Using Electrical Energy Affects Society & the
Environment
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Ideally Human beings will balance the benefits of using
electricity with the need to conserve resources. Currently, about
65% of all electrical power is generated by burning oil, coal, or
natural gas.
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Called fossil fuels
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How good are humans at balancing?
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Coal Most of the fossil fuel used in power plants is coal.
Alberta has large and easy to excavate coal deposits. Coal contains
a lot of stored energy. Burning 1kg produces enough thermal energy
to boil about 1/3 of a bathtub full of water.
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Nuclear Reactors Burning fossil fuels not the only way to
provide heat for a steam-powered generator. In Ontario, USA, and
parts of Europe, nuclear reactors are used. The way it works: Atoms
of a heavy element, usually uranium, are split in a chain
reaction.
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Nuclear Fission This splitting is called nuclear fission, and
releases an enormous amount of energy.
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Chernobyl
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Geothermal Energy Heat from Earths core can also be used to
generate electricity.
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Biomass Biodegradable waste is buried in landfills. When it
decomposes, it produces combustible gases that can be collected and
used as fuel for steam-driven generators. Waste heat from
manufacturing processes can be used to generate electricity. Making
double use of energy in this way is called cogeneration.
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Hydro-electric Power 20% of worlds electricity is generated by
capturing the energy of falling water.
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Alternative Energy Sources Tides: moving water from tides can
also power turbines that run generators. Tide comes in, water is
trapped in a reservoir, and then let out past turbines. Not a lot
in the world; difficulty in finding suitable locations. One in Nova
Scotia- large tides in Bay of Fundy.
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High Tide/Low Tide
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Waves Can be used to generate electricity too.
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Wind The amount of electricity a single windmill can generate
is limited, but a number of wind-power generators can be connected
together to form wind farms.
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Sunlight- Solar Cells Solar modules (several cells connected
together) and arrays (several modules connected together) are used
to power everything from calculators to spacecraft. 1839, French
scientist Becquerel soaked 2 metal places in an
electricity-conducting solution and when he exposed them to
sunlight, detected a small voltage.
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Batteries Recently, a lot of research has been done to develop
fuel cells. These are batteries that generate electricity directly
from a chemical reaction with a fuel such as hydrogen. More fuel is
added as electricity is produced, so the cell is not used up as a
regular cell would be.
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Energy Renewable Resource Wind, tidal energy, solar energy,
geothermal energy, biomass. Trees if managed correctly. A resource
that can be renewed or replenished in a relatively short period of
time. Nonrenewable Resource Coal- cant be replaced as it is used
up. Any fossil fuel (oil and natural gas) when it is used up, is
gone forever.
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Electricity & the Environment Every method of generating
electricity affects the environment.
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Fly Ash Airborne ash that is carried up the smokestack of a
power plant and escapes into the atmosphere. Contains mercury, a
poisonous metal that can damage the nervous system. Sulfur dioxide
(causes acid rain & air pollution), Nitrogen oxides (cause air
pollution) and Carbon dioxide (major cause of global warming) are
also released into the air when coal is burned.
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Other effects to the environment Strip Mining: Removes all
plants and animals from large areas of land. Oil & Gas Wells:
Some deposits of oil and gas contain poisonous gases, and chemicals
can be released into the environment. Steam turbines often release
warm water into lakes and rivers. The resulting increase in water
temperature can kill fish and other life.
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Green sources of energy Wind, tide, solar, and geothermal- harm
the environment much less than fossil fuels do. Even though
nonrenewable fossil-fuel supplies will last for your lifetime,
conserving them & limiting demand, as well as developing
alternate energy sources, will cut down on pollution.
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Sustainable Sustainability means using resources at a rate that
can be maintained indefinitely (forever!).
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Electrical Technology & Society Benefits Improved standard
of living- for example- used to take a lot of hard work to complete
the laundry Now, machines do the washing, rinsing, and drying.
Drawbacks Obsolete devices discarded as waste. Resources needed to
manufacture and operate devices. Too expensive for developing
countries to use. Some people excluded from benefits of
advancements.
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Computers & Information Computers convert all information
to, even audio and video signals, into numbers and then perform
calculations with numbers. Computers use binary numbers, numbers
with ones and zeros.
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Computers & Electricity Different techniques store &
transmit information, but all use electrical current. CD: a
photodetector convers light pulses into electrical pulses; produces
a digital signal with the same sequence of ones and zeros. Hard
Drive: Electric pulses are sent to an arm with read/write heads.
Electrical signals control all the functions of a computer.
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Electrical Transmission of Information Information is now
cheaper to store, easier to find, and much more compact. A single
DVD can store more information than a whole set of
encyclopedias.
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Concerns? Access to technology: Some countries are too poor to
establish the infrastructure necessary to connect computers and
transmit information. Privacy: Data transmission not always secure;
Hackers attempt to break into networks to steal information or
cause damage.
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Concerns? Trust: With huge volumes of information, some of it
is wrong or misleading. Information Overload: Its increasingly
difficult to get the info you need. Search engines help, but all
work in different ways, and in ways that are not always helpful
(popular sites vs useful sites).