Unit 4 Quiz 1

Question 1

Majority of worldwide energy consumption comes from _____

Answer 1

fossil fuels

Question 2

U.S. uses ___ times as much energy as the global average

Answer 2

5

Question 3

commercial vs. subsistence energy sources

Answer 3

-bought and sold
-gathered for personal use

Question 4

why does energy consumption in U.S. vary regionally and seasonally?

Answer 4

regions use energy sources for various purposes
in north, energy goes up in winter to heat homes
in south, energy goes up in summer to cool homes

Question 5

nonrenewable resources ___ be _____

Answer 5

cannot, replenished

Question 6

fossil fuel:

Answer 6

hydrocarbons from ancient bio-material

Question 7

energy return on investment:

Answer 7

energy obtained from fuel/energy invested to obtain

Question 8

US uses approx. ___% of energy for transport

Answer 8

30

Question 9

coal:

formation steps?

uses?

advantages?

disadvantages?

Answer 9

solid hydrocarbons

vegetation dies and is buried under anaerobic conditions, forming peat (partially decomposed OM). Peat is compressed to form lignite. Lignite compresses further to sub-bituminous and bituminous coal. Compresses further to form anthracite.

generate electricity, heat/fire, etc.

plentiful, energy dense, easy to extract and transport

mined (negative externalities), transport and storage can be hazardous, toxic impurities, more CO2 production than any other fuel

Question 10

Petroleum:

Answer 10

liquid hydrocarbons produced by extracting and refining crude oil

Question 11

tar sands (oil sands):

Answer 11

source of crude oil (bitumen), composed of bitumen, sand, clay, and water

Question 12

oil formation, extraction, and transport

Answer 12

remains of ancient oceanic phytoplankton and algae, buried within SHALE rock, time heat and pressure turn it to oil

natural gas can also form under shale rock

drilling is used to access crude oil, and pipelines+tankers+railways transport it.

Question 13

oil separates into compounds through ____ and is separated by ____

these are: (lowest boiling point to highest)

Answer 13

refinement, boiling point

gasoline, kerosene, diesel, and tar/asphalt

Question 14

petrochemicals

Answer 14

petroleum compounds also serve as raw material for petrochemicals, such as plastics, lubricants, pharmas, and cleaning solvents

Question 15

petroleum advantages:

disadvantages?

Answer 15

energy dense (less than coal), convenient for motor vehicles, and burners cleaner than coal. (has a lower EROI though)

extraction and transport cause pollution + deadly leaks
contains toxic impurities that can pollute soil and water and air
still produces CO2 (less than coal, though)

Question 16

Natural gas composition:

Answer 16

80-95% methane and other gaseous hydrocarbons

Question 17

natural gas moves into:

Answer 17

large cracks and spaces between layers of overlying rock

Question 18

natural gas primarily used in ____, but also occasionally for:

Answer 18

electricity generation

heating homes and powering appliances

Question 19

natural gas extraction:

Answer 19

drilling, and increasingly, via hydraulic fracturing (fracking).
fracking involves pumping high pressure mixes of water, sand, and chemicals into a well to create fractures in surrounding rock that release the trapped gas.
Many speculation about this being bad for soil and water pollution! people hide the chemicals they use

Question 20

advantages of natural gas:

disadvantages:

Answer 20

abundant, inexpensive, fairly high EROI
fewer impurities than coal and petroleum, releases CO2 less as well

Fracking is bad…
-large amounts of H2O used
-undisclosed chemicals
-increases earthquake incidence
Incomplete combustion and leaks during extraction release CH4 into air and groundwater, respectively
Still releases a significant amount of CO2

Question 21

Nuclear energy is produced through ____, which is

Answer 21

fission, radioactive nuclei decay, releases large amounts of heat energy and high energy neutrons that propogate decay

Question 22

Uranium-235

Answer 22

common radioactive isotope

1g has 2-3 million times the energy of 1g of coal

Question 23

Understand controlled fission in a nuclear facility

Answer 23

U-235 pressed into pellets and placed in rods
control rods placed between fuel rods to variably control rxn rates and temps

Question 24

nuclear advantages

disadvatages

Answer 24

no GHGs or air pollutants DURING operation
small fuel input (high EROI) for maintenance

U-235 is rare and hazardous, must be mined (NEs ass. w that)
reactor accidents CAN happen, and are really really bad
Waster has to be stored in water or lead lined storage tanks, radioactive

Question 25

electricity is a ___ energy source, meaning it can be both ____ and ____, depending on primary source

Answer 25

secondary, obtain it from energy conversion of a primary source renewable or nonrenewable

Question 26

understand thermoelectric power plant system:

Answer 26

1.combustion heats water, generating steam 2. steam spins turbine 3.turbine shaft turns generator, produces current 4.electricity distributed via grid 5.steam is recycled

Question 27

cogeneration:

Answer 27

steam generated for industrial purposes can be used to produce electricity

Question 28

electricity advantages: disadvantages:

Answer 28

versatile, convenient, etc. Easy to use in general inefficient to generate and transport 40% of our energy resources are used to generate electricity 13% of that energy contained in those resources makes it to target (house, outlet, etc.) sustainability depends on source!!!

