AP Environmental Science Unit 6 Essentials

Fossil fuels and nuclear power provide reliable, on-demand baseload electricity but carry significant environmental costs — combustion emissions for fossil fuels, radioactive waste for nuclear. Solar and wind are clean during operation but intermittent, requiring storage or backup. No energy source is free of tradeoffs; understanding the specific tradeoff for each source is the core skill this unit tests.

Geothermal energy only makes economic sense near tectonically active regions (a direct connection to Unit 4's plate tectonics); hydroelectric power requires consistent river flow; wind and solar depend on local climate and weather patterns. This means there is no single "best" renewable energy source — the right choice depends entirely on a region's physical geography.

Energy conservation and efficiency improvements reduce the total amount of energy that needs to be generated in the first place — avoiding the environmental cost of generation entirely, regardless of source. This is why conservation is sometimes called the "first fuel": it's typically the cheapest and fastest way to reduce energy-related environmental impact, compared to building new (even renewable) generation capacity.