There are many ways to produce energy, depending on the type of fuel used and the location or method used. Conventional thermal power plants, also known as thermoelectric plants, use fossil fuels to generate electricity. Many people do not know what a thermal power plant is.
We are going to dedicate this article to telling you what a thermal power plant is, what its characteristics are and how they generate electrical energy.
What is a thermal power plant?
The conventional thermal power plants, also known as thermal power plants, use fossil fuels (natural gas, coal or fuel oil) to generate electricity through a thermal water vapor cycle. The term "conventional" is used to distinguish them from other thermal power plants, such as combined cycle or nuclear power plants. These plants generate electrical energy by converting the chemical energy of fuels into thermal energy, which is then transformed into mechanical energy and finally into electricity.
Its main components are:
- Boiler: Space that converts water into steam by burning fuel. In this process, the chemical energy of the fuel is converted into thermal energy.
- Coils: Pipes through which water circulates, where it is converted into steam. The combustion gas transfers its heat to the water.
- Steam turbine: Machine that collects steam, causing the shaft that runs through the turbine to move due to a pressure and temperature system. These turbines usually have several bodies (high, medium and low pressure) to make the most of the steam.
- Generator: Machine that converts mechanical energy generated into electricity by means of electromagnetic induction. The turbine shaft is connected to the generator, which produces three-phase alternating current.
Operation of a thermal power plant
The operation of a conventional thermal power plant can be divided into several stages. First, the fuel It is burned in a boiler generating a large amount of heat. This heat is used to to heat water, which is converted into high pressure and temperature steam.
This steam is sent to the turbines, where it exerts pressure on the turbine blades, causing them to spin. turbine movement generates mechanical energy, which is finally transformed into electrical energy in the generator.
The electricity generated passes through a transformer, where its voltage is increased to be distributed over long distances via the electrical grid.
Steam, once used in the turbine, is sent to a condenser where it is cooled and converted back into water, resulting in a closed cycle of steam production. This process is common to all thermal power plants, regardless of the type of fuel used.
Types of cycles in a thermal power plant
- The Rankine cycle: Used in most conventional thermal power plants, this cycle uses the thermal energy of the fuel to generate steam, which then drives a turbine.
- Hirn Cycle: It is a variant of the Rankine cycle, with an additional steam reheating phase. This process improves energy efficiency.
Environmental impacts of a thermal power plant
Thermal power plants generate negative effects on the environment due to emissions derived from the burning of fossil fuels and the release of large amounts of waste heat.
In terms of emissions, these plants produce carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), and sulfur dioxide (SO2), which contribute to global warming and air pollution. Other toxic elements such as mercury and lead may be released.
Filters are used to reduce the amount of particles emitted into the atmosphere, and chimneys are usually tall enough to better disperse particles into the air.
Heat transfer and thermal pollution
Another associated problem is thermal pollution due to the release of residual heat into nearby bodies of water. This raises the temperature of the water, affecting the local ecosystem. Power plants implement cooling systems to mitigate this impact, cooling the water before returning it to its source.
Impact on human health
Pollutants emitted by thermal power plants have a negative impact on human health. Toxic particles and gases produced by combustion can cause respiratory and cardiovascular diseases. In the long term, exposure to these substances increases the risk of cancer.
Current filters and systems have improved, although new technologies still need to be developed to minimise the impact on health and the environment.
Types of thermal power plants
There are different types of thermal power plants, depending on the fuel used and the plant design.
Conventional thermal power plants
They use fossil fuels such as coal, fuel oil or natural gas. Although they are common worldwide, their environmental impact is considerable due to the emissions of polluting gases.
Combined cycle thermal power plants
The combined cycle power plants They are more efficient than conventional ones. They use gas turbines to transform thermal energy into mechanical energy by burning natural gas. The excess hot gases are used to generate steam that feeds another steam turbine, reducing emissions.
Nuclear thermal power plants
They generate energy through the Nuclear fision in a reactor, which releases a large amount of thermal energy to convert water into steam. Although they do not emit greenhouse gases, they pose risks due to radioactive waste and possible nuclear accidents.
Alternatives and renewable energies
The renewable energy, such as solar, wind and geothermal, are gaining ground. These sources do not produce greenhouse gas emissions and are more sustainable in the long term.
Solar thermal and geothermal power plants offer similar alternatives to conventional thermal power plants, taking advantage of natural sources without the negative impacts associated with fossil fuels.
Technological improvements are increasing efficiency and reducing costs, allowing for accelerated adoption worldwide.
Steam power plant
The steam power plants They use a cycle in which the water goes through a vapor phase and returns to its liquid state. This is common in conventional thermal power plants.
Supercritical technology has gained relevance, improving efficiency and reducing energy losses by eliminating phase changes.
They are one of the main technologies in electricity production, although the growth of renewable energies is beginning to gradually replace them.
The energy sector is undergoing a profound transformation. Thermal power plants are still relevant, but renewable energies are already taking the lead in many countries, thanks to their lower environmental impact and high growth potential.