Energy. Motion, position and energy Work and energy related Energy = ability to do work Work =...
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Transcript of Energy. Motion, position and energy Work and energy related Energy = ability to do work Work =...
Energy
Motion, position and energy Work and energy
related Energy = ability to do
work Work = process of
changing energy level
Energy formsMechanical energy Kinetic plus potential
energy
Chemical energy Energy involved in
chemical reactions
Radiant energy Electromagnetic energy Visible light = small part
Electrical energy Charges, currents,
etc.
Nuclear energy Energy involving the
nucleus and nuclear reactions
Energy conversion Any form of energy
can be converted into another form
Energy flows from one form to another in natural processes
Energy conservation
Energy is never created or destroyed Energy can be converted from one form to another
but the total energy remains constant
USA Energy sources today
Primarily wood to coal to petroleum with increasing industrialization
89% can be traced to photosynthesis
Uses 1/3 for heating 2/3 in engines and
generators
Global sources
USA electrical generation sources 2005 data
Petroleum Oil from oil-bearing rock Organic sediments transformed over time
by bacteria, pressure and temperature Natural gas formation similar, except at
generally higher temperatures Petroleum and natural gas often found
together Supplies are limited
Los Angeles, 1920s and 1937
Coal
Accumulated plant materials, processed over time by pressure and temperature
Progression: peat to lignite to sub-bituminous to bituminous—in other words, it comes in different qualities from low to high energy
Impurities Minerals lead to ash Sulfur leads to sulfur dioxide gas (pollutant)
Petroleum, natural gas and coal = fossil fuels
Wyoming Surface Mining Almost all
the coal we burn for electricity comes from here—and a lot of the US as well!
West Virginia Strip Mining
Very bad for the environ-ment. Now, the land is being reclaimed.
Underground coal mining better for surface environment
That was then…
Underground coal mining is common around the world
This is now…still, one of the most dangerous jobs on Earth.
Moving water Renewable with rainfall Hydroelectric plants generate ~3% of US’s total
energy consumption Growth potential limited by decreasing availability
of new sites
Hoover Dam
The falling water turns magnets covered in copper wire…and presto-electrons move back and forth in the wire. We call it, electricity.
The electricity-generating turbines
That’s three million horsepower there--enough for over a million people.
And its water serves 18 million people.
Not bad for 1935.
Turbine Power!
Really, this is how all electricity is generated—just boil water and make steam, have the steam drive fan blades and as they turn, they spin a magnet surrounded by copper wire.
The spinning magnet attracts and repels electrons around the copper atoms and the electrons move in the wire along with the electromagnetic force that holds them in the atoms.
How it all works
Nuclear Based on nuclear fission reactions of uranium and
plutonium Water heated in reactor and then used to produce
steam to turn generating turbines Safety of nuclear power generation is
controversial
Typical nuclear plant
Typical nuclear engineer
Three Mile Island
Yes, they built it in the middle of a river
Susquehanna River
That’s the Chesapeake Bay
Nuclear reactor
15 million people live around the Bayor, about 4 Coloradoes
Modern Solar Technologies Solar Cells
Polycrystalline compounds that generate electricity when exposed to light Power Tower
Steam produced by focused sunlight generates electricity Passive Applications
Natural energy flow without mechanical devices Active Applications
Solar collector; sunlight heats air or liquid material Wind Energy
Sunlight differentially heats earth’s surface creating winds Wind then generates electricity
Biomass Utilizes material formed by photosynthesis
Agriculture and Industrial Heating Utilizes sunlight rather than traditional energy sources
Ocean Thermal Energy Conversion (OTEC) Generates electricity form the temperature difference between water depths
Geothermal Energy Energy from beneath the earth’s surface
Dry steam Hot water Hot dry rocks Geopressured resources
Difficulty in obtaining and economically utilizing
Hydrogen Used directly in fuel cell or burned to
release heat Produces no pollutants
Only emission is water
Problem is that hydrogen does not exist on or under earth’s surface in usable amounts Must be obtained from chemical reaction