Energy Use, Coal, & Energy Efficiency
Oil & Fossil Fuel Choices
Natural Gas & Energy/Electricity
Nuclear Power
Electrical Generation
100
What are fossil fuels? What type of carbon is released when fossil fuels are combusted?
Where do most fuel sources (RENEWABLE & NONRENEWABLE) come from?
What is non-renewable energy?
What affects energy use?
Understand how energy is used differently in developed vs. developing nations.
Understand how energy use in the U.S. has changed over time.
What is the Hubbert Curve? When will we run out of oil?
- Fossil Fuels: fuels derived from biological material that became fossilized millions of years ago. Form in anaerobic environments when fossilized dead biomass experiences heat & pressure. Release additional carbon dioxide into atmo. Contain hydrocarbons = energy dense. Release fossil (old) carbon that's been buried for millions of years (out of circulation --> rapid increase in CO2 concentrations.
- Source of Energy: THE SUN!
- Non-Renewable Energy: An energy source with a finite supply, primarily fossil fuels & nuclear fuels. Can be replaced only by geological, physical, or chemical processes that take millions of years.
- Energy Use = Based on Demographic Transition. Is a massive system of inputs & outputs with political & technological boundaries. Varies regionally & seasonally. Also depends on the ease with which fuel can be transported & energy the fuel contains
1. Developed: More likely to use fossil fuels like coal, oil, & natural gas. Have the industry to transport fossil fuels. Use commercial energy sources - energy sources that are bought & sold.
2. Developing: People in rural areas more likely to use fuels like wood, charcoal, straw, & animal waste. Use subsistence energy sources - those gathered by individuals for their own immediate need.
- Changes in Energy Use: Movement from wood to coal, oil, & natural gas during industrial revolution.
100
What is oil?
How does oil form?
How is oil transported?
How is oil refined?
Who produces the most oil?
What are tar sands?
What is oil shale?
- Oil: Mixture of hydrocarbons (oil, gasoline, kerosene) with water and sulfur that exists in a liquid state underground & at surface level. There is often methane (natural gas) dissolved in oil. Suitable for mobile combustion. Oil, crude oil, & petroleum = synonymous. Use for transportation & production of plastics, pharmaceuticals, lubricants, & cleaning solvents.
- Formed from the remains of ocean-dwelling phytoplankton that died 50-150 mya (no decomposition). Found where porous sed. rocks are capped by nonporous rocks. Oil migrates upward in porous rock. Must be drilled into (either on land or off-shore) and extracted with pumps. Sometimes flows out under pressure (artesian well).
- Oil must be transported by pipeline (land) or supertanker (underwater).
- Producers: U.S., Saudi Arabia, Russia, Canada, & China
- Refinement: Can be refined into a variety of compounds. Takes place in an oil refinery by heating crude oil. Process = dangerous, complex, & $$$. Oil production measured in barrels (1 barrel = 160 L).
- Oil Shale: A fine-grained sedimentary rock from which oil can be extracted. Extracted via surface mining the shale rock containing kerogen (solid bituminous materials). Processed using pyrolysis to convert the kerogen into a liquid, synthetic crude oil. End product = crude oil --> Less efficient & greater CO2 release.
100
What is natural gas and how does it form?
Who is the largest consumer of natural gas?
How is natural gas used to create electricity?
What are conventional sources of natural gas?
What are unconventional sources of natural gas?
What are methane hydrates?
How is natural gas extracted?
- Natural Gas: A relatively clean odorless fossil fuel containing 80-95% methane (CH4) & 5-20% ethane, propane, & butane. Emits smaller amounts of atmospheric pollutants than coal/oil. Must be transported by pipeline (compressed --> partially liquid during transport). Used for electricity generation & industry, in the manufacture of Nitrogen fertilizer, & residentially for cooking, heating, & laundry.
- Natural Gas Formation: Forms as the result of the burial of fossilized marine organisms.
- Largest Consumer: United States
- Electricity:
- Conventional: Forms adjacent to crude oil deposits & is typically extracted simultaneously.
- Unconventional: Wetlands, Agriculture (rice fields), Landfills, Arctic permafrost (bubbles), & Cows (burps/flatulence), & Deep Ocean Sediments/Permafrost (Methane Hydrates)
- Methane Hydrates: White, ice-like solids that consist of methane and water. Are a potential storage mechanism for carbon sequestration & for storing methane for use as a transportation fuel.
