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Microhydropower System Components

Run-of-the-river microhydropower systems consist of these basic components:

  • Water conveyance—channel, pipeline, or pressurized pipeline (penstock) that delivers the water
  • Turbine, pump, or waterwheel—transforms the energy of flowing water into rotational energy
  • Alternator or generator—transforms the rotational energy into electricity
  • Regulator—controls the generator
  • Wiring—delivers the electricity.
Diagram of a microhydropower system in a downhill stream. At the top of the hill is a tank called a forebay. A pipe going down the hill connects the forebay to a small building called a powerhouse, which holds the fan-like turbine. The vertical distance the water falls from the forebay to the turbine is called the head. Just beyond the powerhouse at the base of the hill is a small pool.

Head is the vertical distance the water falls. Higher heads require less water to produce a given amount of power.

Commercially available turbines and generators are usually sold as a package. Do-it-yourself systems require careful matching of a generator with the turbine horsepower and speed.

Many systems also use an inverter to convert the low-voltage direct current (DC) electricity produced by the system into 120 or 240 volts of alternating current (AC) electricity. (Alternatively, you can buy household appliances that run on DC electricity.)

Whether a microhydropower system will be grid-connected or stand-alone will determine many of its balance of system components.

For example, some stand-alone systems use batteries to store the electricity generated by the system. However, because hydropower resources tend to be more seasonal in nature than wind or solar resources, batteries may not always be practical for microhydropower systems. If you do use batteries, they should be located as close to the turbine as possible because it is difficult to transmit low-voltage power over long distances.