AP Environmental Science: Unit 6 Review - Energy 

Renewable and Nonrenewable 

• nonrenewable - those that exist in a fixed amount (ex. nuclear, coal, oil, natural gas)
• renewable - can be replenished naturally (ex. biomass, solar, geothermal)

Global Energy Consumption

• as the world becomes more industrialized the demand for energy increases
• developed countries use more energy than developing countries

Fuel Types and Uses

• peat -  partially decomposed organic material that can be burned for fuel
• three types of coal - lignite (worst), bituminous, and anthracite (best quality)
• cogeneration - fuel source generates both heat and electricity

Fossil Fuels

• combustion of fossil fuels - chemical reaction between fuel and oxygen that yields carbon dioxide and water and releases energy 
• energy from fossil fuels is produced by burning those fuels to generate heat, which then turns water into steam, steam turns a turbine, which generates electricity

Nuclear Power

• nuclear power is generated through fission, which releases a large amount of heat, can be used to generate steam, which powers a turbine and generates electricity
• cases where accidents or natural disasters led to the release of radiation
  
• Three Mile Island - was a partial nuclear meltdown occurring at the Three Mile Island power plant in Pennsylvania on March 28, 1979 (reactor never cooled)
• Chernobyl - nuclear power plant in the Ukraine, 1986 that suffered two large explosions, worst nuclear accident in history (explosion, accident from safety test)
•  Fukushima - series of equipment failures, nuclear meltdowns, and releases of radioactive materials at the Fukushima Nuclear Power Plant on March 11, 2011 (earthquake, tsunami, flood)
• cleaner energy source -  does not produce air pollutants, but it does release thermal pollution and hazardous solid waste

Biomass

• burning biomass - pros: produces heat for energy at a relatively low cost cons: produces carbon dioxide, carbon monoxide, nitrogen oxides, particulates, and volatile organic compounds
• ethanol - can be used as a substitute for gasoline

Solar Energy

• photovoltaic solar cells - capture light energy from the sun and transform it directly into electrical energy
• active solar cells - use solar energy to take liquid through mechanical and electrical equipment to collect the energy captured from the sun
• passive solar energy -  absorb heat directly from the sun but without the use of mechanical/electric equipment
• pros: produce clean energy, low environmental impact cons: expensive, limited

Hydroelectric Power

•  hydroelectric power - electricity produced from hydropower
  
• can be generated in several ways -  dams built across rivers collect water in reservoirs, moving water can be used to spin a turbines
  
• pros: no air pollution or waste cons: expensive, can cause habitat loss

Geothermal Energy

• geothermal energy - thermal energy generated and stored in the Earth
• heat store in the Earth’s interior heats up water, turns to steam, steam is used to drive an electric generator
• pros: no air pollution cons: accessibility, costly, could possibly release hydrogen sulfide

Hydrogen Fuel Cell

• hydrogen fuel cell - use hydrogen as fuel, combining the hydrogen and oxygen in the air to form water and releases energy 
• pros: only emits water cons: expensive, energy is needed to create hydrogen gas

Wind Energy

• wind energy - renewable, clean source of energy powered by wind
• wind turbines -  kinetic energy of air spins a turbine, converts the mechanical energy of the turbine into electricity
• pros: renewable, clean cons: location, flying species, macitence

Energy Conservation

• there are many ways to conserve energy including
• adjusting the thermostat to reduce the use of heat and air conditioning
• conserving water
• using public transportation
• using battery electric vehicles and hybrid vehicles