THERMAL ELECTRICITY :-

1)It is generated from petroleum(oil) or coal.
2)Its sources (coal and oil) are exhaustible.
3)On burning coal and oil they cause a lot of pollution.
4)It is expensive in the long run.

HYDRO ELECTRICITY :-

1)It is generated from water falling on turbines.
2)Its source is perennial, i.e. inexhaustible.
3)It causes no pollution.
4)It is cheaper in the long run.

Hydroelectricity vs Thermal Electricity: Differences and Explanation

Introduction:
Hydroelectricity and thermal electricity are two different methods of generating electrical power. While hydroelectricity harnesses the power of flowing or falling water, thermal electricity relies on the combustion of fossil fuels or the use of nuclear energy to generate steam and drive turbines. Let's explore the differences between these two sources of electricity in detail.

1. Source of Energy:
- Hydroelectricity: It is derived from the potential energy of water, which is converted into kinetic energy as it flows or falls through turbines.
- Thermal Electricity: It primarily relies on fossil fuels like coal, oil, or natural gas, which are burned to produce heat. Alternatively, nuclear energy can also be used to generate steam.

2. Environmental Impact:
- Hydroelectricity: It is considered a renewable and clean source of energy as it does not produce greenhouse gas emissions during operation. However, the construction of dams for hydroelectric power plants can have significant environmental impacts, such as habitat destruction and altered water flow patterns.
- Thermal Electricity: The combustion of fossil fuels in thermal power plants releases carbon dioxide (CO2) and other pollutants, contributing to climate change and air pollution. Additionally, the extraction and transportation of fossil fuels have adverse environmental effects, including habitat destruction and water pollution.

3. Efficiency:
- Hydroelectricity: Hydroelectric power plants are highly efficient, with conversion efficiencies ranging from 80% to 90%. This means that a significant amount of the potential energy of water can be converted into electrical energy.
- Thermal Electricity: Thermal power plants have lower efficiency compared to hydroelectric plants, typically around 30% to 40%. This is due to the energy losses during the conversion of heat into mechanical energy and then into electrical energy.

4. Reliability:
- Hydroelectricity: Hydroelectric power plants are generally more reliable as they can operate continuously, provided there is a consistent water supply. They are not affected by fluctuations in fuel availability.
- Thermal Electricity: Thermal power plants heavily rely on the constant availability of fuel, which might be subject to price volatility or interruptions in supply. Any disruption in the fuel supply can result in power outages.

5. Scalability:
- Hydroelectricity: The scalability of hydroelectric power plants is limited by suitable water resources and the availability of suitable locations for dam construction. Building large-scale hydroelectric plants requires extensive planning and infrastructure development.
- Thermal Electricity: Thermal power plants can be constructed in various sizes and can be easily scaled up or down based on the demand for electricity. However, expanding thermal power capacity also requires access to sufficient fuel resources.

Conclusion:
In summary, hydroelectricity and thermal electricity differ in terms of their energy sources, environmental impact, efficiency, reliability, and scalability. While hydroelectricity is a renewable and clean energy source, thermal electricity relies on fossil fuels or nuclear energy. Both have their advantages and disadvantages, and the choice between them depends on factors such as geographical location, resource availability, and environmental considerations.