Steam power plants (PLTU) are the most common and widely used type of power plant worldwide. A PLTU converts the chemical energy stored in fuels (such as coal, natural gas, or oil) into electrical energy through a series of thermodynamic processes. This process uses high-pressure steam to turn a turbine, which then drives a generator. ♨️

Stages of the Steam Power Generation Process

The electricity generation process in a PLTU involves several main stages that are interconnected and form a closed cycle. Here is a detailed explanation:

1. Combustion and Steam Production

The first stage begins with the combustion of fuel in a boiler. Fuel, such as finely ground coal, is mixed with air and sprayed into the boiler. This combustion produces very high heat.

Steamp Boiler

The heat from this combustion is used to heat water flowing through pipes inside the boiler. The water boils and turns into high-pressure, high-temperature steam. This steam is known as superheated steam, possessing enormous kinetic energy.

2. Turbine Rotation

Superheated steam generated from the boiler is channeled through pipes to a steam turbine. A steam turbine consists of a series of blades mounted on a shaft. When the high-pressure steam strikes the turbine blades, the blades rotate at high speed. The kinetic energy of the steam is converted into mechanical energy in the form of rotation of the turbine shaft.

3. Generator and Energy Conversion

The turbine shaft is directly connected to an electric generator. As the turbine rotates, it drives a rotor inside the generator. A generator is a device that converts mechanical energy (rotation) into electrical energy through the principle of electromagnetic induction. Inside the generator, magnets rotate inside a coil of wire, creating a changing magnetic field, which ultimately produces an electric current.

4. Condensation and the Repetitive Cycle

After passing through the turbine, the pressure and temperature of the steam drop. This steam is not discharged but instead flows to a condenser. In the condenser, the steam is cooled by water from an external source (such as a river, lake, or cooling tower) until it returns to liquid water. This process is called condensation.

This liquid water is then pumped back to the boiler to be reheated, starting the cycle over. This water cycle repeats itself, allowing the coal-fired power plant to operate continuously.

5. Electricity Distribution

The electricity generated by the generator is fed to a transformer to increase the voltage. This high voltage allows the electricity to be distributed over long-distance transmission lines with minimal energy loss. After reaching a substation near the consumer, the voltage is stepped down again by the transformer to ensure safe use in homes and industries.

Advantages and Disadvantages of Coal-Fired Power Plants

Advantages

Large Capacity: Coal-fired power plants can generate very large and stable amounts of electricity, making them reliable as a primary source of electricity supply.

Low Fuel Costs: Fuels such as coal are relatively inexpensive and readily available in large quantities in many locations.

Continuous Operation: Unlike solar or hydroelectric power plants, which are dependent on the weather, coal-fired power plants can operate 24 hours a day.

Disadvantages

Air Pollution: Burning fossil fuels produces greenhouse gas emissions (carbon dioxide) and other pollutants (such as sulfur dioxide and nitrogen oxides), which contribute to climate change and health problems.

Reliance on Fossil Fuels: Coal-fired power plants rely heavily on non-renewable fossil fuels, which are limited in supply.

Ash Waste: Coal combustion produces solid ash waste that must be carefully managed.

Although coal-fired power plants have a significant environmental impact, modern technologies are being developed to improve efficiency and reduce emissions, such as the use of flue-gas desulfurization and carbon capture. However, the transition to cleaner energy sources remains a global priority.