Term
| Nonrenewable: Nuclear Energy |
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Definition
Energy that holds together protons & neutrons within the nucleus of an atom
o We harness this energy by converting it to thermal energy, which can be used to generate electricity |
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Definition
“Burning” recent photosynthesis for energy returns carbon to the atmosphere that would have cycled back to the atmosphere in a relatively short while anyway.
o Using biomass energy can be carbon-neutral with respect to carbon concentrations in atmosphere
o Can be burned, like coal, to generate electricity
o Can be converted to fuels used in transportation |
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Term
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Definition
Ethanol: produced by fermentation of biomass, generally from carbohydrate-rich crops (corn)
• Biodiesel: diesel fuel produced by mixing vegetable oil used cooking grease, or animal fat with small amounts of methanol or ethanol and a chemical catalyst. (Less polluting than Diesel)
o Nontoxic
o Biodegradable
o Nonflammable
o Renewable
o Net energy balance (NEB) = (Energy value of Biofuel) – (energy required to produce Biofuel)
o NEB ratio= Biofuel output/ fossil fuel input
• Biodiesel has much smaller environmental impacts than ethanol in its production and when used as a fuel |
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Term
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Definition
o Water flowing through a dam =>spins turbines that turn generators to create electricity
o 98% of suitable rivers in the U.S. are dammed |
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Definition
Pros
•Renewable as long as water is not overdrawn from the river system
•Clean: no greenhouse gas emissions
Cons
•Damns cause numerous disruptive ecological effects to rives and adjacent terrestrial systems
• Damns thus bring a mix of impacts for people |
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Term
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Definition
o Enormous potential
o Sunlight striking earth the for 40 minutes is equal to global energy consumption for one year
o Currently only 0.06% of primary energy supply in the U.S
o Growing at 33% per year
o More expensive technologies are growing more slowly in developed countries
• Photovoltaic Cell: is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect.
• Photovoltaic power generation employs solar panels composed of a number of solar cells containing a photovoltaic material.
• Concentrated solar |
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Term
| Solar: Concentrated solar |
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Definition
| metallic parabolic mirrors focus sunlight on pipe, heating fluid in pipe |
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Term
| Solar: Photovoltaic power |
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Definition
| generation employs solar panels composed of a number of solar cells containing a photovoltaic material. |
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Term
| Solar Power key limitations |
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Definition
• Transmission lines
• Currently 500 miles DC transmission lines
• Need 100,000-500,000 miles
• Energy storage
• No electricity generated at night; little when cloudy
•Need to store excess power produced in daytime for use at might
o Compressed air storage
• Cost |
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Term
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Definition
Wind
o Takes kinetic energy of wing and converts it to electrical energy
o Fastest growing power source today
o Technology= Wind turbines, machines with turning blades that convert energy of motion into electrical energy by spinning a generator |
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Term
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Definition
• Pros
•Renewable as long as wind blows
•No emission after equipment made, installed
•Call allow local decentralized control over power, and local profit from electricity sales
• Costs lower after initial investments; costs dropping
• Cons
• Not everywhere is windy enough
• Windy sites can be far from population centers
• Some people object to aesthetics
• Blades kill birds, bats
• High start-up costs
Geothermal |
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Term
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Definition
• Geothermal energy is thermal energy generated and stored in the Earth.
• Thermal energy is the energy that determines the temperature of matter.
• Earth's geothermal energy originates from the original formation of the planet (20%) and from radioactive decay of minerals (80%).[27] |
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Term
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Definition
o Simplest and most abundant element in universe
o Could potentially serve as basis for clean, safe efficient energy system
o How it would work:
o Electricity generated from intermittent renewable sources like wind or solar can be used to produce hydrogen
o Fuel cells can then use hydrogen to produce electrical energy for power. |
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Term
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Definition
Pros
• We will never run out of hydrogen
• Can be clean and nontoxic, with no greenhouse gas emissions
• Fuel cells potentially convenient, safe, and efficient
Cons
• Depending on way hydrogen is produced, it may not be environmentally clean
• Emission of hydrogen to atmosphere might have unforeseen impacts |
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Term
| Land & ecosystem disturbances from mining |
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Definition
Coal
• Exclusive, on surface or underground
Nuclear
• Less extensive |
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Term
| Green house gas emissions |
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Definition
Coal
• Sulfur dioxide, nitrogen oxide, particulate matter, and other pollutants
Nuclear
-Pollutant emissions |
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Term
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Definition
Coal
• Considerable emissions
Nuclear
• None from plant operation; much less then coal over the entire life cycle. |
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Term
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Definition
Coal
• No appreciable emissions
Nuclear
• No appreciable emissions during operation; possibility of emissions during severe accident |
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Term
| Occupational health amongst workers |
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Definition
o Coal
• More unknown health problems & fatalities
o Nuclear
• Fewer known health problems & fatalities |
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Term
| Health impact on near by residents |
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Definition
o Coal
• Air pollution impairs health
o Nuclear
• No appreciable know health impacts under normal operation |
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Term
| Effects on accidents or sabotage |
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Definition
Coal
• No widespread effects
Nuclear
•Potentially catastrophic widespread effects |
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Term
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Definition
Coal
• More generated
Nuclear
• Less generated |
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Term
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Definition
Coal
• None
Nuclear
• Radioactive waste generated |
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Term
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Definition
Coal
• Should last several 100 more years
Nuclear
• Uncertain; could last longer or shorter then coal supply |
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Term
| Identify the two fastest growing renewable sources of energy; |
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Definition
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Term
| Identify the main reasons that some people object to wind energy systems; |
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Definition
• Not everywhere is windy enough
• Windy sites can be far from population centers
• Some people object to aesthetics
• Blades kill birds, bats
• High start-up costs |
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Term
| Explain how the use of hydrogen as a “renewable” source of energy can be clean (no greenhouse gas emissions) or not completely clean; |
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Definition
• Electrolysis is the cleanest way:
o Use electrical energy to split water into hydrogen and oxygen.
• 2 H2O=> 2 H2 + O2
o This can potentially be very clean, releasing no greenhouse gas emissions.
However, cleanliness of hydrogen production depends...
o If the source of electricity need for electrolysis is not clean (e.g., From coal), then greenhouse emissions will still occur
• Besides electrolysis, hydrogen can also be produced from organic molecules like fossil fuels, thus results in greenhouse emissions.
o CH4 + 2H20 => 4H2 + CO2
• Also, it is possible that hydrogen production could have environmental impacts of its own. |
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Term
| Explain why hydrogen is considered to be a renewable source of energy; |
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Definition
| • It is considered to be a renewable source of energy because it is Electricity generated from intermittent renewable sources like wind or solar can be used to produce hydrogen |
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Term
Describe how biomass and fossil fuel energy sources are similar, and how they differ;
Similarities |
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Definition
• Can be burned, like coal, to generate electricity
• Can be converted to fuels used in transportation
Differences
• Nontoxic
• Biodegradable
• Nonflammable
• Renewable |
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