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Energy
Consumption and Conservation
Program
Area
This activity
provides practice in operations with real numbers, in problem
solving skills, and in critical thinking. It may be used in the
Grade 9 Mathematics, Science, and Technology program, or in the
Grade 10 advanced and general level mathematics courses as a supplement
to any section on number manipulation skills, problem solving,
or as enrichment material.
Learning
Outcomes
- Teaching,
learning and evaluation will focus on the student's ability
to:
- Practice
number skills and problem solving techniques;
- Learn
about charges for electrical energy;
- Learn
about the various ways to reduce electrical energy consumption
and to compute the savings that can be realized through conservation
measures;
- Discuss
other forms of energy used in homes and cities and to suggest
other ways of conserving energy and reducing costs.
Classroom
Development
- Use this
unit as a supplement to problem solving or number skills.
- Consider
allowing students to work in small groups to discuss where energy
is used and needed in their homes and in the community, the
cost of this energy, and ways to reduce consumption.
- To prepare
students to do the exercises on the attached sheets, it may
be necessary to teach or review the concept of kilowatt and
kilowatt hour and to do some simple calculations of electrical
energy charges.
- Students
should do the questions on the attached pages. Working cooperatively
in groups would be appropriate.
- Have
the solutions presented by groups of students and use these
solutions to encourage discussion of energy conservation, why
it is necessary, and the benefits to society and to the individual.
Timing
Allow 2
periods (70 min)
Resources
This unit
is based on material found in Energy Horizons: Energy Alert. Spring
1986.
- Chuck
Wilson
- Education
Coordinator
- 517 College
street
- Suite
406
- Toronto,
Ontario
- M6G 4A2
- (416)
323-9216
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Student
Activities
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Energy
Consumption and Conservation
Most
people are aware of the need to reduce the amount of energy
that they use in their homes. This conservation protects many
of the natural resources that are used to produce energy and
it also saves money.
- There
are two 100 W (watt) light bulbs in the hallways of your
house. These light bulbs are on for 6 h per day. The cost
for electrical energy is $0.05 per kWh (kilowatt hour).
- (a)
What is the annual cost to operate these light bulbs?
- (b)
If both bulbs were replaced with 60 W bulbs, what would
the annual cost be and how much money would you save?
- (c)
If the bulbs were each replaced with 22 W fluorescent
lights, what would be the annual cost and the amount
of money saved?
- (d)
Reducing the power consumption (wattage) and/or changing
the type of bulb can result in reduced energy use and
money saved. Are there any negative effects to this
approach to energy conservation?
- Turning
lights off when they are not needed is an effective way
to reduce energy usage and save money. Suppose you have
found that you can reduce your use of lighting in your home
as described in the following table:
Light
Bulb (Watts) |
Daily Reduced
Usage (Hours) |
4 X 100W |
2 |
4 X 40W |
3 |
3 X 40W |
4 |
1 X 150W |
1 |
If
the cost for electrical energy is $0.06 per kilowatt hour,
how much money would you save over a 6 month period?
- Cities
and towns need to consider ways to reduce energy consumption.
One method is to switch to a more efficient type of lighting
such as sodium lamps. It is known that one 150 W sodium
lamp gives about the same amount of light as six 150 W incandescent
lamps or two 175 W mercury lamps. Suppose that the main
street of a town has 30 lamp posts each containing two 175
W mercury vapour lamps.
- (a)
If you were a town councilor, what recommendations would
you make to save energy and money for the town?
- (b)
If your recommendations were followed, how much money
would the town save each year? Assume that electrical
energy costs $0.045 per kilowatt hour and use your own
estimate of the number of hours that the lights will
actually be used.
- A
town has a street lighting system consisting of 30 lamp
posts each containing two 150 W incandescent lamps. The
town council has decided to reduce the number of lamp posts
to 15 and to place one 150 W sodium light on each post.
- (a)
Will the new lighting system provide more light, less
light, or the same amount of light? Explain your answer.
- (b)
If electrical energy costs $0.045 per kilowatt hour,
and the street lights are on for an average of 10 h
per day, calculate the annual cost for street lighting
with the old system and with the new system. State the
annual savings provided by the new system.
- (c)
If it costs $10 000 to install the new system, how long
would it take to recover this cost?
- What
other things could a family or a town use to reduce the
amount of electrical energy that they use?
- Most
homes use kinds of energy other than electrical. Name some
other kinds of energy used in your home and say how they
are used. Also, suggest ways to reduce your consumption
of these kinds of energy.
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