Renewable Energy

Question 1

Potentially Renewable Energy

Answer 1

Resources that are renewable as long as it is not consumed faster than it can be replenished
Ex: Wood and Biofuels

Question 2

Nondepletable Energy

Answer 2

Energy sources that cannot be depleted in human time

Ex: Solar, wind, geothermal, hydroelectric

Question 3

Biomass

Answer 3

Organic matter burned to release heat - primarily for home and cooking

Wood, Charcoal, Animal Products, Manure, Plant Remains, Municipal Solid Waste, Biodiesel and Ethanol

• Inexpensive and abundant and used all over the world
• Others require technological demands

Disadvantage: MUCH more expensive to be a powerplant than a FF powerplant

Question 4

Biofuels

Answer 4

Liquid fuels (ethanol, biodiesel) created from biomass 
- Used as replacement fuel sources for gasoline

Question 5

Modern Carbon

Answer 5

Burning biomass releases modern carbon (CO2 that was recently sequestered or taken out of the atmosphere)

• Biomass burning releases CO2 but doesn’t increase atmospheric CO2 levels

Question 6

Fossil Carbon

Answer 6

FF burning releases fossil carbon that has been stored for millions of years

Question 7

Biomass Advantages

Answer 7

• Potentially renewable
• Available in most places
• Little technology needed

Question 8

Biomass Disadvantages

Answer 8

• Produces Air Pollution and its Pollutants
• Deforestation: more in developing nations
• Erosion
• Biomass burning leads to respiration issues
• Smog formation

Question 9

Ethanol

Answer 9

Alcohol - the same one found in alcoholic beverages is made by converting starches and sugars from plant material into alcohol [mostly made of corn]

US is the world’s leaders in ethanol production

Often ethanol is mixed with traditional gasoline (1:9)

Question 10

Biodiesel

Answer 10

Produced by extracting oil from algae and plants like soybeans and palm

Palm oil biodiesel has been found to produce 98% more GHGs and FFs due to clearing of forest for palm plantations

Question 11

Ethanol Pros

Answer 11

• Renewable
• Less Air Pollution
• Supports the farming industry
• Reduces dependence on foreign energy

Question 12

Ethanol Cons

Answer 12

• Lower energy content

- Growing corn requires large inputs of water fertilizer, and pesticides

Question 13

Biodiesel Advantages

Answer 13

• Lower emissions

- Renewable

Question 14

Biodiesel Disadvantages

Answer 14

Fossil fuels are used to grow the plants used to make biodiesel.

Question 15

Top Producers of Biofuel

Answer 15

• US
• Brazil
• Indonesia
• Germany, France

Question 16

Hydroelectricity basics

Answer 16

Kinetic energy of moving water –> spins turbine –> turbine powers generator

Largest renewable source of electricity

Question 17

3 biggest hydroelectricity producers

Answer 17

China, Brazil, US

Question 18

Water Impoundment (Dams)

Answer 18

Dam built in a river creates a large artificial lake behind the dam [reservoir]

Damming the river enables operators to allow more or less water through the channel in the dam

Allows for control of flow downstream (prevention of seasonal flooding)

Reservoirs are also a source of recreation money (tourism)

2 big impacts: flooding of ecosystems, sedimentation

Question 19

Run of River System

Answer 19

A dam diverts the natural current of a river through a man-made channel beside the river

Less impactful to surrounding ecosystem

Doesn’t stop natural flow of sediments downstream

Doesn’t generate nearly as much power and may be unavailable in warmer seasons when river water levels are lower

Question 20

Tidal Energy

Answer 20

Tidal power: comes from tidal ocean flow turning turbine [coastal areas only]

Does not have the potential to be a major source of electric energy

Question 21

Hydroelectricity Pros

Answer 21

• No air pollution
• No waste products
• No CO2 emissions
• Recreation
• Downstream flood control
• Tourist Attractions
• Jobs
• Reliable Electricity