- Extracted: Using hydraulic fracturing (fracking), a method of oil/gas extraction that uses high-pressure fluids to force open existing cracks in rocks deep underground. Allows for extraction of deposits that were thought too deep to reach → increased natural gas in U.S. at lower costs. Creates jobs & increases reliance on a domestic energy source.
100
What is nuclear power?
What is radioactivity?
What radioactive isotope is used to produce nuclear power?
What is the difference between nuclear fission & nuclear fusion?
What two substances does neutron radiation not penetrate?
What does the nuclear fuel cycle include?
Why are nuclear power plants dismantled when they can no longer be used?
- Nuclear Power: Electricity generated from the nuclear energy contained in nuclear fuel.
- Radioactivity: Emission of ionizing radiation or particles caused by the spontaneous disintegration of atomic nuclei.
- Radioactive Isotope Used: Uranium-235 (2-3 million times more energy than equal amounts coal).
- Fission: A nuclear (chain) reaction in which a neutron strikes a relatively large atomic nucleus → splits into two or more parts, releasing additional neutrons & energy in the form of heat.
- Fusion: The joining of atoms to produce energy. Occurs on the Sun!
- Substances Not Penetrated: Water & Concrete!
- Nuclear Fuel Cycle: Includes mining, processing and enriching uranium to make fuel, Using it in a reactor and safely storing the highly radioactive wastes, & Energy required to dismantle reactors. Overall low net energy yield.
- Dismantling Reactors: Done to to safely remove them from service, reduce residual radioactivity to acceptable levels, and potentially allow the site to be reused for other purposes.
100
How is fuel converted to electricity?
- Process of electricity production
1. Fuel is delivered to a boiler & (ususally) burned
2. Energy in fuel is transferred to water → steam
3. Kinetic energy in steam is transferred to blades of a turbine. Turbine can be turned by water, steam, or wind to produce power.
4. The turbine turns a shaft in a generator.
5. Generator generates electricity.
200
What is coal? How does it form?
Understand the difference between peat and coal.
What types of coal exist? How are they different?
How is coal used to create electricity?
Who are the top producers of coal?
- Coal: A solid fuel formed from the remains of trees, ferns, & plant materials that were preserved 280-360 million years ago. Used for electricity & industry.
- Peat: Made up of partly decomposed organic materials. Is the starter form of coal.
- Types of Coal: Differ based on age, exposure to heat/pressure, depth of burial, & energy content.
1. Peat: Partly decomposed organic material.
2. Lignite: A brown coal that is a soft sedimentary rock that sometimes shows traces of plant structure. Contains 60-70% carbon.
3. Bituminous Coal: A black/dark brown coal that contains bitumen (a degraded form of petroleum AKA asphalt). Most common type of coal. Contains up to 80% carbon.
4. Anthracite: Hard coal, containing greater than 90% carbon. Highest quantity of energy per volume of coal & fewest impurities.
- Electricity: coal is combusted --> generates heat --> heats water --> creates steam --> steam turns turbine --> turbine turns generator --> generator generates electricity.
- Top Producers: China, U.S., India, & Australia (& Russia)
200
What are some advantages of oil?
Advantages: Extremely convenient to transport & use (ideal for cars, trucks, & airplanes). Energy-dense. Cleaner burning than coal (contains 85% CO2 of coal).
200
What are some advantages of natural gas?
- Advantages: Contains fewer impurities than coal & oil (almost no SOx or particulates & contains 60% of CO2 in coal). Already an extensive NG pipeline system in U.S. (50% of homes use NG for heating). Very convenient (where pipelines exist). Liquefied petroleum gas (LPG) can be supplied by fuel trucks (where no pipelines exist).
200
Understand how fuel is stored in a nuclear reactor.
Why does the nuclear reaction have to be slowed down and how is it slowed?
Understand what happens in a nuclear reactor to generate electricity.
- Fuel in Nuclear Reactor: A steel or concrete containment structure encloses nuclear fuel (contained in fuel rods) & the steam generator. Uranium fuel processed into pellets → fuel rods.
