What is thermal power? A glance at thermal power plant

1.1 What is thermal power?

Thermal power generation is a method of producing electricity by converting thermal energy into electrical energy. This process typically involves using steam or hot water to generate kinetic energy, which is then transmitted through a turbine to produce electricity. Thermal power can be generated from various natural and artificial energy sources. Some of the main sources include:

• Fossil fuels: Coal, oil, and natural gas are burned to generate heat energy.
• Solar energy: Sunlight is absorbed to produce heat, particularly in solar power plants.
• Geothermal energy: Heat from within the Earth's core is harnessed through geothermal energy systems.
• Biomass energy: Organic materials such as wood and waste are burned to generate energy.

Although renewable energy is expected to grow significantly in the coming years and dependence on thermal power - especially coal - needs to be reduced, thermal power will still play a crucial role in meeting energy demands in the near future. Overall, thermal power remains an essential part of the national electricity system. However, to ensure sustainability and minimize environmental impact, modern technologies must be applied, and alternative energy sources should be integrated.

1.2 Common types of thermal power

Based on the type of fuel or energy source used, thermal power can be classified into several categories. Some of the most common types include:

• Coal-fired thermal power: This is the most widely used form of thermal power in Vietnam, utilizing coal as a heat source to generate electricity. However, its major drawback is CO₂ and fine particle emissions, which contribute to environmental pollution. Vietnam is also on a transition pathway to reduce carbon emissions from coal-fired power plants.
• Liquefied Natural Gas (LNG) thermal power: This type of power generation uses natural gas (primarily methane) as fuel, which is burned to produce the heat needed for electricity generation. In key economic regions such as Quang Ninh and Nhon Trach, gas-fired power projects have been identified as important targets for development.
• Biomass thermal power: This method utilizes biomass and certain industrial waste of biological origin as fuel. With abundant biomass resources, Vietnam's market holds great potential for developing this clean energy source.
• Concentrated Solar Power (CSP): This system converts sunlight into thermal energy. It is particularly suitable for regions with high levels of direct solar radiation.

>>See more: What are the advantages and disadvantages of solar energy

2.1 What is a thermal power plant? How does it work?

A thermal power plant generates electricity by burning fossil fuels such as coal, oil, or natural gas. The heat produced from fuel combustion is used to create steam, which then drives a turbine to generate electricity. After completing its work, the steam is cooled, condensed back into water, and reused in the production cycle.

The power generation process in a thermal power plant includes the following steps:

• Fuel combustion to generate heat: The process begins by producing high temperatures through the combustion of fossil fuels (coal, natural gas) or through nuclear reactions. In some industries, electric boilers are also used.
• Boiling water: This heat is used to boil water in a high-pressure boiler, creating high-energy steam.
• Steam drives the turbine: The high-pressure steam is directed into a steam turbine, causing its blades to spin like a giant fan. The turbine is directly connected to a generator.
• Conversion of mechanical energy into electrical energy: As the turbine rotates, the generator converts kinetic energy into electrical energy, supplying power to the national grid.
• Heat recycling: After performing its function, the steam exits the turbine at low pressure but still retains heat.
• Cooling and reuse: The steam is directed into a condenser, where it is cooled and converted back into water. This water is then returned to the boiler, starting the cycle anew.

This process operates continuously, enabling the production of large amounts of electricity to meet energy demands.

2.2 Components of thermal power plant

To complete the complex electricity generation cycle, a thermal power plant requires the coordination of multiple components. Some of the key components include:

• Boiler: This is a crucial component of a thermal power plant, where fuel is burned to generate high-pressure steam for electricity production. Depending on design and application, boilers are categorized into different types, with the most common being water tube boilers and fire tube boilers.
• Steam turbine: This component converts the thermal energy of steam into mechanical energy to drive the generator.
• Generator: The generator converts the mechanical energy from the turbine into electrical energy for industrial and residential use. When the turbine rotates, it drives the generator’s rotor, which spins at high speed. The spinning rotor generates a rotating magnetic field around the stator windings, inducing an alternating current (AC). This AC electricity is then regulated and transformed to an appropriate voltage level before being transmitted through the power grid.
• Condenser: This system contains cooling water pipes that absorb heat from the steam, reducing its temperature and causing it to condense into liquid water. The condensed water is collected and pumped back to the boiler to continue the power generation cycle.
• Additional systems: Other essential components include the fuel processing system, flue gas treatment system, control and monitoring system…

3.1 Advantages of thermal power

• Stable power supply, independent of weather conditions: Unlike hydropower or wind energy, thermal power plants can operate continuously without being affected by weather conditions such as droughts or weak winds. This ensures a reliable electricity supply for industrial and residential use.
• Low production costs: The use of inexpensive fuels such as coal, lignite, and peat helps reduce the cost of electricity generation. This enhances the competitiveness of thermal power plants in the energy market.
• Short construction time: Compared to other types of power generation, thermal power plants can be built and put into operation relatively quickly, ensuring a timely electricity supply for consumption and industrial production.
• Enhanced national energy security: In countries with abundant coal, oil, and gas reserves, such as Vietnam, thermal power helps reduce dependence on imported energy sources.

4.1 Requirement for cables used in thermal power plants

Electric cables play a crucial role in thermal power plants, ensuring the transmission of electricity from the power source to distribution networks and electrical equipment. To support continuous, safe, and efficient operation, electrical cables in thermal power plants must meet strict technical standards and specifications. Key requirements include:

• High heat resistance: Thermal power plants operate in high-temperature environments, especially around boilers and turbines. Therefore, cables must have high-quality insulation to withstand extreme temperatures.
• Corrosion and moisture resistance: Cables must be resistant to oxidation, chemical corrosion, steam, and other environmental factors.
• Excellent insulation properties: To ensure safety, cables must meet insulation standards that minimize the risk of electrical leakage and fire hazards.
• High mechanical strength: Electric cables in thermal power plants must have a robust structure, capable of withstanding vibrations and heavy loads during installation and operation.
• Flexibility: Certain areas within thermal power plants have complex wiring systems, requiring cables that are flexible enough to bend without compromising electrical transmission quality.