A Thermal Power Plant is a power generating station that uses fossil fuels (like coal, oil, or natural gas) to produce steam, which drives a steam turbine connected to a generator to produce electricity.
Construction:
The main components of a thermal power plant are:
- Boiler – Burns coal to generate heat
- Chimney – Expels filtered flue gases
- Steam Turbine – Converts steam energy to mechanical energy
- Generator – Converts mechanical energy to electrical energy
- Condenser – Cools the exhaust steam
- Cooling Tower – Recycles cooling water
- Feed Water Pump – Circulates water in the system
- Heat Exchanger – Transfers heat from steam to cooling water
These components are arranged as per the plant layout to allow continuous cyclic operation.
Working Principle:
The plant works based on the Rankine Cycle, which involves the conversion of thermal energy to mechanical energy, and finally to electrical energy.
Step-by-step Working:
- Fuel Combustion:
- Coal is burned in the boiler, releasing heat and smoke.
- Smoke is filtered and expelled through the chimney.
- Water to Steam Conversion:
- Cold water is pumped into the boiler using a feed pump.
- Heat from combustion turns the water into high-pressure steam.
- Steam Turbine Operation:
- The steam is passed through a turbine.
- Steam’s kinetic energy rotates the turbine blades.
- Electricity Generation:
- The rotating turbine shaft is coupled with a generator, producing electricity.
- Steam Condensation:
- The low-pressure steam exiting the turbine is sent to a condenser, where it’s cooled down by water from the cooling tower.
- Water Recycling:
- The condensed water is recycled back to the boiler, and the cycle repeats.
♻️ The cooling tower helps maintain efficiency by keeping the condenser water cool using air circulation.
Advantages of Thermal Power Plant:
- ✅ Low initial cost compared to other power stations
- ✅ Requires less land than hydroelectric plants
- ✅ Coal is a relatively cheap and easily available fuel
- ✅ Generation cost is lower than diesel-based plants
Disadvantages:
- Pollutes the atmosphere by emitting CO₂ and smoke → contributes to global warming
- Low efficiency – typically below 30% due to energy losses
- High fuel consumption over time
- Large water requirement for cooling purposes