The basic premise of small hydro is to minimize impact on the surrounding environment. To that end several technologies; all variations of the fundamental waterwheel principal have been developed. For the applications envisioned in this proposal, run of the river systems or systems with dams, already constructed (earthen dams included) are being proposed.
The above diagram illustrates the typical run of the river system, identifying all the essential elements of a small hydro system. No elaborate civil works is required.
Simply a small diversional canal is built to supply the penstock, which depending on the height from which the water falls, The HEAD, determines the power produced from the turbine and generator sets in the power house. A run-of-the-river system uses the river’s natural flow and requires little or no impoundment. It may involve a diversion of a portion of the stream through a canal or penstock, or it may involve placement of a turbine right in the stream channel. Run-of-the-river systems are often low-head.
Most current hydroelectric projects require a large hydraulic head to drive power turbines. Required hydraulic head usually created by constructing a dam in a river bed, creating a reservoir. A hydraulic control tower is constructed towards the opposite end of the reservoir and a pressure pipe line (penstock) is drawn to the power house at the other end.
Another distinct advantage of this method is that we can find so many new locations for hydro power generation that cannot be utilized by the presently known hydro power generation techniques.
Where there are earthen dams already built a, there is already an impoundment area where the water is stored so the stored water can be used to power the turbine as illustrated here.
An impoundment is simply a dam that holds water in a reservoir. The water is released when needed through a penstock, to drive the turbine. This illustration shows the parts of a standard hydroelectric dam. Most large, high-head hydropower facilities use impoundments.
The operational management of the development and management process is summarized by the graphic below. It is based on a US model but the process is essentially the same globally.
Typical the preconstruction phase is longer than the actual construction of the works. However, one of the advantages of the Power Purchase agreement model. Financing can be secured soon after issuance and execution of a power purchase agreement (PPA), very early in the process, Accelerating the procurement process and enabling concurrent development of the civil works and equipment manufacture, since almost certainly the equipment will have to be custom made for the specific application.