Renewable Energy Flashcards
Potentially Renewable Energy
Resources that are renewable as long as it is not consumed faster than it can be replenished
Ex: Wood and Biofuels
Nondepletable Energy
Energy sources that cannot be depleted in human time
Ex: Solar, wind, geothermal, hydroelectric
Biomass
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
Biofuels
Liquid fuels (ethanol, biodiesel) created from biomass - Used as replacement fuel sources for gasoline
Modern Carbon
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
Fossil Carbon
FF burning releases fossil carbon that has been stored for millions of years
Biomass Advantages
- Potentially renewable
- Available in most places
- Little technology needed
Biomass Disadvantages
- Produces Air Pollution and its Pollutants
- Deforestation: more in developing nations
- Erosion
- Biomass burning leads to respiration issues
- Smog formation
Ethanol
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)
Biodiesel
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
Ethanol Pros
- Renewable
- Less Air Pollution
- Supports the farming industry
- Reduces dependence on foreign energy
Ethanol Cons
- Lower energy content
- Growing corn requires large inputs of water fertilizer, and pesticides
Biodiesel Advantages
- Lower emissions
- Renewable
Biodiesel Disadvantages
Fossil fuels are used to grow the plants used to make biodiesel.
Top Producers of Biofuel
- US
- Brazil
- Indonesia
- Germany, France
Hydroelectricity basics
Kinetic energy of moving water –> spins turbine –> turbine powers generator
Largest renewable source of electricity
3 biggest hydroelectricity producers
China, Brazil, US
Water Impoundment (Dams)
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
Run of River System
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
Tidal Energy
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
Hydroelectricity Pros
- No air pollution
- No waste products
- No CO2 emissions
- Recreation
- Downstream flood control
- Tourist Attractions
- Jobs
- Reliable Electricity
Hydroelectricity Cons
- 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
Fish Ladders
Cement steps of pools that migratory fish like salmon can use to continue migration upstream
Geothermal Energy
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
Ground Source Heat Pump
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
Geothermal Heating
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
Geothermal Pros
- 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
Geothermal Cons
- 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
Top Geothermal Energy Producing Countries
- US
- Indonesia
- Philippines
- Turkey
Wind Energy
- 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
Wind Turbine Electricity Generation
Kinetic energy of moving air spins a turbine
Only produces electricity in 8-55 mph winds
Top Producers of Wind Energy
China US (Texas) Germany India Spain
Wind Turbine Location
- Clustered in groups (wind projects or farms) in flat, open areas
- Offshore wind = wind farms in oceans or lakes
Wind Energy Pros
- Non-depletable
- No GHG
- No CO2
- Can share land uses
Wind Energy Cons
- Intermittency
- Can’t replace base-load power
- Can kill birds and bats
- Can be considered an eyesore
Passive Solar Energy
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
Active Solar Energy
use of mechanical/electrical equipment to capture sun’s heat or convert light rays
Photovoltaic Cells (PV)
“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)
Concentrated Solar Thermal (CST)
- 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
Large scale solar farms
can generate lots of electricity, but take up land and cause habitat fragmentation
Rooftop solar
doesn’t take up land, but only produces a little electricity
Solar Energy Pros
- no air pollutants
- no co2
- no mining
- renewable
Solar Energy Cons
- semiconductor still need to be mined
- can disrupt habitats and pollute water with mine tailings
- silicon is limited
- expensive