- Slowing Nuclear Reaction: Must be able to slow down fission to allow collision of neutrons to take place at appropriate speed --> otherwise can cause nuclear meltdown. Use moderators (i.e. - water) to slow down neutrons & Control rods (cylindrical devices inserted between fuel rods to absorb excess neutrons & slow/stop nuclear reaction).
- Electricity: Uranium undergoes nuclear fission --> releases heat. Water is heated → steam → turns turbine → turns generator → creates electricity.
200
Understand how each type of fuel generates energy.
1. Coal, Oil, Biomass (Liquid/Solid), & Natural Gas = combusted to produce heat that creates steam which turns a turbine (coal, solid biomass, & natural gas) or which run a combustion engine (oil & liquid biomass/biofuels).
2. Uranium-235 (nuclear fuel) = undergoes nuclear fission which create heat that creates steam which turns a turbine.
3. Active Solar = can be used to heat water/fluid directly or in photovoltaic cells (solar panels) by direct generation of an electrical current.
4. Hydro, Wind, & Tidal = kinetic movement of water or air moves a turbine.
5. Geothermal = Earth's internal heat (from radioactive decay & pressure) heats water which creates steam which turns a turbine.
300
What are some advantages of coal?
- Benefits: Energy-dense. Plentiful. Easy to obtain (surface mining --> increased environmental impact). Low technological demands to obtain & cheap. Easy to move & store for future use. Requires little refinement.
300
What are some disadvantages of oil?
Disadvantages:
1. Must be located & extracted. Located by geologists using dynamite, heavy weights, or vibroseis trucks (trucks that pound the ground) --> can increase seismic activity (EQs). Extracted by drilling into ground and often using pumps.
2. Must be refined. Refinement process deals with separating the oil into different substances based on boiling point. Refinement is expensive, often requires fossil fuels, & uses toxic chemicals.
3. Must be transported by pipeline (land) or tanker (sea) --> increased risks of leaks & spills.
4. Contains sulfur & heavy metals which are released thru combustion. Can be removed through refining process but is more expensive.
5. Construction of pipelines can cause habitat destruction, habitat fragmentation, and can leak/spill.
6. Oil fields (tar sands) can be adjacent to homes --> Thick, gelatinous crude oil covers ground & creates local air pollution problems.
300
What are some disadvantages of natural gas?
- Disadvantages:
1. Is mostly methane: Unburned gas that escapes (leaks) is a potent greenhouse gas. Is 28x more potent than CO2.
2. Fracking: Uses large amounts of water --> Millions of gallons taken out of streams/rivers/aquifers & injected into gas wells. Depletes aquifers → competition with drinking water & agriculture. Variety of chemicals added to fracking fluid to facilitate release of natural gas (companies not required to identify chemicals). Can lead to surface & groundwater contamination with brine and methane seepage. Increased frequency of EQs due to vibroseis trucks (trucks that pound the ground to search for natural gas deposits). USGS reports that fracking is responsible for EQs.
3. Fracking releases volatile organic compounds (VOCS - types of organic compound air pollutants that evaporate at typical atmospheric temperatures): Precursor to other air pollution & can harm human health.
4. Large amounts of natural gas is lost as “leakage” → adds methane to atmosphere → global climate change. Estimating lost gas (AKA fugitive gas) is difficult. Many uncertainties due to natural gas extraction process, measurement difficulties, & industry secrecy --> estimate of 2-9%.
5. Can be found as methane hydrates. Found on the ocean floor. Expensive to obtain.
300
What are some advantages of nuclear power?
What are some disadvantages of nuclear power?
- Advantages: Does not produce air pollution. Does not produce greenhouse gases. Helps achieve independence from foreign oil. Is not reliant on fossil fuels. Risk of accidents = low.
- Disadvantages: Low net energy & high overall cost. Nuclear accidents/release of radioactivity. Spread of nuclear weapons. Radioactive waste disposal (takes 704 million years for radioactivity of U-235 to decrease to half its original level).
300
What is the electrical grid? Have a basic understanding of how electricity is transferred from a power plant to residential areas.
Is electrical generation an efficient process?
- Electrical Grid: A network of interconnected transmission lines. Distributed to homes, business, factories, & consumers. Converted to heat (cooking), kinetic energy (motors), radiant energy (lights), etc.
