If youâ€™re an alternative energy advocate seeking for ways to green your living and you happen to live by a river or creek, you might be in luck. We all know energy is generated by building dams over giant underwater turbines, but this technology doesnâ€™t have to be built on such large scales.

Micro hydro generators use modest water flows to generate electricity, and they trump solar and wind power in reliability because water runs day and night, independent of weather situations.





Letâ€™s take a look at a typical hydroelectric power plant to better understand how this technology works…

How It Works

Water is a heavy medium that moves quickly. Similar to a car, which has similar properties, it takes a lot of energy to get water flowing. Anyone who has ever stood by a waterfall or gone swimming in the ocean can vouch for the power of water flow. In a hydroelectric power plant, engineers use the energy stored in running water to generate electricity.

Today, hydroelectric power is the most widely used renewable energy source. It accounts for approximately 16% of worldwide electricity production, far outweighing the contributions of solar, wind, and geothermal combined.

The most prominent feature of a hydroelectric plant is the dam. Large dams are immense structures, sometimes hundreds of meters high, which can hold back several cubic miles of water. Since water is the source of energy for a hydro plant, the dam is important for storing and controlling the flow of energy.

Once the dam is constructed, underwater gates are opened to regulate flow through an underwater turbine.

The pressure of the water pushes on the turbine blades, causing the turbine to spin a shaft that is connected to a generator.

Spinning magnets and coils in the generator produce current that is directed through a transformer and out to the grid, where it is used by you and me.

For residential generation, you probably wonâ€™t be blocking off a river or storing a cubic mile of water. Instead, a typical residential generator uses a pipe to collect water from a stream or river. The water gains energy by flowing downhill and is passed through a turbine that is connected to the end of the pipe. The type of turbine you will need depends on the type of flow available on your property.

Go with the Flow: Calculating Water Flow

There are two numbers that measure the amount of energy available in your water supply: flow and head. Before installing a hydropower generator for your house, you will have to determine both of these numbers. Most hydroelectric installers will help you to estimate these values, but letâ€™s take a look at them to get the general idea.

Flow means just what you think it meansâ€”the amount of water that you have available to turn your water wheel or turbine. The more flow, the more energy you can produce. In terms of a micro hydro generator, it will be the amount of water running down the pipe to your turbine.



In one second, how many cubic feet of water can you safely divert from your stream to turn a turbine? To put things into perspective, for a residential application (which typically requires a few kilowatts of electricity):

a few cubic feet of flow per second is considered an ample flow rate

a number below 0.1 cubic feet is considered low



Low flow rates can still be used to generate electricity, as long as your water source has enough head. Remember to consider seasonal changes in water level when estimating flow.

Head refers to the pressure of the water that strikes your turbine blades. To understand the importance, imagine a high-pressure fire hose spraying a water wheel. Clearly, the pressure of the fire hose would deliver more energy to the wheel than a typical garden hose.

In order to determine your head, you will need to estimate the distance water will fall before reaching your turbine. The farther the water falls, the more energy you can produce with your water source.