Homemade Hydroelectric Plants

Topography

• The most efficient place to build your hydroelectric plant is near a hill where the water runs downhill. The distance that the water drops on its way to the power plant is known as the head. Increasing the head of your power plant will give the water more energy allowing it to produce more power from a smaller volume of water. Power plants with a head greater than 10 feet can often use smaller turbines that are cheaper and more efficient.

Dams

• Installing a dam is a useful way to regulate the amount of flow through your homemade power plant. Installing a dam will provide a reservoir of water that can generate power during dry spells and limit excessive flow rates. Water is routed to your power plant from the top of the dam through a pipe. Dams artificially increase the height of the stream's head, making your system more efficient. Although dams can make your power plant more effective, building a dam is an expensive process that requires extensive surveys and legal permits.

Diversions

• A diversion uses a length of pipe to divert part of the flow from a stream directly to the power plant's turbine. This system has the advantage of minimizing the ecological impact of your power plant but can not provide regular flow throughout the year. Diversions consist of a low concrete box with a screen, located upstream from your turbine. This box provides physical support for the pipe and uses a filter to prevent trash and debris from clogging the line.

Equipment

• Hydroelectric power plants use a water turbine and generator to create power. Water from the stream is diverted into the turbine which uses the energy from the moving water to turn the generator. There are two basic types of turbine known as impulse and reaction turbines. Reaction turbines consist of a wheel that is spun using a mass of moving water pushed through a duct surrounding the wheel. This type of turbine works well for power sources with a low head and a high level of water flow but require pressure seals and are typically more expensive. Impulse turbines convert the flow of water into a jet of water that strikes cups or buckets attached to the water wheel. Impulse turbines are more efficient for water sources with a high head and a lower water flow. Since the turbine is not sealed, it is generally easier to build and less expensive.

Considerations

• Water turbines and generators are often sold together since the speed and torque of the turbine has to match the requirements of the generator to avoid damaging it. You will also need to install a flow regulating valve in the pipes leading to the turbine to control the amount of water flowing into the turbine. And you'll need equipment to regulate the electrical output of your generator so that it will not create equipment-damaging power spikes. Micro hydroelectric plants often require a number of permits from state and federal agencies. Depending on the construction requirements and intended uses of your dam you may have to contact the Federal Energy Regulatory Commission or the Army Corp of Engineers in addition to state and county level regulatory bodies in your area.