State four of the transformation of energy which occurs at a power station which uses coal as its fuel. Account for the energy losses.
At a power station that uses coal as its fuel, the transformation of energy goes through several stages. Here are four of the main transformations along with an explanation of the energy losses that occur:
1. Chemical to Thermal Energy (Combustion): Coal is burned in a furnace, which releases chemical energy stored in the coal as heat. This transformation involves the conversion of chemical energy to thermal energy. However, this process is not completely efficient, and there are energy losses due to incomplete combustion and heat losses in the flue gases and combustion chamber.
2. Thermal to Mechanical Energy (Steam Generation): The heat from the combustion of coal is used to boil water and produce steam. The steam then expands against the blades of a turbine, causing them to rotate. The turbine is connected to a generator, which converts the mechanical energy of the rotating turbine into electrical energy. In this transformation, some energy is lost as heat in the process of generating steam, and there are mechanical losses due to friction in the turbine and generator.
3. Mechanical to Electrical Energy (Generator): As mentioned earlier, the rotating turbine is connected to a generator. Inside the generator, the mechanical energy from the turbine is converted into electrical energy through electromagnetic induction. However, this process is not perfect, and there are losses due to resistance in the generator windings, friction in the rotating parts, and electromagnetic losses.
4. Electrical Transmission and Distribution: Once electricity is generated, it is transmitted through power lines to consumers. During this transmission and distribution process, there are energy losses due to resistance in the power lines, called line losses. These losses occur due to the heating effect of current traveling through the wires, and they can vary based on the length and quality of the power lines.
Overall, these energy transformations involve various losses at each stage, including incomplete combustion, heat losses, mechanical losses, electromagnetic losses, and line losses. These losses contribute to the overall inefficiencies of converting coal's chemical energy into usable electrical energy.