A small, low head dam used to raise the river’s water level and divert part of its flow to the millrace of a small hydropower plant. Weirs can complicate fish migration, so in some countries weirs are complemented with fish ladders.

Even a small river not suitable for building a large concrete dam with huge turbines could be used for electricity production.

Gates that can close a penstock or regulate water intake to the turbine. Several types of gates can be used, e.g. radial gates or vertical-lift wheeled gates.

Small hydropower plants are defined as projects that generate between 100 kilowatts and 10 MW of power.

Steel bars designed to catch larger impurities, like branches or plastic bottles, which could harm the turbine.

A house situated at one side of the river, sitting above a penstock, housing a turbine and generator.

An inlet guide vane divides and directs the flow so that the water enters the runner smoothly and hits the blades at the proper angle to maximize efficiency.

The electric generator is connected to the turbine by a shaft and transfers its rotational energy into electric current.

Water is directed onto the turbine through a nozzle that creates a flat sheet of water.

The guide vane can be set by control levers.

Crossflow turbines, sometimes known as Banki-Mitchell or Ossberger turbines, are a type of hydro turbine that tends to be used in smaller hydroelectric sites. These turbines are usually chosen for heads below 40 meters where they are more efficient. Crossflow turbines get energy from water by reducing its velocity, while the pressure stays the same. Crossflow turbines consist of a cylindrical runner surrounded by a 'cage' of blades (up to 37) arranged into a water wheel shape. Water is directed onto the turbine through a nozzle that creates a flat sheet of water, and then is directed onto the blades using a guide vane. Water first hits the blades and moves to the inside of the turbine, with the water hitting the blades one more time as the water exits the central part of the turbine. The first impact passes more energy to the blades than the second one.