- Electrical Generation: Inefficient process. Much energy is lost as heat & sound.
400
What are some disadvantages of coal?
- Disadvantages:
1. Surface mining: tailings contain arsenic, lead, mercury, cadmium, & chromium → heavy metal water pollution. Depletion of surface mines → subsurface mining → increased costs & impacts on human health.
2. Air pollution: Combustion releases sulfur dioxide (→ acid rain), particulates, & heavy metals. Releases more carbon dioxide than oil or natural gas → global climate change.
3. Production of Ash: 3-20% of burnt coal is left as ash. Ash contains selenium, lead, chromium, & mercury (heavy metals). Large deposits stored near power plants in tanks or ponds. Can collapse --> fatalities and soil/water pollution.
4. Use of potentially toxic or carcinogenic chemical compounds: coal is washed in substances to reduce pollutants. Storage tanks can leak → surface/groundwater contamination.
400
What are the two most catastrophic oil spills in U.S. history?
1. Exxon Valdez Spill of 1989: Tanker ran aground & spilled 11 million gallons of oil in Prince Williams Sound, AK. Impacted 1300 miles of coastline.
2. BP Deepwater Horizon Spill of 2010: Oil rig exploded & sank → 206 million gallons of oil spilled into Gulf Coast of Louisiana. Well spewed oil for 87 days. 11 people died & 1300 miles of coastline was affected.
400
What is electricity?
What is the difference between a primary and second energy source?
What is an energy carrier?
What is the most common unit of energy? What are some other common units used to measure energy?
Be able to describe the process of electricity generation.
- Electricity: A form of energy resulting from the existence of charged particles (such as electrons or protons). Can be generated using many different sources. Is an energy source itself.
- Primary: coal, oil, & natural gas.
- Secondary: obtained from conversion of primary sources.
- Energy Carrier: Energy source that can move & deliver energy in a convenient, usable form to end users.
- Common Unit & Others: Joule
- Electricity Generation: Clean at the point of use & highly convenient. Pollution released at location of production. Energy source that undergoes fewest conversions from original form = most efficient. All thermal power plants work the same way. Potential energy of fuel → electricity. Electricity generation = not very efficient.
400
What is radioactive decay? How is it measured?
What is a half-life? Why is it a useful tool for scientists?
What is radioactive or nuclear waste? What kinds exist?
What is the half-life of Uranium-235?
Where must nuclear waste be stored?
How often do nuclear fuel rods need to be replaced? How are they stored?
What must be considered when choosing a site for nuclear waste storage?
What are the consequences of exposure to radiation?
- Radioactive Decay: When a parent radioactive isotope emits alpha/beta particles or gamma rays. All radioactive isotopes undergo radioactive decay. Measured in half-lives.
- Half-Life: The time it takes for one-half the original radioactive parent material to decay. Allows scientists to calculate the time people/the environment must be protected from a substance.
- Radioactive Waste: Nuclear fuel that can no longer produce enough heat to produce electricity but continues to emit radioactivity. Three types: High-level (used fuel rods), Low-level (contaminated protective clothing, tools, rags, etc.), & Uranium mine tailings (residue left after uranium is mined/enriched). Different storage requirements for different types of waste. Can’t be incinerated, destroyed using chemicals, buried in ocean trenches, or shot into space (run risk of large amount of radioactivity to enter ocean/atmo).
- Half-life of U-235: 704,000,000 years
- Currently Stored: Power plants required to store waste on site. Waste remains a threat to human health for 10+ half-lives.
- Replaced: every 3-4 years
- Stored: Stored in water-filled pools to cool down over (5+ years). When cool, they are moved to lead-lined concrete or steel containers (thousands of years).
- Considerations for Nuclear Waste Storage Sites: Ensure waste can’t leach into groundwater or escape into environment. Far from human habitation. Secure from terrorist attacks. Transportation to site must be low risk & safe.
- Radiation Exposure: Leads to radiation sickness. Damages cells, tissue, & DNA.
400
How is water used in electricity generation?
Water: Heated and used to make steam which turns turbines. Can be condensed & reused in electricity generation. Can be discharged into nearby water bodies. Can be treated & used in homes.
500
What is energy conservation?
What is energy efficiency?
How can you make energy efficiency choices in your daily life?
