Electricity Generation and Distribution: Power Plants
Power Plants Producing Energy
The immediate need for large quantities of electricity requires power plants that convert primary energy into electrical energy. These facilities have driving machines and equipment to generate electricity.
Production, Transportation, and Energy Consumption
The main element of most power plants, except photovoltaic, is the electric generator or alternator that converts mechanical energy into electrical energy. Electricity is transferred from power stations to consumption centers using main lines, including transport and distribution lines, and transformer stations. A key disadvantage of electricity is that it cannot be stored; if not consumed, it is lost. Therefore, production must be regulated to match consumption.
Types of Power Plants
Power plants are classified based on their service in the overall consumption network:
Base Load Plants
These supply electricity continuously. They are usually high-power plants, including nuclear, large thermal, and hydroelectric plants.
Peak Load Plants
These meet energy demands during peak times, working in parallel with base load plants.
Reserve Power Plants
These replace the production of a base load plant in case of breakdown or repair.
Pumped Storage Plants
Hydroelectric plants use excess energy during off-peak periods to pump water to an upper reservoir, releasing it to generate electricity during peak demand.
Hydroelectric Power Plants
These harness the energy of rivers to convert water flow into electricity using turbines coupled to alternators. The energy transformations are:
- Potential energy (reservoir)
- Kinetic energy (pipe)
- Rotational kinetic energy (turbine)
- Electrical power (alternator)
- Consumption
There are two types:
Run-of-River Plants
Built where water power can directly drive turbines. These have low power output as the water flow is unregulated and can be irregular.
Storage Hydro Plants
Water is accumulated in a reservoir and used based on electricity needs. The terrain’s orography determines the plant’s design.
Diversion Plants
River water is diverted through a channel with a minimal slope. The water level difference between the channel and river increases with the channel’s length. Water is fed to a turbine through a pressurized pipe.
Storage Plants
A dam creates a reservoir, increasing the water’s potential energy. Water is released to drive turbines at the dam’s base.
Components of a Hydroelectric Plant
Key elements include water conductors, turbines, transformers, and a distribution park.
Dam
A structure, usually concrete, built across a river to raise the water level and form a reservoir. There are two types:
Gravity Dams
The stored water’s force is resisted by the dam’s weight. They have a triangular cross-section and require substantial material.
Arch Dams
A curved structure anchored to the river’s sides, transmitting forces to contain the water. They require less material than gravity dams.
Water Conductors
Dams have gates to regulate water flow to the turbines, protected by screens. Overflows and drains allow water evacuation without passing through turbines.
Engine Room
Houses the turboalternator groups. Different turbine types (Pelton, Francis, Kaplan) are used based on the water head and flow.
Transformers and Distribution Park
The alternator’s voltage is raised by transformers for efficient transport. The distribution park connects to the main grid via high-voltage lines.