energy concepts energy, forms, power units, conversions, and laws of thermodynamics energy...
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ENERGY RESOURCES AND CONSUMPTION
Areas Tested Energy Concepts
Energy, forms, power units, conversions, and laws of thermodynamics
Energy Consumption History – Industrial Revolution, exponential growth,
and energy crisis Present global energy use Future energy needs
Fossil Fuel Resources and Use – formation of coal, oil, and natural gas, extraction/purification methods, world reserves and global demand, synfuels, and environmental advantages/disadvantages of sources
Nuclear Energy – nuclear fission process, nuclear fuel, electricity production, nuclear reactor types, environmental advantages/disadvantages, safety issues, radiation and human health, radioactive wastes, and nuclear fusion
Hydroelectric Power - dams, flood control, salmon, silting, and other impacts
Energy Conservation - energy efficiency, CAFE standards, hybrid electric vehicles, and mass transit
Renewable Energy - solar energy, solar electricity, hydrogen fuel cells, biomass, wind energy, small-scale hydroelectric, ocean waves and tidal energy, geothermal, amd environmental advantages/disadvantages
Energy Concepts See packet for energy forms and units See free-response for and example of a
conversion problem MW to kW to kWh/yr
First Law of Thermodynamics Energy can not be created or destroyed
Second Law of Thermodynamics When energy is converted from one form to
another a less useful form results Most of the energy lost is lost as heat and is
considered low-quality energy
Energy Consumption
History wood was the predominant form of energy
until the Industrial Revolution During the Industrial Revolution coal became
the primary source 20th century has seen petroleum overtake coal
but natural gas and coal has seen an increase in the later half of the 20th century
Present Global Use US was self-sufficient until the late 1950s Industrial, Transportation, residential and
commercial (greatest to least amount used) US accounts for 25% of the world consumption
of petroleum (tar, oil, and natural gas) See comparison chart of production vs
consumption Future Energy Needs
The forecast is a continued reliance of oil, natural gas and coal
Viable resources are clean coal, methane hydrates, oil shale, and tar sands
Clean coal This technology refers to the process that
reduces the negative environmental impact of burning coal
The coal is washed and the sulfur dioxide and carbon dioxide gas is captured (see picture)
Other forms of clean-coal technology has to do with natural gas or microbial fuel cells which are charged from biomass or sewage
Methane Hydrates Methane locked in ice – found in permafrost
and deep beneath the ocean floor Type of natural gas can create a greater
amount of carbon dioxide a greenhouse gas
Oil Shale Contains an organic material called kerogen
that converts to oil in the absence of air Net energy considered moderate due to the
energy needed to put into extracting it Huge negative environmental impact due to
surface mining Can be mined underground through heating it
in the ground and extracting the oil and gases though this can affect aquifers
Tar Sands Contain a semisolid form of oil called BITUMEN Similar issues with oil shale – oil in tar sands
represents two-thirds of the world’s total oil reserves
Fossil Fuel Resources and Use
Coal Produces by ancient organic matter (286
million year old) under high temperature and pressure
Lignite – softest and lowest heat content Subbituminous – lower sulfur content leading
to cleaner burning fuel Bituminous - high sulfur content and most
plentiful in the US – use to make electricity Anthracite – hard and high heat component
and relatively low sulfur content – home heating least amount
Oil Fossil fuel produced by the decomposition of
deeply buried organic material under high temperature and pressures for millions of years
Natural Gas Known as methane produced by
decomposition of organic matter under high temp and pressure usually found along with oil reserves
Can be liquefied mainly for easy worldwide distribution
Extraction-Purification Methods Coal – largest in China
Surface mining and underground mining Removal of foreign material, screening for size,
crushing, and washing to remove contaminants Oil – Middle East
Expensive machinery used to drill a well…initially high pressure and later pumped
Sent to a refinery to be ‘cracked’ which is where it is separated by its boiling points (see picture)
Natural Gas – Russia and Kazakhstan Flows from wells under its own pressure and is
collected by small pipelines that feed into the large gas transmission pipelines
Removal of water and condensates
Synfuels Liquid fuel synthesized from a non petroleum
source such as coal (shale oil and synthetic natural gas)
Pros Easily transported through pipelines Produces less air pollution Large supply of raw materials to meet current demands for
hundreds of years Can produce gasoline, kerosene, or diesel directly without
cracking or refining Cons
Low net energy yield and use of energy to produce most Plants are expensive and increase depletion of coal More expensive product than petroleum products
Nuclear Energy
Nuclear fission – an atom splits into two or more smaller nuclei along with by-product particles (neutrons, photons, gamma rays, and beta and alpha particles)
If controlled – heat produced makes steam that turns generators that produce electricity
If NOT controlled – nuclear explosion
Nuclear Fuel
U-235 – called enriched uranium, nuclear weapons contain 85% or more, nuclear power plants contain about 3%
U-238 – most common isotope, hit with neutrons to decay into Pu-239, most depleted uranium
Pu-239 – 1/3 of energy produced in a typical commercial plant, amount of Pu-239 produced is regulated and control rods have to be changed frequently due to the build up of Pu-239 and Pu-240 – can be used for nuclear weapons
The US produces the most nuclear energy but it only makes up 19% of the energy we consume
France produces the highest percentage of what it consumes at 78%
Types of reactors
Light-water, heavy-water, and graphite-moderated Common features
The core contains up to 50,000 fuel rods each stacked with many fuel pellets
Uranium oxide is the fuel: 97% U-238 and 3% U-235 Control rods move in and out to absorb neutrons and slow
down the reaction Neutron moderator is a medium that reduces the velocity
of fast neutrons making them capable of sustaining a nuclear chain reaction (water, graphite – produces plutonium for weapons, or deuterium oxide – heavy water)
Coolant removes heat and produces steam to generate electricity
See the Price-Anderson Nuclear Indemnity Act - 1957
Health Risks
Premature death per year Nuclear – 6,000 Coal – 65,000
Genetic defects/damage Nuclear – 4,000 Coal – 200,000
Nuclear Fusion
Two or more atomic nuclei joining together to form a single heavier nucleus
Not yet controlled enough for use as nuclear power
Hydroelectric Power Supplies 10% of the electricity in the US and 3%
worldwide Flood control
Channelization Dams Identify and manage flood-prone areas Levees or floodwalls Preserve wetlands
Salmon Migratory runs blocked and many spawning and
rearing habitats are destroyed Fish passage facilities and fish ladders to help
juvenile and adult fish migrate over or around dams
Other impacts Disease – breeding grounds for mosquitoes,
snails and flies Displacement – behind dams destroy rich
croplands and displace people Effects on watershed – downstream deprived
of nutrient-rich silt Impact on wildlife – migration and spawning
cycles Silting – forms behind the dam Water loss – evaporation and seepage
CAFE standards
Corporate Average Fuel Economy The average fuel economies of a
manufacturer’s fleet of passenger cars or light trucks
Standards have not improved since 1996 Could be expanded to include
Transition to a hybrid technology Performance-based tax credits Optimizing transmission improvements
Hybrids
Parallel hybrid – gas engine and electric engine work at the same time – Honda Insight
Parallel-split hybrid – can change back and forth with the engine charging the batteries – Toyota Prius
Plug-in hybrid – plug in each time and used first, when used up changes to fuel tank
Renewable Energy
Solar Energy Hydrogen Fuel Cells Biomass Wind Energy Small scale Hydroelectric Ocean Waves and Tidal Energy Geothermal