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RE-newable energy
Renewable Energy
| Question | Answer |
|---|---|
| What are solar thermal systems? | systems that heat water using solar energy that is used to produce steam and generate electricity. Essentially a solar power plant that sends electricity out through lines like other power plants. |
| Advantages os solar energy for electricity | moderate net energy. moderate environmental impact, no CO2 emitted, construction is fast, cost reduced w/natural gas back-up |
| Disadvantages os solar energy for electricity | low efficiency, high costs, need back-up, need access to sun most of time, vulnerable to sabatoge, may disturb desert areas where most are located |
| Passive solar heating | essentially just a super-insulated structure and energy efficient windows that traps heat from the sun |
| Active solar heating | structure that absorbs heat from sun w/help of heat absorbing fluid in special collectors on roof.This system can store heat and is used to heat water as well as home. |
| Advantages of passive and active solar heating | free, net energy is moderate-high, quick instulation, no CO2 emissions, moderate cost for passive, very low pollutin and land disturbance |
| Disadvantages os passive and active solar heating | must have sun 60% of time without blockage, high cost for active, active collectors unattractive, need heat storage system and cost of repairs w/active |
| Photovoltaic cells (solar cells) | thin,transparent,wafer like cells made of silicon and other metals (used for conduction)that emit electrons as sun strikes it. can be connected to power grid if wanted or batteries.great in developing countries where villages are too far from power grids. |
| Advantages of hydropower | moderate-high net energy, 80% efficiency, long life span, provides irragation water, flood control below dam, large untapped potential, low-cost electricity |
| Disadvantages of hydropower | high constructin costs, uproots people, decreases fish harvest below dam, environmental impact from flooding land to form reservoir, high CO2 emissions in shallow, tropical reservoirs (decay of biomass) |
| 3 cheapest ways to produce energy (including environmental costs) | 1. wind 2. geothermal 3. hydropower |
| Advantages of wind power | high efficiency, low electricity cost, no CO2 emissions, quickly built and expanded, low environmental impact, moderate-high net energy, land below usable for crops, livestock |
| Disadvantages of wind power | steady winds needed, backup needed, visual pollution, noise heard if by populated areas, plastic component made from oil, can kill migratory birds |
| biggest producers of biofuels are | Brazil, U.S., European Union, China |
| Advantages of biomass energy | moderate costs, no net CO2 increase if all biomass is harvest/burned/replanted sustainably, can make use of waste from agriculture and timber industry, can make use of arid lands |
| Disadvantages of biomass energy | nonrewable and CO2 emission increase if not done sustainably, moderate-high environmental impact, soil erosion and pollution, loss of habitat |
| advantages of biofuels over gasoline | 1.oil sources concentrated in few places, some hostile-biofuel crops grown anywhere 2.no net CO2 increase if biofuels used sustainably 3. biofuels are available now, easy to store and transport |
| biodiesel is produced from | vegetable oil from soybeans, sunflowers, oil palms, rapeseeds and even leftover oils in restaurants |
| ethanol is produced from | fermentation and distillation of sugars in plants like sugarcane, corn and switchgrass. |
| Advantages of biodiesel | reduced CO and CO2 emissions, better gas mileage (40%), moderate-high net energy depending on oil, potentially renewable |
| Disadvantages of biodiesel | higher cost than regular diesel, higher NO emissions=smog, may compete with food crops and drive up their prices, loss of biodiversity due to plantations |
| Advantages of ethanol | reduced CO emissions, high octane, Ethanol's advantages seriously outweighed by costs |
| Disadvantages of ethanol | low net energy and higher CO2 from corn (which is what's used in U.S.), much higher price,higher NO emissions=smog, corrosive, low driving range, may compete with food crops and drive up their prices, loss of biodiversity due to plantations |
| Geothermal energy is | heat stored in soil, underground rocks and earth's mantle |
| Places in U.S. using geothermal energy | California, Nevada, Utah, Hawaii |
| Advantages of geothermal energy | lower CO2 than fossil fuels, cheap at favorable sites, high efficiency, moderate net energy, low land use and moderate environmental impact |
| Disdvantages of geothermal energy | scarcity of suitable sites, CO2 emissions, moderate-high local air pollution, noise and odor (H2S), can be depleted if used to rapidly |
| Hydrogen powered fuel cells | combining hydrogen gas (H2) and oxygen gas (O2)to produce elctricty and emit water vapor |
| Why are we not using hydrogen power? | 1.takes lots of energy/$ to seperate H2 from cmpds 2.currently very expensive 3. produces less air pollution and CO2 than fossile fuels DEPENDING on how hysrogen is produces=d |
| Advantanges of hydrogen power | if produced from water-pentiful and no CO2 emissions, nontoxic, safer than gasoline & natural gas, low environmental impact, good sub for oil |
| Disadvantanges of hydrogen power | H2 not found alone in nature,lots of energy need to produce, negative net energy, high costs, will take 25-50 yrs to phase in, excessive H2 leaks could deplete ozone, |
| Best way to save energy now | decrease use, improve energy effieciency, use current energy efficient appliances and technology for homes, buildings, vehicles, ect. |
Created by:
sallywentzell
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