Transcript Slide 1

Lesson 12
November 25th, 2010
 The
electricity used in most homes in Ontario
is usually generated quite some distance
away at some large scale electricity
generation facility. The facilities are
generally large scale products built by the
government or businesses.
 The
production of energy can be classified
into two categories:
Non-renewable resources.
1.

A resource that cannot be replaced
once it is used up.
Renewable resources.
2.

A resource that can be reused or
replaced.
 In
1831, Michael Faraday, an English chemist
and physicist, demonstrated that an electric
current can be generated by moving a
conducting wire through a magnetic field, a
process called electromagnetic induction
 Electromagnetic
induction is used to day to
generate electricity in large-scale generators.


An apparatus that transforms the energy of motion
into an electric current.
Magnets inside the generator are rotated by a
turbine. The magnets spin coils of copper wires.
This pulls electrons away from their atoms and
creates a current in the copper wire.
 The
current is sent through transmission lines to
cities and towns.
 The transmission lines and substations are
known as an energy grid.
 In
many areas, thermoelectric generating
plants use a fuel such as coal or biomass to
heat water to create high-pressure steam.
Coal,
oil, and natural gas are fossil
fuels,
 Organic matter of organisms that
lived millions of years ago.
The chemical energy stored in the
fuel is released as heat when it
burns.
1.
2.
3.
4.
the fuel is burned to boil
water to make steam
the steam makes a turbine
spin
the spinning turbine turns
a generator which
produces electricity
the electricity goes to the
transformers to produce the
correct voltage
 Ontario’s
electrical energy needs far surpass
what hydroelectric and thermoelectric
generators supply. Fifty-one percent of our
electricity in Ontario is thermonuclear,
which means it is produced by heat in
nuclear power stations.
 In
a nuclear reactor, atoms of a heavy
element, usually uranium, are split in a chain
reaction. This splitting, called nuclear
fission, releases an enormous amount of
energy.
 The nuclear fission of just 1 kg of uranium is
equivalent to burning about 50 000 kg of
coal. The energy released by the fission
process is used to heat water to produce
steam to turn a turbine.
 Most
electricity generated in Canada is
hydroelectricity, which means it is generated by
harnessing the power of flowing water.
 The water is directed through a channel called a
penstock to a turbine with ridges around it. The
water turns the turbine, which is connected to
a generator
 60
% of Canada’s electricity is generated by
hydroelectric
 Organic
material made up of plant and
animal waste.

Examples of biomass include wood, peat,
straw, nut shells, sewage, and corn husks
 Organic
waste decomposes to produce a gas
called methane. The methane gas can be
burned to boil water to make steam. The most
common biomass material used today is wood
waste from lumber and from pulp and paper
industries.
 In
some places in the world, water is
naturally heated by hot rock deep in Earth’s
crust and rises to the surface as hot water
and steam
 Geothermal
energy sources at or near Earth’s
surface are hot enough to heat homes and
other buildings. For generating electricity,
hotter sources are needed. High-temperature
geothermal sources are found deep in areas
where there is volcanic activity.
 19
% of Iceland’s power id generated by
geothermal
 1839,
French scientist Edmond Becquerel soaked
two metal plates in an electricity-conducting
solution. When exposed to sunlight, there is a
small potential difference between the plates.
 The sun is used to knock electrons off atoms.
The electrons flow then creates a current.
A
solar farm includes arrays of mirrors that
focus sunlight onto a liquid that is heated
and used to turn water into steam to drive
the turbines
 One
of the world’s largest solar energy
projects includes solar farms in Sarnia and
Sault Ste. Marie and aims to produce enough
electricity for about 9000 homes
 Wind
turbines use the energy of moving air
to spin their blades, which are connected to
a generator
 Wind energy currently provides about 1
percent of Ontario’s electricity, but it is one
of the fastest-growing energy sources in
the world.
 Tidal
energy uses the energy of the
gravitational pull of the Moon to fill
reservoirs full of water which then turns
turbines.
 Research is being done tidal stream
generators.
 Ocean wave and Ocean thermal energy are
also being looked into
Source
Advantages
Disadvantages
Fossil - Fossil fuel generating - The burning of fossil
stations can quickly
fuels releases
Fuels
adjust to changes in
demand
- The technology for
using these fuels is
already in place
pollutants into the
atmosphere and
directly contributes to
global warming.
- Mining coal is
hazardous to the
workings and damages
the environment
Source
Advantages
Nuclea - Nuclear power is
inexpensive to
r
produce
- Produces enormous
amounts of energy
from very little fuel.
Disadvantages
- Waste is poisonous
and radioactive and
needs to be stored very
carefully for hundreds
or thousands of years
- Nuclear plants are
very costly to
construct and
maintain.
Source
Advantages
Hydroel - Large generating stations
produce electricity
ectric
-
-
Disadvantages
-
inexpensively
Reservoirs may be used for
flood control, irrigation,
drinking water, and
recreation
Small scale hydroelectric
plants using the local rivers
can be practical for some
communities
-
There is a huge
environmental impact
when the dam is
constructed, including
flooding large areas of
land, disruption or
destruction of wildlife and
fish habitat and migration
routes, and displacement of
Aboriginal communities.
Hydroelectric stations are
very expensive to build
Source
Advantages
Sunlig - Solar cell energy is a
convenient source of
ht
energy for small
appliances, such as
calculator’s Solar
energy is useful in
remote areas.
Disadvantages
- Solar cell efficiency is
low, so many
photoelectric cells
have to be used, which
takes up large areas of
land.
- Solar energy is the
most expensive energy
source at present.
Source
Tides
Advantages
Disadvantages
- Once tidal generating - The environmental
stations are built, tidal
impact of marine life
energy is very
in area can be
inexpensive.
significant, due to
- Tides are more
changes in water level
predictable than wind
and water quality.
or sunlight
- Tidal energy is
suitable for few areas
as it requires very high
tides.
Source
Wind
Advantages
-
-
Wind energy production
does not produce
greenhouse gases that
contribute to global
warming.
Farming and grazing can
continue on land where
wind turbines are located.
Disadvantages
-
The wind does not always
blow or remain constant.
Wind turbines can present
barriers to bird movement,
cause bird fatalities due to
collisions with turbine
blades, and can disturb
breeding, wintering, and
staging sites.
 Canada
is the world’s largest producer of
hydroelectricity, the fifth-largest producer of
electricity in general, and the second-largest
exporter of electricity.
 - A large part of our electricity is generated
using non-renewable resources
-
Renewable energy projects for generating
electricity are under way or being planned.
 To
reduce our use of non-renewable
resources, we have to find ways to use less
electricity through technology and changing
our usage habits.
 Sustainability
means using resources at a rate
that can be maintained indefinitely. With
renewable energy methods, resources such
as solar energy and wind are available
indefinitely. We may never be able to
achieve complete sustainability, but the
decisions we make personally and as a
society can move us closer to this goal
 An
example of a personal decision would be
to turn off the lights in your bedroom or
classroom if you are the last person out of
the room.
 Three
Gorges: Potential Disaster or Good
Choice?
 Answer the questions and hand in