Micro Hydropower
Water flow can be harnessed on large and small scales in order to produce electricity. Water can be transported from its existing level to a lower level, resulting in higher water pressure. This water pressure can be used to move a mechanical component, converting the potential energy of the water into mechanical energy. In converting the water pressure into mechanical shaft power, hydro turbines can be used. This can drive an electric generator, grinding mill, or other effective device. Micro-hydropower has the capabiliy of producing up to100kW (with a minimum capability of producing 5 kW), which usually provides power for small communities or areas far away from the energy grid.
In determining the potential of the water flowing in a waterway, it is necessary to calculate the flow rate of the water and the head through which the water can fall. Water flow is the instantaneous amount of water flowing through a given point. The vertical height from the intake pipe down to the turbine is called the Head. The theoretical potential power can be found by taking the flow rate (Q), multiplying it by the Head (H) and the gravity constant (9.81 m/s 2).
P = 9.81 x Q x H (kW)
Due to frictional losses in either the intake pipe or the penstock and low efficiency levels in low production turbines, the efficiency of micro hydropower is often about 50% of its theoretical power.
Water flow is greater around winter time, yielding higher productions. Photovoltaic systems are often at their lowest point of efficiency during this time of year. Due to this occurrence, many micro hydropower systems are complimented with photovoltaic systems.