Mega-dams are renewable or nonrenewable energy sources?

• A. Renewable
• B. Nonrenewable
• C. Inexhaustible
• D. Not an energy source

Answer: (B)

The key idea is how we judge renewability in energy sources. Mega-dams generate power from water that flows through turbines, and water is part of a cycle that replenishes itself, so hydroelectric power is often treated as renewable. However, the dam creates a finite reservoir of stored water. Over time, that storage can shrink due to sediment buildup, evaporation, and changing river flows, and droughts or shifts in watershed use can limit how much water is actually available for generation. In some curricula, that finite, potentially diminishing capacity makes mega-dams be viewed as nonrenewable in practice, especially when considering long-term sustainability and the need for ongoing maintenance and reshaping of the landscape to keep producing power. So the choice reflects that perspective, even though the underlying water resource is part of a renewable cycle. The other options don’t fit because the system does produce usable energy, and it isn’t considered inexhaustible on human timescales.