How is energy efficiency quantified?
What determines the best energy choice?
What is Energy Return on Energy Investment (EROEI)?
- Energy Conservation: methods for finding & implementing ways to use less energy (i.e. - choosing not to use an electrical appliance).
- Energy Efficiency: ratio of the amount of energy expended in the form you want to the total amount of energy that is introduced into the system (i.e. - using an energy efficient appliance).
- Efficiency Quantified: Refers to both the efficiency of the process to obtain the fuel & efficiency of the process that converts fuel into work. Energy is lost all throughout the process thru the 2nd Law of Thermodynamics (when energy is transformed, its ability to do work diminishes) & because energy is lost as waste heat or other undesired outputs.
- Energy Choice: Best form of energy depends on the purpose for which it is needed. Considers energy-to-mass ratio, ability to store & transport the fuel source, ability to be started & stopped quickly, amount of pollution produced, & whether refinement is necessary.
- EROEI: The amount of energy we get out of an energy source for every unit expended on its production. Larger EROEI = more efficient & desirable process.
500
How do we choose the best fuel source?
Understand why different forms of transportation use different fuel sources?
What forms of transport are most efficient?
What are some of the options available for energy efficient transportation?
- Best Fuel Source: Necessary to consider best fuel for work needed as well as overall system efficiency. Must consider energy efficiency, convenience, ease of use, safety, cost, & pollution.
- Different Modes of Transport: Use different petroleum-based fuels & some are more efficient.
- Most Efficient Forms of Transport: Public transport (buses, trains, etc.) & ground transport (cars, buses, trains, NOT PLANES).
- Energy Efficient Transport:
500
What determines the efficiency of electricity generation?
What is a combined cycle power plant?
What is the capacity of a power plant?
What is capacity factor? Why do power plant close throughout the year?
What is cogeneration?
What shifts are being observed in energy use?
- Electricity: Efficiency depends on the fuel source. Older coal-burning power plant - 36%. Newer coal-burning power plant - 40%. Combined-cycle power plant - 60%.
- Combined Cycle Power Plant: Feature in some natural gas-fired power plants that uses both a steam turbine to generate electricity & a separate turbine that is powered by the exhaust gases from natural gas combustion to turn another turbine to generate electricity.
- Capacity: The maximum electrical output of a power plant. Ex: average power plant capacity = 500 MW. Most power plants don’t operate 24/7.
- Capacity Factor: The fraction of time a power plant operates during a year. Closings occur due to voluntary shutdowns, ease of operation, low demand for electricity, & electricity production by other power plants.
- Cogeneration: The use of a fuel to both generate electricity & deliver heat to a building or industrial process (AKA combined heat & power). Used when steam is used to generate electricity because it generates waste heat. Provides greater overall efficiency.
- Shifts: Have been made away from coal toward renewable energy sources.
500
Be able to list and give information about the three nuclear meltdowns that have occurred throughout history.
1. Three Mile Island, PA: March 28, 1979. Occurred due to low coolant → reactor overheated & caused a partial meltdown. Large part of containment structure became radioactive. Least disastrous. Women & children were evacuated. 20,000 others evacuated voluntarily. No recorded deaths & no documented increase in local health problems.
2. Chernobyl, Ukraine: April 26, 1986. Caused by human error. Operators disconnected cooling systems & removed control rods. No control rods + no coolant → uncontrolled nuclear reactions → plant overheated. Caused an explosion & fire that damaged plant beyond use. 31 plant workers & firefighters died of acute radiation exposure & burns. 100,000+ were evacuated. Wind blew radiation across Europe. Contaminated crops & milk from cows grazing on contaminated grass. Increased adverse health effects (cancers, specifically).
3. Fukushima, Japan: March 11, 2011. Magnitude 9.0 EQ → tsunami (49 feet high). Flooded nuclear power plant → structural damage, fires, hydrogen gas explosions, & release of radioactive gas. 100,000+ were evacuated. No recorded deaths due to radiation. 20,000 dead due to EQ & tsunami. Japan shut down ALL nuclear reactors (54) & have since opened 10.
500
What is energy quality?
What is a high quality energy source?
- Energy Quality: The ease with which an energy source can be used to do work.
- High quality energy source: Are convenient, concentrated, & easily transported.