What happens to the efficiency of hydroelectric power plants compared to traditional fossil fuel plants?

Hydroelectric power plants often demonstrate higher efficiency compared to traditional fossil fuel plants. This is primarily because the conversion of potential energy from water into mechanical energy (and subsequently into electrical energy) in hydro turbines is typically more efficient than the thermal processes involved in fossil fuel combustion.

In hydroelectric systems, the efficiency can frequently be above 90%, while fossil fuel plants may see efficiencies in the range of 33% to 45% for conventional steam cycles. This difference arises due to energy losses associated with combustion, heat transfer and other inefficiencies in converting chemical energy to electrical energy in fossil fuel systems.

Considering this, the statement that hydroelectric plants are equally efficient as fossil fuel plants does not reflect the reality of their operational efficiencies. Thus, while fluctuating efficiencies can be part of both systems depending on operational conditions (like water availability for hydropower), the overall efficiency typically favors hydroelectric generation significantly more than fossil fuels.