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→Listing of the main elements of an installation
#: the turbine room of the facility, is a kind of wheel that is rotated by the flow of water flowing through it. The type of wheel is to be chosen depending of the given instantaneous waterflow, but also depending of the water pressure. Some of these turbines resemble the old bucketwheels are particularly suitable for plants that need to operate with significant waterflow variations. The turbines may be vertical or horizontal axis.
#: The speed regulator controls the speed of the turbine. In times of normal operation, speed is a balance between the hydraulic load that turns the turbine and the resistive load of the electricity production. In case of a ruptured electrical circuit, the resistive electrical is canceled and the speed of the turbine will accelerate because the hydraulic load remains unchanged. Too much speed can be fatal to the equipment and the presence of the regulator corrects the beginning of the acceleration also called the runaway.
Other equipment to provide is an sand trap on the feeder canal. The grains of sand that accompany the water on the turbine have an abrasive effect that reduces the life of the machine. The biggest materials (stones, bricks) have an even more destructive effect and gratings should be installed at the entrance to the intake line but also at the penstock to prevent such incidents.
When a need of power emerges, we should seek one site or several sites that could host a hydroelectric powerplant. We understand that the research begins by identifying all sources of energy such as wind, solar, biomass and so on. Our preposition considers the conclusion of this inventory as a preceeding to the decision to install a hydroelectric plant, perhaps in addition to wind turbines or solar energy collectors.
A power plant demands a drop height and a waterflow. Terrain reconnaissance on the field or on topographic map pinpoints the locations of both waterflow and a slope of the terrain. These spots are easily identified on the ground where the river flows torrentially but other locations may also be appropriate.The extent of the drop is easily to determine for a surveyor by means of a theodolite. However, the estimation of the available waterflow is much more difficult because of its variation depending on the season (see instantaneous flow and low waterflow above). It is wise to underestimate the rate available because the powerplant should also not take off all water from the network. For example, in complete removal, the aquatic biotope will be severely disrupted by lack of water and make the spawning of fish impossible. Therefore, a reserve of waterflow should be left in the river to avoid biological depletion. It is possible that other -already authorized- waterusages impose a higher reserve waterflow.
When several sites are identified, the remoteness of the consumer is another criteria for inclusion in the feasibility analysis. Remoteness means a longer power line and makes monitoring of the plant more difficult. An electrical power line represents a important expense and is a source of powerloss.
The following mathematical formula allow to estimate the hydropower potential:
P=10 x Q x H x r
It is difficult at first to estimate the effective electricity output since it depends on the project which is associated with the construction of the hydroelectric powerplant. It is known that the provision of electricity promotes its use. Without any regulation system of the consumption (limiting the amount available to the consumer via electrical switchboard, billing of the consumption).
The lighting of offices is an important element for the development of the electricity grid, as well as the sponsoring of communication facilities such as the telephone network, operation of television channels, computers. The electrical energy is also useful to activate the cooling chain (storage of medicines, vaccines ...). Foremost, we must exclude, in the context of a micro-powerplant, thel use of electricity as a means of heating because consumers will become prohibitive for the small network.
It is also possible to set, among the regular customers of a small network, priority clients such as those that manage a cooling chain for vaccines and drugs, or a surgical hospital. These customers will be supplied as long as possible. These provisions should be exposed to all users as a way to maintain cohesion and avoid conflicts. This regulating system allows to supply electricity to more customers but for a more limited period.
The area of the water intake in the river is to be avoided by the other users of the river (risk of getting caught up in the waterflow and risk of drowning); intake channel may be used for other purposes (laundry, irrigation), the manager informs the public to incidents such as blocked grates, overflow, etc ... The practice of bathing is regulated or prohibited in the absence of a basin with restraints to prevent the risk of drowning or sudden spills of large volumes of water.
Information on the dangers of electrocution will be presented at both the facility and at the home.
From an average unit cost of 2000 €/kW installed, it is easy to estimate the investment budget for 10, 100 or 1000kW, as being € 20,000 to € 2,000,000. On the other hand, pico-powerplants of 300W are sold in Vietnam for U.S.D. $20 and are very popular.
It is likely that the complexity of a facility of more than 100kW extends the delay of realisation because of forgoing feasibility studies, which probably increases the quality and reliability of the project.
Compact installation kits are sold in commerce, requiring only a minimum of know-how for the installation. This equipment series offers the advantage of being available quickly and to be well calibrated for operating conditions. Unless you have control of all parameters (location, project funding, expertise for the construction of infrastructure), an installation project requires several years between the first sketches on paper and the effective operation of the distribution network.
The Chinese authorities have helped a great amount of areas removed or isolated from major electricity distribution networks in acquiring small powerplants. Similar projects have been developed, especially in Kenya.
These measures allow the local population to develop activities that meet their expectations and to avoid, for example, migration to the already congested suburbs of major cities. These populations can emerge from the isolation, communicate with the rest of the world and participate in the evolution.