Small-scale hydro plant and machinery review: report

Small Scale Hydro Electricity – Infrastructure

8. Small-scale hydropower has long been recognised by successive governments and energy experts as being one of the most long term cost-effective and reliable energy technologies to be considered for providing clean electricity generation. A typical run of river hydro scheme (without storage) generates electricity when water is diverted from a river through an intake at a weir. The water descends through a network of pipes and penstocks before driving a turbine which generates the electricity.

9. The main elements of a small-scale hydro scheme are shown below and includes the following process:

• Water is taken from the river by diverting it through an intake at a weir.
• In medium or high-head installations water may first be carried horizontally to an intake chamber by a small canal or 'leat'.
• The intake chamber is usually protected by a screen which filters out water-borne debris.
• A pressurised pipe, or 'penstock', conveys the water from the intake chamber to the turbine, which is enclosed in the powerhouse together with the generator and control equipment.
• After leaving the turbine, the water discharges down a 'tailrace' back into the river.