Post on 26-Dec-2015
Energy Basics
Energy: the ability to do work
Potential Energy: energy that is stored
Kinetic Energy: energy of motion
Energy Conservation, Increased Efficiency and Cogeneration
Conservation: getting by with less demand for energy
Energy Efficiency: designing equipment to yield more energy output from a given amount of input energy
Cogeneration: a number of processes designed to capture and use waste heat rather than simply to release it into the atmosphere
Energy Policy• Hard Path vs. Soft Path
• Hard Path: finding greater amounts of fossil fuels and building larger power plants
• Soft Path: involves energy alternatives that emphasize energy quality and flexibility
• Energy for Tomorrow• Integrated, Sustainable Energy Management
• Integrated Energy Management: no single energy source can provide all the energy required by the world
• Sustainable Energy Management: provides reliable sources of energy without causing serious harm, all while ensuring that future generation inherit a fair share of Earth’s resources
Energy: Quality
High-quality energy
Low-quality energy
Laws Governing Energy Changes
First Law of Thermodynamics (Energy)
1. Energy is neither created nor destroyed
2. Energy only changes form
3. You can’t get something for nothing
ENERGY IN = ENERGY OUT
Laws Governing Energy Changes
Second Law of Thermodynamics
1. In every transformation, some energy is converted to heat
2. You cannot break even in terms of energy quality
Transfer of Heat EnergyConvection Conduction Radiation
Heat from a stove burner causes atoms or molecules in the pan’sbottom to vibrate faster. The vibrating atoms or molecules then collide withnearby atoms or molecules, causingthem to vibrate faster. Eventually, molecules or atoms in the pan’shandle are vibrating so fast itbecomes too hot to touch.
As the water boils, heat from the hot stove burner and pan radiate into thesurrounding air, even though airconducts very little heat.
Heating water in the bottom of a pancauses some of the water to vaporizeinto bubbles. Because they are lighter than the surrounding water, they rise. Water then sinks from the top to replace the rising bubbles.This up and down movement (convection) eventually heats all of the water.
Energy Efficiency• (Power out) / (Power in) = percent efficiency
• See page 350-351 for clarification
•Insulation•Elimination of air leaks•Air to air heat exchangers•Cogeneration•Efficient electric motors•High-efficiency lighting•Increasing fuel economy
Ways to Improve Energy Efficiency
Fossil Fuels
Forms of stored solar energy created from incomplete biological decomposition of dead organic matter
• Crude Oil• Natural Gas• Coal
Crude Oil and Natural Gas• Crude Oil
• Naturally occurring petroleum, normally pumped from wells in oil fields.
• Refinement of crude oil produces most of the petroleum products we use today
• Natural Gas• Naturally occurring gaseous hydrocarbon generally produced
in association with crude oil or from gas wells• An important efficient and clean burning fuel commonly used
in homes and industry
Oil in the 21st Century• The U.S has an energy problem caused by dependence of fossil
fuels, especially oil• Maximum global
production is expected between 2020 and 2050
• The challenge is to planfor the decline in oil supply and shift to alternative energy sources
Environmental Effects of Extracting Mineral Resources
Environmental Effects of Oil and Natural Gas
• Recovery: damage to fragile ecosystems, water and air pollution, and waste disposal
• Refining: soil, water and air pollution• Delivery and Use: energy to power automobiles,
produce electricity, etc.• Prince William Sound Alaska – Most ecologically
damaging oil spill in history. Exxon Valdez.• 10.8 million US gallons (40.9 million liters) of crude oil
Natural Gas50-90% methane
Conventional gas
Unconventional gas
Methane hydrate
Liquefied petroleum gas (LPG)
Liquefied natural gas (LNG)
Approximate 200 year supply
Methane Hydrates
• White ice-like compound made up of molecules of methane gas trapped in “cages” of frozen water in the sediments of the deep seafloor
Coal
• Solid, brittle, carbonaceous rock that is one of the world’s most abundant fossil fuels. Originally formed in swamps.
• Classified according to energy content as well as carbon and sulfur content
• Used mostly for electricity production• We currently have enough coal to last us approximately
1,000 years.• Highest environmental impact• Burning of coal releases significant amounts of mercury.
Coal
coal formation in order from youngest to oldest
Coal Mining and the Environment
• Strip Mining• A surface mining
process in which the
overlying layer of
soil and rock is
stripped off to reach
the coal
Associated with environmental problems including acid mine drainage, land subsidence and coal fires
Underground Mining
• Transport of Coal
• The Future of Coal• Scrubbing: removes sulfur dioxides
• Allowance Trading• Reduces pollution• EPA grants utility companies tradable
allowances for polluting
Coal
Oil Shale and Tar Sands
• Oil Shale• A fine-grained
sedimentary rock• The oil is a synfuel
• Tar Sands• Sedimentary rocks or
sands impregnated with tar oil, asphalt or bitumen
Introduction to Alternative Energy Sources
• Alternative Energy• Renewable and nonrenewable energy resources that are
alternatives to the fossil fuels
• Renewable Energy• Alternative energy sources, such as solar, water, wind and
biomass, that are more or less continuously made available in a time framework useful to people
• Nonrenewable Energy• Alternative energy sources, including nuclear and
geothermal, that are dependent on fuels or a resource that may be used up much faster than it is replenished by natural processes
Nuclear Energy• Nuclear Energy
• The energy of the atomic nucleus
• Nuclear Fission• The splitting of the atomic nucleihttp://www.amphi.com/~crobson/APES/Videos/Fission.swf
• Nuclear Fusion• The fusing of atomic nuclei
• Nuclear Reactors• Devises that produce controlled nuclear fission• Uranium is a common fuel (not renewable!)
