Renewable & Nonrenewable Energy Sources (College Board AP® Environmental Science) : Study Guide

Nonrenewable energy sources

• Nonrenewable energy sources are finite and will eventually run out

• Fossil fuels are the remains of fossilized plants and animals from millions of years ago and include:

  • coal

  • crude oil, which is refined into petrol, diesel and other fuels

  • natural gas (mostly methane), which is used in domestic boilers and cookers

• Chemical energy stored in fossil fuels originally came from sunlight

  • Energy from the sun was transferred to chemical energy stores within plants through photosynthesis (plants use energy from sunlight to make food)

  • Animals ate the plants and the energy was then transferred to their chemical store

• Nuclear energy is generated from radioactive fuels such as uranium

• In the U.S., current energy demand is mostly from nonrenewable energy sources

Renewable energy sources

• Renewable energy sources can be replenished naturally at or near the rate of consumption and reused

• They include:

  • hydroelectric

  • wave/tidal

  • wind

  • solar

  • geothermal

  • biomass/waste

• There are two types of renewable energy sources

  • Depletable

  • Nondepletable

• Depletable renewables can run out if overconsumed, such as biomass (ethanol, wood, etc.)

• Nondepletable are infinite and include solar, wind, hydro, etc.

Life cycle assessment (LCA)

• LCAs look at how renewable energy systems affect the environment at all stages of their lives, from extracting raw materials to installing, running, maintaining, disposing, or reusing them

• This analysis helps policymakers make better choices about how to promote sustainable energy