ENSC 1000 Exam 2 (Ch. 3 + Ch.4)

Non-renewable energy source

*Using more than is being produced, doesn’t always indicate negative impact

Energy

Conserved property that allows for changes in position, composition, and temperature of matter

Kinetic Energy

Movement, on an object and molecular scale, heat energy, sound energy, atoms moving/vibrating

Potential Energy

Could have kinetic energy but doesn’t, stored energy (ex: spring that’s compressed, bonds of molecules, food), ability to work soon, chemical energy

What are the ways to measure energy use?

Sector, application, source, nation of origin, primary use, secondary use

Sector

Industrial, vehicular, residential, commercial, portion of economy

Application

electricity, transportation, heating/coolingS

Source

Coal, oil, natural gas, nuclear, renewable

Nation of origin

Domestic use, imports, exports

Primary use

More efficient, ex: using natural gas to heat something up

Secondary use

Using natural gas to create electricity to warm something up, electric stove, not as efficient

Evaluation of energy sources for electricity generation

-Availability + cost of fuel

-Environmental impacts of fuel

-Availability + cost of infrastructure

-Geographic impacts

-Ability for storage and/or on-demand use

-Efficiency: cost per unit energy

How is non-renewable energy created?

1. Aquatic/swamp biomes

2. Anaerobic decomposition

3. Heat and pressure transform the remains

Why is anaerobic decomposition so important?

In order for the energy source to be formed the carbon needs to be present, anaerobic decomposition doesn’t allow carbon to escape

What are some of the advantages of using coal as an energy source?

Coal is cheap and has lots of energy (energy-dense)

What are the disadvantages of using coal as an energy source?

Mining is not safe and pollution (smog)

What are the two main ways to extract coal?

Underground mining and strip mining

Underground mining

Risky for workers (black lung, cave-ins and earthquakes), costly (have to pay workers good wages, only have so much you can extract, can’t mine super fast bc it can be dangerous), need lots of workers

Strip Mining

Can be reckless but no possibility of cave-in, less-manned, no health concerns, quicker and gets more coal out, not environmentally friendly (blowing up soil and ecosystems)

Mountaintop Removal

Type of strip mining, becoming less efficient, blasting away rock that isn’t coal can fall into water sources/valleys that go into water ways, changing typography and condition of water, acid mine drainage

Acid Mine Drainage (AMD)

Deposits can be high in Sulphur and nitrites, created from chemical reaction between rock and water, most common form of water pollution in mining states, hard to remediate bc waterways are all connected, impacts water under soil

pH Scale

pH= -log[H+], 1-6 = acidic, 8-14 = basic, 7= neutral, AMD affected rivers can have pH of 4 or below, impacts humans and organisms around, gets into ground water

Impacts of Coal Combustion

Coal has other stuff in it, stuff that has leeched into it

Gas emissions

-carbon monoxide : CO

-carbon dioxide: CO2

-methane: CH4

-sulfur dioxide: SO2

-nitrogen oxides: NOx

Particulate emissions

-mercury: Hg

-lead: Pb

-carbon-based particulate matter: PM

Other hazards: coal ash

Acid rain

effect of SO2 and NOx

1) SO2 and NOx are released from fuel combustion (coal especially releases a ton of emissions)

2) These amissions react w/ water and form sulfuric acid H2SO4 and nitric acid HNO3 in the clouds, they are super acidic

3) The acids reach Earth through precipitation and dry depositions

4) This impacts terrestrial and aquatic ecosystems, major impacts are on soil, waterways, and plants (first line of defense is leaves, they get damaged from acid and affects everything later down the food chain)

Chemistry behind acid rain

2SO2 + O2 + 2H2O yields 2H2SO4

sulfur dioxide + oxygen gas + water yields sulfuric acid

nitrogen dioxide + oxygen gas + water = nitric acid

-this can happen w/ NO (nitric acid) through the reaction is altered

-NOx is shorthand for NO and NO2 combined

Both sulfuric acid and nitric acid are strong acids

-they give up all of their H+ ions immediately, causing an instant drop in pH

Mitigating coal impacts

-Clean Air Act Amendments of 1990 required reduction in NOx and SO2 emissions (reduces acid rain)

How can we emit less of these gases while still burning coal for energy?

-Scrubbers: gases are pulled out of smoke before it’s released, turns SO2 into solid H2SO4, reduce SO2 and NOx emissions

-Low-sulfur coal

-”Clean Coal”: physically remove contaminants from coal so that it emits less when it’s burned

Toxic metals from coal burning

-lands in soil and in waterways

-coal plants are a leading source of mercury pollution

-Mercury undergoes dry deposition into surface water where it bioaccumulates and biomagnifies

Bioaccumulation

-happens w/ an individual throughout its life, poor excretion pathways, substance builds up over time

-big in aquatic systems because that’s where mercury is, increased concentration in older individuals

Biomagnification

-happens at the community level, through trophic interaction

-increased concentration in top predators

-happens alongside bioaccumulation

ex: avoid eating lots of tuna (predator), even after death mercury is still present

Coal ash

-byproduct from coal production

-solid material

-super toxic, high in heavy metals: arsenic (As), lead (Pb), mercury (Hg), chromium (Cr)

How is coal ash disposed of?

-coal ash is put in ponds, modern ones are lined so that it doesn’t touch soil, however there are some that aren’t lined

-GA power has 29 ash ponds, 19 are being evacuated to lined landfills, 10 will be closed in place

-some unlined ponds remain in GA

let the top of the pond flow off because the heavy metals sink down to bottom, isn’t terrible solution, but isn’t great

-unlined ponds have the potential to cause seepage into groundwater

-municipal landfills have strict requirements for impermeable linings