine. The water hits the turbine and causes it to spin, which generates electricity.

Before you can choose the correct hydro system for your home, you need to measure the amount of energy available in your water supply. To do this you need to determine two important numbers—flow and head. Hydroelectric installers will work with you to estimate these numbers, but you will want to have a general idea of how the process works.

The flow is the amount of water available to turn your turbine; the more flow, the more energy. Flow is measured in cubic feet per second. So, if you were to use a pipe to divert water from your source, how much would be diverted in one second?

Head is the pressure of the water when it hits the turbine. To determine head, you need to estimate the distance the water will fall (go downhill) before it reaches your turbine; the further the fall, the higher the energy.

In order to use hydroelectric power efficiently, one or both of these numbers—flow or head—has to be fairly high to make the investment worth your while.