What are the three largest sources of energy for the United States?

What are the three largest sources of energy for the United States?

• A. Nuclear, solar, and wind
• B. Coal, hydropower, geothermal
• C. Petroleum, coal, and natural gas
• D. Petroleum, natural gas, and coal

Answer: (D)

The main idea being tested is how energy is used across the whole economy, not just for electricity. Petroleum dominates because transportation consumes the largest share of energy, and most transportation fuels come from petroleum liquids like gasoline, diesel, and jet fuel. The second-largest source is natural gas, which powers a large portion of electricity generation and is widely used for heating and industrial processes. The third-largest is coal, which still provides a substantial chunk of electricity and industrial energy, even as its use declines in some sectors. Other options don’t fit because nuclear, solar, and wind contribute much smaller shares of total energy use, and while hydro is important for electricity, it typically contributes less to total primary energy than coal.

The main idea being tested is how energy is used across the whole economy, not just for electricity. Petroleum dominates because transportation consumes the largest share of energy, and most transportation fuels come from petroleum liquids like gasoline, diesel, and jet fuel. The second-largest source is natural gas, which powers a large portion of electricity generation and is widely used for heating and industrial processes. The third-largest is coal, which still provides a substantial chunk of electricity and industrial energy, even as its use declines in some sectors.

Other options don’t fit because nuclear, solar, and wind contribute much smaller shares of total energy use, and while hydro is important for electricity, it typically contributes less to total primary energy than coal.