Small Hydro Basics
Find out all you need with our small hydro introduction.
What are Small Hydro Systems?
Small HydroPower generation projects can be defined as a generating capacity of up to 10 Megawatts (mw) which further sub-divided into mini Hydro which is typically defined as up to 1 mw (1000 Kilowatts-kw) and a smaller micro Hydro up to 100kw. As a practical example micro hydro projects will typically supply enough power for from 5-100 homes, mini Hydro up to 1000 homes and a small hydro for a community of up to 10,000 homes.
Why Use Small Hydro?
Small hydro plants may be connected to conventional electrical distribution networks as a source of low-cost renewable energy. Alternatively, small Hydro projects may be built in isolated areas where there is no electrical distribution network. Since small Hydro projects usually have minimal reservoirs and civil construction work, they are seen as having a relatively low environmental impact.
How Does It Work?
Most small Hydro Systems operate a generator at an arbitrary frequency and feed its output through an inverter which produces output at grid frequency. Power electronics now allow the use of permanent magnet alternators that produce wild AC to be established. This approach allows low speed and low head water turbines to be competitive. They can run at the best speed for extraction of energy, and the power frequency is controlled by the electronics instead of the generator.