Thermal energy is produced by which source in typical power plants?

• A. Fossil fuels
• B. Solar panels
• C. Nuclear fusion
• D. Wind turbines

Answer: (A)

The main idea is how heat is generated to drive electricity production. In many power plants, the thermal energy comes from burning a fuel. The heat from combustion boils water to create steam, and that steam pushes a turbine connected to a generator, converting heat into electrical energy. Fossil fuels are used widely because they release a large amount of energy when burned and can be burned in large, controllable furnaces to produce steady steam. The other options don’t fit the typical process: solar panels convert sunlight directly into electricity rather than providing the heat for a steam cycle; nuclear fusion isn’t used in commercial power plants (they rely on nuclear fission for heat); and wind turbines generate electricity from moving air without producing the steam-cycle heat.