A mini-hydroelectric power station is a plant that uses hydraulic energy to produce electricity. They are characterized by the fact of having a reduced installed power. Its small size implies the use of structures of much smaller size than a normal dam.
These mini-hydro plants are safer, thanks to the lower volume of water in the basin, and they also have a lower environmental impact and landscape.
There is no globally accepted limit for which a hydroelectric plant is defined as mini hydro. According to ESHA (European Association of Small Hydroelectric Power Plants), this limit is considered equal to 10 MW of installed power.
The mini hydro plant has some peculiarities compared to large hydro plants, as well as the advantages of using renewable energy.
- Limited investments: The construction of such a system generally takes place in running waters that do not require the construction of particularly expensive works (such as large dams). This allows for a quick return on investment.
- It allows an improvement of the hydrogeological conditions of the territory;
- Contributes to the reduction of the greenhouse effect and, therefore, benefits from green certificates for the production of energy from renewable sources
Like any hydroelectric plant, the construction of a small hydroelectric power station naturally requires an appropriate feasibility study.
How does a mini hydro power plant work?
The objective of a small hydroelectric power station is to take advantage of hydraulic energy; transform the potential energy of a waterfall into mechanical energy by means of a turbine. Then in electricity through an electric generator.
The installed power of the plant is a function of the flow of the turbinated water and the height of the fall.
The small river hydroelectric power plants are built on the river bed and are equipped with Kaplan jet turbines .
The unique power of each turbine can reach up to 50 MW.
In principle, jet turbines operate efficiently with amounts of water that vary over a very wide range, making them suitable for rivers and canals with constant water runoff.
Another variant of the Kaplan turbines that are widely used in small-scale hydroelectric plants are the Bulb turbines : double-regulated Kaplan turbines, in which the turbine and generator are integrated into a single housing called the "Bulb".
This design circumstance significantly increases the efficiency of the hydroelectric installation. The technology for the construction of a channel-type hydroelectric power station with the " Mobile Light Bulb Turbine " is also innovative .
Vortex Hydraulic Power Plant
This type of hydraulic power plant developed in Austria. It has immense potential and requires little technique, does not need a large slope to function. A water supply channel from a river to a basin allows the production of 80 to 130 MWh per year. Production depends on the amount of water and the depth of the basin.
The rotor works by the force of current and gravity, driving a generator that will produce electricity.
A hydraulic vortex hydraulic power plant can operate from a drop height of 0.7 meters and an average amount of water of 1000 liters per second.
This technology is practically safe for fish because they can safely pass through the small hydropower plant both upstream and downstream.
Advantages and disadvantages of mini-hydraulic power plants
Small hydroelectric power plants can be built with running water, potable water pipes, dam walls, and some irrigation channels in the irrigation system. They are suitable for remote consumers and adapt well to the environment without disturbing the ecological balance. Furthermore, they are relatively easy to connect to the power grid. The characteristic of this type of innovative hydroelectric power systems is that they also aerate the water.
A disadvantage is its strong dependence on rain, since in the schemes of small hydroelectric power plants, as a rule, no compensation deposits are provided. As a result, they have low effluent utilization rates (up to 60%). Last but not least, your energy production must meet the irrigation or water supply schedule when built on such systems.