AP Environmental Science Unit 6 Energy Resources and Consumption

Unit 6: Energy Resources and Consumption ● Energy Concepts ○ Forms of Energy ■ Potential = energy at rest, or stored energy ■ Kinetic = energy in motion ■ Radiant = sunlight, or electromagnetic energy ■ Thermal = heat, or the internal energy in substances ■ Chemical = energy stored in chemical bonds between atoms ■ Electrical = energy from the motion of electrons ■ Nuclear = stored in the nuclei of atoms ○ Laws of Thermodynamics ■ First Law of Thermodynamics ● Energy can neither be created nor destroyed ● It can only be transferred and transformed ○ Eg: Photosynthesis ■ Second Law of Thermodynamics ● Entropy (disorder) of the universe is increasing ● In most energy transformations, a significant fraction of energy is lost to the universe as heat ○ Eg: Food chains ● Sources of Energy ○ Nonrenewable ■ Electricity ■ Nuclear ■ Fossil Fuels ● Oil ● Coal ● Natural gas ● Synfuels ○ Renewable ■ Hydroelectric ■ Solar ■ Wind ■ Biomass ■ Geothermal ■ Ocean Waves and Tides ■ Hydrogen fuel cells ● Fossil Fuels ○ What Are Fossil Fuels? ■ Oil ● Long chains of hydrocarbons ■ Coal ● Mixture of carbon, hydrogen, oxygen, and other atoms ● Types of Coals ○ Anthracite = Purest Form ○ Bituminous ○ Subbituminous ○ Lignite = Least Pure ■ Natural Gas ● Mostly methane gas (CH4) with a mixture of other gases such as Pentane (C5H12) and Butane (C4H10) ○ Where Are Fossil Fuels Found? ■ Oil & Natural Gas ● Source = Ancient marine organisms such as zooplankton; Organisms in ancient swamps, especially plants ● Locations ○ Deep in the Earth ○ Under both land and ocean floor ○ Stored in spaces between rocks ○ Long continuous deposits called seams ○ At various depths underground ■ Coal ● Source = Living organisms found in landfills, swamps, wetlands, and the intestines of various animals ● Location = Many locations around the world ○ Extraction & Use of Fossil Fuels ■ Crude Oil ● Raw or fresh oil when it is pumped up from a reserve ● Methods of Extracting Oil: ○ Primary Extraction ■ Oil well is tapped and pumped to the surface ■ Easiest way to extract oil ○ Pressure Extraction ■ This method is used when oil is harder to extract ■ Mus, saltwater, or CO2 is used to push oil out from the reserve ○ Heat Extraction ■ Steam, hot water, or hot gases are used to partially melt very thick crude oil ■ This makes the oil easier to extract ■ Coal ● Coal mining occurs through two processes ○ Strip Mining ■ Removal of the Earth’s surface, all the way down to the level of coal seam ■ Removed earth is called the overburden ■ Coal is removed; overburden is replaced with and topped with soil ■ Area contoured and re-vegetated ○ Underground Mining ■ Sink shafts to reach underground deposits ■ Networks of tunnels are dug or blasted ■ Humans enter these tunnels to manually retrieve coal ■ Natural Gas ● Uses ○ ○ ○ ○ ● Pros ○ ○ ● Cons ○ ○ ○ ○ Heating homes Cooking Burned to generate electricity Can be used in some cars and trucks Produces only CO2 and H2O when it burns Cleaner than burning oil or coal A leak can cause a violent explosion More difficult to transport than oil or coal Liquified before transportation, which requires energy Can be transported via pipes, but these can leak and explode, as well as damage habitats when they’re installed ○ Synfuels ■ Characteristics ● Synthetic fuel ● Obtained from non-petroleum sources such as coal, natural gas, or biomass ● Can also be derived from waste such as plastic or rubber ● Can be liquid or gas ● A mixture of carbon monoxide and hydrogen ■ Pros ● Large potential supply ● Lower air pollution than coal ● Can replace oil or natural gas in some cases ● Used in transportation and industry ● Holds promise to be a more sustainable or renewable energy source in the future ■ Cons ● Low to moderate net energy yield ● More costly than fossil fuels ● Currently still requires coal ● High water use ● Higher CO2 emissions than coal ○ Environmental Considerations of Fossil Fuels ■ Oil Drilling ● Pros ○ Drilling for oil is only moderately damaging to the environment ○ Little land is needed to drill ● Cons ○ Oil is transported thousands of miles by tankers, pipelines, and trucks ○ A lot of environmental damage can occur during transportation ■ Burning Coal ● Burning coal produces: ○ Air pollutants such as CO2, NOx, Hg, and SO2 ○ Fly ash - small dark flecks that are carried into the air ○ Boiler residue - solid waste left at the bottom of the boiler ● Nuclear Energy ○ Fusion & Fission ■ Fusion ● Combining two small atoms to produce heavier atoms and energy ● Can release more energy than fission without producing as many radioactive by-products ● Reactions occur in the Sun ● Practice is still being developed ■ Fission ● Discovered first ● Energetic splitting of large atoms into two smaller atoms ● To split an atom, you have to hit in with a neutron ● Several neutrons are released, which continue the chain reaction ● Used by all commercial nuclear power plants ○ Nuclear Reactors ● Steam is piped directly to the turbines ● Steam spins turbines to generate electricity ● Water is cooled back into a liquid then pumped back to the core to be turned into steam again ● Renewable Energy Energy Source Definition/Exam ples Pros Cons Hydroelectric Electricity generated as moving water turns a turbine Doesn’t produce chemical pollutants Produces thermal pollution Affects river flow and nearby habitats Solar Solar panels convert solar energy into heat or electricity Doesn’t produce pollutants No moving parts Requires little maintenance Silent Producing PV cells requires fossil fuels Not every location receives enough light to Pays off in the long term make solar panels worthwhile Initially expensive Limited by Sun exposure and energy storage potential Biomass Wood Charcoal Animal waste products Carbon neutral Widely available Still being optimized Expensive Can lead to deforestation Wind Wind is used to rotate blades Fastest growing alternative energy source Safe Doesn’t produce pollutants Expensive Loud Unattractive to some Need an alternative for when there is no wind Geothermal Energy that is obtained from within the Earth Harness Earth’s internal heat Cost effective Reliable Doesn’t produce pollutants during typical operation Minimal harm to land and habitats Virtually infinite supply Only possible in some locations Affects and is limited by groundwater Salts in the water corrode machinery Gases or trace toxic chemicals trapped in the water may be released as the water is used Ocean Waves & Tides Incoming and/or outgoing tides pass through the dam, turning turbines and generating electricity Doesn’t produce pollutants Predictable Long life span Expensive Limited locations Environmental impact is still being determined Hydrogen Fuel Cells Hydrogen is obtained from Use is clean and safe Expensive Making the fuel water or organic matter, stored, and used to generate electricity can release pollutants