Microhydro NY

Matt Deady, Professor of Physics, Director of the Physics Program, Bard College

The power calculator and mapping tools are just two ways of calculating maximum power. There are other tools that you can use to estimate maximum power, and to look at how changing the head or flow will affect the potential power output of a site.

The formula presented in Calculate Maximum Power is fairly straightforward, but there are other ways ways to look up and double check your power calculation. The table allows you to find the power by cross-referencing the flow rate (columns) with the head (rows). For instance, (h=3m , Q = 1.2m³/s) gives P = 35.3 kW, as expected, just a bit bigger than the calculated value using (h=2.7m , Q = 1.2m³/s); and (h=18m , Q = 1.2m³/s) gives P = 212 kW, as calculated. This table can also help to quickly see the difference in power output by changing the head and flow.

Table: Maximum Hydro Power (in kW) for Head and Flow

Or, you can use the graph to estimate the power by looking up the flow rate (x-axis) and head (y-axis). Lines of various values of power are plotted for reference, and can help to illustrate the head vs. flow trade-offs.

Note: This is a logarithmic graph, with the axis hash marks corresponding to values:

{ 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50 }

Figure: Maximum Hydro Power (in kW) for Head and Flow