FRIDAY, FEB 3, 2023: NOTE TO FILE
Module 4-11
Hydroelectric Generation
Power is drawn from hydroelectric projects in relation to the hydraulic head (the height of the water above the generator) and volume of water available at a particular site to run through a generator. If a site has a good source of water, such as a dam, and a fall to a point where the generator can sit, a pipe or pipes can carry the water from the dam to the generator. The volume of water released from the pipe can control the power.
Siphon intake systems have advantages to reduce initial civil construction cost
Hydro Dam
The table below illustrates different design solutions for generating a 100 kW supply. If the head is low at 50 metres, the flow has to be high at 379 litres per second and the pipe to carry the water will be big at 610 mm diameter. However, if the head is 300 metres, the flow is only 63 litres per second and the pipe diameter 244 mm. The turbine efficiency is like the capacity factor of a wind generator, taking into account the energy losses in the pipe and the turbine.
Often rainfall is seasonal and the water level in the dam can run low. In this case, the output will be less as the flow is cut from the design optimum.
Rivers can now be harvested with floating turbine assemblies as illustrated. Often these can be quite small systems. If you have two dams or lakes with a small head between them, a siphon system can generate some useful power.
Module 4, lesson 12
