Run-of-River Hydro » How it works
Location & natural factors
The energy available from a hydropower scheme is proportional to the amount of water flowing in the river and the pressure (head) at the turbine. Each scheme is unique, since the local topography and river catchment are unique. Although more water is available, a large river from a large catchment will generally run on a flatter gradient than a more upland river with a smaller catchment, leading to some balancing of factors contributing to power output. Figure 1 shows power rating as a function of available head and flow of schemes that Shawater have been involved in recently.
Traditional pumped storage schemes operate with significant head and water flow due to the modified topography arising from the use of Dams, and hence produce significantly higher output than would otherwise be available. Shawater Limited specialises in schemes more in harmony with the natural environment, i.e. with no landscape enhancement. This type of hydro-scheme comes under the “run-of-river” category.
Some upland areas of the UK are ideal for small run-of-river schemes. Steep topography produces a relatively large head per metre of installed pipeline. Furthermore, high-head, low-flow schemes require smaller, faster generating equipment than vice-versa. Providing nearby grid connection is available, small upland run-of-river hydro is an economically attractive form of generating renewable energy.
Once a site has been chosen a decision must be made to fix the intake, powerhouse and outfall locations. Contributing factors include: Visibility; Gradient; Riverbed Profile; Accessibility; Land Ownership; Grid Connection, Access and Geology, however a good solution can almost always be found.