Fission Reactors• As fission occurs, energy is released. • Major components of a fission reactor:
• Core, control rods, coolant, reactor vessel
• Burner Reactors: a type of nuclear reactor that consumes more fissionable material than it produces
• Meltdown: a nuclear accident in which the nuclear fuel forms a molten mass that breaches the containment of the reactor, contaminating the outside environment with radioactivity.
Pressurized Water Reactor1. The steam turbine is used to extract heat energy from steam and convert it to
mechanical power (rotary motion)
2. The nuclear chain reaction in the fuel rods heats the water to approximately 600 degrees Fahrenheit (315.5 Celsius).
3. This hot water gets pumped to the steam generator, or heat exchanger, where the cooler water flowing from the condenser becomes steam.
4. The steam drives a conventional steam turbine.
5. The condenser converts used steam back into water after it passes over the blades of the turbine
6. The water recirculates on the outside of the steam generator tubes.
7. The steam turbine turns the electric generator to produce electricity
Sustainability and Nuclear Power• Nuclear Radiation occurs when when a radioisotope
spontaneously undergoes radioactive decay and changes into another isotope
• 3 types of nuclear radiation: Alpha, Beta, Gamma• Breeder Reactor:
• a type of nuclear reactor that utilizes between 40-70% of its nuclear fuel and converts fertile nuclei to fissile nuclei faster than the rate of fission
• Produces nuclear fuels
Palo Verde Nuclear Generating Station
• The largest nuclear generation facility in the US. Generating power for S. California and Phoenix Arizona.
• Located in outside of Phoenix in Tenopah AZ.
• It has been the largest power producer of any kind in the United States since 1992. Its three units are capable of generating nearly 4,000 megawatts of electricity.
Palo Verde Nuclear Generating Station
• It is the only nuclear plant in the United States that does not sit on a large body of water. Instead, it uses treated effluent from several area municipalities to meet its cooling water needs.
Nuclear Energy and the Environment
• Nuclear Fuel Cycle: • the process involved in producing nuclear power
from the mining and processing of uranium to controlled fission, the reprocessing of spent nuclear fuel, the decommissioning of power plants and the disposal of radioactive waste
• Each part of the cycle is associated with different potential environmental problems
Effects of Radioisotopes
• Radioisotope: an isotope of a chemical element that spontaneously undergoes radioactive decay
• Effect Environment in 2 Ways• Emitting radiation• Entering ecological food chains
Nuclear Power Plant Accidents• Three Mile Island
• Pennsylvania 1979.• The most serious US accident.
• Chernobyl• The site of the worst accident
in the history of commercial nuclear power in 1986
• Because of events in this city, it is theorized that in the next 20 to 30 years, there will be an increase in cancer in northern Europe.
Radioactive Waste Management• Low-Level Radioactive Waste
• Waste materials that contain sufficiently low concentrations or quantities of radioactivity so as not to present a significant environment hazard if properly handled
• Transuranic Waste• Radioactive waste consisting of human-made radioactive
elements heavier than uranium• Contaminated clothing rags, tools, etc.
• High-Level Radioactive Waste• Extremely toxic nuclear waste, such as spent fuel
elements from commercial reactors. • How do we dispose of this waste material?
Dealing with Nuclear Waste
• Undergound burial
• Disposal in space
• Burial in ice sheets
• Dumping into subduction zones
• Burial in ocean mud
• Conversion into harmless materials
Yucca Mountain NuclearWaste Repository
• Located in Nevada
• Was being considered as a deep geological repository for nuclear waste until President Obama cancelled the proposal this year.
Solar Energy• Passive Solar Energy Systems
• Direct use of solar energy through architectural design to enhance or take advantage of natural changes in solar energy that occur throughout the year without requiring mechanical power.
• So in the United States we would place our windows facing in which direction? Why?
• Active Solar Energy Systems• Direct use of solar energy that requires mechanical power;
usually consists of pumps and other machinery to circulate air, water or other fluids from solar collectors to heat sink where the heat may be stored
• Solar Collectors: provide space heating or hot water
• Photovoltaic: converts sunlight directly into electricity
• Power Towers: type of solar energy system• Solar Ponds: generate low-temperature water• Ocean Thermal Conversion: involves using the
ocean as a giant solar collector
Hydrogen
• Fuel generated by the sun
• Fuel cells: uses and stores hydrogen
Hydrogen Fuel Cell Video
http://www.amphi.com/~crobson/APES/Videos/FuelCell.swf
Requires Flash to Open
Water Power
• A form of stored solar energy
• One of the world’s oldest and most common energy sources
• Sources vary in size
Tidal Power• Form of water utilizing ocean tides in
places where favorable topography allows for construction of a power plant
Wind Power• Alternative energy source
that has been used for
centuries
• More recently thousands
of windmills have been
installed to
produce electric energy
Biomass EnergyEnergy that is recovered from biomass, which is organic material such as plant and animal waste
Geothermal Energy
Natural heat from the interior of the Earth that is converted to heat buildings and generate electricity
Energy Primer for APES studentsVisit this site and STUDY it!
http://apcentral.collegeboard.com/apc/members/courses/teachers_corner/49184.html
There is a link on my homepage as well under assignment downloads.