The correct answer is: a) Coal.
Coal is the primary fuel used in thermal power plants in Tamil Nadu. In 2019, coal accounted for 86% of the total electricity generated in the state from thermal power plants. Lignite, natural gas, and hydropower are also used in thermal power plants in Tamil Nadu, but to a lesser extent.
Coal is a fossil fuel that is formed from the remains of ancient plants and animals. It is a non-renewable resource, meaning that it cannot be replaced once it is used up. Coal is a major source of greenhouse gas emissions, which contribute to climate change.
Lignite is a type of coal that is less mature than bituminous coal. It is brown in color and has a high moisture content. Lignite is a lower-quality fuel than bituminous coal and has a lower energy content.
Natural gas is a fossil fuel that is formed from the remains of ancient plants and animals. It is a non-renewable resource, meaning that it cannot be replaced once it is used up. Natural gas is a cleaner-burning fuel than coal and emits fewer greenhouse gas emissions.
Hydropower is a renewable energy source that uses the power of moving water to generate electricity. Hydropower is a clean and efficient source of energy, but it can have a negative impact on the environment. Dams can disrupt the flow of rivers and streams, and they can also displace people and wildlife.
In conclusion, the thermal power plants in Tamil Nadu primarily utilize coal. Coal is a fossil fuel that is formed from the remains of ancient plants and animals. It is a non-renewable resource, meaning that it cannot be replaced once it is used up. Coal is a major source of greenhouse gas emissions, which contribute to climate change.