Question 22

Hydroelectricity Cons

Answer 22

• Flood prevention is good, but deprives river flood plains of nutrient rich sediment that supports plant growth
• People may need to relocate once dam is built and water reservoir builds up
• Impedes or stops animal movement
• Downstream ecosystems get less water
• Sediment accumulation: changes upstream and downstream conditions [downstream loses sediment, upstream becomes warmer]
• Fossil Fuel combustion during dam construction
• Methane release due to anaerobic decomp
• Human homes and businesses have to be relocated

Question 23

Fish Ladders

Answer 23

Cement steps of pools that migratory fish like salmon can use to continue migration upstream

Question 24

Geothermal Energy

Answer 24

Geothermal does not come from the sun

Heat the comes from radioactive decay of elements deep within Earth

Water can be piped down into the ground and heated by this heat from the mantle

Question 25

Ground Source Heat Pump

Answer 25

Heat absorbing fluid is pumped through a pipe into the ground where it either takes on heat from the ground, or gives off heat to the ground

Question 26

Geothermal Heating

Answer 26

Involves piping water deep into ground to be heated by magma and then transferring heat from water to the building DIFFERENT THAN GROUND SOURCE HEAT PUMP Well must go thousands of meters down to reach heated water reservoir

Question 27

Geothermal Pros

Answer 27

- Potentially renewable: only if water is piped back into the ground - Much less CO2 emission than FF electricity - No release of pollutants as is case with FFs

Question 28

Geothermal Cons

Answer 28

- Not everywhere on earth has access to geothermal energy reaching close enough to surface to access it - Hydrogen sulfide can be released, which is toxic and can be lethal - Cost of drilling is HUGE

Question 29

Top Geothermal Energy Producing Countries

Answer 29

- US - Indonesia - Philippines - Turkey

Question 30

Wind Energy

Answer 30

- Wind is caused by the uneven heating of Earth's surface - Warm air rises, Cool air sinks: creates circulation patterns - US has the largest wind generating capacity in the world - Wind turbines convert the kinetic energy of moving air into electricity

Question 31

Wind Turbine Electricity Generation

Answer 31

Kinetic energy of moving air spins a turbine Only produces electricity in 8-55 mph winds

Question 32

Top Producers of Wind Energy

Answer 32

``` China US (Texas) Germany India Spain ```

Question 33

Wind Turbine Location

Answer 33

- Clustered in groups (wind projects or farms) in flat, open areas - Offshore wind = wind farms in oceans or lakes

Question 34

Wind Energy Pros

Answer 34

- Non-depletable - No GHG - No CO2 - Can share land uses

Question 35

Wind Energy Cons

Answer 35

- Intermittency - Can't replace base-load power - Can kill birds and bats - Can be considered an eyesore

Question 36

Passive Solar Energy

Answer 36

Absorbing or blocking heat from the sun without the use of mechanical or electrical equipment ex: using sun's heat to cook food in a solar oven, orienting building design

Question 37

Active Solar Energy

Answer 37

use of mechanical/electrical equipment to capture sun's heat or convert light rays

Question 38

Photovoltaic Cells (PV)

Answer 38

"solar panels": contain semiconductor (silicon) that emits low voltage electrical current when exposed to the sun DRAWBACK: intermittency (solar energy can only be generated during the day)

Question 39

Concentrated Solar Thermal (CST)

Answer 39

- Heliostats (mirrors) reflect sun's rays onto a central water tower in order to heat water to produce steam to turn a turbine DRAWBACK: habitat destruction and light beams frying birds

Question 40

Large scale solar farms

Answer 40

can generate lots of electricity, but take up land and cause habitat fragmentation

Question 41

Rooftop solar

Answer 41

doesn't take up land, but only produces a little electricity

Question 42

Solar Energy Pros

Answer 42

- no air pollutants - no co2 - no mining - renewable

Question 43

Solar Energy Cons

Answer 43

- semiconductor still need to be mined - can disrupt habitats and pollute water with mine tailings - silicon is limited - expensive