Ch. 5 Energy Resources & Consumption

Energy
measured the ability of an object to perform work & move objects
Potential Energy
form of mechanical energy; energy in an object (usually stationary) that can be converted into movement; ex. chemical energy
Chemical Energy
a chemical reaction between bonds of atoms to create molecules; most practical form of energy; two types of chemical reactions – endothermic & exothermic; i.e. chem energy -> thermal energy when burning wood
Kinetic Energy
mechanical energy; energy possessed by a moving object. ex. thermal energy
Thermal Energy
kinetic energy; the energy created by the movement of molecules within a substance (molecules move when they are ___ed up)
Mechanical Potential Energy
energy stored in objects by tension/position; gravitational energy is included in this; i.e. stretched rubber band or a ball ready to roll down a hill
Electrical Energy
Created by the motion of electrons; potential energy; can be converted into the kinetic energy of an electrical current; static electricity; ex. stationary water in reservoirs & batteries
British Thermal Unit (BTU)
amt of heat it takes to raise 1 lb H2O’s temp by 1F
Calorie (c)
amt of heat needed to raise 1g H2O 1C (1.8F)
Kilocalorie (C)
amt of heat needed for 1 kg H2O to increase by 1C (1.8F)
Horsepower (hp)
used in combustion engine market (autos, boats, generators); 1 unit = 746 watts
Joule (J)
force of 1N applied through 1m displacement; unit of work
Watt (electrical) (W)
measures rate of energy conversion (1J/s); used in kWh (kilowatt-hr) for energy consumption; used to describe how much energy powerplants generate (megawatt-hr) & on home energy bill (kWh)
Watt (thermal)
Used in nuclear power plants to measure thermal energy produced
First Law of Thermodynamics
Energy can be changed in form, but never created nor destroyed. Equilibrium.
Second Law of Thermodynamics
Systems move from states of high energy (low entropy) to high entropy (low energy); ex. a food chain loses energy as the trophic level increases as energy is lost to heat & movement
4 Categories Users of Energy
Industry (production of economic goods & services, 1st largest consumer of __), Transportation(2nd largest consumer, divided into infrastructure, vehicles, & operations), Residential (homes), Commerical (places where goods & services are exchanged for money)
Fossil Fuels
Coal, Oil, Nat’l Gas; nonrenewable; world energy is dependent on them
Coal
dirtiest and most abundant of fossil fuels; clean ___ removes the pollutants that have a harmful effect on the environment (removing sulfer dioxide, carbon dioxide, etc); formed in an oxygen-less environent; primarily obtained by underground mining
anaerobic environment
environment w/o Oxygen
Oil Shale
Sedimentary rock rich in kerogen; more costly than oil w/ more neg. envirom’l impacts; several major deposits in the US
Kerogen
Compound that liquid hydrocarbons are extracted from when heated; req’s more processing than crude oil
Tar Sands, Oil Sands, Bitumen
unconventional petroleum deposit; contains nat’ly occurring mixtures of sand, clay, water, and an extremely dense form of petroleum; have to be heated up & req’s more processing than crude oil
Crude Oil
naturally occurring, complex mixture of hydrocarbons & other organic compounds found in geological formations; obtained by drilling through Earth’s surface into deposits
Petroleum
literally means “oil from the Earth” or “rock oil”
Nat’l Gas & Crude Oil Formation Formation
Organisms die, get covered w/ silt & mud, decaying anaerobically, pressure squeezes out most of the liquid, the dry carbons left behind form carbon chains. Long chains = crude oil; shorter chains = natural gas
Methane Hydrates
recently discovered source of nat’l gas. Found in ice formed at low temps but high pressures (“burning ice”). Comes from decomposing plants & animals trapped in permafrost
Synthetic Fuels (Synfuels)
liquefied fuels made from nonpetroleum sources (i.e. coal, nat’l gas, biomass feedstocks) through chemical conversion
Nuclear Fission to Power Reaactors
an atom is split into smaller elements w/ by-products, which gives off lots of heat (exothermic rxn). Heat makes water -> steam, which turns turbines to generate electricty
U-235
one of the most common nuclear fuels, half-life of 704 million years; waste must be stored “forever” in a secure location
Nuclear Reactors
7 components – Fuel, Moderator, Control rods, coolant, containment, and core.
Half-life
the amt of time it takes for half of the isotope to decay. to be safe, a radioactive must complete 10 half-lives
Hydroelectric Power
Water turns a turbine, which turns the shaft of an electric generator and produce electricity
Office of Energy Efficiency & Renewable Energy (EERE)
established by the US Dept of Energy to reduce US dependence on foreign crude oil and develop tech to increase energy efficiency in the US
Energy Star
US Environmental Protection Agency created ___ in 1992 to reduce energy consumption and greenhouse gases emitted by power plants by labeling energy-efficient products; now an intern’l standard for consumer products from US
Corporate Average Fuel Economy (CAFE)
enacted in 1975 in response to Arab oil embargo & improving fuel economy on cars and trucks. US has the least strict ____ standards among developed nations.
Percent Change
(V2-V1)/V1
Mobile-Source Pollution
pollution emissions can be moved from one location to another (i.e. cars)
Point-Source Emissions
pollution emissions that stay at one source/one location (i.e. power plants)
Passive Solar-Energy Systems
used to capture electrical energy from the sun; require no input of electrical activity. Sun hits transparent solar cells, causing them to emit electrons and the many cells wired together produce electricity.
Active Solar-Energy Systems
use pumps and fans to move water heated by the sun through buildings, req electricity; used to heat the house & for hot water
Hydrogen Fuel Cell
uses H and O in a chemical reaction to create energy and water.
Biomass
any biologically based fuel source – wood, charcoal, manure. Can be grown specifically for energy or re-appropriated. 50% of US energy comes from _____.
Geothermal
use the heat from the Earth to generate electricity. Top 3 producers – US, Philippines, Mexico.