Announcements Clicker question MIN 185: 12 ... - Civil Engineering

Announcements
This Thursday, April 5 th , 3:00-4:00pm in room SF1101:
talk by Jean Habimana (Jacobs):
“Problematic of Tunnelling in Urban Environment”
Bring your clickers!!!!
Next Tuesday (April 10 th )
General material review + questions and answers
Final Exam on April 16 th
Clicker question
On a scale of 100, how useful do you rate last Friday tutorial
on the OPG tunnel at Niagara Falls?
(A) 80 -100. Very useful. It has opened my eyes on several
great work directions that I was not aware of.
(B) 65 - 80. Useful. It provided me useful information that will
help me to make informed decision regarding my future
studies.
(C) 45 - 65. Mild. Nothing to comment.
(D) 0 – 45. Not very useful.
(E) NA. I did not go.
MIN 185:
12. Energy equal to
Natural Resources
Charly Bank
Giovanni Grasselli

1.
clicker question:
The energy needed to heat one liter of water from
freezing point (0 degrees Celsius) to boiling point (100
degrees Celsius) is comparable to the energy
(A) needed to lift a 1 kg mass by 1 m.
(B) used when taking the stairs to the fifth floor.
(C) required to stay awake in class.
(D) in an adult person's daily diet (2000 calories).
1. conventional power stations
principle of a dynamo
- magnet rotated in coils
produces AC current
aside:
- can be used as engine
or break (electric trains,
hybrid cars)
- electric engines have
immediate torque
1. Surface water = Rivers = Energy

1. Hydroelectric power stations
hydroelectric dam
- power depends on elevation difference & flow
- often used for peak demand
- Sir Adam Beck: 1,400 MW; smallest in Ontario 1 MW
(video 10’49”)
1. Coal = Mines = Energy
1. Thermoelectric power stations
Coal plant with steam turbines
- water cycled through heating and cooling
- expanding steam (pressure >100 kg/cm2) drives turbines
- efficiency ~45%
- 5 Ontario plants:
8,600 MW
problems:
- CO2 emissions
- steam needs to
be condensed
(cooling tower,
river)

1. Oil & gas = Underground reservoirs = Energy
1. Thermoelectric power stations
combustion turbines
- usually run on natural gas, also oil
- like a jet engine
- can be started quickly for peak demand
1. Uranium = Mines = Energy
McClean Lake

1. Nuclear power stations
nuclear power plant
- steam turbines
- 1/3 of Ontario's electriciy
- baseball-sized bundles of 25 kg
- 100,000 bundles used per year
in Ontario's 3 plants
- no CO2 emissions
problems:
- steam needs to
be condensed
(cooling tower,
river)
- radioactive waste
- nuclear proliferation
1. Nuclear power stations
http://video.google.ca/videoplay?docid=3794377094345515334&q=nuclear+waste+management
video length 8’07”
1. What power station is best for our needs?
Energy
- base demand
around-the-clock operation
cost efficient
mainly nuclear, coal, and running water
- additional demand
more flexible, cheaper to build, but not so cheap to run
often coal, and oil
- peak demand
very flexible (quick on/off)
cheap operating costs
mainly gas engine, and hydroelectric power stations

1.
electric grid
1.
clicker question:
Why is overland transmission of electricity done using high
voltage?
(A) to allow for high current
(B) to keep the current low
(C) it is more dangerous
(D) it looses more energy
2. alternative energy
biofuel, eg wheat pellets
garbage combustion
problems:
- CO2 emissions

2. alternative energy
wind energy
eg, turbine at Exhibition Place
- 94 m (30 storeys) tall,
blades 29 m long
- spins ~21 times /minute
- 750 kW
- owned by Toronto Hydro Energy
Services and WindShare co-op
- up to 1,000 MWhrs per year
(250 homes, displaces 272 tonnes
of carbon)
2. alternative energy
geothermal energy
- steam or hot water from Earth
- often not converted to electricity
- cycling of water also possible
- extensively used in Iceland (->),
Philippines,... (volcanic areas)
in Canada:
- geothermal project at
Meager Mountain, BC
(100 MW facility possible)
aside:
heat-exchange pumps
cooling using Lake Ontario
2. alternative energy
tidal power
(a) kinetic energy (water flowing in
channels)
(b) potential energy (height difference)
can have 80% efficiency
in Canada:
- Annapolis Royal Generating Station
(NS, 18 MW)
- Bay of Fundi (tides > 10 m) being
– other stations considered here
(>5,000 MW)

2. alternative energy
solar power
- array of mirrors heats a fluid which
passes through a heat exchanger,
steam then drives turbine
- or solar towers (heat liquid sodium)
- Solar Energy Generating System
(350 MW, California)
also for home use
- solar panels produce DC current
- requires batteries (maybe inverter)
2. And the future? Is it sustainable?