AP Environmental Unit 6

renewable energy sources

can be replenished naturally, at or near the rate of consumption & reused

depletable renewables

can run out if overused (biomass)

nondepletable renewables

don’t run out if overused (solar, wind power)

nonrewnewable energy sources

exist in fixed amounts on earth & can’t easily be replaced or regenerated (fossil fuels, nuclear energy)

fossil fuels

rock-like, gas, or liquid resources that are burned to generate power; most used energy source globally

hydroelectric energy

water spins turbines (in dams) to generate electricity; second largest energy source

nuclear energy

uranium fission releases heat to turn water into steam to turn a turbine to generate electricity; third largest energy source

subsistence fuels

biomass that residents of less developed/developing nations can gather & rely on easily & cheaply (can drive deforestation or be depleted)

availability

fossil fuel use depends on discovered reserves & accessibility of those reserves

price

fossil fuel prices fluctuate dramatically w/ discovery of new reserves or depletion of existing ones

fracking

process that uses high-pressure fluid injections to shatter rock formations and extract natural gas; opens natural gas reserves

gov regulation

* gov CANNOT directly raise or lower prices of energy sources
* gov CAN increase taxes to discourage companies from building fossil fuel power plants
* gov CAN use rebates/tax credits to encourage companies to build renewable energy power plants

subsistence fuels

biomass fuel sources that are easily accessible (can be found & gathered by hand)

peat

partially decomposed organic matter found in wet, acidic ecosystems

coal formation

pressure from overlying rock & sediment layers compacts peat into coal over time

natural gas

decaying remains of plants & animals (mostly marine life) are buried under layers of rock & converted by pressure into oil (petroleum) & natural gas over time

crude oil

(petroleum) decaying organic matter trapped under rock layers is compressed into oil over time & is extracted through wells

tar sands

a mixture of clay, sand, water & bitumen; bitumen deposits are where crude oil can be recovered, but w/ higher water & energy inputs

fractional distillation

crude oil is burned in a furnace & vapor passes into a column where different hydrocarbons are separated based on their boiling points

hydrolic fracturing

(fracking) method of natural gas extraction that has extended access to natural gas

shale gas reserves

represent economic profits to countries

fracking fluid

mixture of salt, detergents and acids used in drilling operations to increase hydrocarbons extracted

wastewater injection wells

store fracking fluid deep underground

electricity generation

heat → water into steam → steams turns a turbine → turbine powers a generator → generator produces electricity

cogeneration

when heat produced from electricity generation is used to provide heat (air & hot water) to a building

nuclear fission

a neutron is fired into the nucleus of a radioactive (unstable) element

radioactivity

energy given off by the nucleus of a radioactive isotope

radioactive half-life

amount of time it takes for 50% of a radioactive substance to decay (breakdown)

control rods

lowered into reactor core to absorb neutrons & slow own the reaction, preventing meltdown

water pump

brings in coal water to be turned into steam & cool reactor down from overheating

cooling tower

allows steam from turbine to condense back into a liquid & cool down before being reused

spent fuel rods

used fuel rods remain radioactive for millions of years & must be stored in lead containers at power plant sites

mine tailings

leftover rock & soil from mining may have radioactive elements that can contaminate water or soil nearby

thermal pollution

hot water from power plants released back into surface waters can cause thermal shock (decreased oxygen & suffocation)

three mile island (US)

partial meltdown due to testing error; radiation released, but no deaths or residual cancer cases

fukshima (japan)

earthquake & tsunami triggered cooling pump failure that lead to a meltdown (reactor core explosion) & widespread radiation release

chernobyl (ukraine)

stuck cooling valve during test lead to complete meltdown, several deaths & widespread radiation release

biomass

organic matter burned to release heat (primarily for heating homes/cooking)

biofuels

liquid fuels (ethanol, biodiesel) created from biomass

modern carbon

CO2 that was recently sequestered or released by burning biomass

fossil carbon

formed by decomposing organic matter over millions of years; released by burning fossil fuels

ethanol

corn & sugar cane ferment into ____ which is mixed w/ gasoline; “renewable” in that corn production is sustainable

E85

“flex fuel;” 83% ethanol + gasoline mix; used in flex-fuel vehicles & decreases oil consumption

biodiesel

liquid fuels produced specifically from plan oils (soy, canola, palm)

passive solar

absorbing or blocking heat from the sun w/o use of mechanical/electrical equipment

active solar

use of mechanical/electrical equipment to capture sun’s heat (solar water heaters or CST) or convert light rays directly into electricity (PV)

photovoltaic cells

(PV cells); contain semiconductor that emits low voltage electrical current when exposed to sunlight

intermittency

electrical energy that is not continuously available due to external factors that cannot be controlled

concentrated solar thermal

(CST); heliostats reflect sun’s rays onto a central water tower in order to heat water to produce steam to turn a turbin → energy generation

heliostats

mirrors

rooftop solar

solar for individual homes/businesses; doesn’t take up a lot of land, but produces a little energy

community solar

large-scale solar farms; produces lot of electricity, but takes up a lot of land (contributes to habitat loss/fragmentation)