Question 29

renewable energy resources include two categories:

Answer 29

non-depletable: can never be depleted in span of human lifetime potentially renewable: can be regenerated indefinitely as long as not overharvested usually plant based such as wood and biofuel

Question 30

among renewable energy sources, combustibles make __%

Answer 30

>75% of them

Question 31

Biomass energy & carbon fossil carbon fresh carbon

Answer 31

combustion still releases carbon into atmosphere, similar to fossil fuels carbon that was out of circulation for 50+ million years until we reintroduced it very recently removed from atmosphere, so theoretically it is carbon neutral

Question 32

renewable biomass energy sources can be classified as solid biomass or biofuels solid? 3 major types and traits? biofuel? most are ___ and ___ gasoline produced from ____ ____ biodiesel is a substitute for ____ ____produced from ____

Answer 32

solid: primary energy source in rural parts of world for subsistence some used in developed world as an alternative or supplementary energy source -wood -charcoal: generated by burning wood under oxygen limited conditions. Ligher, more energy dense, and produces les smoke than wood. -manure: where wood is scarce it is used biofuels: liquid fuel from processed or refined fresh biomass! ethanol based, substitute plant-tissue carbs petroleum diesel, oils extracted from plants

Question 33

energy density of fresh biomass is ___ compared to fossil fuels

Answer 33

low

Question 34

waste can be used as fuel, but this introduces ____ challenges

Answer 34

pollution

Question 35

biofuel advantages disadvantages ways to make sustainable

Answer 35

potentially renewable relies on fresh carbon (less GHGs) burns cleaner (less impurities) lower EROI than FFs can compete w/ food production for land (shares impacts w/ conventional agriculture) crop production can be GHG intensive conversion to fuel requires energy inputs and more efficient tech has been slow to develop So in the end, NOT carbon neutral in most cases use perennial crops: produced less intensively and can be grown on marginalized land use algae for biodiesel (very efficient, no food agriculture comp)

Question 36

hydrogen fuel cells convert ___ to ___ advantages disadvantages

Answer 36

H2 to electric current! direct pathway for e- generation, making it efficient lack of pollutants, waste, or GHGs DURING OPERATION easily scalable H2 can be energy intensive and GHG intensive to produce, as well as costly (relies on FFs) H2 is explosive H2 tanks are extremely large

Question 37

advantages for all non-depletable resources all disadvantages?

Answer 37

non-depletable! they can generate large amounts of current without any GHGs, air pollution, or toxic waste DURING OPERATION Building and maintaining the infrastructure required for use requires a lot of resources and is often expensive and GHG intensive availability varies geographically, and output varies seasonally (esp for wind, solar, and some hydroelectric sources)

Question 38

hydroelectric power: factors affecting output: run of the river system? water impoundment systems? advantages of water impoundment systems disadvantages of water impoundment systems siltation?

Answer 38

harnesses water movement depends on water pressure turbines placed into small rivers. Low pressure, seasonal fluctuations. Less expensive and GHG intewnsive to build, minimally disruptive, no flood risk uses large damns that store water in a reservoir, higher pressure, greater consistency inexpensive and highly productive once operating, high EROI\ can be used to reduce downstream flooding dams are often used to support fishing and recreation\ can distrupt water flow and cause upstream flooding disruptive to aquatic organisms expensive and GHG intensive to build siltation sediment pollution/accumulation reduces flow of water threatens aquatic organisms

Question 39

tidal energy? requirements?

Answer 39

uses movement of water in ocean driven by moon gravity proximity to coast significant difference between high and low tide

Question 40

wind energy? best implemented advantages? disadvantages?

Answer 40

movement of air to generate electricity open landscapes, offshore, in mountain passes along with advantages of all non-depletable sources, potential to share land w/ other uses along w/ disadvantages of non-depletable sources, low EROI (on the rise) Turbines are not made of sustainable materials and are difficult to recycle energy storage can be a big challenge noise and visual pollution (not in my back yard principle) can threaten wildlife

Question 41

Solar energy? passive heating? active heating? -household use -commercial use photovoltaic solar cells? PV solar panels? advantages of PV solar? disadvantages of PV solar?

Answer 41

can harness heat or light as energy absorbs sun heat w/out equipment uses equipment to capture and store heat energy from sun -most commonly used to heat water, and spaces -solar driven thermoelectricity generation (heat --> steam), costly, low EROI (rising) captures solar energy as light rather than heat and directly converts to electricity arrays of many solar cells, can generate enough electricity to supply human needs normal non-depletable advantages long lifespan, can produce surplus (cost effective, maybe profitable) max energy production occurs during peak demand (mid day) potential to share land w/ other uses normal non-depletable disadvantages high upfront cost relatively low EROI energy storage is a challenge

Question 42

energy conservation vs. efficiency

Answer 42

finding and implementing ways to use less energy finding ways to get more bang for buck w/ electricity

Question 43

3 ways individuals can conserve energy or use it more efficiently 3 ways government can facilitate this

Answer 43

conservative w/ running heat and water, energy efficient appliances, turn off things when not in use. etc. public transport increase, tiered billing systems, taxing fossil fuels, etc.

Question 44

tiered rate system?

Answer 44

pay more as you use more electricity discourages higher levels of energy being used

Question 45

peak demand? why is it relevant to energy conservation?

Answer 45

greatest quantity of energy used/demanded at once companies try to match it, even though it is sometimes much larger than average demand. reducing it causes the energy produced by companies to also go down.

Question 46

sustainable design?

Answer 46

improve efficiency of buildings and communitiesp

Question 47

passive solar design

Answer 47

take advantage of solar radiation without active technology or devices